摘要
银精矿除含银、铅、硫等主成分外,还伴生有多种可回收利用的金属元素(如锡等)。因此,准确测定银精矿中锡的含量,对提升银精矿的综合利用水平有着重要意义。实验将样品灼烧,采用过氧化钠熔融分解,水浸取熔融物,酸化后加入还原铁粉,使铜、锑、铋和砷还原为单质析出,过滤,实现了这些共存元素与锡的分离,用铝片将滤液中锡还原为二价,以淀粉溶液为指示剂,用碘酸钾标准滴定溶液滴定锡,建立了碘酸钾滴定法测定银精矿中锡的分析方法。对过氧化钠用量、铁粉用量及其还原时间进行了优化。干扰试验表明,样品中共存元素不干扰锡的测定。按照实验方法对成分与银精矿较为相似的铅精矿标准物质中锡进行测定,结果表明,测定值与认定值一致。按照实验方法对4个银精矿实际样品中锡进行测定,测定结果的相对标准偏差(RSD,n=8)为0.59%~4.3%,加标回收率为98%~104%。采用实验方法对银精矿实际样品中锡进行测定,并与铍共沉淀分离-碘酸钾滴定法进行方法对照试验,结果表明,两种方法的测定值相吻合。
In addition to main components such as silver,lead and sulfur,the silver concentrate was also associated with a variety of recyclable metal elements(such as tin,etc).Therefore,the accurate determination of tin content in silver concentrate was of great significance for improving the comprehensive utilization level of silver concentrate.The sample was decomposed by fusion with sodium peroxide after ignition.Then,the molten material was extracted by water.After acidification,the reduced iron powder was added into the test solution to reduce copper,antimony,bismuth and arsenic to elementary substance.Therefore,the separation of tin from these elements could be realized by filtration.Tin in the filtrate was reduced to divalent with aluminum sheet.Then the content of tin was determined by titration with potassium iodate standard solution using starch as the indicator.A determination method of tin in silver concentrate by potassium iodate titration was established.The sodium peroxide dosage,the iron powder dosage and reduction time were optimized.The interference tests showed that the coexisting impurity elements in silver concentrate had no influence on the determination.The content of tin in certified reference material of lead concentrate with similar composition to silver concentrate was determined according to the experimental method.The determination results were consistent with the certified values.The experimental method was also applied for determination of tin in four actual silver concentrate samples.The relative standard deviations(RSDs,n=8)of determination results were between 0.59%and 4.3%.The recoveries were between 98%and 104%.The proposed method was applied for the determination of tin in silver concentrate actual sample.The results were consistent with those obtained by beryllium coprecipitation separation-potassium iodate titration.
作者
周智勇
肖刘萍
谢磊
ZHOU Zhi-yong;XIAO Liu-ping;XIE Lei(National Quality Supervision and Inspection Center of Precious Metal and Heavy Nonferrous Products(Hunan),Chenzhou 423000,China)
出处
《冶金分析》
CAS
北大核心
2019年第9期74-80,共7页
Metallurgical Analysis
关键词
银精矿
碘酸钾滴定法
锡
还原铁粉
silver concentrate
potassium iodate titration
tin
reduced iron powder
