METHOD OF PREPARING IRON-CONTAINING PIGMENT Russian patent published in 2010 - IPC C09C1/24 

FIELD: chemistry.

SUBSTANCE: to obtain an iron-containing pigment, aqueous solutions of sodium or ammonium carbonate and magnesium chloride or sulphate are first mixed in equimolar ratio. A magnesium carbonate pulp is obtained and settled. After that the clear portion is decanted and washed 2-3 times with water in volume ratio pulp : water=1:(2-3), each time decanting the clear portion. Iron (III) sulphate solution is then added to the magnesium carbonate pulp. The obtained residue of iron hydroxides or hydroxocarbonates is filtered off, washed with water, dried and annealed.

EFFECT: invention increases output when preparing a pigment owing to 2-3 times faster filtration of the iron-containing residue.

2 tbl, 2 ex