METHOD FOR PRODUCTION OF BROWN FERROUS-CONTAINING PIGMENT Russian patent published in 1996 - IPC

FIELD: production of paint and varnish. SUBSTANCE: finely dispersed slime of open-hearth furnace and electrosteel mills is affected by hydrothermal treatment within 1.-1.5 h at 60-80 C. The process is carried out in mixture with calcium dihydrophosphate, ratio of said ingredients being 1: (0.05-0.08). The process is followed by washing thus prepared product against water-soluble compounds and by its heat treatment at 150-350 C. Calcium phosphate is prepared by interaction of 50-65 % orthophosphoric acid and waste of marble dust, their ratio being (3.0-6.0):1. EFFECT: improves efficiency of method. 2 cl, 2 tbl