Quartz sand is quartz particles obtained by crushing quartz stone. Quartz stone is a non-metallic mineral. It is a hard, wear-resistant and chemically stable silicate mineral. Its main mineral component is silica. The color of quartz sand is milky white, or colorless and translucent, with a Mohs hardness of 7.
Quartz tailings include waste residue from quartz mining, tailings and tailing mud during processing, of which tailings account for the vast majority. The chemical composition of quartz tailings is mainly SiO2, and the impurities are mainly feldspar, clay, mica, iron minerals, etc. As long as it is rationally developed and scientifically utilized, pollution can be eliminated, waste can be turned into treasure, the scope of mineral applications can be broadened, and mineral additions can be increased. value and broad development prospects.
1. Road construction materials
The SiO2 content of quartz sand tailings is overwhelmingly ≥75%. The SiO2 material has stable performance and good cohesion with alkaline materials. The improved quartz sand tailings can become a good roadbed and pavement base filling material, especially today’s green water In the environment of Qingshan, the application of quartz sand tail road construction materials has broad prospects.
2. Functional filler
The purity of the product obtained after ultrafine powder quartz tailings is similar to that of silicon powder products, and the whiteness is increased by nearly 12%. It can be used as fine ceramics, high-quality microporous calcium silicate, insulating materials, rubber, plastics, paints, coatings, etc. of filler. Using powdered quartz tailings with a SiO2 content of 98.0%-99.0%, through processes such as grinding, impurity removal, and epoxy resin treatment, ideal fillers for electrical engineers can be produced.
For some low-iron quartz sand plant tailings, electrical and electronic grade silicon powder that meets the requirements can be produced through purification processes such as “magnetic separation-scrubbing-desliming (drug)-flotation”.
Quartz sand tailings are prepared through magnetic separation, hydraulic classification, vibration grinding and other processes to produce -325 mesh greater than 99% and -200 mesh greater than 85% quartz powder, which can be used as alkali-free glass fiber and glaze frit respectively. Silicone raw materials can of course also be used in other fields.
Silica bricks are acidic refractory materials and are widely used in facilities such as glass melting furnaces, coke ovens or hot blast furnaces. Their load softening starting temperature is as high as 1640-1670. The requirements for the raw materials of silica bricks are that the SiO2 content should not be less than 96%, and there should not be too much Al2O3, N2O, K2O and other impurities. Some of the waste rocks generated during the mining of quartzite or quartz sandstone can meet this requirement.
6. Paint filler
Some quartz sand tailings have fine particle sizes and can be used as paint fillers after classification and purification. For example, when used in polyvinyl acetate coatings, its coating products can absorb ultraviolet rays very well. Zhang Xuemei and others added quartz sand tailings and white carbon black to epoxy floor coatings, which can improve the comprehensive properties of the floor coatings such as hardness, wear resistance and wash resistance.
7. White carbon black
Purified quartz tailings and sodium carbonate are used as raw materials, and sodium silicate solution is prepared through calcination and leaching. White carbon black is then prepared using sulfuric acid precipitation method, and potassium sulfate is prepared from the by-product sodium sulfate using the “two-step method”.
8. Silica aerogel
Using quartz tailings as raw material, SiO2 aerogel was prepared through activation treatment, caustic soda dissolution, sol-gel method, and normal pressure gradient drying.
9. Sintered bricks and new wall materials
By utilizing shale resources and adding 40%-50% of quartz sand tailings and waste mud, high-grade modulus thermal insulation wall materials can be produced. Quartz tailings can also be used to develop sand aerated heat insulation, sound insulation, and thermal insulation materials to provide materials for building energy conservation.
At present, there are three main types of aerated concrete products in my country: one is fly ash type; the other is silica sand type; and the third is sand slag type (sand aerated concrete). Sand aerated concrete is mainly divided into two types: mine tailings and river sand. It is a high-end product in the market. In particular, aerated concrete products using quartz sand as raw material have the best characteristics.