Quartz sand is a hard, wear-resistant, chemically stable silicate mineral, its main mineral component is SiO2, the color is milky white or colorless translucent, the hardness is 7, the shell-shaped fracture, the grease luster, the density is 2.65 , its chemical, thermal and mechanical properties have obvious anisotropy, insoluble in acid, slightly soluble in KOH solution, melting point 1750 ℃.

Quartz sand

The unique physical and chemical properties of quartz sand make it occupy a pivotal position in aviation, aerospace, electronics, machinery and today's rapidly developing IT industry, especially its internal molecular chain structure, crystal shape and lattice change rules , so that it has high temperature resistance, small thermal expansion coefficient, high insulation, corrosion resistance, piezoelectric effect, resonance effect and its unique optical characteristics, playing an increasingly important role in many high-tech products.

Quartz sand is an important industrial mineral raw material, non-chemical dangerous goods, widely used in glass, casting, ceramics and refractory materials, smelting ferrosilicon, metallurgical flux, metallurgy, construction, chemicals, plastics, rubber, abrasives and other industries.

The use of quartz sand

1. Glass: the main raw materials for flat glass, float glass, glass products (glass jars, glass bottles, glass tubes, etc.), optical glass, glass fiber, glass instruments, conductive glass, glass cloth and special radiation-proof glass.

Glass

2. Ceramics and refractory materials: raw materials such as blanks and glazes for porcelain, high-silica bricks, ordinary silica bricks and silicon carbide for kilns.

Ceramics

3. Metallurgy: raw materials or additives and fluxes of silicon metal, ferrosilicon alloy and silicon aluminum alloy, etc., can be used as shot blasting and sand blasting for derusting metal surface.

Metallurgy

4. Construction: concrete, cementitious materials, road construction materials, artificial marble, cement physical property testing materials (ie, cement standard sand), magnesite manhole covers, etc.

Construction

5. Chemical Industry: raw materials such as silicon compound and water glass, filling of sulfuric acid tower, amorphous silica powder.

Chemical industry

6. Machinery: the main raw materials of foundry sand, abrasive materials (sandblasting, hard abrasive paper, sandpaper, emery cloth, etc.).

Machinery

7. Electronics and Aerospace: Its inherent molecular chain structure, crystal shape and lattice change rule make it high temperature resistance, small thermal expansion coefficient, high insulation, corrosion resistance, piezoelectric effect, resonance effect and its unique optical characteristics. It can be used as electronic filler, high-purity metal silicon, optical fiber for communication, circuit board, aerospace industry, etc.

Electronics and aerospace

8. Rubber and Plastic: filler (can improve wear resistance).

rubber and plastic

9. Paint: can improve the acid resistance of paint.

paint

10. Purified Water: it is the main raw material of the water filter container. As pure water or sewage filter material.

glass of water

In the field of mineral processing, the quartz mineral resources that can be used for industrial applications are called siliceous raw materials, mainly including quartzite, vein quartz, quartz sandstone, powder quartz, natural quartz sand and natural crystal. Among them, vein quartz and quartzite have less impurities and are usually used to produce high-purity or ultra-high-purity quartz sand, which is generally used in high-end fields.

Natural quartz sand is often used in glass, ceramics and foundry fields due to the high content of hybrids and the poor quality of the mineral itself. my country's quartz mineral resources are rich in reserves, but there are many poor ore, few rich ore, and very few high-grade quartz ore. Most of the quartz resources are accompanied by a large amount of impurities, which can only be used as industrial raw materials after separation and purification by certain means.

The purification process of quartz sand

1. Water washing, grading and desliming

The content of sio2 in quartz sand decreases with the increase of particle size, while the grade of impurity minerals such as iron and aluminum is opposite, especially for quartz sand containing a large amount of clay minerals. Therefore, it is very necessary to separate quartz ore with water before beneficiation, and the effect is obvious. Water washing and classification desliming has been widely used as a pretreatment method before quartz beneficiation, but the removal effect of thin film iron and adherent impurity minerals on the surface of quartz sand is not significant.

Classifying desliming machine

2. Scrub

Scrub is to use the mechanical force and friction between the quartz sand grains to remove the thin film iron, bond and muddy impurity minerals on the surface of the quartz sand, and further crush the mineral aggregates that have not become monomers to achieve further purification effect. At present, there are mainly two methods for scrubbing quartz sand: rod friction cleaning and mechanical scrubbing. For mechanical scrubbing, it is generally believed that the main factors affecting the scrubbing effect are the structural characteristics and structure of the scrubbing tower, followed by process factors, including scrubbing time and scrubbing concentration.

scrubber

3. Magnetic separation

The use of magnetic separation process can remove weak magnetic impurity minerals such as hematite, limonite and biotite, including conjoined particles, to the greatest extent. Intensive magnetic separation usually adopts wet strong magnetic separator or high gradient magnetic separator. Generally speaking, for the quartz sand whose impurities are mainly weak magnetic impurity minerals such as limonite, hematite, biotite, etc., it can be selected by using a wet strong magnetic machine above 10000Gs; for the impurities mainly containing magnetite For strong magnetic minerals, it is better to use a weak magnetic machine or a medium magnetic machine for separation.

Magnetic separator

4. Flotation

Fluorine-free flotation method is a flotation method developed in recent years. It is a new process for developing quartz and feldspar flotation separation. In a natural neutral medium, feldspar and quartz are separated by flotation preferentially by reasonably mixing cationic and anionic collectors. The use of anionic collectors under acidic conditions or the use of anionic-cationic collectors under alkaline conditions can achieve better results. Generally speaking, after washing, desliming, magnetic separation and flotation, the purity of quartz sand can reach 99.3%-99.9%, which basically meets the needs of industrial sand.

Cylinder washing machine

5. Acid leaching

Acid leaching is the use of quartz insoluble in acid (except HF), and other impurity minerals can be dissolved by acid solution, so as to further purify quartz sand. Acid leaching commonly used acids are sulfuric acid, hydrochloric acid, nitric acid, acetic acid and hydrofluoric acid. The reducing agent includes sulfurous acid and its salts. The above acids have a good removal effect on non-metallic impurity minerals in quartz. The removal effect of various dilute acids on Fe and Al is obvious, while the removal of Ti and Cr is mainly treated with concentrated sulfuric acid, aqua regia and hydrofluoric acid.

Acid leaching

According to the acid leaching temperature, the acid leaching test can be divided into hot acid treatment and cold acid treatment. The cold acid treatment adopts the immersion intermittent stirring leaching method, and the time is generally 24h. The hot acid treatment generally takes a short time and adopts stirring leaching. High-purity quartz sand with a purity of 99.99% can be obtained by acid leaching.

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