calcium sulfate

Использование

Calcium Sulfate is a general additive available as both calcium sul- fate anhydrous, made by the high-temperature calcining of gypsum which is then ground and separated, and calcium sulfate dihydrate, which is made by grinding and separating gypsum containing about 20% water of crystallization. calcium sulfate anhydrous contains approximately 29% calcium, and calcium sulfate dihydrate contains approximately 23% calcium. it is used, among other things, as a filler and baking powder for standardization purposes; a firming agent in canned potatoes, tomatoes, carrots, lima beans, and pep- pers; in dough as a source of calcium ions (because the absence of calcium ions causes bread dough to be soft and sticky and to pro- duce bread of poor quality); in soft-serve ice cream to produce dry- ness and stiffness; as a calcium ion source for reaction with alginates to form dessert gels; and as a calcium source for food enrichment.

Подготовка

Calcium Sulfate may be prepared by the addition of a soluble calcium salt to a solution of sodium sulfate:
CaCl2＋ Na2SO4→CaSO4＋ 2NaCl
The product is generally a dihydrate although other hydrates are also known. The CAS numbers of these materials are: 7778-18-9 (anhydrite); 10034-76-1 (hemihydrate); 10101-41-4 (dihydrate).

Промышленное использование

Calcium sulfate (CaSO₄?2H₂O) is the common blackboard chalk.