硫氰酸盐比色法测定钨的改进

杭健; 高若柳

硫氰酸盐比色法测定钨的改进

杭健,
高若柳

1.
中国地质调查局西安地质调查中心, 陕西西安 710054
2.
中国地质调查局西安地质调查中心, 陕西西安 710054

基金项目:

内蒙古自治区地质勘查基金资助(05-6-KC3)

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出版历程
- 收稿日期: 2010-05-14
- 修回日期: 2010-09-04

Improvement of Determination of Tungsten by Thiocyanate Colorimetry

1.
Xi'an Center of Geological Survey, China Geological Survey, Xi'an 710054, China
2.
Xi'an Center of Geological Survey, China Geological Survey, Xi'an 710054, China

摘要

摘要: 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。
- 氯化亚锡 /
- 三氯化钛 /
- 比色法 /
- 钨 /
- 还原剂
Abstract: 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 and stannous chloride were choosed as dual reducing agents. The stable complex can be obtained by controlling acidity, temperature and reaction time and the stability of the analytical results can be remarkably improved. The method has been tested by the determination of tungsten in national standard reference materials and the results are in good agreement with certified values. The improved method is suitable for routine analysis of trace tungsten in geological samples.
- titanium /
- trichloride /
- stannous /
- chloride /
- colorimetric