测定铬铁矿中氧化亚铁的溶样方法研究

来源期刊：冶金分析2011年第3期

论文作者：李玉茹 周海波 吴爱华 杨林 张志勇 黄宝贵

文章页码：55 - 59

关键词：铬铁矿； 氧化亚铁； 溶样方法； 湿烧法； 缩合磷酸

Key words：chromite； ferrous oxide； sample dissolution method； wet combustion method； condensed phosphoric acid

摘    要：证明了经沸腾硫酸(~330℃)湿烧法预处理的铬铁矿的物质组成发生相变、反应产物硫酸铬生成、化学活性增强以及磷酸(硫-磷混合酸)对其溶解反应明显变易等,从而改进了测定铬铁矿中氧化亚铁的溶样方法。试样首先与钒(Ⅴ)-钒(Ⅳ)溶液和硫酸混合,于2 000 W电炉上加热至冒浓三氧化硫烟,并至腾空1~3 min,然后加入缩合磷酸,再加热至冒浓烟,并至腾空3~5 min。所得试液适当冷却、稀释,用硫酸亚铁铵标准溶液滴定剩余的钒(Ⅴ),通过空白实验计算氧化亚铁的含量。同时对硫酸湿烧法的作用及其反应机理也进行了探讨。方法用于铬铁矿中氧化亚铁的测定,经标样以及生产样品分析数据对比,结果均较满意。

Abstract: This paper proved that after pretreatment by boiled sulfuric acid wetting combustion(about 330℃),chromite went through a series of changes,including phase change,formation of chromium sulfate,enhancement of chemical activity and inclination to dissolution reaction with phosphoric acid,all of which improved sample dissolution in the determination of ferrous oxide in chromite.The sample was firstly mixed with vanadium(Ⅴ)-vanadium(Ⅳ) solution and sulfuric acid,heated on electric furnace(2 000 W) until thick sulfur trioxide smoke appeared and soared for 1-3 min.Then,the condensed phosphoric acid was added.The solution was heated until thick smoke appeared and soared for 3-5 min.The obtained solution was properly cooled and diluted.The residual vanadium(Ⅴ) was titrated using ammonium ferrous sulfate standard solution.The content of ferrous oxide was calculated by blank experiment.Meanwhile,the function of wetting combustion method with sulfuric acid and the reaction mechanism were discussed.The proposed method has been applied to the determination of ferrous oxide in chromite.The comparision of the analytical results of certified reference material and production sample indicated the results were satisfactory.