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镁铝合金中镁的测定,不外反复分离大量杂质;用氰化钾等掩蔽杂质,调整至 pH10左右,以铬黑 T作指示剂,用 EDTA 滴定。但氰化钾是剧毒试剂。经过试验总结了镁的不分离,不使用剧毒药品,在酒石酸钠十三乙醇胺联合掩蔽大量铝铁,在 pH9～11以铜试剂掩蔽少量杂质,调整 pH10左右,以甲基麝香草酚蓝(MTB)或铬黑 T 为指示剂直接络合滴定的方法。若铁、钛两元素合并作一系统分析,比单独测定更快、准确、稳定,且重现性、准确度均有提高。
Determination of magnesium in magnesium alloy, but repeatedly separated a large number of impurities; with potassium cyanide and other masking impurities, adjusted to about pH10 to chromium black T as an indicator, with EDTA titration. However, potassium cyanide is a highly toxic reagent. After the experiment summarizes the non-separation of magnesium, do not use highly toxic drugs, sodium triethanolamine sodium tartrate masking a large number of aluminum and iron, in pH9 ~ 11 with copper reagent to mask a small amount of impurities, adjust pH10 or so, methyl thymol blue MTB) or chromium black T direct complexometric titration method. If iron, titanium two elements combined for a systematic analysis, faster than the single determination, accurate, stable, and reproducibility, accuracy have increased.