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于较强盐酸介质中,锌与硫氰酸根生成硫氰酸锌络阴离子。可用4-甲基戊酮(2)定量萃取,以与铜、铅、锡、铝、镍、锰等元素分离,反萃后用EDTA滴定.条件试验一试验方法取锌标准液10毫升(5毫克),加入40%硫氰酸钠3毫升,加1∶6盐酸7毫升,水20毫升(使水相总体积=40毫升),加4-甲基戊酮(2)10毫升,于分液漏斗中振荡1分钟,分层后弃去水相,将有机相放入500毫升锥形瓶中,加水约100毫升,pH5.5缓冲液15毫升、抗坏血酸0.2克,摇匀,加0.2%二甲酚橙指示剂数滴,用0.0050M EDTA滴定至黄色即为终点。
In a strong hydrochloric acid medium, zinc and thiocyanate to generate zinc thiocyanate anion. Quantitative extraction with 4-methylpentanone (2) to separate it from elements such as copper, lead, tin, aluminum, nickel, manganese, titration with EDTA after stripping Condition Tests A Test Method Ten milliliters of a standard solution of zinc Mg), 40 ml of 3% sodium thiocyanate, 7 ml of 1: 6 hydrochloric acid, 20 ml of water (total volume of the aqueous phase = 40 ml) and 10 ml of 4-methylpentanone (2) Shake for 1 minute in a funnel, discard the aqueous phase after layering, put the organic phase in a 500 ml Erlenmeyer flask, add about 100 ml of water, 15 ml of pH 5.5 buffer, 0.2 g of ascorbic acid, shake well, add 0.2% Xylenol orange indicator a few drops titrated to 0.0050M EDTA yellow is the end.