What is quartz sand powder? What is the production process of silica powder? What are the types of silica powder? What are the uses of silica sand powder?

What is silicon powder?

Quartz powder (quartz sand) is also called silica micro powder. Its English name is quartz sand powder, silica flow, ground quartz. Silica micropowder is a kind of hard, wear-resistant and chemical stable silicate mineral. Its main mineral composition is SiO2. The color of quartz sand is milky white or colorless and translucent, hardness is 7, brittle and non cleavage, shell fracture, oil luster, density is 2.65, bulk density (20-200 mesh is 1.5). Its chemical, thermal and mechanical properties are obviously anisotropic and insoluble in acid. Slightly soluble in KOH solution, melting point 1650 ℃. Quartz sand is a kind of product whose fineness is below 120 mesh (less than 120 mesh) after being processed. More than 120 products are called quartz powder.

Production process of silica powder

Quartz powder can be produced in two ways: quartz sand powder making plant (dry method) and quartz sand powder making plant (wet method). Various conventional specifications are 100m, 150m, 200m, 325m, 400m, 600m, 1500m and 2000m (M is mesh). In addition, it can also process the special specifications according to the customer's requirements, and the general particle size distribution can also be processed.

Quartz sand powder making plant

Quartz sand powder making plant (dry method)

the main equipment is quartz sand ball mill, classifier, etc. The dry process of producing silica fume (quartz powder / quartz sand) is to grind the silica fume raw materials in a ball mill. The grinding process can continuously feed and discharge materials, or put in several weight raw materials at a time, and then discharge materials after continuous grinding for a certain time. When discharging materials, the granularity shall be controlled by the powder classifier, and the coarse products shall be returned to the mill for regrinding or as products, while the fine ones are products. Dry grinding should strictly control the moisture content of the grinding material, and the product will not be dry.

The quartz powder produced by dry method can be divided into ordinary quartz powder and refined quartz powder. Because when quartz ore is mined from the mountain, it has a yellowish brown skin. Ordinary quartz powder is selected as the product of direct crushing and screening of small quartz ore, which appears yellow brown and white alternately. Its advantages are low price and disadvantages are more impurities, so it is mostly used in construction industry. A large mineral material is selected, the surface of which is removed by hand and then processed into refined quartz powder, which is white and bright, just like white sugar. In general, silicon powder is produced by dry process.

Quartz sand powder making plant (wet method)

The wet production of silica fume (quartz powder / quartz sand) is to put several weight silica fume raw materials into the ball mill at one time, add appropriate amount of water, and the operating concentration is 65% - 80%; after continuous grinding for more than ten hours, pour out the slurry, use the method of pressure filtration or put in the barrel to naturally precipitate and dehydrate to obtain the water containing material cake; after crushing and dispersing with the crusher, evenly and continuously put them into the hollow shaft stirring dryer. Medium, dry to get the product.

Compared with dry process quartz powder, wet process quartz powder produces less equipment iron and water to wash away impurities due to the production process, and the iron content and impurities are less than dry process quartz powder, but it costs labor and materials, and the price is expensive.

Classification of silica powder

Silicon micro powder has many excellent properties, such as good temperature resistance, acid and alkali corrosion resistance, poor thermal conductivity, high insulation, low expansion, chemical stability, high hardness and so on. According to its application, silicon micro powder can be divided into the following categories: Ordinary silicon micro powder, electrical silicon micro powder, electronic silicon micro powder, fused quartz silicon micro powder, ultra-fine quartz silicon micro powder, nano silicon micro powder, etc.

Different kinds of silica powder have different uses.

A. ordinary silica powder

Ordinary silica powder is used in epoxy resin castable, potting material, electrode protective layer, metal casting, ceramics, silicone rubber, coating and other chemical industries.

B. electrical grade silicon powder

Electrical grade silicon powder is used for insulation pouring of common electrical parts, insulation pouring of high-voltage electrical appliances, APG process injection materials, epoxy potting materials, high-grade ceramic glaze, etc.

C. electronic grade silicon powder

Electronic grade silicon powder is mainly used for plastic and packaging materials of integrated circuits and electronic components.

D. fused silica powder

The raw material of fused silica powder is the amorphous SiO2 which is melted and cooled by natural quartz and processed by multiple processes. The product has high purity, small thermal expansion coefficient, low internal stress, high moisture resistance, low radioactivity and other excellent characteristics. It is used in large scale and super large scale integrated circuit plastic sealing material, epoxy castable, potting material and other chemical fields.

E. ultrafine quartz powder

Superfine quartz powder is mainly used in coatings, paints, engineering plastics, adhesives, Kui rubber, precision casting advanced ceramics.

F. nano silicon powder

Nano silicon powder belongs to nano materials, which is mainly used in electronic packaging materials, polymer composite materials, plastics, coatings, rubber, pigments, ceramics, adhesives, FRP, drug carriers, cosmetics and antibacterial materials, and has become a new material for upgrading traditional products.

Application of silica powder

Silica micropowder is made of natural quartz (SiO2) or fused quartz (amorphous SiO2 after high temperature melting and cooling of natural quartz) by crushing, ball milling (or vibration, air flow grinding), flotation, pickling purification, high-purity water treatment and other processes. Silicon powder is a non-toxic, tasteless and pollution-free inorganic non-metallic material. It is widely used in chemical, electronic, integrated circuit (IC), electrical appliances, plastics, coatings, advanced paints, rubber, national defense and other fields because of its excellent properties such as good temperature resistance, acid and alkali corrosion resistance, poor thermal conductivity, high insulation, low expansion, stable chemical performance and high hardness.

A. Quartz sand powder In the field of concrete and refractories

The addition of silica powder to special refractories can form a multi-layer protective layer in the oxidation process, which has good mechanical properties and high temperature resistance and oxidation resistance. After the addition of silica powder to special refractories, its fluidity, sintering, binding and filling porosity properties have been improved in different degrees. The structure density and strength are increased, the wear rate of the material is reduced, and the erosion resistance is enhanced.

B. application of silica powder in adhesives and sealants

The application of silica powder in new adhesives and sealants can quickly form a network like silica structure, inhibit the colloid flow, accelerate the curing speed, and greatly improve the bonding and sealing effect.

C. application of silicon powder in electronic industry

Silicon powder is used in electronic assembly materials, its main function is to prevent water, dust, harmful gas, vibration, external force damage and stable circuit. The addition of high-purity ultra-fine and nano silica in the epoxy plastic electronic materials can make them have excellent processability, small shrinkage, small coefficient of thermal expansion, good acid and alkali resistance and solvent insulation.

D. application of silica powder in plastics and modified resins

The application of silica powder in plastics, especially in the translucent plastic film, has greatly improved its strength, toughness, water resistance, energy storage and thermal insulation. The mechanical properties of plastic structural materials can be increased by 1-3 times after adding silicon powder. For modified resin matrix composites, it can improve the strength, toughness, elongation, wear resistance, finish and aging resistance of the composites.

E. application of silica powder in rubber materials

It can be used in new rubber materials (silicone rubber, etc.), so that its dispersing and leveling ability is excellent, tear resistance, tensile resistance and aging resistance can be strengthened. Compared with the precipitated silica in the middle and low end of the market, the main technical indexes of quartz powder, such as SiO2 content (more than 99.6%), moisture content (less than 0.1%), product granularity and oil absorption, are better than those of precipitated silica.

(1) it can improve the strength and product quality of silicone rubber (filling amount 30-70%); it is an indispensable excellent filler for anti ultraviolet radiation, infrared reflection and high dielectric insulation;

(2) more than 20% ultra-fine silica is filled into the tread rubber of large-scale truck tire and high-speed radial car tire, which makes the tire have good characteristics of antiskid, heat dissipation and antiwear. Adding ultra-fine quartz powder to the tread can significantly reduce the rolling resistance of the tire, enhance the tear resistance, cutting resistance and strength, and maintain the ice and skid resistance of the tire. It's called a green tire.

(3) the elasticity, toughness, wear resistance and strength of other tires and rubber products with superfine silica powder are obviously better than those with conventional and ordinary silica as filler.

(4) the ultra-fine quartz powder is filled in natural rubber, cis-1,4-polybutadiene rubber and NBR. The powder is easy to disperse, has good mixing process performance, excellent calendering and extruding performance, and can improve the vulcanization speed of vulcanizate, improve the rubber viscosity, replace 50% white carbon black to fill in the rubber, and has good mechanical properties (tensile strength, constant elongation, elongation at break, permanent deformation at break, etc. Tear strength and product hardness have no obvious influence, but can greatly reduce product cost, especially suitable for rubber products such as rubber roller, rubber tube, wire and cable and their sheath.

F. application of spherical silica powder

Spherical silica powder is mainly used in large-scale and super large scale integrated circuit packaging and insulation pouring of electronic components and high-voltage electrical devices. It can also be used in high-grade rubber tires, silicone rubber, substrate materials, high-grade inks, coatings, sealants, adhesives, electronic ceramics, optical quartz glass, engineering plastics reinforcement and modification, functional plastic film, drawn optical fiber, medical teeth. It is widely used in materials, cosmetics, chemical medicine, environmental protection and many other fields.

G.Application of silica powder in paint

The application of silica powder in paints and coatings (commonly used in: mixed paint, primer, antirust paint, anticorrosive paint, road paint, square paint, ship paint, etc.) can reduce the use of resin and dispersant in paints and coatings. It can not only increase the filling capacity, thickening and extinction, but also improve the fineness, leveling performance, film hardness, arc resistance and insulation. The effect of anti-corrosion, anti-corrosion, anti caking, anti flow column, thixotropy, anti ultraviolet radiation, anti-aging and improving the storage stability of the paint are significant.