三氯化钛还原-重铬酸钾滴定法测定球团矿中TFe  

Determination of TFe in Pellet by Titanium Trichloride Reduction-Potassium Dichromate Titrimetry

作　　者：吴诚[1] 王际祥[2] 李西忠[2] 董丙成[2] 王成林[2] 

机构地区：[1]上海材料研究所 [2]莱芜钢铁集团有限公司技术中心

出　　处：《莱钢科技》2010年第5期63-65,共3页Laigang Science & Technology

摘　　要：采用碱混合熔剂熔融试样代替硫磷混酸冒烟溶解试样，熔融物以热水浸取盐酸酸化后，首先用tin将大部分Fe^3＋还原成Fe^2＋；然后用TiCl3还原剩余的Fe^3＋，以钨酸钠做指示剂指示还原终点，即当Fe^3＋定量还原为Fe^2＋后，过量一滴TiCl3溶液，可使作为指示剂的六价钨（无色）还原成蓝色的钨化合物，故溶液呈蓝色，俗称“钨蓝”。过量的TiCl3可在硫酸铜的催化下，借水中的溶解氧和空气中的游离氧氧化使钨蓝色泽褪去，从而消除过量的TiCl3还原剂的影响。在硫磷混酸介质中，以二苯胺磺酸钠为指示剂，用重铬酸钾标准溶液滴定TFe量，分析结果令人满意。该法测定TFe的绝对误差小于0．15％，避免了用重铬酸钾氧化褪去钨蓝色泽时易引入的误差。By adopting alkali mixed solvent to melt samples instead of sulphur-phosphor mixed acid smoking to dissolve them, after the fusant is leached by hot water and acidified with hydrochloric acid, first tin is used to reduce most Fe3＋ into Fe2＋ , then TiCl3 is used to reduce the remaining Fe3＋. With sodium tungstate as an indicator showing the end of reduction, that is, when Fe3＋ is quantitative-reduced into Fe2＋ , an excessive drib of TiCl3 can reduce hexavalent tungsten as indicator （no color） to blue quinquevalent tungsten compound, which is called ＂tungsten blue＂ , because the solution assumes blue. Excessive TiCl3 can make tungsten blue fade under the catalysis of cupric sulfate, by means of dissolved oxygen in water and free oxygen in air , thus eliminating the influence of excessive TiCl3 reducing agent. In the medium of sulphur-phosphor mixed acid, with diphenylamine sodium sulfonate as an indicator, the standard solution of potassium dichromate is used to titrate the content of TFe, the result of which is satisfactory. Absolute error in the determination of TFe for this method is less than 0. 15% , avoiding the error which appeared when potassium dichromate oxidation made tungsten blue fade.

关 键 词：球团矿 碱混合熔剂熔融 盐酸浸取酸化 三氯化钛 硫酸铜催化 重铬酸钾滴定法 

分 类 号：TQ621.12[化学工程—精细化工]