直接灰吹法测定金泥中金和银

Determination of Gold and Silver in Gold Mud with Direct Cupellation

通过对铅捕集贵金属原理的研究,首次提出铅覆盖再次富集的概念,建立了高品位金泥中金、银的测定方法。以经典火试金法测得的金银含量为准确值,计算金泥直接灰吹对金银的回收率,探讨了铅箔用量、称样量、灰吹温度和铅箔覆盖方式对金银回收率的影响,获得了高品位金泥直接灰吹的最佳工艺条件。在最佳工艺条件下,对氰化-置换得到的高品位金泥进行直接灰吹法与火试金方法对比实验,结果显示直接灰吹法的分析结果与火试金重量法结果相吻合。金的回收率为99.8%~100%,相对标准偏差(RSD≤0.10%,n=6),银的回收率为99.4%~101%,相对标准偏差(RSD≤0.40%,n=6)。方法操作简便、快捷准确,劳动强度低,有很好的适用性。

Based on the principle of precious metals enrichment by lead trapping,the concept of twice enrichment of gold and silver in gold mud was proposed and tested using direct cupellation method.Recoveries of gold and silver were calculated based on accurate gold and silver values measured with the application of classical fire assay.The influence of the amount of lead foil,sample volume,ash blowing temperature and lead foil covering mode on the recoveries of gold and silver were discussed and the optimal conditions for direct ash blowing high grade gold mud were obtained.Under the optimum conditions,comparative experiments of direct cupellation method and fire assay method were also conducted using high-grade gold mud prepared by cyanide-displacement method,the results show that direct cupellation method conformed the results of fire assay with gold recovery of 99.8%—100%,RSD≤0.10% and the silver recovery of 99.4%—101%,RSD≤0.40%.The direct cupellation method is simple,rapid and accurate,requiring lower labor intensity.