METHOD OF PREPARING IRON OXIDE PIGMENTS Russian patent published in 1999 - IPC

FIELD: chemical industry. SUBSTANCE: method comprises separating and washing red slime from alumina production alkali, taking fine red slime fraction of desired size (e.g by means of siphon) from zone where last washer is deposited or packed, and said fraction is filtered. The deposit formed on filter is washed, dried and calcined to give final product such as iron oxide pigment. Method makes it possible to use semiproduct from slime zone of the last (tail) red slime washer rather than uncondensed red slime which is then diluted with water to stabilize operation of hydrocyclones to take off desired fraction of red slime, which does not require using hydrocyclones in the system and dilution of slime with water. EFFECT: more efficient preparation method. 1 dwg