Calcium sulfate with the chemical formula CaSO4 is a white mineral that is insoluble in water. Anhydrous calcium sulfate is used for drying. Its hydrated type is the cause of water hardness and appears in various forms such as gypsum and anhydrite.
This substance is both available in nature and can be produced in the laboratory.
Physical and chemical properties:
Calcium sulfate appears as an odorless, white, or colorless crystalline salt. The crystals of this mineral compound are sometimes blue, gray, or red or can be brick red.
This compound is stable at room temperature and is one of the most common sulfates used in industry.
The most important physical and chemical properties of this compound can be summarized in the following table:
|Molar mass||136.14 g/mol (anhydrous)|
145.15 g/mol (hemihydrate)
172.172 g/mol (dihydrate)
|Density||2.96 g/cm3 (anhydrous)|
2.32 g/cm3 (dihydrate)
|Melting Point||1,460 °C (2,660 °F; 1,730 K) (anhydrous)|
|Solubility in water||0.26 g/100ml at 25 °C (dihydrate)|
|Solubility||Insoluble in ethanol|
|vapor pressure||0 mm Hg (approx)|
|Color||White with blue, gray or reddish tinge, or brick red|
|Other names||Drierite, Anhydrous gypsum|
|Chemical Structure Depiction|
Formula and structure of Calcium sulfate:
The chemical formula of calcium sulfate is CaSO4. It is composed of calcium cation and sulfate anion, which form an orthorhombic or monoclinic structure. Calcium sulfate has three hydrated forms: anhydrous, dehydrated, and hemi-hydrated.
Solubility of different forms of calcium sulfate:
The physical properties of the three forms of calcium sulfate are different, but their chemical properties are the same. Calcium sulfate is insoluble in water without water, but both dehydrate and hemi-hydrate are slightly soluble in water.
Production and synthesis of calcium sulfate:
The main sources of calcium sulfate are gypsum and anhydrite, which are mined. In addition to natural resources, this material is obtained as a by-product in the production of several products.
As a by-product in the production of phosphoric acid from phosphate rock, hydrogen fluoride and refining on calcium sulfate precipitate are also obtained.
Calcium sulfate is also a common precipitate in industrial heat exchangers because its solubility decreases with increasing temperature.
Applications and uses of calcium sulfate:
Gypsum is used in the production of molds that contain hard and complex shapes.
This combination is widely used in sculpture and decor.
Calcium sulfate is used in the production of pigments.
This compound is used as an additive agrochemical due to its sufficient calcium and sulfur for plant growth in arable lands.
Used in cement production and as a filler in paper production
This compound is also used as a raw material in the synthesis of other calcium compounds and the production of plaster Paris.
calcium sulfate in food:
Pure calcium sulfate is widely used as a food additive in the food industry. It is a natural source of calcium, a pH regulator, and an anticoagulant, found in many foods such as bread, pasta, and animal foods. like Calcium propionate
Safety information of Calcium sulfate:
- The ingestion of calcium sulfate may cause nausea, vomiting, irritation, abdominal
pain, and diarrhea.
- Skin exposures can cause symptoms ranging from skin irritation, redness or tearing.
- May cause eye irritation.
- Inhalation may irritate the respiratory tract.
- It is not flammable and does not react with other chemical compounds.
- Skin Contact: Immediately flush skin with water.
- Inhalation: move the person to the fresh air.
- Eye Contact: Rinse eyes with water for at least 15-20 minutes.
- Ingestion: Do not induce vomiting. Get medical aid immediately. Call a poison control center.
Packing and storage:
Store in a cool, dry, well-ventilated area away from incompatible substances. Keep containers tightly closed.