测定钙热还原二氧化钛制备钛粉产物中氧化钙的含量

Determination of calcium oxide in product of calciothermic reduction of titanium dioxide by EDTA titrimetry

研究了EDTA络合滴定法测定钙热还原二氧化钛得到的还原产物中氧化钙含量的方法。用钙羧酸作指示剂,三乙醇胺掩蔽干扰元素,同时采用NaOH溶液调节试样溶液的pH值在12～14,用EDTA标准溶液滴定。为防止钛离子影响滴定终点的判断,实验选用不同浓度的盐酸溶解样品,分析不同量的盐酸、溶解时间对溶样的影响以及不溶物对滴定的干扰影响。采用确定的分析方法对不同还原时间得到的样品进行测定,还原时间1h、2h、4h、6h、8h、10h,RSD均小于1%,加标实验回收率为98%～101%。

The determination method of calcium oxide was developed in product calciothermic reduction of titanium dioxide （TiO2 ）. The calcon carboxylic acid was used as indicator and small amount of interference elements were masked by triethanolamine. The sample solution of pH was adjusted by NaOH and was controlled for 12 ～ 14, then standard solution EDTA was titrated. To prevent the titanium to affect the end point of titration, hydrochloric acids with different concentrations were selected to dissolve the samples, and analysis of different amounts of hydrochloric acid, and the effects of dissolving time and undissolved substances were considered on the titration. The prepo6ed method was applied to the determination of samples with different reduction time. When the reduction time was lh, 2h, 4h, 6h, 8h, 10h, the relative standard deviation （RSD） was smaller than 1% ,and recoveries of 98%～101%.