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在金的湿法冶金中,通常用氰化钠或硫脲浸出。氰化物和硫脲溶液中金的富集和测定已有报道,并有金的分析专著及各种物料中金的分析文献等。我所为研究金矿石中金的赋存状态,采用KI-I_2溶液处理矿石。但在这种介质中金的测定未见报道。本文研究了KI-I_2体系中痕量金的富集和测定。确定先用SnCl_2还原试样中大量的I_2,接着用活性炭富集分离金,含金的活性炭-纸浆混合物经灰化,并用王水溶解金,最后在乙酸介质中,Au~(3+)与KI反应析出等量的I_2,用Na_2S_2O_3标准液滴定。试样用本法测定获得满意结果,测定下限为0.05mgAu·L~(-1),方法的相对标准偏差±5%以内。回收率为90～105%。
In gold hydrometallurgy, sodium cyanide or thiourea is usually leached. The enrichment and determination of gold in cyanide and thiourea solutions have been reported, as well as gold analytical monographs and gold analytical literature for various materials. To investigate the occurrence of gold in gold ore, I used KI-I 2 solution to treat ore. However, the determination of gold in this medium has not been reported. In this paper, the enrichment and determination of trace gold in KI-I 2 system was studied. It is determined that a large amount of I_2 is firstly reduced with SnCl_2, then the activated carbon is used for enriching and separating gold, and the gold-containing activated carbon-pulp mixture is ashed, the gold is dissolved in aqua regia, and finally, in the acetic acid medium, Au 3+ and KI reaction precipitated the same amount of I_2, with Na 2 S 2 O 3 standard solution titration. The sample obtained by this method to obtain satisfactory results, the lower limit of determination of 0.05mgAu · L -1, the relative standard deviation of the method within ± 5%. The recovery rate is 90 ~ 105%.