Quartz sand is a kind of hard, wear-resistant, chemical stability of silicate minerals, its main mineral composition is SiO2, quartz sand color is milky white, or colorless translucent, hardness 7, brittle without cleavage, shell fracture, grease luster, density of 2.65, packing density (1-20 mesh 1.6~1.8), 20-200 mesh for 1.5, Its chemical, thermal and mechanical properties have obvious anisotropy, insoluble in acid, slightly soluble in KOH solution, melting point 1750℃.
Common specifications are: 0.5-1mm, 1-2mm, 2-4mm, 4-8mm, 8-16mm, 16-32mm, 10-20 mesh, 20-40 mesh, 40-80 mesh, 100-120 mesh.
Quartz sand is a variant of the colorless, transparent quartz that the Greeks called "Krystallos," meaning "white ice," convinced that quartz was durable and strong ice. Ancient Chinese believed that a cold crystal in the mouth could quench thirst. Quartz sandstone is a consolidated clastic rock, quartz clastic content of more than 95%, from a variety of magmatic rocks, sedimentary rocks and metamorphic rocks, less heavy minerals, associated minerals for feldspar, mica and clay minerals. Quartzite can be divided into two types of sedimentary origin and metamorphic origin. The former has an unclear boundary between clastic particles and cements, while the latter refers to the quartzite ore with deep metamorphism and pure quality. Gangue is formed by hydrothermal action, almost all composed of quartz, dense block structure. Quartz sand mineral content changes greatly, mainly quartz, followed by feldspar, mica, debris, heavy minerals, clay minerals and so on.
Quartz sand has important uses in daily life, production and scientific research, but sometimes it can cause harm to human body.
Some silicon substances, such as asbestos, are harmful to humans. Asbestos is a fibrous, siliceous mineral. Long-term inhalation of asbestos may cause damage to lung tissue. These very fine asbestos fibres may be deposited in lung bubbles, leading to progressive fibrosis of lung tissue and further affecting the function of lung gas exchange.
Because asbestos fibers are not visible to the naked eye, the average person can not take precautions against its spread. There is no safe limit to the danger of asbestos exposure. Basically, all types of asbestos cause cancer. There are no drugs, surgeries or radiotherapies available to treat asbestos-related conditions.
Asbestos also causes lung cancer, pleural mesothelioma and benign pleural lesions. People with asbestosis may later develop bronchitis and pulmonary heart disease due to extensive fibrosis of the lungs, leading to death from heart failure.
Quartz sand dust is very fine, the specific surface area of more than 100m2/g can be suspended in the air, if people long-term inhalation of dust containing quartz sand, will suffer from silicosis (because of silicon old called silicon, silicosis old called silicosis).
Silicosis is an occupational disease. Its occurrence and severity depend on the content of dust in the air, the content of quartz sand in the dust, and the contact time with people. People who work in places with high quartz sand dust content for a long time, such as mining, sand turning, sand blasting, ceramic making, refractory materials and other places are prone to this disease.
Therefore, in these dusty workplaces, strict labor protection measures should be taken, and a variety of technologies and equipment should be used to control the dust content in the workplace, so as to ensure the health of the staff.
Quartz has high fire resistance, industrial quartz sand is often divided into: ordinary quartz sand, refined quartz sand, high purity quartz sand, fused quartz sand and silica powder.
Ordinary quartz sand
Ordinary quartz sand, namely SiO2≥90 -- 99%, Fe2O3≤0.06 -- 0.02%, refractoriness 1750℃, appearance: some large particles have yellow skin cyst on the surface. Ordinary quartz sand is generally made of natural quartz ore, broken, washed, dried, secondary screening of a water treatment filter material; The filter material has: no impurities, no edges, high density, high mechanical strength, fouling capacity line long service cycle characteristics, is the ideal material for chemical water treatment. Granularity range 5-220 mesh, according to user requirements of granularity production. Main Applications: metallurgy, ink silicon carbide, glass and glass products, enamel, cast steel, water filtration, paohua alkali, chemical industry, spray noise and other industries.
Refined quartz sand
Also known as pickling quartz sand, SiO2≥99-99.5%, Fe2O3 0.005% or less, the use of high quality natural quartz sand, mortar.
High purity quartz sand
SiO2≥99.5-99.9%, Fe2O3 0.001% or less, the use of high quality natural quartz stone, mortar. (mm: mm)
Fused quartz sand
Chemical composition: SiO2 99.9-99.95%, Fe2O3 5PPM-25PPM max, Li2O 1-2PPM max, Al2O3 20-30PPM max,
K2O 20-25PPM max and Na2O 10-20PPM max (PPM is one part per million).
The appearance is colorless transparent block, granular or white powder.
Relative gravity: 2.21.
Mohs hardness: 7.0.
pH value: 6.0.
Silicon powder: the appearance of gray or gray powder, fire resistance >1600℃. Bulk weight: 200 ~ 250 kg/m3. The chemical composition of silicon powder is shown in the following table:
75 ~ 96%
1.0 + / - 0.2%
0.9 + / - 0.3%
0.7 + / - 0.1%
0.3 + / - 0.1%
1.3 + / - 0.2%
Origin of raw materials
Quartz ore is usually divided into quartz, squamous quartz, white silica three categories. Unconsolidated crushed rock consisting essentially of quartz grains is called quartz sand.
Main producing area
In terms of the whole country, quartz ore is more extensive. Quartz sand is the use of natural quartz ore, quartz stone mined from the mine after processing, by grinding, screening, washing and other processes. Appearance is prismatic, spherical, pure white, with high mechanical strength, pollution interception ability, good acid resistance and other characteristics. Generally fineness within 120Mesh products called quartz sand. Products over 120Mesh are referred to as quartz powder. High quality mineral sources are mainly distributed in Jining of Inner Mongolia Autonomous Region, Fengyang of Anhui Province, Huanggang of Hubei Province, Lingshou County of Hebei Province with large output and high quality, in addition to a small number of distribution in Guangdong and Jiangxi.
Quartz stone, refractory materials, smelting ferrosilicon, metallurgical flux, ceramics, grinding materials, casting, quartz stone in the construction of the use of its strong acid medium corrosion resistance, used to make acid-resistant concrete and acid-resistant mortar.
As the core of silicon raw material, silica plays an important role in the production and supply of silicon raw material. IT has unique physical, chemical and optical properties, so that it is playing a more and more important role in many high-tech products, such as, IT industry's core technology products - computer chips, optical fiber, electronic industry resonator, new electrical light source, high insulation sealing materials, aerospace instruments, military technology products, special optical glass, Chemical analysis instruments, etc., are inseparable from these basic materials. Quartz stone crystals and beautiful shape can be used for glasses and valuable artifacts, the use of quartz crystal piezoelectric, can be made without wire industry in the frequency stabilizer, quartz filter. Can produce a variety of lenses, reflectors, spectral tubes, light tubes and optical instruments in the prism, polarizing mirror. The method of hydrothermal temperature difference has been widely used to make artificial quartz crystals for piezoelectric components. In the chemical industry, quartz can be used in acid and temperature resistant instruments and utensils; In the electrical industry, quartz is often used as an excellent insulating material; Quartz stone is also an excellent raw material in the glass, enamel and firebrick manufacturing industry; The excellent properties of fused quartz also make it widely used in metallurgy, food, pharmaceutical and papermaking industries. The quartz stone (sand) exported is mostly used in metallurgy and refractory industry.
Quartz tube, gray quartz tube, black quartz tube, blue quartz tube, also produces UV filter quartz tube, transparent quartz tube, quartz rod and other quartz products.
Quartz sand has unique physical and chemical properties, so that IT in aviation, aerospace, electronics, machinery and today's rapid development of IT industry occupies a pivotal position, especially its internal molecular chain structure, crystal shape and lattice change law, So that it has high temperature resistance, thermal expansion coefficient is small, high insulation, corrosion resistance, piezoelectric effect, resonance effect and its unique optical characteristics, in many high-tech products are playing an increasingly important role.
The main raw materials of glass plate glass, float glass, glass products (glass jars, glass bottles, glass tubes, etc.), optical glass, glass fiber, glass instruments, conductive glass, glass cloth and special anti-ray glass.
Ceramic and refractory porcelain embryo and glaze, kiln with high silicon brick, ordinary silicon brick and silicon carbide raw materials; Metallurgical silicon metal, ferrosilicon alloy and silicon aluminum alloy raw materials or additives flux concrete, cementitious materials, road materials, artificial marble, cement physical performance test materials (i.e., cement standard sand), etc.
Main raw materials, abrasive materials (sandblasting, hard abrasive paper, sandpaper, emery cloth, etc.), sand cleaning, rust removal, removal of oxide skin treatment electronic high purity silicon metal, communication fiber and other rubber, plastic filler (can improve wear resistance). Coating filler can improve the weatherability of coating. The next is: Applied in casting, forging, machinery, metallurgy, heat treatment, steel structure, grid structure, container, ship, repair, bridge, mine, and other fields of sand cleaning, rust removal, strengthening, forming, stress elimination and various profile surface cleaning and coating, roughness before electroplating (hair) pretreatment, stone cutting, magnetic ball casting, as the addition of heavy concrete and blast furnace refractory materials Agent to increase its wear resistance, high temperature resistance, anti-erosion, electrostatic shielding, anti-radiation, oil well filter tank, counterweight and so on. Granite, marble surface treatment using high quality quartz sand as raw material specially designed and produced lawn products for sports venues, with high hardness, significant, uniform particle size, small corners, natural color and other characteristics, small damage to artificial turf, the formation of the protection of grass hair role, make the lawn more durable. It has been used in many colleges and universities in China. Quartz sand is the ideal material for artificial venues such as modern track and field, football field and golf course.
Water treatment filter material
Because the size of the quartz sand of the three-layer filter material filter bed is smaller than the quartz sand of the double-layer filter material, and there is a layer of heavier anthracite filter material under the quartz sand layer, so in other conditions are the same, and even some high filtration speed, the water quality of the three-layer filter material filter is better than the water quality of the double-layer filter material filter. When using quartz sand, try to cooperate with the use.
Most of our country sewage treatment plant implements primary B standard in the "standards of pollutants discharge of urban sewage treatment plant", while the implementation of Primary A standard can greatly limit the sewage "removal of phosphorus and nitrogen", reduce the pollution of subsequent received water bodies, and the effluent can be used as a reuse water to solve the problem of water resources shortage in part of our country.
Quartz sand filter
The tail water of the sewage plant enters the bottom of the filter through the water inlet pipe, and passes through the filter material layer from top to bottom after being evenly distributed by the water distributor. In the process, the tailwater is filtered to remove contaminants from the water. At the same time, the content of pollutants in quartz sand filter material increases, and the degree of pollutants in the lower filter material layer is higher than the upper filter material. At this time, open the air lifting pump located in the center of the filter, and lift the lower quartz sand filter material to the sand washing device at the top of the filter for cleaning. The filter sand is returned to the filter bed after cleaning, and the pollutants produced by cleaning are discharged.
Quartz sand filter material in the lifting pump under the action of top-down movement, the tail water plays a stirring role. Filter material in the filter can be cleaned in time, strong anti-pollutant load impact ability. Quartz sand filter special internal structure and its own operating characteristics, so that coagulation, clarification, filtration can be completed in the same pool body.
Technical characteristics of quartz sand filter
(1) The quartz sand filter material layer is thicker, the filter is deeper, and the civil construction cost is higher.
(2) High filtration efficiency, good filtration effect, no need to stop backwash, low operating cost.
(3) High head loss, usually need to set up a secondary lifting pump room, increase the operating cost.
(4) The active sand filter can flexibly increase or decrease the number of filters according to the change of water quantity, which is mainly suitable for small-scale sewage treatment plants.
Active sand filter is a kind of continuous filtration equipment integrating flocculation, clarification and filtration, widely used in drinking water, industrial water, sewage advanced treatment and reclaimed water treatment fields. The system adopts the upflow flow bed filtration principle and a single homogeneous filter material, filtering and sand washing at the same time, can be 24 hours continuous automatic operation, clever sand extraction and sand washing structure instead of the traditional high-power backwashing system, very low energy consumption.
Therefore, upgrading the urban sewage treatment plant is the requirement of water environmental protection, but also the requirements of energy conservation and emission reduction put forward by the state.
Quartz sand filter material is made of natural quartz ore as raw material, processed by crushing and washing fine screen. It is the most widely used and the largest water purification material in the water treatment industry. It has no impurities, pressure and wear resistance, high mechanical strength, stable chemical performance, strong intercepting capacity, high efficiency, long service cycle, and is suitable for single and double layer filter, filter and ion exchanger. All the indicators reached the (CJ/T43-2005) standard.
Quartz sand filter material: mainly used in sewage treatment, with three or five years is no problem, as long as to prevent the loss of quartz sand on the line, it does not matter if it is polluted, because in sewage treatment, sludge can be aerobic or anaerobic respiration, the pollutants in sewage degradation.
Common specifications: 0.5-1.0mm, 0.6-1.2mm, 1-2mm, 2-4mm, 4-8mm, 8-16mm, 16-32mm.
Physical and chemical analysis of refined quartz sand filter material:
Solubility of hydrochloric acid
Strong acid resistance
Good alkali resistance
Other metal content
Do not exceed national drinking water standards
The raw material grade of quartz sand in industry is getting lower and lower. In order to meet the needs of industry, the grade can be improved by beneficiation process. There are mainly the following purification methods:
1. Scrub and remove mud
Scrubbing refers to the use of mechanical force and the grinding and stripping force between sand particles to remove the film iron, bonded and mud impurity minerals on the surface of quartz sand and further wipe the mineral aggregate that has not become a monomer, and then achieve the effect of further purification of quartz sand through the classification operation. Nowadays there are mainly rod friction washing and mechanical scrubbing. The main factors affecting the scrubbing effect are the structural characteristics and configuration of the scrubbing machine; Secondary factors for scrubbing time, scrubbing concentration (scrubbing concentration generally to 50% - 60% is appropriate). The main methods include mechanical scrubbing, rod friction scrubbing, high efficiency and ultrasonic scrubbing.
2. Magnetic separation
Magnetic separation is mainly used to remove magnetic minerals in quartz sand, such as hematite, limonite, biotite and other weak magnetic minerals can be removed by strong magnetic machine, and strong magnetic minerals such as magnetite can be removed by weak magnetic separator.
Flotation is used to remove impurities such as feldspar and mica in quartz sand that can not be removed by magnetic separation to further improve its purity.
4. Acid leaching
Acid leaching is to make use of quartz insoluble in acid (except HF acid), and other impurities can be dissolved by acid solution characteristics, can achieve further purification of quartz.
5. Microbial leaching
It refers to the use of microbial leaching quartz sand particles surface of the film iron or impregnated iron, which is a newly developed iron removal technology.
1. Large stone material enters the warehouse
2, choose rough break
3, select fine break
4, sand machine vibration screening
5. Finished sand is washed by the sand washing machine
6, dryer drying or natural airing