钨的测定方法的改进  

The Improvement of Determination Method for Tungsten

作　　者：张青艳 

机构地区：[1]山西省地质勘查局217地质队实验室,山西大同037008

出　　处：《科学之友（下）》2011年第8期28-29,共2页Friend of Science Amateurs

摘　　要：硫氰酸钾比色法测定钨是基于W5+与硫氰酸钾形成黄色络合物。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。Potassium thiocyanate colorimetric determining tungsten is based on the yellow coordination compound composed by W5＋ and potassium thiocyanate. In order to fully restore tungsten to 5 valence, titanium trichloride is usually used alone as reducing agent. In the application process of this method, as Ti3＋ is purple, if adding more, it will cover the yellow of coordination compound, while less will occur red filaments of iron thiocyanate affecting the colorimetric situation. Through a large number of experiments, using stannous chloride - titanium tfichloride as a double - reducing agent, best controlling acidity, temperature and time can achieve a stable coordination compound, and improve the stability of analysis results. Through the analysis and verification of national first - class standard material, it is confirmed that the method is feasible, to ensure the test precision and accuracy of sample. This method is especially applied in the determinationof low level and large quantities of tungsten ore samples.

关 键 词：氯化亚锡 三氯化钛 比色法 钨 还原剂 

分 类 号：O657.32[理学—分析化学]