不同金锡合金中金含量的火试金测定

Determination of Gold Content by Fire Assay in Different Au-Sn Alloy

当金锡合金中锡含量超过35%,直接进行灰吹时,金、银合粒松散,不聚珠,灰皿中存在灰吹残留渣,导致火试金测定结果偏低。对高含量样品,研究采用熔炼-灰吹的操作可去除锡干扰,得到完整的合粒。对不同含量的样品宜选择不同的分金硝酸浓度。根据不同含量采用不同的操作步骤,测定金锡合金中金的加标回收率为99.74%~100.27%,方法精密度(RSD)为0.021%~0.127%。

When the content of tin in the gold tin alloy is more than 35%,the gold and silver grains are loose and not agglomerated,and there is residual slag in the ash dish,which results in the low result of fire assay.For high content samples,the operation of smelting soot blowing can remove the interference of tin.The complete zygote was obtained.Different concentration of gold and nitric acid should be selected for different samples.Different operation steps were adopted according to different samples.The recovery of gold in gold tin alloy was 99.74%~100.27%,and the precision of the method(RSD)was 0.021%~0.127%.