USES OF GYPSUM

USES OF GYPSUM

·        Wallboard − The use of gypsum-based wallboard, once common only in the US and Canada, has spread to virtually all developed countries. The gypsum core provides a strong, fire-resistant, and inexpensive construction material. The -100 mesh stucco (hemihydrate) form is used. Japan is the largest user of synthetic gypsum products in wallboard, because it lacks natural gypsum resources. The other major source of synthetic (FGD-based) product for this market is Germany, which serves all of Europe. Most of current US wallboard production is based on natural sources.

·        Portland cement − Uncalcined gypsum crushed to -11/2 +3/8 inch is used with portland cement to retard the setting time of concrete. This is the primary market in developing countries.

·        Soil conditioners − Gypsum rock ground to -100 mesh is used in treating alkaline, saline, and clayey soils, and as a source of sulfur. In the US its main application is in the cultivation of peanuts.

·        Other uses − The hemihydrate form is used in a wide variety of construction and industrial plasters. Minor amounts of purified gypsum are used in glassmaking and as a white filler (terra alba) in paint and paper. “Soluble anhydrite”, made by dehydrating gypsum into porous, highly absorbent granules, is used as a desiccant