Hydration of activated anhydrate phosphogypsum

Abstract

Phosphogypsum(PG) calcined at 500 °C was activated by K₂SO₄ and salt lime with loose structure as seed crystal. To determine the effect of activation, hydration of the anhydrate PG activated was investigated by examination of the setting time, the proportion of hydrated anhydrate PG, the microstructure of the hardenite and the resistance to water. Results show that activated anhydrate PG hydrates much more rapidly than that in the absence of activators. The activated anhydrate PG has proper setting time and hydrated proportion. The resistance to water was greatly improved. SEM photos show that the set activated PG has hydrated products of rod-like and closely connected crystals. The different addition of activator leads to different compact structure.

Keywords

hydration / anhydrate phosphogypsum / activation / K₂SO₄ / seed crystal

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