碘-聚乙烯醇在铜精矿测定铜含量中的应用

Application of Iodine-Polyvinyl Alcohol in the Determination of the copper content in Copper Concentrate

铜精矿中的存在组分较为复杂、干扰较多,因此在铜精矿铜量测定的过程中,选取合适的分析方法十分重要。碘量法方法成熟,操作简便,在铜精矿化学分析中的应用最为广泛。但由于采用标准法进行滴定时,其专属指示剂——淀粉指示剂与碘会形成大量吸附物,导致体系中的碘与硫代硫酸钠反应不充分且在偏酸性环境中,淀粉易被微生物分解变质,显色迟钝灵敏度下降。这些都将影响滴定终点的判断而造成分析误差。为了有效的避免此类情况的出现,引入聚乙烯醇表面活性剂,将改进型碘量法与标准法进行对比分析,发现新型指示剂消除了传统指示剂存在的干扰和弊端,提高了实验的准确度和精密度,PVA指示剂性能稳定且易于保存,在碘量分析中的表现更加出色。

The presence of copper concentrate is much complex and interferes.Therefore,it is very important to select the appropriate analytical method for the determination of copper concentrate.Iodimetry is mature and easy to operate,it is widely used in chemical analysis of copper concentrate.However,the proprietary indicator of the standard method—starch indicator will form a mass of adsorbate with iodine during the titration process,resulting in insufficient reaction between iodine and sodium thiosulfate in the system;Under the acidic PH,starch indicator is easily Microbial decomposition and deterioration,the sensitivity of color reaction is reduced.These will affect the judgment of the end point of the titration and cause a mass of analysis errors.In order to avoid the disadvantages effectively,we introduced the polyvinyl alcohol indicator.The modified iodometric method is compared with the standard method,we found that it eliminate the drawbacks of traditional indicator and increase the precision and accuracy by the new indicator.Meanwhile,the PVA indicator is much more stable and easier to store.So we can conclude that PVA have a better performance on the analysis of iodometry.