Synthetic gypsum

Synthetic gypsum is a term used to describe a number of gypsum based products than can be used as a alternative to or in conjunction with natural gypsum.

There are a number of different processes involved with the production of synthetic gyspum and different terms to decribe these;

• Flue Gas Desulphurisation (FGD) gypsum is a by-product of the wet purification procedure with natural lime, formed in scrubbing towers of power plants, a extremely sped up process, similar to that of forming natural Gypsum. The SO2 is washed out by water, oxidised to Sulphates SO3 in an aqueous solution, calcium from quicklime precipitates into a purer form (than natural) of gypsum, Dihydrous Calcium Sulphate (CaSO4,2H2O). It is the most common process to create synthetic gypsum.
• Phosphogypsum, is based on reaction with phosphoric acid, a commodity chemical used in the production of fertilisers and detergents which also produces Calcium Sulphate, which can be separated filtration. It can be problematic in terms of crystal shape, quality and riskss of natural radioactivity,
• Titanogypsum, half the production of Titanium Dioxide (a mass produced white pigment) comes from a sulphate, (the other by a chloride) process, of around half produces a white gypsum which can be used.
• Citrogypsum, is a by product in the processing of citric acid, normally blueish in colour by can be purified.
• Fluoroanhydrite, calcium sulphate can form in the production of hydrofluoric acid from heated fluorspar or fluorite with Sulphuric Acid in dry conditions.
• Other synthesised gypsums have potential to be formed by processes with a by-product of sulphuric acid, whilst similar to citrogypsum and citric acid, tartaric, lactic, formic and oxalic acid also produce gypsum.

In 2007 the European gypsum industry organisation (EuroGypsum) stated that;

"Natural Gypsum will continue to cover the basic raw material needs of the Gypsum industry, followed by FGD Gypsum. The most important potential of other synthetic Gypsums than FGD Gypsum lies in the use of purified Phosphogypsum. Next to that is some potential in the use of purified Titanogypsum. In the past, both the Phosphoric Acid and the Titanium Dioxide industries have shown a systematic close down of production facilities in Europe. Investments in either the purification of the produced Gypsums, or in finding applications for the Gypsums produced, may be essential for the future viability of these sites."

[edit] Related articles on Designing Buildings

• Aggregate.
• Coal ash.
• Construction materials.
• Drywall construction.
• Flue Gas Desulphurisation gypsum (FGD)
• Lime plaster.
• Minerals of local and national importance.
• Permission for mining or working of minerals.
• Plaster.
• Natural gypsum.
• Types of materials