PHOSPHOGYPSUM UTILIZATION METHOD Russian patent published in 2003 - IPC

FIELD: manufacture of building materials. SUBSTANCE: phosphogypsum originating as waste from chemical and metallurgical entertainments is utilized in building materials industry as artificial gypsum stone. In the method of invention, crude phosphogypsum is first neutralized with calcium hydroxide and then subjected to filtration compaction applying force ensuring mechanical activation of material, which exceeds strength of initial phosphogypsum crystalline hydrates, ratio of filtrate withdrawal velocity (l/Pa.s) to compaction velocity (l/Pa.s) being 0.3:0.4. Method allows strength of artificial stone to increased at lower power consumption achieved owing to eliminating power-consuming mechanical activation stages and drying of product. Simultaneously, large-scale industrial waste is disposed. Process is completely automated. EFFECT: enhanced process efficiency. 1 tbl