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Gypsum and Water
At 25°C, a litre of water saturated with calcium sulphate contains 1.45g of sulphate (SO42-) and 0.65g of calcium (Ca2+). When the water is saturated, an addition of calcium sulphate will not change the concentration of sulphate. This concentration can only increase if another sulphate (e.g. Magnesium sulphate) is added into the water. An example is seawater, which contains 2.65g of sulphate.The concentration of sulphate in groundwater highly depends on the nature of the natural ground: in gypsum areas groundwater may be saturated (1.45g of sulphate per litre) and in this case the addition of gypsum will not change the sulphate concentration.
Understanding the Management of Indoor Moulds
Even though moulds are a fact of the day-to-day life, mould growth can be eliminated by preventing the conditions which allows the spores (seeds) to develop into moulds and by taking sensible prevention measures detailed in this document. Basically, the key to mould is to control moisture impeding the mould’s spores to come inside the building.
Why is Gypsum so effective in Fire?
Gypsum plasters and plasterboards provide good fire protection in buildings due to the unique behaviour of gypsum when exposed to fire. Pure gypsum (CaSO4.2H2O) contains nearly 21% chemically combined water of crystallisation, and about 79% calcium sulphate, which is inert below a temperature of 1200°C.
What is Gypsum?
The mineral Gypsum precipitated some 100 to 200 million years ago when sea water evaporated. From a chemical point of view it is Calcium Sulphate Dihydrate (CaSO4,2H2O) deposited in sedimentary layers on the sea bed. Under high pressure and temperature Gypsum turns into Anhydrite (CaSO4).
Calcium Sulphate and its Release into Soil and Groundwater
Gypsum is a rock like mineral commonly found in the earth’s crust, extracted, processed and used by Man in construction or decoration in the form of plaster and alabaster since 9000 B.C. The facts show that calcium sulphate is a substance with no adverse health and environmental effects.
FGD Gypsum: Quality Criteria and Analysis Method
FGD Gypsum quality criteria parameters are determined in accordance with VGB Instruction Sheet "Analysis of FGDP Gypsum".
FGD Gypsum quality shall be such that it can be used for for the production of gypsum-based products which are equivalent to those made from natural gypsum.