What are the uses of anthracite ? It is used for filtration and purification of domestic and industrial water supply. When using, determine the use parameters according to the form of the filter. Generally, the paving thickness of the double-layer filtration section is 300-400mm; the normal filtration rate is 10-14m/h, and the forced filtration rate is 14-18m/h; three-layer filter material paving The thickness is 450mm, the normal filtration rate is 18-20m/h, and the forced filtration rate is 20-25m/h. The filter backwash adopts water flushing, steam flushing or supplemented by surface flushing. In addition, anthracite filter material is a filter material for water treatment industry, which is specially selected from deep well minerals and has the highest carbon content percentage. Anthracite filter media are manually sorted to reduce extraneous minerals and reduce ash content, filtered and rinsed to ensure they are suitable for water filtration. Anthracite can reliably improve suspended particle removal due to its better solid retention capacity. How to distinguish the quality of anthracite?
- Color refers to the natural color of the surface of fresh coal, which is the result of coal’s absorption of light waves of different wavelengths. It is brown to black, and generally deepens with the increase of the degree of coalification.
- Gloss refers to the reflective ability of the surface of coal under ordinary light. Generally, it has asphalt , glass and diamond luster. The higher the degree of coalification, the stronger the luster; the more mineral content, the darker the luster; the deeper the degree of wind and oxidation, the darker the luster, until it disappears completely.
- Pink refers to the color of coal ground into powder or the traces left when the coal is scratched on a glazed porcelain plate, so it is also called streak color. Light brown-black. Generally, the higher the degree of coalification, the deeper the pink.
- Specific gravity and bulk density The specific gravity of coal is also called the density of coal, which is the ratio of the weight of a certain volume of coal excluding pores to the weight of water at the same temperature and volume. The bulk density of coal, also known as the weight of coal or pseudo-specific gravity, is the ratio of the weight of a certain volume of coal including pores to the weight of water at the same temperature and volume. The bulk density of coal is an important indicator for calculating coal seam reserves. The bulk density of lignite is generally 1.05 to 1.2, that of bituminous coal is 1.2 to 1.4, and the range of anthracite is large, which can be 1.35 to 1.8. Coal rock composition, degree of coalification, composition and content of minerals in coal are the main factors affecting specific gravity and bulk density. Under the same mineral content, the specific gravity of coal increases with the deepening of coalification.
- Hardness refers to the ability of coal to resist external mechanical action. According to the different modes of action of external mechanical force, the hardness of coal can be further divided into three categories: scratch hardness, indentation hardness and anti-wear hardness. The hardness of coal is related to the degree of coalification. The hardness of lignite and coking coal is the smallest, about 2 to 2.5; the hardness of anthracite is the largest, close to 4.
- Brittleness is the degree to which coal is broken by external force. The raw material of coal formation, the composition of coal rock, and the degree of coalification all have an impact on the brittleness of coal. Among the coals with different metamorphisms, the brittleness of long-flame coal and gas coal is smaller, the brittleness of fat coal, coking coal and lean coal is the largest, and the brittleness of anthracite is the smallest.
- Fracture refers to the shape of the cross-section formed after the coal is hit by external force. Common fractures in coal include conchoidal fractures and staggered fractures. The original material composition and coalification degree of coal are different, and the fracture shape is different.
- Conductivity refers to the ability of coal to conduct electric current, usually expressed in resistivity. Lignite has low resistivity. When the lignite coal transitions to bituminous coal, the resistivity increases sharply. Bituminous coal is a poor conductor. As the degree of coalification increases, the resistivity decreases, and it drops sharply when it reaches anthracite, but it has good electrical conductivity.