Activation of anhydrate phosphogypsum by K₂SO₄ and hemihydrate gypsum

Abstract

Lime pretreated phosphogypsum(PG) was calcined at 500 °C to produce anhydrate gypsum cement. Due to the slow hydration of anhydrate gypsum, additives, K₂SO₄ and hemihydrate gypsum were selected to accelerate the hydration of anhydrate. The hydration characteristics, the resistance to hydrodynamic water, and the mineralogical studies were investigated. The experimental results suggest that activated by K₂SO₄ and hemihydrate, anhydrate PG hydrates much more rapidly than that in the presence of only K₂SO₄ or in the absence of additives. The binder has proper setting time, good strength development, and relatively better resistance to water. The hardened binder has hydrated products of rod or stick like shaped dihydrate gypsum crystals.

Keywords

activation / anhydrate phosphogypsum / hemihydrate gypsum / hydration

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