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 and news
Designing Buildings reaches 20,000 articles
We take a look back at some of the stranger contributions.
Lessons learned from other industries.
The Buildings of the Malting Industry. Book review.
Conserving places with climate resilience in mind.
Combating burnout.
The 5 elements of seiri, seiton, seiso, seiketsu and shitsuke.
Shading for housing, a design guide
A look back at embedding a new culture of shading.
The Architectural Technology Awards
The AT Awards 2025 are open for entries!
ECA Blueprint for Electrification
The 'mosaic of interconnected challenges' and how to deliver the UK’s Transition to Clean Power.
Grenfell Tower Principal Contractor Award notice
Tower repair and maintenance contractor announced as demolition contractor.
Passivhaus social homes benefit from heat pump service
Sixteen new homes designed and built to achieve Passivhaus constructed in Dumfries & Galloway.
CABE Publishes Results of 2025 Building Control Survey
Concern over lack of understanding of how roles have changed since the introduction of the BSA 2022.
British Architectural Sculpture 1851-1951
A rich heritage of decorative and figurative sculpture. Book review.
A programme to tackle the lack of diversity.