• The raw material gypsum is sorted and washed with water for removal of sand and other impurities. The lumps thus obtained are then dried and powdered in pulverizer. The dried gypsum powder is calcined in a rotary drumcalciner using light diesel oil as fuel. The low pressure burner is used for calcination at a temperature of 160ºC to 180ºC.

•  The process of calcination is done over a period of about 2 hours, so that one and half molecules of water is removed to convert the gypsum into plaster of paris. After cooling the product (plaster of paris) is further pulverised to a fineness of 150 mesh and packed in air tight polythene lined gunny bags to avoid the plaster of paris from absorption of moisture.

• Calcium sulfate hemihydrate has been used for many years and is still used extensively in both industrial and consumer areas.

• Plaster of paris is extensively used in ceramic industry for the preparation of models, moulds and plaster of toys.

• It is also used as a main raw material in the manufacture of toys and statues, chalk crayons, gypsum plaster boards, decorative picture frames, besides a wide range of applications in the interior decoration of buildings

• Plaster of Paris is ideal for hobby molding , casting, making forms, patterns & sculptured figures

Safety Issues

• Rubber gloves and eye protection are recommended. Prolonged contact with skin should be avoided. During cure, product may develop enough heat to cause burns if a large mass is permitted to harden in contact with skin

• Plaster of Paris is of course used for setting fractured bones but in such cases it is never put in direct contact with the skin. In addition, it is used in relatively thin layers so the heat can dissipate.

• Ensure that Plaster of Paris is not mixed by hand .Pupils should be warned to avoid skin contact when using Plaster of Paris. Risk assessments must be followed and safety data sheets held for all Plaster of Paris.

• There is a growing industrial activity in the field of white ware, such as pottery, sanitary ware, chemical and electrical porcelains, requiring large quantities of plaster of Paris for making moulds and preparation of moulds. The demand for the product is ever increasing. There is also considerable demand for the plaster of Paris arising from a large number of shops and establishments engaged in making statues and interior decoration as well as decorative plaster boards for false ceiling etc., which is in turn creating a good scope for setting up new units.

• Plaster of Paris, first introduced hydrous calcium sulphate or gypsum to the U.S. market. By the early 1900s, the gypsum business in North America was fragmented into many regional markets. In 1902, 30 independent gypsum rock and plaster manufacturing companies combined to form the United States Gypsum Company, which would later be known as USG Corp. Fast forward to 2006 and USG produced $5.8 billion in sales and approximately $950 million in adjusted operating income – new company records.