络合滴定法连续测定钨镍铜合金中的镍和铜

CONSECUTIVE DETERMINATION OF COPPER AND NICKEL IN W-Ni-Cu ALLOY BY COMPLEXOMETRIC TITRATION

拟定了用络合滴定法连续测定钨镍铜合金中镍和铜的方法.在两份试液中,一份控制pH≈8,以疏代硫酸钠掩蔽Cu(Ⅱ),氟离子掩蔽W(Ⅵ),用EDTA标准溶液直接滴定Ni(Ⅱ),求得镍含量.另一份在过量氨水介质中,用EDTA标准溶液滴定Ni(Ⅱ)、Cu(Ⅱ),求得镍-铜合量,铜含量由差减法求得.指示剂为紫脲酸铵.方法简便、快速,结果准确可靠.

A method of consecutive determination of Cu and Ni in W-Ni-Cu alloy by complexometric titra-tion is described in this paper. In one of the sample solution, the Ni content is determined by titrating with EDTA in a buffer medium of pH≈8 after masking the Cu(Ⅱ) with Na2S2O3. The total amount of Cu and Ni is determined in another sample solution by titrating with EDTA in an ammonical solution using murexide as indicator. The cop-per content is obtained by difference. The method proves to be simple and rapid.