硫氰酸盐比色法测定钨的改进

硫氰酸盐比色法测定钨是基于W5+与硫氰酸盐形成黄色络合物。为使钨完全还原为5价,通常单独使用三氯化钛或氯化亚锡作还原剂。此方法在应用过程中,由于Ti3+本身呈紫色,加多会掩盖络合物的黄色,加少则出现硫氰酸铁之红色丝状物影响比色的情况。通过大量的试验,采用氯化亚锡-三氯化钛作双还原剂,控制最佳酸度、温度和时间,从而获得稳定的络合物,提高了分析结果的稳定性。通过对国家一级标准物质进行分析验证,从而证实方法可行,能够保证样品的测试精密度和准确度。本方法尤其适用于低含量、大批量钨矿样品的测定。

Improvement of Determination of Tungsten by Thiocyanate Colorimetry

Thiocyanate colorimetric method used in determination of tungsten is based on the fact that W5+ reacts with thiocyanate and forms a yellow complex.In order to reduce tungsten to W5+ completely,titanium trichloride or stannous chloride were generally used as reducing agents.In application,when adding more reducing reagents,Ti3+ purple color masks yellow color from the complex,and when adding less reducing reagents,red ferric rhodanide affects determination.Through plenty of experiments,titanium trichloride a...