Malononitrile Extraction of Gold from Ores.
Heinen-HJ; Eisele-JA; Scheiner-BJ
NTIS: PB 196 691 :11 pages
Malononitrile [ch2(cn)2], which forms a carbanion in basic solutions, was investigated as a potential leachant for gold and was shown to be an effective extractant in alkaline pulps. Malononitrile was comparable to equal molar quantities of sodium cyanide (nacn) in leaching gold from an oxide ore and yielded 10 to 20 percent higher recovery in leaching a refractory carbonaceous ore, although dissolution was slower with malononitrile than with cyanide. Complete recovery of the gold from the pregnant solutions was achieved by coprecipitation with a lead salt on zinc dust; the leachant was shown to be capable of regeneration and recycling a limited number of times. Addition of an anion-exchange resin to the carbonaceous pulp containing malononitrile increased gold recovery from 67 to 95 percent. Some malononitrile derivatives were also shown to be gold solvents.
IH; Report of Investigations
NTIS Accession No.
NTIS: PB 196 691