恒电流库仑分析法测定铬矿中三氧化二铬  

Determination of Cr_2O_3 content in chromium mineral by the constant current coulometric analysis

作　　者：梁述忠[1] 李智 

机构地区：[1]徐州工业职业技术学院,江苏徐州221002 [2]张家港浦项不锈钢厂,江苏张家港215625

出　　处：《冶金分析》2006年第4期47-49,共3页Metallurgical Analysis

基　　金：江苏省高校自然科学研究指导性计划项目(04KJD150182)

摘　　要：在0·1mol/LH2SO4-H3PO4介质中电解0·02mol/LFe2(SO4)3溶液,使Pt阴极上产生Fe2+;采用H2SO4-H3PO4-(NH4)2S2O8分解铬矿,用KMnO4将其中Cr3+氧化为Cr2O27-;以Fe2+对Cr2O27-进行库仑滴定,采用永停终点法确定库仑滴定终点,根据电解定律计算三氧化二铬含量。用本法和硫酸亚铁铵滴定法分别测定铬矿标样中三氧化二铬,本法相对误差为0·22%,RSD(n=11)为0·034%,测定结果的准确度和精密度明显高于硫酸亚铁铵滴定法。The solution of 0.02 mol/L Fe2 （SO4）3 is electrolyzed in the medium of 0.1 mol/L H2SO4 - H3PO4 to produce Fe^2 ＋ in the platinum cathode. The chromium mineral is dissolved in a mixture of H2SO4, H3PO4 and （NH4）28208 and Cr^3＋ in the solution is oxidized to Cr2O7^2- by KMnO4,which is titrated by the Fe^2 ＋ . The reactions are quantitative proceeding. The end point of the titration is confirmed by the forever stop end point method. The content of Cr2O3 in chromium mineral is calculated based on the electrolyse law. The proposed method and the titration with ferrous ammonium sulfate are served to the determination of Cr2O3 in a standard sample of chromium mineral, respectively. The relative deviation and relative standard deviation of proposed method are 0.22% and 0. 034% （ n =11）. The accuracy and precision of the method are higher than those of the titration with ferrous ammonium sulfate.

关 键 词：恒电流库仑分析法 铬矿 三氧化二铬 分解 氧化 还原 

分 类 号：O657.12[理学—分析化学]