Yuan Lei's Little Knowledge | Seven Technological Characteristics of Talcum Powder
The main component of talc is talc water-containing magnesium silicate, molecular formula Mg3[Si4O10](OH)2. Colorless transparent or white, but with a small amount of impurities and light green, light yellow, light brown or even light red; cleavage surface was pearl luster. Hardness 1, specific gravity 2.7~2.8. In addition to soft, smooth talc has the following process characteristics:
Talc itself is not conductive, when the talc does not contain conductive minerals, its insulation performance is good. Talc as raw material made of talcum porcelain, with a high degree of insulation. When the temperature rises, the dielectric loss of the block talc porcelain is lower and slower than that of ordinary electric porcelain.
Talc is not only heat resistant and thermally conductive, refractoriness as high as 1490-1510 ℃. Talc after calcination, its mechanical strength and hardness increased, but the shrinkage rate is very low, the expansion rate is also very small, is a kind of high temperature mineral.
Talc is generally ineffective with strong acids and bases. Only 2%-6% is dissolved in boiling 1% hexachloroethane. Talc powder is mixed with other substances at a high temperature of 400°C and does not change chemically.
Talc powder oil absorption and hiding power, its grease, pigments, chemicals and impurities in the solution have great adsorption capacity.
Ultrafine grinding talcum powder, because of its good dispersion, large surface area, coated on the surface of the object to cover a large area, can form a layer of uniform fire, weatherproof film. Because of its characteristics, it is widely used in the pharmaceutical, paint, paint, linoleum industry.
Talc is soft, with a smooth feeling, the coefficient of friction in the lubricating medium is less than 0.1, is an excellent lubricating material. With the increase of talc content, the lubrication performance of slip rock is also enhanced, and vice versa.
If the talc is gradually heated to 1100 ℃ for about two hours and then slowly cooled, its appearance is unchanged, but the hardness is greatly increased, mainly because the talc has been transformed into oblique enstatite. The manufacture of blocks of talcum porcelain is to take advantage of this property.
With talc or talcum powder plus adhesive, the use of semi-dry pressing method, wet pressing method, extrusion method or plastic method for processing molding, product performance unchanged. Using this feature, it is possible to manufacture products of various shapes required by people, thereby expanding the application field of talc.
Characteristics, talc, talc, hardness, performance, lubrication, increase, utilization, impurities
The difference between barium sulfate（BaSO4） and barium sulfite（BaSO3）
Kaolin is a non-metallic mineral, which is a kind of clay and clay rock mainly composed of kaolinite clay minerals. Because it is white and delicate, also known as white earth. It is named after Gaoling Village, Jingdezhen, Jiangxi Province.