材料期刊网

以甲基橙作指示剂采用硫酸铈滴定法对含锑金精矿中锑进行测定时,若样品中铁含量较高,则溶液中Fe(Ⅲ)的颜色会对终点颜色变化产生严重干扰,使终点判断较为困难.经过多次试验发现,采用亚甲基蓝-甲基橙作指示剂能够消除Fe(Ⅲ)对滴定终点的干扰,使终点颜色变化敏锐.据此,实验采用硫酸和硫酸钾溶解样品,用硫化钠将Sb(V)还原为Sb(Ⅲ),在盐酸介质中,加热溶液温度至70~90 ℃,以亚甲基蓝-甲基橙为指示剂,建立了硫酸铈滴定法测定含锑金精矿中锑的方法.采用实验方法对含锑金精矿实际样品进行精密度和加标回收试验,测定结果的相对标准偏差(RSD,n=8)小于4%,锑的加标回收率在99%~102%之间.将实验方法应用于含锑金精矿实际样品中锑的测定,所得结果与国家标准方法GB/T 15925-2010的测定值相吻合.

During the determination of antimony in gold concentrate containing antimony by cerium sulfate titrimetry with methyl orange as indicator, the endpoint color would be seriously interfered by the color of Fe (III) in solution when the content of iron in sample was high.As a result, the endpoint was hardly judged.It was found that the interference of Fe (III) on titration endpoint could be effectively eliminated with methylene blue-methyl orange as indicator, and the color change at endpoint was obvious.In view of the above, after the sample was dissolved with sulfuric acid and potassium sulfate, Sb (V) in solution was reduced to Sb (III) with sodium sulfide, and the solution was heated to 70~90 ℃ in hydrochloric acid medium, then a determination method of antimony in gold concentrate containing antimony was established by cerium sulfate titrimetry with methylene blue-methyl orange as indicator.The proposed method was applied to the precision and recovery tests of actual samples of gold concentrate containing antimony.The relative standard deviation (RSD, n=8) was less than 4%, and the recoveries were between 99% and 102%.The content of antimony in actual sample of gold concentrate containing antimony was determined according to the experimental method.The results were consistent with those obtained by national standard method GB/T 15925-2010.