METHOD OF GOLD POWDER PREPARING Russian patent published in 1995 - IPC

FIELD: chemical technology. SUBSTANCE: method involves chemical precipitation of powder gold from aqueous solution of goldhydrochloric acid. Reaction mixture is prepared by addition of surface-active substance, oxalic acid or its alkaline salts, goldhydrochloric acid and octyl alcohol to solution. Powder is precipitated at heating and stirring, powder is separated by decantation, washed and dried. Carboxymethylcellulose sodium salt at concentration 0.004-0.01 of gold mass is used as surface-active substance. Before addition of oxalic acid or its alkaline salts polyacrylamide at concentration 0.0008-0.015 of gold mass is added to reaction mixture additionally. Then goldhydrochloric acid is added and hydrazine hydrochloride at concentration 0.10-0.16 of gold mass is added additionally. Method ensures to increase process reproducibility at retained particle size (2.5 mcm, not above) and filling density 3,5-6,0 g/cm³.. EFFECT: improved method of gold powder preparing. 1 tbl