Flue gas desulphurisation gypsum (FGD)
Flue Gas Desulphurisation (FGD) gypsum is a type of synthetic gypsum that can be used to supplement the supply of natural gypsum, it can be 96% pure which is higher than most natural gypsums at 80%, so can be used in gypsum blends.
It is a by-product of a wet purification procedure with natural lime, formed in scrubbing towers of power plants. It forms in the same process as natural gypsum only one that is extremely accelerated down to a few hours. 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 and an important supplement to natural gypsum, although it is a by product is is also reliant on the firing of coal powered energy centres. Other synthetic gypsums are phosphogypsum, titanogypsum, citrogypsum, fluoroanhydrite, as well as other processes.
[edit] Related articles on Designing Buildings
Featured articles
Check out some of the best features and news from Designing Buildings as well as key stories from around the web.
Undervaluing our industrial past
Heritage value changes as taste for building styles changes.
Changing expectations around competence and compliance
New information sheet from CIAT.
Grenfell investigation files passed to CPS
Angela Rayner apologises on behalf of the British state.
Electrical contractors need to understand the practical implications.
The real barrier to getting more value from digital technology.
Your guide to The Construction Reset at UKCW Birmingham.
Accommodating the Victorian and Edwardian working woman. Book review.
Rethinking passive fire protection in design
PFP demands the same level of design rigour as structure or services.
38% of Gen Zs feel safe when a fire door is wedged open.
Stunning images from around the world
Shortlist for CIOB’s Art of Building photography competition.
Guidance for conversion of traditional pre-1919 stone buildings.
Industrial heritage in the Ruhr
A marked difference to the fate of industrial landscapes in the UK.