Gray lime powder is a natural limestone primarily composed of CaCO3, which, after high-temperature calcination to form quicklime (CaO), is then refined and partially digested, with the main component being Ca(OH)2. It is then ground into a fine, white powder using a high-speed air-swept hammer mill.
Gray Calcium Powder Applications:
Applications include construction activities like bricklaying and wall painting, but with the increasing recognition and acceptance of calcium sulfate powder, it is widely used in industries such as industrial, agricultural, construction, manufacturing, and food. Specific application industries include: putty powder, latex paint, thermal insulation mortar, architectural coatings, wire and cable, plastic steel windows and doors, and also used in desulfurization of flue gas and wastewater treatment.
Due to the excellent performance of gray calcium carbonate at a lower cost, it has been increasingly used in synthetic resin emulsion paints to meet the new standards, such as GB/T 9756-2001 and GB 18582-2001, at a reduced cost. The container condition, leveling, and hand feel of the paint film are also favorable. Therefore, under the new requirements, gray calcium carbonate still holds value. However, there is still a possibility of the paint film turning yellow when applied over old coatings, so the role of gray calcium carbonate should not be exaggerated and should only be used for medium to low-end interior paints.
Gypsum powder production process:
The traditional lime production process involves layering limestone with fuel (wood) and burning it. Modern methods use machinery, semi-mechanized kilns, and equipment like rotary kilns and fluidized bed boilers for production. The firing time has also been shortened; producing lime with a rotary kiln takes only 2 to 4 hours, which can increase production efficiency by over 5 times compared to vertical kilns. In recent years, energy-saving technologies and equipment like cross-flow, double-inclined slope kilns, oil-fired circular kilns, and short rotary kilns with preheaters have emerged, significantly reducing fuel consumption to include coal, coke, heavy oil, or liquefied gas.
