乙酸除铋-火试金法测定粗铋中的金、银含量

Determination of Gold and Silver in Crude Bismuth by Fire Assay for Removing Bismuth with Acetic Acid

建立了用乙酸分离粗铋中铋-火试金重量法测定粗铋中金和银含量的方法。首先把粗铋焙烧氧化,然后用乙酸溶解粗铋的氧化物,过滤除去铋,消除铋对火试金法的干扰,将沉淀物灰化后,配料、高温熔融,熔态的金属铅捕集试样中的贵金属形成铅扣,将铅扣灰吹,得到金银合粒,用硝酸溶解分离金,用重量法测定金含量。方法准确度高,精密度好,金的加标回收率为99.2%~101%,银的加标回收率为98.2%~99.7%。能很好地满足粗铋中金、银的测定。

A gravimetric method for the determination of gold and silver in crude bismuth by bismuth-fire assay was established.The crude bismuth was first roasted oxidation,and then dissolved crude bismuth oxide in acetic acid,filtered to remove bismuth to eliminate the influence of bismuth against fire assay method,after ashing the precipitate,batching and melting at high temperature,the molten metal lead captureed the precious metals in the sample to form a lead button.The lead button was ash blown to obtain gold-silver composite particles.The gold was dissolved and separated with nitric acid,and the gold content was determined by the gravimetric method.The method has high accuracy and precision,and the recovery of gold is 99.2%—101%and silver is 98.2%—99.7%.It can satisfy the determination of gold and silver in coarse bismuth well.