Any of the Portland cement clinker, 20-50% volcanic ash mixed materials (such as volcanic ash, tuff, pumice, zeolite, diatomaceous earth, fly ash, burnt clay, burnt shale, coal gangue, etc.), appropriate amount of gypsum A mixture of ground hydraulic cementitious materials, called pozzolanic Portland cement, referred to as volcanic ash cement, code P·P. According to the Chinese standard, the amount of volcanic ash mixed material in cement is 20-50% by weight; granulated blast furnace slag which does not exceed 1/3 of the total blending amount of mixed materials is allowed to be replaced, instead of some volcanic ash mixed materials, after replacement The volcanic ash mixture in the cement shall not be less than 20%. Volcanic ash cement is divided into five numbers 275, 325, 425, 525 and 625. Compared with ordinary cement, volcanic ash cement has a small specific gravity, low hydration heat, good corrosion resistance, water requirement (the amount of water required to make the cement slurry reach a certain degree of fluidity) and dry shrinkage, and frost resistance is higher. Poor, early strength is low, but late strength development is faster, environmental conditions have a significant impact on the hydration and strength development of volcanic ash cement, and the humid environment is conducive to the development of cement strength. Volcanic ash cement is generally suitable for concrete works in underground, water and humid environments, and should not be used in dry environments, freeze-thaw cycles, dry-wet cycles, and projects requiring high early strength.
SIC
Emery, also known as Silicon Carbide (SiC), is produced by high-temperature smelting of resistance furnaces using quartz sand, petroleum coke (or coal coke), and sawdust (need to add salt when green silicon carbide is produced). Silicon carbide also has a rare mineral, Moissanite, in nature. Silicon carbide is also called Carbon silica. Among the non-oxide high-tech refractory raw materials such as C, N, B, etc., silicon carbide is the most widely used and the most economical one, and it can be called gold grit or refractory sand. At present, China's industrial production of silicon carbide is divided into two types of Black Silicon Carbide and green silicon carbide, are hexagonal crystals, the specific gravity of 3.20 ~ 3.25, the microhardness of 2840 ~ 3320kg/mm2.
Silicon carbide has two common basic varieties of black silicon carbide and green silicon carbide, both of which are α-SiC. 1 Black silicon carbide contains about 95% of SiC. Its toughness is higher than that of green silicon carbide. It is mostly used for processing low tensile strength materials such as glass, ceramics, stone, refractory materials, cast iron and non-ferrous metals. 2 Green silicon carbide contains more than 97% SiC, self-sharpening, mostly used for processing hard alloys, titanium alloys and optical glass, also used for honing cylinder liners and grinding high-speed steel cutters. In addition, there is cubic silicon carbide, which is a yellow-green crystal made by a special process, used for the production of abrasives for bearing superfinishing, surface roughness can be processed from Ra32 ~ 0.16 microns to Ra0.04 ~ 0.02 micron.
Silicon Carbide
Silicon Carbide,Black Silicon Carbide,Silicon Carbide For Abrasives,High Purity Silicon Carbide
Hwa Seng Resources (Hong Kong) Co., Limited , http://www.hwaseng-resources.com