Flue gas desulphurisation gypsum-based hydraulic binder - contg. metallurgical by-products and opt. lime

摘要

A hydraulic binder based on flue gas desulphurisation gypsum and metallurgical by-prods. (mainly blast furnace slag, foundry sand or steelworks slag) in ground form is claimed. The binder is produced by (i) mixing at the site of use; (ii) mixing and drying in processing equipment, opt. with addn. of fine white lime, hydrated white lime or hydrated dolomitic lime; or (iii) mixing and drying, together with fine white lime, in mixer units. The metallurgical by-products may be added at a subsequent or later stage to flue gas desulphurisation gypsum treated as in (ii) or (iii). USE/ADVANTAGE - The binder is useful as an underground construction material and for binding prods. for disposal. The moist flue gas desulphurisation gypsum is dried by heating and/or lime addn. such that its crystalline structure is not altered. The binder is pourable and can be used to form mortars and concretes with high compressive and tensile bending strengths.