METHOD OF RED IRON-OXIDE PIGMENT PRODUCING Russian patent published in 1998 - IPC

FIELD: paint and varnish materials, plastics, chemical fibers. SUBSTANCE: method involves isolation of iron-oxidizing bacteria from shaft waters containing iron (II) at pH 1.5-3.5. Shaft waters are passed through reactor filled with inert fiber. Bacterium amount is 10⁹- 10¹⁰ cells/1 g inert fiber. Air is bubbled through reactor at 15-50 C at amount P/min where P - reactor volume. Obtained ferric hydroxide (III) is subjected for thermic treatment in autoclave at 180-260 C or in air at 500-1000 C. Pigment is washed out, dried and ground. Pigment has color from orange to cherry-brown, its covering power is 4-8 g/m², dispersity is 15-20 mcm, oil absorption is 20-25 g/100 g pigment. Coloring agent is used for pigmenting paint and varnish substances, luminophores, plastics, chemical fibers. EFFECT: improved method of pigment making. 3 cl, 2 tbl