粗金粉高效湿法提纯研究

Research on High-Efficiency Wet Purification Technology for Coarse Gold Powder

以粗金粉为研究对象,提出“王水溶金-稀释除铅银-氯化铵除钯-还原沉金-EDTA除杂-熔铸”的金粉提纯新工艺。在分析提纯过程机理的基础上,对提纯过程环节进行了研究。结果表明,王水浸金1 h时,金的浸出率已经达到98.85%;稀释比为3时,溶液中Ag含量降至0.14 g/L;当Na2SO4加入量为1.5 g时,溶液中铅含量降至4.5 mg/L,约86.9%的Pb都被除去;还原沉金150 min时,溶液中的金已完全沉淀,随后经50%EDTA除杂和熔铸,Au回收率可达到99.85%,所得金锭满足IC-Au99.95标准。该工艺能明显减少提纯工艺中金的积压,金直收率提高24.7%,生产周期提高了1.925 kg/d,每公斤黄金降低生产成本544.3元,在黄金领域具有广阔的推广价值。

The coarse gold powder is taken as the research object,it is proposed a new process that"gold dissolution by aqua regia-lead and silver removed by dilution-palladium removed by ammonium chloride-reduction of immersion gold-impurities removed by EDTA-fusion casting".Based on the analysis of purification process mechanism,the purification steps are researched.The results show,when gold is immersed in aqua regia for 1h,the gold leaching rate has reached to 98.85%.When the dilution ratio is 3,Ag content in the solution decreases to 0.14 g/L;When the addition amount of Na2SO4 is 1.5 g,the lead content in the solution decreased to 4.5 mg/L,and about 86.9%of Pb is removed.The gold in the solution has been completely precipitated,when the reduction time of immersion gold is 150 min.After the impurities removed by 50%EDTA and fusion casting,Au recovery rate can reach to 99.85%,and the obtained gold ingot can reach IC-Au99.95 standard.This process can significantly reduce the gold backlog,the direct yield rate of gold is increased by 24.7%,the production cycle is increased 1.925 kg/d,and the production cost per kilogram of gold can be reduced by￥544.3,which has a broad promotion value in the field of gold.