我厂熔制镁合金用的铝镁锰三元中间合金,大致成分为:铝70%,镁20%,锰10%。三个元素的分析,一般采用 EDTA 络合滴定法。但多数是要分开进行单独测定,或先测锰镁总量,然后以三乙醇胺、氰化钾联合隐蔽锰再测镁,此法对于炉前控制稍嫌费时,而且要用剧毒的氰化钾。特别在大量 Al~(3+)、Mn~(2+)存在下,以铬黑 T 为指示剂,在 pH=10测定 Mg~(2+),常常因为隐蔽剂质量问题,Mn~(2+)的 My plant melting magnesium alloy with magnesium-manganese-ternary master alloy, the general composition: aluminum 70%, 20% magnesium, manganese 10%. Three elements of the analysis, the general use of EDTA complexometric titration. However, most of the separate test to be separate, or first test the total amount of manganese and manganese, then triethanolamine, potassium cyanide combined manganese retest magnesium, this method for the furnace control a little time-consuming, but also with highly toxic cyanidation Potassium. Especially in the presence of a large amount of Al ~ (3 +) and Mn ~ (2+), chrome black T was used as an indicator to determine Mg ~ (2+) at pH = 10. +)