What Is Gypsum Cement?

An insoluble anhydrous gypsum obtained after calcining dihydrate gypsum at a temperature of 600 to 800 ° C is added to an appropriate amount of catalyst, such as lime, shale ash, granulated blast furnace slag, sodium sulfate, sodium sulfate, etc. An air-hardening cementitious material, called anhydrous gypsum cement. It has high strength and can be used in the preparation of building mortar, thermal insulation concrete, plastering, manufacturing of gypsum products and gypsum boards.

Anhydrous gypsum cement is a kind of air-hardening cement. It is obtained by grinding anhydrous gypsum (anhydrite) with a small amount of various mineral admixtures as a coal contact agent. Anhydrous gypsum cement can be produced by baking dihydrate gypsum at 500-700 .

1. Anhydrous gypsum: There is no special requirement for its crystal shape and crystal porosity, and it does not need to be pulverized too much. Generally, it can be used with a particle size of less than 1 mm. But the best average particle size is 10-70 microns, and the Blaine value should be 8500-3000 cm3 / g.

2. Portland cement: commercial products can be used directly, but the effect will be better if it can be further crushed. The ratio of the amount of cement to anhydrous gypsum is 20 ~ 80: 80 ~ 20.

3. Accelerator: Using potassium sulfate as a coagulant can promote the hydration and coagulation speed of anhydrous gypsum.

The raw material was charged into a regulating tank with a stirrer together with water to prepare a slurry. Then use a bucket pump to inject the slurry onto the surface of local commercial materials such as cement board, foamed concrete mortar board, etc. that have been coated with polymer latex in advance, so that it flows naturally to form a horizontal floor. At this time, even if the amount of water mixed in is small, the slurry easily flows. And when left for a long time, the cement,

Boiler slag or granular blast furnace slag, sawn and planed layers, tanning materials, needle leaves, and tuff, opalite, diatomite, pumice stone, and some other materials are used as aggregates on the insulation coagulation prepared with anhydrous gypsum cement. Insulating concrete blocks made from anhydrous gypsum cement have many excellent qualities. The slag insulation concrete block has frost resistance and water resistance, and can be well bonded with mortar and plaster. Its characteristics are: porous, low weight, low heat transfer, strong fire resistance and weather resistance, and easy to transport. This kind of block is used to build this block. The built wall is dry and lighter than a brick wall, and it is more economical.

The strength and weather resistance of sawn-layer insulation concrete blocks are worse than those of slag insulation concrete blocks. Therefore, it can be used as the primary wall material for single-story buildings, and can only be used as a secondary wall material for multi-story building projects. The slag heat-insulating concrete specimens rich in components (1: 0.25 ~ 1: 3) did not break even when immersed in cold water under the hot condition. The poorer composition (1: 4 ~ 1: 6) of the test body is not damaged to a great extent under the direct influence of the flame (more than 1.5 cm in the end). It can be seen that the slag insulation concrete is very safe in terms of fire prevention. ^[2]