부생 인산석고(燐酸石膏)에 관한 연구 = Studies on By-produced phosphogypsum - Preparation of high-strength calcined gypsum by hydrotherrnal treatment -

다국어 초록 (Multilingual Abstract)

This study is to make high strength calcined gypsum from by-produced phosphogypsum of wet phosphoric acid process.
By-produced phosphogypsum was autoclaved under various vapor pressures and stirring rates.
Results of the present experiment are followings: a) Optimum conditions for good wet tensile-strength to autoclaving sample only are 0.5-3 hr, treatment under 1㎏/㎠ pressure. b) Optimum conditions for good wet tensile-strength to autoclaving sample-water slurry are 0.5-4 hr. treatment under l ㎏/㎠ pressure. c) In case of autoclaving sarnple added reagents optimum conditions are 1 hr. under ㎏/㎠ pressure with 90 ml of 0.5-1.0% Al₂ (SO₄)₃ solution and 23 hr. under ㎏/㎠ with 30 ml of 0. 1 N NaOH solution. d) Wet-tensile strengths of calcined phosphogypsum prepared by those described conditions are higher than K.S. special grade value and normal consistencies meet to K.S. value, but setting times are faster than K.S. value. e) Desirable crystal forms of calcined phosphogypsums with high strength are rod-like and board-like forms.