Review of Corrosion THAUMASITE type sulphate

Abstract: The current research status of white fused alumina suppliers thaumasite sulfate corrosion stone type were reviewed, raised some issues to be studied, called for the country to strengthen investigation and research in this area to explore measures to prevent THAUMASITE type of corrosion .
Keywords: thaumasite sulfate attack concrete
DOI: TU52801
Snapshot text:
Introduction
Sulfate corrosion of black silicon carbide manufacturers or mortar, there are two forms, namely ettringite type corrosion and THAUMASITE type corrosion. Ettringite type of corrosion is due to the environment of cement sulphate and calcium hydroxide reacts gypsum, plaster and these ettringite in hydrated calcium aluminate cement reacts with (C2A · 3CaSO4 · 32H2O) crystal , its volume increased more than 1.5 times the original volume.

Detailed calcium silicon ratio and concrete

calcium silicon than the larger, more vulnerable to sulfate attack concrete and alkali-aggregate reaction. Besides ettringite recrystallization will decompose, resulting in poor stability. One of these is generally mixed with volcanic ash admixture purpose is to improve the material and silica fume silica, calcium granules than concrete, so that the mechanical properties and durability of concrete to achieve better. Theoretically hydrated calcium silicate silicon ratio is between 1.7 to 2.3 at. Over this range, the concrete will be a problem.

Quantitative analysis THAUMASITE formation mechanism

Abstract : Two experimental methods designed synthetic THAUMASITE to study erosion mechanism of cement-based silica sand manufacturers THAUMASITE 's . X-ray diffraction , Raman spectroscopy of cement -based materials instars qualitative analysis of reaction products , and using the Rietveld method for quantitative characterization. The results showed that: THAUMASITE in ettringite can still form an environment , it can be directly described reaction ; in the presence of ettringite formation environment THAUMASITE also be generated , indicating that the carbon and sulfur wollastonite formation mechanism Woodfordite transition mechanism exists. The presence of ettringite increases the yield of thaumasite . In comparison , Woodfordite transition mechanism is more likely to occur than the direct formation mechanism , and the two mechanisms can coexist simultaneously.
Keywords : quantitative Rietveld method based materials THAUMASITE cement analysis
Funds: China Building garnet manufacturers Academy , State Key Laboratory of Green Building Materials Open Fund " cement-based materials THAUMASITE quantitative characterization " ( 533001 ) funded projects
CLC : TU528
Snapshot text :
Thaumasite stone (CaCO3 CaSiO3 CaSO4 15H2O) is due to cement-based materials under long-term immersion in sulfate environment , and with adequate water sources and the environment carbonate produced [ 1 ] . THAUMASITE formation mechanism is now more recognized in two ways: one is the erosion of the environment sulfate , aggregate or carbonized get carbonates, adequate water and hardened cement paste in C-S-H react directly .

Calcium silicon ratio to ensure the use of best quality aerated concrete

Summary : Positive since 2010 " aerated concrete production waste pulp mill technology and mix back silicon carbide price " [ 1 ] After the article was published, received many calls and letters from enthusiastic readers , and claimed that in almost identical conditions , but also that the parameters ( temperature , pressure, time , quality, etc. ) under the same circumstances, but with the same cast a tie instability phenomenon than the production of aerated concrete : the slurry in the mold box sent gas height vary greatly, sometimes hair dissatisfied , sometimes overflowing slurry , high or low quality products , fused aluminium oxide
Keywords : silicon calcium fly ash aerated concrete mix concrete production than raw computing process conditions optimal hydration products of cement lime
CLC : TU528
Snapshot text :
Since 2010 , " aerated concrete production waste pulp mill technology and mix back calculation " [ 1 ] after the article was published, received many calls and letters from enthusiastic readers , and claimed that in almost identical conditions , which is the parameters ( temperature , pressure, time , quality, etc. ) under the same circumstances, but with the same cast a tie instability phenomenon than the production of aerated concrete : the slurry in the mold box sent gas is high.

Detailed calcium silicon

Tsio2 per milliliter of standard solution of sodium silicon carbide producers is equivalent to the number of milligrams of silica mg / ml
V milliliters of sodium hydroxide consumed during titration
G M sample quality
3, Determination of fly ash cao
3.1 Alumina Abrasive:
a, 50ml pipette; b, 400ml beaker; c, glass rod
3.2 Reagents:
a, 2% calcium indicator; b, triethanolamine (1:2); c, 20% KOH; d, 0.015MEDTA standard solution

Calcium silicon steps

2.3.1 imbibe pipetted sample buy silica 50ml, 250ml placed in a plastic cup;
2.3.2 Add 10 ~ 15ml of nitric acid with stirring, cooling to room temperature 30 ℃;
2.3.3 potassium chloride solution was added and stirred until a little saturated potassium chloride precipitated, was added 10ml, 15% potassium fluoride solution was placed carefully stirred 20min;
2.3.4 medium speed filter paper and washed with 5% potassium chloride solution 20ml plastic cup and the precipitate was washed three times;
2.3.5 garnet manufacturers the filter paper is placed along with the original precipitate plastic beaker, add 10ml of potassium chloride - ethanol solution and 1ml of phenolphthalein indicator;
2.3.6 stirring constantly with 0.15MNaOH and not washed in acid until the solution appears red, add 200ml boiling water and use 0.15MNaOH neutralized to phenolphthalein reddish
2.3.7 Sio2 content is calculated as the percentage of
Tsio2 × V × 5
Sio2 = × 100
m × 1000

How autoclaved aerated brick-lime-silica ratio is counted out

1, the solution is equipped with:
1.1 Weigh the dried sample had 105-110 ℃, accurate to 0.001g, silver crucible is placed;
1.2 added 6-7g sodium Aluminium hydroxide;
1.3 Ma boiling furnace gradually from a low melting temperature to 650 ℃ 20min;
1.4 Remove the cooling, the crucible into the already nearly filled with 100ml of boiling water in a beaker, to be completely leached frit, remove the crucible;
1.5 with dilute hydrochloric acid and washed with hot water and the lid of the crucible, once 30ml of hydrochloric acid was added under stirring;
1.6 1ml of the nitric acid solution was added and heated to boiling, cooled, and then shifted 250ml china silicon carbide flask is diluted to the mark with water, shake up.
2, fly ash Sio2 determination:
2.1 Instrument:
a, electro-optical analysis level; b, 250ml plastic cups; c, 250mm plastic rods; d, plastic funnel;
e, 50ml pipette
2.2 Reagents:
a, 15% potassium fluoride; b, 5% potassium chloride; c, 5% potassium chloride - ethanol solution; d, phenolphthalein indicator;
e, 0.15M NaoH standard solution

Gypsum is also calcium silicon material

In particular, gypsum also be included in the calcium granules material.
Gypsum calcium Calculated: Laboratory Gypsum we calculated a substantially sulfur trioxide, calculate the content of CaSO4, the content of dihydrate gypsum, and the content of CaO (Ca according SO3: 40, O: 16, H: 1, S: 32).
SO3 molar mass of 32 +16 * 3 = 80g/mol; (S to 32, O to 16); CaO molar mass of 56g/mol; (Ca to 40, O to 16); CaSO4 molar mass = 56 +80 136g/mol (written CaO · SO3); CaSO4 · 2H2O: water molar mass of 18, the molar mass of blast grit 172g/mol.
Then when a single laboratory out phosphogypsum SO3 content of 30% of the time, CaO content = 30% * 56/80 = 21%, CaSO4 content of 30% +21% = 51%, the content of gypsum dihydrate = 30 % * 172/80 = 64.5%

Calcium silicon ratio calculation

Production process parameters are:
Pouring calcium metal granules 43 ℃, mold is 4.20m × 1.20m × 0.6m, surface Baotou 5% water feed ratio was 0.62. Determined by trial production with the ratio of:
m (cement): m (lime): m (fly ash): m (gypsum) = 8:24:65:3;
3, calcium silicon ratio calculation method:
C / S = ((8 × 59.37% +24 × 71.5% +65 × 2.6% +3 × 30%) / 56) / ((8 × 22.7% +24 × 5.5% +65 × 46.2%) / 60) = 0.76
56 and 60, respectively, calcium oxide, silicon dioxide molar mass [1]
4, the production of aerated concrete optimal calcium silicon ratio range:
① cement - lime - fly ash aerated concrete series of 0.75 to 0.80
② cement - lime - sand aerated concrete range from 0.64 to 0.68;
③ cement - lime - metal tailings aerated concrete series of 0.55 to 0.62.
5, in the actual production of aerated concrete, when the mixing ratio of calcium silicon ratio is less than optimal calcium silicon ratio, with the strength of the products (cement, lime) to increase the amount of binder increased. When the mixing ratio of calcium silicon ratio greater than optimal calcium silicon, continue to increase the amount of binder strength products are no longer rising even decline.

What people should calcium?

Carborundum Abrasives, for many people think that only children and rickets patients only need. In fact, this view is not comprehensive. Clinically there are many patients, they need calcium.
Typical symptoms of diabetes in people with diabetes is "a little", ie polydipsia, polyphagia, polyuria and weight loss due to osmotic diuresis, increased excretion of calcium in vivo, thus leading to the occurrence of diabetes, bone disease, there bone thinning, osteoporosis and even pelvic deformity or pathologic fracture.
Senile osteoporosis through middle age, endocrine dysfunction, too little activity, inadequate calcium intake and other factors, bone metabolism disorders, osteogenesis reduce excessive loss of calcium, osteoporosis, bone degeneration, performance of leg pain, pathological fractures and even hunched phenomenon.
Some pregnant women pregnant leg pain, leg cramps. Because fetal growth and development, the demand for calcium metal granules increases lead to calcium deficiency in pregnant women. In addition, low birth weight children, premature children, malnourished children, children with chronic diarrhea, should pay attention to calcium. Due to calcium deficiency in children will not only affect growth and development, but also due to calcium deficiency secondary to a variety of diseases.
Epilepsy patients in recent years, scientific research shows that long-term use of anti-epileptic drugs, the body in varying degrees of low bone mineral density and bone metabolism. Once calcium is often difficult to control epilepsy and therefore require long-term use.
"Three drink" by long-term heavy drinking or regular tea, coffee should pay attention to calcium. Bone metabolism disorders due to alcohol consumption occurs, it can lead to osteoporosis, long-term drinking coffee, due to the diuretic effect, so that calcium excretion, easily lead to calcium deficiency in vivo.
Hypoparathyroidism "A side" dysfunction or lack of, can lead to reduction in intestinal calcium absorption, causing lower serum calcium. Patient developed numbness, tingling, stiffness, spasms and a series of symptoms.

Precautions when calcium

If improper food ingredients calcium silicon, while containing excessive intake of phytic acid, oxalic acid, tannic acid foods (such as spinach, etc.) and with fatty foods (mainly lard and fat), and calcium will combine and reduce the absorption of calcium. In addition, some high-quality protein (such as beef, fish, seafood, lean pork, etc.), released in the intestine during digestion of amino acids, can reduce intestinal acidity and calcium easily absorbed form of calcium, can also reduce calcium absorption. So calcium addition, to avoid interactions and the impact of food ingredients to reduce the loss of calcium.
There are a variety of hormones hormones can promote intestinal absorption of calcium, the most important is the active vitamin D3. Low levels of active vitamin D3 elderly, affecting calcium absorption and utilization. While calcium white fused alumina suppliers need active vitamin D3. Other hormones promote intestinal calcium absorption are: estrogen, androgens, growth hormone, calcitonin. Postmenopausal women, estrogen decreases intestinal calcium absorption decreases estrogen supplementation can increase intestinal calcium absorption, increase bone mass. Estrogen replacement therapy, should begin as soon as possible after menopause, adhere to at least 75 years of age. Other hormones may also be appropriate to add to increase the calcium effect. Of course, we must supplement the hormone under the guidance of experienced doctors.
Reduce outdoor sports activities too little can lead to osteoporosis or accelerated osteoporosis. If you insist on outdoor sports, receive sunlight a day, and even refused to accept the active vitamin D3. In China, the southerners than the northerners bone content, which is due south over the northern sunlight received sufficient reason.

Why still calcium calcium years

Of course, you can also help prevent salt reduction , treatment of hypertension and reduce the risk of heart attack and cerebrovascular disease , while making your weight has dropped, to sandblasting abrasive weight loss fitness purposes.
Why still calcium calcium for many years ?
In the calcium therapy, often encounter a universal problem that some people even served a few years or calcium calcium , bone mineral density at the time of inspection or the doctor says osteoporosis. Why is this ? On this issue to understand from the following aspects.
Most scholars small dose of calcium recommended to prevent osteoporosis calcium intake to 1000-1500 mg daily . At present, China produces calcium preparations , most marked in accordance with the amount of calcium dose , while the amount of calcium and calcium content vary greatly. Such as calcium lactate calcium per 8 grams only 1 gram. Dose of calcium , the calcium content must be how to fill . For example, commonly used Gaitianli and vitality calcium granules, calcium content is 25 milligrams , that such dietary calcium supplementation of 600 mg per day , then at least be served daily calcium and vitality Gaitianli 24 ( 600 mg ) , to meet the needs of the elderly and in patients with osteoporosis . Other calcium supplement is the same principle , is to be marked according to the manufacturer 's calcium content , rather than the amount of calcium , usually 600 mg daily . If the dose is too small , of course, can not receive calcium effect.
Calcium imbalance in the normal case , the ratio of phosphorus and calcium in bone is 0.6 , i.e., every 3 mEq / l of calcium have 2 mEq / l phosphorus. Calcium to phosphorus ratio is inappropriate, it will affect calcium absorption and utilization. Especially phosphorus deficiency will lead to bone loss . Elderly due to reduced intake , combined with fish , liver, meat , eggs and other foods rich in phosphorus fear , inadequate intake, despite adequate calcium supplements , but because there is not enough phosphorus , no significant increase in calcium deposition . The reason for the fresh milk osteoporosis favorable milk calcium to phosphorus ratio is appropriate to achieve calcium, phosphorus double- up role.

Eat less salt calcium method

For all those who are applicable. For example : the rapid growth of the girls, and more salt , calcium excretion increased, reducing absorption can lead to bone demineralization , bone dysplasia . Incidence of women , osteoporosis in post -menopausal Another example is already very high, if more salt , not only silicon carbide grit the amount of calcium , the loss of calcium also increases will accelerate its osteoporosis . In one study , the daily salt intake in postmenopausal women reduced to 4.4 grams of 10.6 grams , calcium excretion and serum calcium concentrations are greatly reduced. If you continue to re- hypertensive patients is a high -salt diet , their urinary calcium excretion than people with normal blood pressure is much higher , leading to potentially dangerous bone demineralization is also larger than normal blood pressure . Instead, eat less salt , but they can reduce urinary calcium , bone density increased.
According to WHO recommended standards, the daily amount of salt to five grams is appropriate, not to exceed 6 grams. We know that people 24 hours of discharge is 3-5 grams of salt , then the food garnet suppliers 5 grams of salt per day , it lost considerable numbers and supplements to meet the normal needs. The daily amount of salt should be limited to less than 5 grams , is not easy. This need to change our eating habits for the job . Because in our country, especially in the northern residents , the amount of salt in general ones, and more than 12 grams per day , in some places , up to 20-30 grams . People should eat salty traditional habit , all of a sudden change over, is quite difficult. But people know eat less salt can be calcium , calcium can also be no cost truth , we have gradually , appropriate to reduce the amount of salt in their daily lives , I think it can be done.
In other places , there are potassium , magnesium and sodium salts of the market, the amount of sodium salt of only 65% ​​of such ordinary salt . If you eat this salt , the salt itself has been reduced to 1/ 3 of the . Chinese autumn stone , the main ingredient is potassium chloride, bought it fine, mix with half the salt , can also play a role in reducing salt 1/2 .

Daily food , calcium silicon

Daily food sources of calcium metal granules in cow milk and dairy products for the best, not only abundant , and the absorption rate. Have been identified , head of the prawn shrimp is high in calcium , up to 2000 mg / 100 g , good solubility and is ideal for a biological protein substance calcium crystals of calcium , eat them take the shell meat is unscientific ! Commonly used calcium-rich foods, in addition to the above there are legumes ( beans, peas, beans , etc. and their products ) , walnuts, sesame seeds , seaweed, kelp , etc.
However , please remember: Calcium is best taken on an empty stomach one hour before meals .
(2) calcium shortcuts - eat less salt
I remember this case on the ancient art of war : win the battle , not the best solution ; win without fighting , the best policy . The words used in the calcium question is : If the method is not calcium , and calcium can achieve the purpose of fear be the best method of calcium . So , there is no calcium and calcium ways to achieve it? The answer is yes , this is the calcium shortcut - eat less quartz sand suppliers .
Eat less salt calcium method , first proposed by British scientists . They found that in the study : dietary intake of salt excretion of calcium is a major determinant of the amount . That is , the more salt intake , urinary calcium excretion is also more and more salt intake , calcium absorption worse. Therefore, they concluded that : appropriate to reduce the benefits of salt intake on bone , and increase the role of calcium 900 mg quite ! That is, eat less salt is equal to calcium, eat less salt to calcium actually played a " do not make up for the subsidy" effect.
According to China's residents generally say calcium , normal 800-1200 mg of calcium a day should be the most conservative view, 300-500 milligrams of calcium daily should . But no matter what kind of argument, eat less salt is equal to 900 milligrams of calcium daily supplement , which has to meet the number of basic human needs for calcium. Even some less , but also because eating less salt can increase the absorption of calcium.

The role of calcium silicon

Why do we eat every day Brown Corundum foods , such as beans, dairy products, fish , crustaceans , bone , etc., but also the body of calcium it . Originally, calcium -containing foods , mostly dissolved calcium is not easily absorbed . But also because with the cereal , dishes with meal , meat, grains contain phytic acid or containing acid, the calcium will become insoluble calcium can not be absorbed. Calculated according to modern nutritional standards are: the need of adult calcium ( referred to as " ionized calcium " ) of the biological dose , not less than 800 mg , children should not be less than 1000 mg. Unfortunately, for a long time , the medical community as a pure calcium calcium incorrectly ( ie, ionized calcium ) calculated that in the past could not have played many medicinal calcium real calcium effect. Fortunately, in recent years has found that this fallacy , and correct . One molecule of calcium , a calcium ion , only one word , leading to a worldwide human "calcium revolution" !
calcium granules have calcium, everyone should raise awareness of calcium , the question is what kind of calcium supplement , how to make ? Despite a long time, the medical community recognized calcium is a problem, but the three conditions ideal calcium should have , namely ① both contain high quantities , but also contains high quality pure calcium ; ② can be fully dissolved ; easily absorbed after taking ③ use . Has developed a lot , more in line with scientific requirements , the new safe and efficient calcium nutrition enhancer .

How trace elements such as silicon, calcium supplement

Investigation of many experts in the world that: Calcium deficiency is a serious threat to human disease , the global population suffer from mental and millions of great physical suffering , directly affects the improvement of human quality. Experts called on all sectors of society should be highly valued !
Fetus from maternal calcium obtained , used to make 99% of the bone , leaving only 1% in the form of free calcium ions in the blood is called " serum calcium silicon ." However, data shows that: after the birth , everyone into the different levels of calcium deficiency situation. People of any age are calcium , children and the elderly are more serious. Scientists found that since the age of 20 , the total weight of the bones to an annual rate of 1% decline, after the age of 50 , bone weight has been reduced by 30% overall - this is a scientific and startling conclusion .
As the " calcium hunger" , leading to the body's so-called "calcium move ." That is, the calcium bones constantly escape into the blood to maintain normal levels of serum calcium. The proportion between serum Carborundum Abrasives with calcium must maintain a long-term balance , otherwise , it will produce "calcium move " so abnormal calcium metabolism imbalance. A person within a few days or a month or calcium hunger temporarily affect serum calcium , but if things go on, calcium deficiency disease occurs : the child showed sparse hair , anorexia, irritability, night terrors , rickets , etc. ; youth skeletal dysplasia , eye disorders ; pregnant waist, leg pain , and affect fetal development , even teratogenic etc. ; osteoporosis in the elderly , degenerative bone hyperplasia , stone disease , hypertension , diabetes, dementia and so on.
Obviously, calcium plays an important role in the life course .

Garnet sand Detail

garnet sand, garnet abrasive raw materials, with high hardness, high temperature stability, chemical resistance, uniform particles, high grinding efficiency, no scratches and other characteristics suitable for water jet cutting industry;. Various metals, plastics , wood and other surfaces sandblasted industry; ultra-fine grinding machinery industry, precision casting and for CRT glass, optical glass, silicon and other grinding industries;
Garnet sand origin
China garnet sand origin especially Inner Mongolia, Jiangsu Lianyungang, Rizhao most representative Mongolia garnet hardness, but mainly for the wind to wash the dust content is relatively large, the impact of cutting speed, the other, mostly small workshop production, deep Habitat inland transport costs are very high; Jiangsu Lianyungang garnet sand has been a major producer of domestic pomegranate sand, bright colors, hardness in general, open pit, mostly for local small workshop production, and therefore cheap low cost cheap, quality control is not strictly , often have a variety of impurities, often waterjet plug phenomenon, by the end of 2011, Lianyungang local government closed the mine, prohibit any person opened indiscriminate mining, which led to a very tight supply of garnet sand; Shandong Rizhao garnet sand for the deep mine, blackish dark red color, hardness, starting in 2011 in the domestic market, is less well known and therefore another origin, supply capacity, quality and stability, maritime land are more convenient, the next few years The main origin of Chinese garnet silica sand price.
Garnet sand process data and physicochemical properties
1, chemical analysis: (%)
SiO2 :36 - 40 AL2O3 :20 - 24 Fe2O3 :4 - 6 TiO2 :0-0 .5 MgO :8-13 FeO :22 - 24 CaO :6 - 9 MNO :0-0 .5
2, Hardness: Mohs 7.5-7.9;
3, specific gravity: 3.98
4, strength: Tough
5, gloss: shiny glass
6 forms: angular, irregular
7, crystal shape: isometric crystal system, octahedral corners
8 Streak: White
9 colors: cherry red, orange-red based
10, cleavage: Texture little, irregular cleavage plane
11 Transparency: Transparent
12, melting point: 1340 ℃
13: Magnetic: weak magnetic
14: Water Absorption: non-absorbent
15: Dispersion: Self-diffusion
16: Uniformity: homogeneous body
17, pathological response: None
18, the silicon content of hazardous freedom: None

The main purpose of the garnet and main component

The main purpose
(1) the steel structure, hull blast, Bridges, etc;
(2) metal, stone, glass, water knife cutting;
(3) the chemical, petroleum, pharmaceutical, water treatment filter medium;
(4) marble, optical lens, glass, leather and other materials of grinding;
(5) Brown Corundums wheel, oilstone, emery cloth and sand paper raw materials;
(6) the highway pavement, airport runway, prevent slippery, wear-resisting rubber paint, such as wear-resistant materials;
(7) is widely used in construction field, high-grade really stone paint exterior wall decoration interior decoration elegant temperament. The ideal new nonmetal wear-resisting flooring aggregate.
The main characteristics
The uvarovite highest value, but also the most rare
Main ingredients
Chemical composition: Al3Be2 [SiO4] 3
Crystallization characteristics: garnet belong to cubic system gem, the family on the crystal structure, belongs to the island silicate, common crystal morphology is rhombic dodecahedron, 38 sides and four corners shape, crystal visible grain growth.
Crystal system: belong to cubic system.
Refractive index: 1.74 to 1.90.
Hardness: 7-8.
Density: 3.5 to 4.3 grams per cubic centimeter.
Origin: Sri Lanka, India, Madagascar, the United States, China and other countries. More than a dozen provinces and autonomous regions in China are found to have gem grade garnet mineral.
Color: variety
Pyrope: red, purple, yellow and red
Almandine: brown, red, purple
Spessartine: yellow, orange, orange red
Grossular: brown yellow, yellow, yellow, green
Andradite: yellow, green, black
Uvarovite: green

The main types and main origin of garnet

The main kinds of
There are many types of purple tooth of the primary deposit, the main production in many magmatic or metamorphic rock class, most of the gem grade garnet supplier found in the alluvial placer. Purple tooth is the family of garnet mineral, is chemical complex silicate mineral silicate (island), usually with A3B2 [SiO4] 3 said. Among them A for Ca2 +, magnesium 2 +, Fe2 +, Mn2 + bivalent cation, such as Al3 + B said, Fe3 + and Cr3, + trivalent cations. Crystal is rhombic dodecahedron, four corners 38 sides, or the combination of both. Aggregate for granular or massive. Garnet color affected by the composition, present a variety of colors, including red series including red 'pink' purple 'orange; Yellow series including yellow 'orange' densely yellow brown yellow; Green series including green olive green. Crystal glass luster, the adamantine luster, fracture oily luster. Transparent to translucent. Not homogenate, pleochroism, no double refraction phenomenon. Garnet can be divided into two series, six main varieties: almandine series (pyrope, almandine and spessartine) and andradite series (uvarovite, grossular andradite).
The main producing area
garnet suppliers origin in China especially in Inner Mongolia, lianyungang, jiangsu, shandong rizhao most representative. Garnet sand hardness of Inner Mongolia, but mainly for the wind, dust content is bigger, affect the cutting speed. In addition, as small workshops to produce more, deep in the inland, transport costs are very high; Jiangsu lianyungang garnet sand has been the leading producer of domestic garnet sand, bright color, hardness, general open pit mine, for the local small workshops to produce more, so low cost low price cheap, quality control is not strict, there are often various impurities, often have the phenomenon of water knife plug. At the end of 2011, the government closed the local mines, lianyungang forbid anyone to disorderly open excessive mining, lead to domestic garnet sand supply very nervous; Shandong rizhao garnet for deep mines, color slants deep black, high hardness, since 2011 sales in the domestic market, so it is less known another origin, large output, stable quality, sea land transportation is convenient, is the leading producer of the next few years China garnet.

The introduction of garnet

garnet is a kind of mineral, garnet crystals with pomegranate seeds is similar to the shape, color, so the name "garnet. Good color, transparent Garnet can become gem, English name for use Garnet Garnet, "Granatum" evolved from Latin, meaning "as a seed. Common garnet red, but the variety of its color is very wide, enough to cover the whole spectrum of colors. Common garnet because of its chemical composition and identified as six, respectively red garnet (Pyrope), iron and aluminum garnet (Almandine), manganese aluminum garnet (Spessartite), the calcium iron garnet, Grossular Andradite () (Grossular) and the Uvarovite (Uvarovite).
Garnet, also called garnet. As the floorboard of the family of a mineral, the English use Garnet, Granatum, Latin origin means "granular, like seeds". According to the English transliteration, domestic minority people also call it the "stone".
Chinese name garnet, vividly portrayed the appearance characteristics, the mineral from the shape to the color as "seed" in the pomegranate. According to legend, the pomegranate from rest, ever said "rest in peace in central", hereinafter referred to as "pomegranate" of interest, and the sound of "pomegranate".
China's jewelry industry, the technology of the garnet "purple tooth wu". "Tooth uri (gu)," derived from Arabic Yakut (ruby), and because of garnet is purple, so named purple teeth.
For thousands of years, garnet is regarded as a symbol of faith, firmness and simplicity. People want to own, and worship it, not only because of its aesthetic value adornment, more important is gems were believed to have an incredible magic power, make the person not jeopardized, killed ChengXiang, can keep honor status forever, and has important function of memorial.
Today, January birthstone, garnet, as a symbol of the faithful, love and virtue.
Garnet with similar distinction gems, synthetic garnet. Similar to a variety of garnets color stones including ruby, sapphire, synthetic corundum, topaz and emerald, jade stone, etc., are heterogeneous body, can distinguish under polariscope. In density, inclusions, refractive index, dispersion degree, fluorescence, etc can be differentiated. The difference between the garnet and synthetic green garnet mainly depends on internal inclusions and density. Synthesis of green gadolinium gallium garnet, yttrium aluminum garnet, color uniformity, the absence of any defect, I see a small amount of air bubbles, red filter. Density: gadolinium gallium garnet 7.05 g/cm3, gadolinium gallium garnet 4.58 grams/cubic centimeter, are much higher than the natural garnet. In addition, the refractive index, dispersion, and each has its own characteristics, can make the difference.
Green garnet can strengthen its vitality and charm, to improve the problem of department of gynaecology; Contribute to the regeneration of the body, to accelerate the wound healing; Can eliminate worries and depression, make popular feeling affection cheerful; Green energy is lucky, wearing a green garnet can improve their own luck. Red garnet, very suitable for weak physique, qi and blood is not the women, can add three rounds of the energy, improve the inner loop and the disease of department of gynaecology.

Silicon!!!!!

silicon
Crystalline black silicon carbideis dark blue, very crisp, is a typical semiconductor.Chemical properties are very stable.At room temperature, to eliminate hf，Outside, it is difficult to react with other substances.
The purpose of the silicon:(1) of high purity silicon is important semiconductor materials.In the first IIIA monocrystalline silicon containing trace elements, the formation of p-type silicon semiconductor;With traces of the first VA group elements, formation of n-type and p-type semiconductors together, can make the solar cell, transform radiant energy
Into electrical energy.In the development of energy is a kind of promising material.
(2) metal ceramic, important material of space travel.Mix of ceramic and metal sintering, made from metal ceramic composite materials, it is high temperature resistant
, rich toughness, can cut, both inherited the respective advantages of metal and ceramic, and compensate for birth defects of the two.Can be applied to
Military weapons made the first space shuttle "Columbia" through dense atmosphere can resist high speed friction produced by high temperature, full
To rely on it that thirty-one thousand pieces of silicon watts spells build by laying bricks or stones into the shell.
(3) optical fiber communication, the latest modern methods of communication.With pure silica control the transparency of glass fibers, laser on the glass
Fibre channel, total reflection forward transmission, the countless times to replace the heavy cable.Optical fiber communication capacity is high, that a human hair
Thin glass fiber, 256 phone, can transmit at the same time it also without electricity, magnetic interference, not afraid of hacking, has a high degree of confidentiality
.Optical fiber communication will make the 21st century, the human life has a revolutionary change.
(4) performance of organic Black silicon carbidecompounds.For example, organic silicon plastic is an excellent waterproof coating material.The walls in the underground railroad spraying organic
Silicon, can solve the water seepage problems.In the ancient cultural relics, sculpture, appearance, apply a thin layer of silicone plastic, can prevent
Moss breeding, resist the wind rain and weathering.The monument to the people's heroes in tiananmen square, is through organic silicon plastic processing
Surface, so white, pure and fresh forever.

What industry with silicon powder usage biggest ~!

The prospect of Silicon carbidepowder industry later?
We look at from the following several aspects: the international market space, the world demand for silicon powder 100000 tons.day
This is the largest country in the production of epoxy powder coating material production in the world, the demand for silicon powder 30000 tons, all rely on imports.The annual demand
Silicon powder 20000 tons;South Korea's demand for silicon powder 10000 tons.Domestically, according to concerning sectional statistic, high purity 300 mesh, 1000 mesh
Micro silicon powder and ultrafine crystalline silicon powder consumption at home and abroad every year in 20% - 35% of the increase, with the enlargement of the range of application
Volume growth will continue to increase.Molten class of 2001, China's total consumption of 18000 tons, 12000 tons of imports, in 2004 total amount 78000
Tons, with imports of 48000 tons, the total amount of this year is expected to exceed 100000 tons, has imported 25000 tons in the first half of the year.Silicon micro technology field
Annual demand for 20000 tons of powder. it is presumed that the domestic demand for type molten silicon powder, 15, 2010-2010
Tons;In terms of electronic products, the demand for crystalline silicon powder, the annual demand is expected to exceed 700000 tons;In the fused silica ceramics
Surface, the domestic demand for black silicon carbidepowder in will reach 30000 tons, the wide prospect of market.It is understood that the silicon powder mainly in high-end products
Rely on imports.With China's accession to the WTO market, as well as the rapid development of China's IT industry, electronic packaging in the industry will gradually move to
Countries.Experts predicted: the new century China will become the world's superpower encapsulation, high-purity ultrafine silica powder and other downstream products market will be over
The expanded.Is profit space, though with silicon powder products, but the price is a far far, such as ordinary silicon powder is only 600 yuan / 300 courses
8000-8000 tons. And ultrafine high-purity electronics for micro powder price is as high as 100000 yuan/ton, if you upgrade to nanoscale
Molten micro powder tons price is higher more than 200000 yuan/ton.Product upward development space in our country the relevant units and successfully developed electronic levelHigh-purity ultrafine silica powder.This is a market attractive electronic materials products.High-purity ultrafine silica powder is large-scale integrated electricity subgrade
Board and electronic packaging materials of the main raw material, it combined with epoxy resin to complete chip or adhesive sealing components.Ultrafine silica powder
In the epoxy resin mixed ratio determines the thermal expansion coefficient of the substrate.The higher the proportion of silicon powder, thermal expansion coefficient of the substrate
Small, that is, the closer it gets to the thermal expansion coefficient of silicon wafer, which can avoid uneven expansion caused by damage to the micro line.Therefore, the silicon
The purity of powder, fineness and particle size distribution have strict requirements.Enterprise instance above analysis it can be seen that the silicon powder has the attractive
Market prospect and wide development space.With the development of new and high technology, more and more high to the requirement of micro silicon powder materials, the enterprise can be completely
Based on the needs of the market, less investment, adjust product structure, develop the deep processing products, in order to improve the competitiveness of the enterprises
But these should have a necessary premise - science and technology innovation.Only rely on science and technology to develop high-tech products, to make empty market
Between the development and form a virtuous circle.

Green silicon carbide is what, how is it made of

Green silicon carbide is a petroleum coke and the high quality silica as the main raw material, adding salt as additive, via high temperature electric resistance furnace smelting.Its hardness is between fused alumina and diamond, mechanical strength is higher than fused alumina.

Silicon carbide purpose

Black silicon carbide semiconductor can handle "extreme environment", it is alleged that silicon carbide wafer can withstand even Venus or near the sun's heat. Previous studies show that even at a temperature of 560 degrees Celsius, silicon carbide wafer in the absence of cooling device is still functioning normally. calcium siliconwafer has wide applied prospects in the field of communication, can let the high-definition TV transmitters provide a clearer signal and image; Also can be used in jet and automobile engine, monitoring the motor running. At the same time, it also can be used in the field of space exploration, help nuclear-powered spacecraft perform more complex tasks. French physicist predicted that in the field of chip manufacturing silicon carbide replace silicon has been far too.

How to identify black silicon carbide

Black silicon carbide as chemical stability, high thermal conductivity , thermal expansion coefficient, good wear resistance , except for the abrasive used , there are many other uses , for example: a special process the silicon carbide powder coating on the turbine impeller or cylinder block the wall, can improve the wear resistance and extended service life 1 to 2 times ; made ??of high-grade refractory to , thermal shock resistance , small size, light in weight , high strength, good energy saving effect .
How do black silicon carbide identification:
1 Appearance Density : And you want to see the density of silicon carbide , silicon carbide and high chamber generally loose content is higher than the number ;
(2) Test Hardness: It 's more than the glass hard , can use when glass cutter ;
3 see color: from the color , the difference with green silicon ;
4 experiment : to find a glass container , put the pieces into a certain amount of silicon carbide , add water , shake , look at its turbidity , water darker , indicating its higher carbon , silicon carbide, but less ; the water drained , look silicon carbide in the quartz sand how many unfired raw numbers , then make a preliminary judgment, if you engage in over- testing, your judgment will not be up and down the error 3 .

Green silicon carbide powder magnetic separation is very important

Green silicon carbide is a high temperature high-tech products , its color is green, crystal structure is shaped products, microscopic shape of a hexagonal crystal , silicon carbide Mohs hardness of 9.2 , a Vickers hardness of 3000 - 3300 kg / mm 2, the Knoop hardness of 2670-2815 kg / mm , hardness of 3300 kg per cubic millimeter.
Green silicon carbide material to be crushed by magnetic separation . Green silicon carbide powder is very important that such general magnetic material after the wet- milled into a concentration of 25 % to 40 % of the slurry for wet magnetic separation to remove iron into the milling time , the production scale is small , can be permanent block wet magnetic separation . The aircraft magnetic field strength of 7000 Oe or more , stopping every 20 ~ 30min filters cleaned once removed , can make the material magnetic material content to 0.002% or more, when the large-scale production , can be wet magnetic separator as CST162 electromagnetic iron machine . Green silicon carbide powder Scope: do bonded and coated abrasives , and polishing , machining cast iron , tungsten carbide, titanium, high-speed steel , etc., can grind glass, ceramics, stone , agate and jade fine jewelry other non-metallic materials, heating elements and thermal elements , such as : Carbide , optical glass, glass and ceramics and other hard and brittle ma non-metallic materials , can also be used to manufacture high-grade refractory , electric components and electrical component products.

About emery introduce the main functions

Emery Because high temperature, corrosion resistance, high strength and other properties, it poured with steel sliding gate, smelting rare metals, special alloys, ceramics, blast furnace lining (walls and tubes); chemical containers, spark plugs, anti- Thermal oxidation resistant coating.
Because of hardness, wear resistance, high strength characteristics, in the chemical system, used to do all kinds of repercussions vessels and pipelines, chemical pump parts; make machine parts, all kinds of mold, such as wire drawing dies, extrusion die nozzle pencil etc.; make tools, dies abrasives, bulletproof material, human articular, seal mold ring.

brown fused aluminium oxide insulating material, such as lightweight corundum bricks, corundum hollow spheres and fiber products, used in various high-temperature furnaces throughout the furnace wall and roof, both high temperature insulation. Size sand corundum corundum block by artificial selection, admission on the roll, ball mill, and other settings Barmac deployment processing equipment, particle size by the F8-F325. Important for polishing, grinding, industrial grinding, etc., you can also press customer requirements at washing, pickling disposal punishment essentials processing, the difference can probably satisfied customers demand.

Britain at the end of low-carbon corundum furnace and special process and then dispose of punishment, corundum low carbon content in the waste, so that the product is not in use powder, not burst, toughness is the Carborundum Abrasives
industry, refractory material industry of choice material. Emery important for ceramic abrasive, high abrasive, organic abrasive, abrasive belt, coated abrasives, etc., credentials residual carbon content is divided into: calcined corundum C ≤ 0.05%, carbon corundum C ≤ 0.10% , ordinary corundum C ≤ 0.15%.

Explains how to better develop the corundum

Corundum is the most common major abrasive a product, the product has many advantages, abrasives carried out related to the conduct. Current national exercise restraint corundum, screening exercise small stove, but in fact is encouraging enterprises to take a group of road.
Known as dental abrasives industry reputation. Commonly used in the grinding or abrasive abrasive grinding thing as the parts to be processed to be machined, and reaches a certain skill requirements. Twelfth Five-Year Plan "beginning to carry out abrasive professional conduct has brought great opportunities and challenges. Energy conservation, hygiene production will showcase the produce in abrasive occupational category, in addition, the state machinery , shipbuilding, automobiles, airplanes and other areas of policy will also abrasive corundum abrasives production and carry out a great impact.
As a special abrasive incomparable career, there is abrasive in terms of energy saving exercise problems, current domestic overcapacity corundum appearance, followed by the implementation of national energy conservation policy, the next step will be a screening approach point behind corundum occupations capacity. Estimates of future five-year career abrasives tone will also be carried out throughout the country's economic policy tone.
Our abrasive mall after nearly a decade of conduct, constitutes a fundamental mall format once. China has become abrasive producing countries, but not power. As a special abrasive incomparable career, there is abrasive in terms of energy saving exercise problems, current domestic overcapacity corundum appearance, followed by the implementation of national energy conservation policy, on small corundum processing Square To filter on brown corundum continue to carry out, to embark on the Group of the road.

Black silicon carbide simple way to identify what

In fact, distinguish black silicon carbide method is very simple, generally can tell from the color on the out, but some are dyed , and this time we should better understanding and from the other side to compare .
Black silicon carbide simple identification method :
Color difference compared with green silicon ; hardness, it is much harder than glass , can be used when the glass cutter ; find a glass container , put the pieces into a certain amount of silicon carbide , add water , shake , look at its turbidity , AGUA black , indicating its higher carbon , silicon carbide abrasive , but less ; the water drained , watching the black silicon carbide in the quartz sand how many unfired raw numbers , and thus make a preliminary judgment, if you engage in over- testing , your judgment will not be up and down the error 3 . There you look at the density of silicon carbide , silicon carbide and high chamber generally loose content is higher than the number .
 

There are new developments in silicon carbide carbon double success

Technology is evolving , is endless , master of science and technology to master the future , the current silicon carbide in science and technology , there has been a new development , the standard of silicon carbide prospects bright.
In an atmosphere of carbon tetrachloride carbon SiC surface layer made ??new progress in preparing for the chlorine source and carbon tetrachloride by carbide derived carbon (CDC) process and chemical vapor deposition (CVD) law , successfully prepared on the surface of the silicon carbide layer carbon . The carbon layer respectively formed by chlorination of silicon carbide and carbon tetrachloride CDC subsurface formation of pyrolytic CVD surface composition. Film forming temperature of the layer has an important role . Since the CDC chlorination process is much higher than the deposition rate of CVD process , so CDC layer is thicker than the CVD layer .
The researchers believe that by introducing hydrogen as well as ways to reduce low temperature evaporation of carbon tetrachloride CDC layer thickness. The carbon layer formation mechanism of chloride and CVD silicon carbide layers are formed , but these two competing processes occur simultaneously . The carbon layer may be used as a better interface than the CDC coatings on metal matrix composite material, the mechanical seal can also be used as lubricating coating.
Extensive use of silicon carbide , silicon carbide almost all walks of life are inseparable , but the most important of the earliest silicon carbide is used in abrasive applications on . Silicon carbide abrasive industry is one of the most basic ingredients . Although there is now a new development of silicon carbide , silicon carbide , however the most important application areas or in the abrasive article .

Black silicon carbide materials include what are

Including black silicon carbide and green silicon carbide, wherein: Black silicon carbide is quartz sand , petroleum coke and quality silica as the main raw material in electric arc furnace smelting .
Its hardness between corundum and diamond , the mechanical strength is higher than corundum, brittle and sharp .
Green silicon carbide are petroleum coke and quality silica as the main raw material, add salt as an additive in electric arc furnace smelting .
Its hardness between corundum and diamond , the mechanical strength is higher than corundum .
There are commonly two different silicon carbide abrasive crystals , one is green silicon carbide, with SiC 97% above, the main tool used for grinding hard gold .
Another black silicon carbide , metallic luster, containing SiC 95% more strength than the large green silicon carbide , but the hardness is low, primarily used for grinding cast iron and non-metallic materials .

Stone processing abrasive composition and classification

Is abrasive abrasive, binders, fillers, porosity, and attachments and other components.
The basic requirements of the abrasive:
1, the hardness is higher than the hardness of the material to be processed;
2, has a certain toughness and strength, and with sharp skills.
3, should have a certain degree of mechanical strength.
4, maintaining the inherent high strength and hardness (hardness or thermal stability or red).
Abrasive Category:
Abrasive for natural and artificial sources can be divided into two categories, according to the nature of abrasives and super abrasives can be divided into two general categories.
Common natural abrasives:
A natural diamond: diamond abrasive with high efficiency, long life, low cost, good quality grinding series of advantages.
2, quartz sand: also known as silica sand, 95% of the particles of quartz sand.
3, garnet sand: to loose abrasives for cutting soft marble blocks.
4, natural corundum: mainly composed of A1203. Mohs hardness of 9, second only to diamond.
Commonly used artificial abrasives:
1, corundum: Suitable for grinding the tensile strength of the material, the price is cheaper.
2, corundum: grinding capacity slightly higher than corundum (0.12 for the diamond). Moderately fine grinding.
3, chromium corundum: purple or pink, slightly higher than corundum grinding capacity (as diamond 0.13), especially for the profile grinding. Widely used alloy gears, cutting tools, thread management tools and instruments of precision grinding parts.
4, SiC: commonly known as carborundum, its ability to wear diamond 0.25-0.28, brittle and sharp, is very versatile and an abrasive.
5, synthetic diamond: wear ability and natural diamond almost there in the stone industry will gradually replace traditional.

Silicon carbide powder production steps are as follows

Silicon carbide powder production process there are five main steps:
First, take the silicon carbide materials, through the crusher, and sieved to less than 5mm of silicon carbide particles, and then shaping machine shaping them to no more than 2mm of silicon carbide particles, and the particles of which accounted for 80 Oval % or more, performs, pickling to remove impurities, and then during drying
Second, milling, the dried particles of silicon carbide powder mill crushed into d50 = 9.5-11.5μm silicon carbide powder, crushed when the mill is set to host the current 65-75A, fan flow is set to 40-50m3/min, analysis machine speed of 400 - 600 rpm / min for milling process.
Third, grading, grading machine with vortex flow silicon carbide powder grading, grading, vortex flow fan air classifier is 25-43m3/min, classifier wheel rotational speed of 2600 - 3300 rev / min, from grading mouth ceded ds94 = 6.5-5.5μm particle size of the finished product A, cyclone separation ds94 ≤ 5.5μm mouth semi-finished products;
Fourth, the vortex type air classifier with cyclone mouth impeller semi separated gas stream classifier then re-classifying, grading, the impeller of the fan air flow classifier 25-10m3/min, classifier wheel rotation speed is 1300 - 1700 rev / min, separated from the particle size classification mouth ds94 = 4.5-3.0μm finished product B, then the separated product cyclone mouth. Fifth, testing, according to the standard detected in the production of silicon carbide powder is qualified.

Garnet sand

Garnet sand, garnet abrasive products in the mountains of the high-quality natural garnet ore as raw material, according to the modern craft sticks refined products self-sharpening . Grinding efficiency . Sand consumption is low , grinding pieces of good finish .
The abrasive shell-shaped fracture , hardness, toughness, sharp corners , constantly smashing step in the formation of new edges and the side edge , making it superior to other abrasive grinding capacity .
It has a high hardness. Than significant . Chemically stable and its unique self -sharpening advantages , making it have the other abrasives , synthetic abrasives irreplaceable advantages, as grinding, polishing glass bulb . Monocrystalline silicon is an ideal material ; right optical Industry lenses. lens grinding on the printing plate , glass, crystal , ceramic products . leather stone . nuclear contamination protective plastic layer processing and electrical degrees , can obtain good results ; also sand-blasting , manufacturing grinding wheels and high-precision sandpaper emery cloth . abrasive paste . cutting discs ; water cutting sand is an ideal material ; since than the major . chemically stable for water filtration media , water purification ; due to its wear . Aciduric alkali, use it for filling agent manufacturing wear-resistant rubber . wearing plastic , non-slip paint and other new products ; using it as cement filler, can be made efficient wear cement, is the construction of motorways. airstrip . pier. entrance of the hotel . parking sporting venues . resistant floor of advanced materials such as high-grade building ; using its micro- level products , applied to the tile surface can be made ??"permanent" wear-resistant floor tiles, floor tiles improve wear non-slip and strength properties .

Silicon carbide powder production process

Silicon carbide powder production process, characterized by the following steps:
(A) take the silicon carbide raw material, crushing machine, crushing and sieving to not more than 5mm of silicon carbide particles, and then shaping machine shaping them to no more than 2mm of silicon carbide particles, and the particles of which accounted for 80 Oval % or more, and then its acid cleaning, drying;
(2) above the dry mill with silicon carbide particles smash into d50 = 9.5-11.5μm silicon carbide powder, crushed when the mill is set to host the current 65-75A, fan flow is set to 40 - 50m3/min, analysis machine speed of 400 - 600 rpm / min;
(3) and then use the vortex air classifier silicon carbide powder grading, grading, vortex flow fan air classifier is 25-43m3/min, classifier wheel rotational speed of 2600 - 3300 rev / min, from grading mouth ceded ds94 = 6.5-5.5μm particle size of the finished product A, cyclone separation ds94 ≤ 5.5μm mouth semi-finished products;
(4) The cyclone vortex air classifier mouth separated by semi-impeller type air classifier and then a second grading, grading, impeller fan air classifier flow 25-10m3/min, classifier wheel rotational speed of 1300 - 1700 rev / min, separated from the particle size classification mouth ds94 = 4.5-3.0μm finished product B, then the separated product cyclone mouth.

Garnet degaussing method

Mineral water immersion Garnet
Buy a new bottle of mineral water, then let a glass bowl, pour the garnet sand into the cup and mineral water soak for 24 hours. To balance the negative energy spar.
Defense salt immersion method
The spar into a glass house, in accordance with each bracelet 10 grams defense salt, calculated against 500 ml of mineral water, soak for 24 hours, after soaking with mineral water or purified water rinse and then dry, then digestion crystal magnetic field around the stone, you can also give pieces Crystal degaussing, the amount of Cadogan several defense salt and mineral water. Note that the salt say is Japan's defense salt, non-ordinary salt, defense salt of the metal, crystal-corrosive, does not change the nature of crystal. Obsidian recommended defense salt demagnetized.
Under what circumstances need degaussing
Long time no degaussing (recommended at least once a month eliminate magnetic), is not like touch, wishes come true, and out of the filthy places (such as funeral homes, hospitals, cemeteries), met sewage stolen goods and so need degaussing.

Corundum smelting general method of operation

Corundum smelting belong mineral hot furnace melting, smelting There are three main ways: Fixed furnace melting block method, dumping furnace smelting and refining flow mode method, because large-scale investment exile smelting, present, China mainly uses a fixed block method and dumping melting furnace furnace smelting two ways:
1, the dumping of the furnace (method) the production of corundum crystalline aggregates many small crystal size, and the distribution of high glass phase in the grain boundary, so that poor toughness, brittleness, shedding from sharp abrasive resistance, good compactness, compared with bonded abrasives and refractories adapted.
2, frit furnace (France) produced corundum, crystal aggregates small crystal size large, glassy less, so poor brittleness, toughness, wear resistance is good. Because crystals, toughness and brittleness better this way produced corundum smelting more adapted to the manufacture of coated abrasives. It is still the largest production and use of abrasive abrasive.
In recent years, due to bauxite resources for corundum smelting bauxite serious decline in quality, in particular commodity quality corundum difficult to achieve downstream product quality requirements, so corundum abrasives production, processing and post-processing becomes increasingly more important.

How to correctly select the corundum

1, white fused alumina abrasive, slightly higher than the hardness of corundum, but poor toughness, easy to cut into the workpiece during grinding, good self-sharpening, less heat, grinding ability, high efficiency. Chromium corundum abrasive is its derived varieties.
2, corundum abrasive, the main component of Al2O3, with medium hardness, toughness, particle Fengrui, relatively inexpensive, suitable for machining high tensile strength of the metal. Microcrystalline corundum abrasives and black corundum abrasives are its derived varieties.
Many of my friends in the purchase of corundum, grit and other abrasives, there will be carefully selected, select the correct product corundum blasting machines and other equipment will not affect the operation of the machine can cause serious trouble, corundum and other abrasives are generally divided into steel cut wire shot, alloy balls, white cast iron balls just in the use of corundum, because of the hardness of corundum is low and difficult to break, to maintain the shape of a blunt garden, on the leaves to shock, move-based, so the In this case the role of blade grinding suffered weak, partial grinding surface cracks and scratches a little more. In the scanning electron microscope samples for imported true for low-times be observed, that the lateral wear surface of a bulk wave, ripple motion perpendicular to the direction of the projectile.
3, single crystal corundum abrasive material particles are composed of a single crystal, and has a good polygonal cutting edge, high hardness and toughness, grinding ability, less grinding heat, the disadvantage is the high cost of production, yield lower, so the price is relatively high. White fused alumina abrasive is crystalline compound, slightly lower hardness, crystal size is fine, good wear resistance.
4, black silicon carbide abrasive, green silicon carbide abrasive, abrasive cubic silicon carbide, silicon carbide abrasive cerium, etc., are silicon carbide abrasive, the main ingredient is silicon carbide SiC, high hardness, brittleness, sharp abrasive grains, good thermal conductivity, strong wear resistance, more suitable for processing hard and brittle metallic and non-metallic products.

Corundum coating knife cutting wear a variety of reasons

The color is white corundum state, its simple structure, flexibility is softer than corundum, high reliability and a very wide range of applications. Metal cutting process, resulting in the tool wear is mainly due to the contact between the tool and the workpiece and the friction and blade near the extreme high temperature and pressure conditions. Cutting area of ??any one unit change in contact conditions will affect the tool wear, these conditions include tool material, tool coating and tool geometry specifications, there are other conditions and the physical properties of the workpiece material, corundum cutting tool parameters and the appropriate conditions , cooling and lubrication conditions, the process of cutting machine tool vibration greater or more serious causes the tool to jump fluctuate overload.
Because of different cutting conditions when machining different materials, corundum tool wear mechanism is different: at low cutting speeds, often dominated by abrasive wear; speed cutting, with the cutting speed, cutting temperature increases, bond wear and chemical wear more and more prominent. This paper mainly Ti (C, N) ceramic coated carbide cutting Cr12 mold steel knife tool wear failure analysis studies.
Corundum diffusion wear when cutting steel, cutting temperatures often reach 800 ~ 1000 ℃, or even higher, diffusion wear of carbide cutting tools become one of the main reasons for wear, beginning from 800 ℃, cemented carbide Co, C, W will spread to the chip and other elements to be taken in; the chips to the alloy of Fe diffusion, to form a new, low hardness, high brittleness of the composite carbide. The diffusion of Co, WC, TiC and other carbides reduced due to the Co binder reduce the bond strength with the substrate, which would accelerate the wear of the tool. Meanwhile, the temperature rises to a certain degree of adhesion occurs, therefore, diffusion wear and adhesive wear is often occur simultaneously.
In the tool wear surface morphology observed in the process, we found that more or less the clearance face of the tool, there are some small round particles. To explore these little balls of ingredients, using EDS energy dispersive spectroscopy analysis performed on the part. Found that these pellets mainly composed of a metal Fe and O, presumed to be iron oxides. Corundum ball shape is round, can not be generated in the cutting chips. According to theory of metal crystallization, to form such a round spherical objects, the most likely route is through the liquid - solid transition to achieve, because the liquid substance in order to have a minimum surface energy, with automatic shrink into a ball trend. In high-speed cutting, the temperature is high, although the cutting groove wear areas there is no theoretical temperature at the tip and the rake is high, but the trench oxidation and diffusion regions violent, especially from high-speed chip flow, Tool wear resulting in a trench area in contact with the sharp edges of the chip generates strong friction, wear the trench area and micro contact the local temperature is high, reaching some of the chips on a micro melting temperature, so he formed a lot small balls.
To reduce the corundum small tool wear, cutting parameters can be optimized to ensure product quality and processing efficiency in the case of small cutting parameters selection cutting force for cutting; coating material composition can be optimized to improve the coating material machinability, using advanced multi, multi-layer, gradient coating system, by increasing the intermediate layer to improve the coating and the substrate adhesion and corundum coated cutter when appropriate substrate pretreatment.

Corundum: What are the main component of corundum

Corundum name comes from India, Department of Mineralogy name, gemology gemstone conditions have called on Ruby (Ruby), Sapphire (Sapphire). Isomer like corundum Al2O3 There are three main variants, namely α-Al2O3, β-Al2O3, γ-Al2O3,, according to X-ray diffraction analysis indeed there is η-Al2O3 (equiaxed), ρ-Al2O3 (Crystal Department of uncertainty), χ-Al2O3 (hexagonal system), κ-Al2O3 (hexagonal system), δ-Al2O3 (tetragonal), θ-Al2O3 (monoclinic [1]). Corundum variety of colors, there is a colorless, white, yellow (pigment ion Ni, Cr), yellow (pigment ion Ni), red (pigment ion Cr), blue (pigment ion Ti, Fe), green (pigment ion Co, Ni , V), purple (Ti, Fe, Cr), brown, black (pigment ion Fe, Fe), incandescent violet, purple under fluorescent effect (pigment ion V).
Corundum glass luster, hardness 9. Weighting 395-410. In the high-temperature aluminum-rich C depleted silicon formed under conditions, mainly related magmatism, contact metamorphism and regional metamorphism.
Corundum is bauxite mining as the main raw material refining furnace artificial materials with corundum, green silicon carbide powder. Yu do abrasives and refractories. Called high purity white fused aluminum oxide, a small amount of impurities is called as a brown corundum.

For green silicon carbide powder characteristics and magnetic introduction of knowledge

Green silicon carbide powder characteristics Green, high hardness and cutting ability, chemical stability, good thermal conductivity. High purity, brittle, microhardness 3280-3400 kg / mm2. It is made of abrasive, suitable for processing high hardness, brittleness of the material, green silicon carbide powder Scope: do bonded and coated abrasives, and polishing and so on. Suitable for machining cast iron, tungsten carbide, titanium, high-speed steel. Can grind glass, ceramics, stone, agate and jade and other non-metallic materials, fine jewelry, heating elements and thermal elements. Such as carbide, optical glass, glass and ceramics brittle ma non-metallic materials, can also be used to manufacture high-grade Sic Refractory, electric components and electrical component products. Green silicon carbide powder separator Green silicon carbide material to be crushed by magnetic separation. Generally the wet milled material into a concentration of 25% to 40% of the slurry, a wet magnetic separation to remove the ball into the iron. Production of smaller, can be used wet permanent magnetic blocks. When the large-scale production, can be wet magnetic separator, such as CST162 electromagnetic iron machine. The aircraft magnetic field strength of 7000 Oe or more, stopping every 20 ~ 30min filters cleaned once removed, can make the material magnetic material content to 0.002% or more.

Under the new situation of silicon carbide industry, new thinking

First, the silicon carbide industry development statusSilicon carbide fine powder as a new multi-functional composite materials, in recent years, is widely used in high-end solar energy, cutting grinding semiconductor, LED, nonmetal ceramics, high-performance sealing rings and other fields. Especially in recent years, both domestic and foreign media and industrial policies are strongly boost the rapid development of this emerging industry. Strong development of photovoltaic industry expectations, resulting silicon carbide industry hot, attracting a large number of enterprises and social investors flocked to overcome the energy conservation and other multi-pressure silicon carbide production enterprises of all sizes can be described as everywhere, the burgeoning optimism .In recent years, as the global voice of the yearly high energy saving, new energy photovoltaic enterprises to obtain a triumph of development, especially in the photovoltaic industry in 2010 experienced a spurt of development. With the rise of the photovoltaic industry, for important materials as silicon wire cutting silicon carbide fine powder to form a huge demand. 2010, the global installed capacity of 15.7GW, the demand for silicon carbide fine powder of about 260,000 tons (of green silicon carbide fine powder), known to be projected green silicon carbide blocks about 500,000 tons of raw materials. In the case of expectations and optimism, our green silicon carbide production capacity has reached 1.6 million tons, mainly distributed in Qinghai, Gansu, Xinjiang and other regions, serious excess capacity.Into 2011, the photovoltaic industry experienced a 2005-2010 compound annual growth rate of more than 40% of rapid growth, this year from April to May, the most important by the European PV market policy changes, the PV installed capacity is almost stagnant state. Serious overcapacity photovoltaic industry chain inventory pressure makes drastic correction, prices have been falling, from integrated systems, components, into silicon, and even higher threshold to the upstream polysilicon raw materials, industrial chain spared. Statistics show that since the start of April 1st polysilicon spot market prices fell 40% (by early April of 780,000 yuan / ton down to the current 350,000 yuan / ton), silicon prices fell more than 40%, component prices fell 27%.The whole industry chain prices fell rapidly, so that all photovoltaic enterprise gross margins have fallen sharply, rapidly narrowing profit margins, some no-cost or even a loss advantage for SMEs, the operating rate fell below 50%. Tragic extent comparable to the 2008 financial crisis.In this context, as part of its industrial chain on a ring, silicon carbide, can not escape the production enterprises, the products have no market price, business situation deteriorated sharply, the industry reshuffle is inevitable.Second, the silicon carbide industry, "danger" and "machine"1, the prices are low, silicon carbide market boom downAs the product homogeneity serious, 2011 massive release of new capacity, the formation of short-term relative surplus in the western region of silicon carbide falling price trend was sustained for several months.Price from raw material silicon carbide blocks early April 11,000 yuan / ton down to the current 9000 yuan / ton, and even some manufacturers have reported 8000-8500 yuan / ton, has formed a short-term vicious cycle. Now, with the western region to cancel preferential tariff policy (tariffs generally reached 0.4 yuan / kWh), a lot of silicon carbide smelting enterprises have already meager profit, almost in barely maintain production.In terms of silicon carbide fine powder, as its main application market, the swings in the photovoltaic industry but also to the silicon carbide fine powder tremendous impact on the market. January and February this year, the price of PV modules and cells begin to fall, followed by silicon, in May after the upstream polysilicon prices also began a marked decline. After nearly three months of continuous decline, the price of polysilicon has been the lowest in six years. Quotes from the entire PV industry decreased downstream to upstream reverse conduction, still no signs of recovery, according to a rough estimate, at least silicon carbide fine powder prices fell more than 15%, or even higher. More worrying still is that prices fell sharply, while turnover has not significantly expanded, and have actually appeared in price and volume of Qi or situation.2, the impact of changes in the economic environment of silicon carbide industrySince March, the country and more off-season "power shortage" phenomenon. National Energy Board and the Development and Reform Commission has issued restrictions, especially high energy-consuming industries industrial electricity, industrial electricity price increases and a series of policies already in a recession for the silicon carbide industry and form a larger impact.2011 With the tightening of national macro-control, the central bank to raise interest rates three times, five times raised the deposit reserve ratio, survival and development of SMEs facing difficulties. SiC bad financial strength within the industry enterprises, survival woeful.Sharply increasing pressure of RMB appreciation, silicon carbide products belong to the state limit the export products, should be noted that this may result in more domestic-oriented enterprises, domestic market competition further intensified.Labor shortageWith the domestic economy to pick up, now the national general labor shortage, silicon carbide industry is no exception, in the current industry downturn, industry and employment issues more prominent, general workers, the wages of skilled workers have a considerable margin in the years after rise, because silicon carbide industry production environment is relatively poor labor intensity is relatively large, the actual labor costs are more difficult to circumvent the hard costs, has given enormous pressure on silicon carbide business.3, changes in the silicon carbide industry's largest PV market bearishAs the world's top two photovoltaic market, Germany, Italy accounted for more than 60% of the world PV market share, and in 2011, following the German government decided to cut solar subsidies 16% after, 1 April, the Italian government introduced a new PV subsidy policy, from the commencement date until the end of 2012, the PV subsidy cuts of 15% -20%; 2013-2015 PV subsidy will be reduced by 30% -35%. As opposed to the traditional current cost of photovoltaic energy is still at a high level, has always been driven by the development of policy, the amount of subsidies granted by the government sector and the development of photovoltaic industry boom of the high positive correlation sudden policy lowered, causing the biggest photovoltaic industry amplitude adjustment, the adjustment even more than in 2008 when the international financial crisis is even larger. This led directly to the silicon carbide fine powder prices and demand reduction.4, alternative technologies diamond wire saw (with wire-cutting example) has developed rapidlyWafer cutting technology currently available as an alternative to recent advances in technology, that Meyer Berger embedded diamond wire saw technology.Diamond wire saw has the world's largest wafer manufacturers - GCL Group successfully tested, while China PV industry representatives - Suntech currently being tested, is expected to the recent success. In addition, listed companies Henan diamond, Huanghe Whirlwind and other companies also recently announced a major investment strategy, the establishment of a joint venture to enter the diamond powder production, mainly used for diamond wire cutting wafers. This information is all reflected: Diamond wire cutting is accelerating to enter the field of solar wafer cutting pace. Will have a direct impact on the future use of the silicon carbide powder.5, quasi-monocrystalline solar cell has been officially put on the marketQuasi-monocrystalline solar cell conversion efficiency of monocrystalline cells with the same, but with the cost of the process rather polycrystalline cells, quasi-monocrystalline ingot technology resulting product has a single crystal efficiency, also has a low cost of polysilicon, the advantages of low attenuation .June 18, 2011, China Henan Anyang Phoenix Solar in Shanghai announced mass production of its quasi-monocrystalline material, will be officially put on the market. At present, more than 10 companies are using the quasi-monocrystalline silicon photovoltaic Phoenix, where two will begin in July bulk orders.From these unfavorable factors, the silicon carbide industry to achieve healthy development as soon as possible out of the current shadow, in addition to expect gradual improvement in the external environment outside the industry itself should be as soon as possible to improve and enhance the revolutionary future situation, the arduous tasks and Road away.