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由于烃类转化制氢催化剂中含有的镍、铁、铝等元素的干扰。给EDTA络合滴定氧化钙、氧化镁带来很大的困难。以前曾在络合滴定前用三乙醇胺和氰化钾掩蔽干扰元素,但由于氰化钾剧毒,给分析工作带来了不便。为此,我们研究了在试样分析前先用六次甲基四胺铜试剂分离镍、铁、铝,然后在pH>12及pH=10用EDPA络合滴定,得到了满意的结果。一、方法原理在六次甲基四胺溶液中,铝钛等成为氢氧化物沉淀,铜试剂则和镍钴铝等形成内络盐沉淀。铁则先成为氢氧化物,然后在铜试剂内转为内络盐沉淀。分离沉淀后,在滤液中加少量三乙醇胺掩蔽残留的铁铝,用KOH
Due to hydrocarbon conversion into hydrogen catalyst contains nickel, iron, aluminum and other elements of the interference. To EDTA complex titration calcium oxide, magnesium bring great difficulties. Triethanolamine and potassium cyanide were used to mask interfering elements before complexometric titration, but inconvenience was caused to the analysis due to the high toxicity of potassium cyanide. To this end, we studied the separation of nickel, iron and aluminum with hexamethylenetetramine copper reagent prior to sample analysis, and then gave satisfactory results with EDPA complexometric titration at pH> 12 and pH = 10. First, the principle of the method Hexamethylenetetramine solution, aluminum and titanium into a hydroxide precipitate, and copper reagents such as nickel cobalt and aluminum formed within the network of salt precipitation. Iron first becomes hydroxide, and then transferred to the internal network salt precipitation in the copper reagent. After the precipitate was separated, a small amount of triethanolamine was added to the filtrate to mask the remaining iron and aluminum, using KOH