矿石中微量Au的测定,常用甲基异丁酮(MIBK)富集,原子吸收法在有机相中测定。但喷雾有机相读数不稳定及MIBK有较强的刺激性。本文提出在MIBK萃取的基础上,用硫脲反萃取,在水相中测定Au。试验表明:萃取时盐酸、磷酸浓度分别低于20％和1.8N时,对硫脲反萃取均无影响;硫脲浓度在5～50mg/ml能完全反萃取,同时应考虑“粘度”, Determination of trace Au in ore, commonly used methyl isobutyl ketone (MIBK) enrichment, atomic absorption method in the organic phase determination. But the spray organic reading unstable and MIBK strong irritant. In this paper, based on the extraction of MIBK, thiourea back extraction was used to determine Au in the aqueous phase. The results showed that when the concentrations of hydrochloric acid and phosphoric acid were less than 20% and 1.8N, respectively, no effect was found on the back extraction of thiourea. The concentration of thiourea at 5 ~ 50mg / ml could be fully stripped and the “viscosity”