TH2299U - The chemical alpha plaster manufacturing process uses synthetic gypsum as a raw material. - Google Patents

Abstract

The process of producing chemical alpha-plaster from synthetic gypsum, a byproduct of the citric acid production process, involves preparing a slurry to be fed into an autoclave. Afterward, the slurry is transferred out and filtered to obtain an alpha-plaster cake with a moisture content of approximately 2-20%. The resulting cake is then dried to obtain alpha-plaster powder, which is then fed twice into a grinder to achieve the desired size.

Claims (5)

1. The chemical process of producing alpha-plaster from synthetic gypsum consists of the following steps: 1.1 Slurry preparation, which includes water, synthetic gypsum, and additives such as reactive agents to control alpha-plaster crystallization, mixed in a mixing tank. 1.2 Feeding the slurry into the autoclave in batches or in specified amounts until the desired level is reached, and heating until the slurry temperature meets the specified criteria under a stirring mechanism, then proceeding with the heating process. 1.3 Adding more slurry to the autoclave for a second time until the slurry level in the autoclave reaches the specified high level. 1.4 Continuing the heating process at a specified temperature of approximately 120-130 degrees Celsius under a stirring mechanism. Then, the material is continuously transferred out of the autoclave, but slurry is fed in batches. 1.5 The slurry that has been processed during the startup phase is continuously discharged from the autoclave via a conveyor pipe. Simultaneously, fresh slurry is fed into the autoclave periodically to maintain the slurry level within the high and low ranges. The prepared slurry has a controlled amount of reaction material added, approximately 0-0.1%. 1.6 The slurry containing alpha plaster crystals is discharged from the autoclave through a filter to obtain a cake with a moisture content of approximately 2-20%. 1.7 The cake obtained from filtering is fed into an oven until plaster powder is obtained. The resulting plaster is then ground with a grinder. 2. The process under claim 1, where the resulting slurry consists of approximately 55-65% water by weight, 35-45% synthetic gypsum by weight, and additives such as reaction inhibitors to control alpha-plaster crystallization, at 0-0.2% by weight. 3. The process described in Claim 1 is characterized by the feeding of slurry into the autoclave in approximately 3-6 batches, or 300-600 kilograms of gypsum, per 450-900 kilograms of water. 4. The process described in Claim 1 is characterized by a calcination temperature for alpha plaster crystallization between 120-130 degrees Celsius under a stirring pot, and a calcination duration of 2 hours. 5. The process described in Claim 1 is characterized by 24-29 second slurry feedings, or 2400-2900 kg of gypsum, per 3600-4350 kg of water, and a heating time of 2-4 hours.