摘要
建立了磷钼酸铵沉淀-硝酸返滴定法测定高硫高磷铜磁铁矿中磷含量的方法。先焙烧试样,再用盐酸、硝酸和高氯酸分解焙烧后的试料;残渣用氢氟酸除硅,碳酸钠熔融;采用氨水沉淀法收集磷,用盐酸溶解沉淀,在酸性介质中,磷酸根与钼酸铵生成磷钼酸铵沉淀,经过滤、洗涤后,将沉淀溶解于过量的氢氧化钠标准溶液中,以酚酞为指示剂,用硝酸标准滴定溶液返滴定过量的氢氧化钠以测定磷量。磷含量在0.20%-6.5%之间,方法的相对标准偏差为0.60%-3.2%;与电感耦合等离子体-原子发射光谱法和X射线荧光光谱法的相对误差小于5.0%,重复性限为r=0.0069x+0.0591,再现性限为R=0.0638x+0.0515,可作为常规方法使用。
The ammonium phosphomolybdate precipitation-nitric acid backing titration was established to determinate phosphorus content in high-Sulfur and high-Phosphorus copper magnetite.Sample materials should be roasted first,after which hydrochloric acid,nitric acid and perchloric acid should be used to resolve them.Apply hydrofluoric acid to remove silicon for the residuals,and then melt with sodium carbonate.Collect phosphorus by means of ammonia precipitation method,whose sediments should be dissolved in hydrochloric acid.In the acid medium,phosphate group and ammonium molybdate would generate precipitation of ammonium phosphomolybdate.After filtration and washing,dissolve the precipitation in excessive sodium hydroxide standard solution,the excess sodium hydroxide is titrated with a standard solution of nitric acid using phenolphthalein as an indicator.In this way,the content of phosphorus is determinated.As to the determination range of 0.5%-6.5%,the method can yield satisfactory results with RSD between 0.60%and 3.2%,which is 5.0%less.The repeatability limit is r=0.0069x+0.0591,and the reproducibility limit is R=0.0638x+0.0515.This method can be used as a routine method of determination of phosphorus content in practical samples.
出处
《检验检疫学刊》
2015年第3期29-33,共5页
Journal of Inspection and Quarantine
基金
工信部行业标准计划项目(2013-0345T-YS)
关键词
铜磁铁矿
磷含量
磷钼酸铵沉淀
硝酸返滴定法
Copper Magnetite
High-Sulfur
High-Phosphorus
Phosphomolybdate Coprecipitation
Nitric Acid Backing Titration
