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锡青铜中锌、铅的络合滴定,一般都要加入剧毒试剂氰化物以掩蔽铜、锌、镍、钴、镉、铁等元素,再用三乙醇胺掩蔽铝、锰等杂质元素,然后以铬黑T作指示剂,用EDTA滴定铅,继用甲醛解蔽锌,用EDTA直接滴定锌。为了改善操作条件,避免污染环境,近来已有许多不用氰化物的报道。我们吸取前人经验,进行改进,提出锡青铜中锌、铅及铅青铜中铅的无氰快速络合滴定新方法,方法快速、准确、简便,无需分离手续,能及时满足生产需要。一、锡青铜中锌、铅的分析步骤称取0.5000克试样于250毫升高型烧杯中,加入5毫升盐酸、3毫升30％过氧化氢,试样分解完全(必要时稍加热)后低温加热煮沸约半分钟,以分解过量过氧化氢。用20—30毫升水冲洗烧杯内壁,流水冷至室温,移入100毫升容量瓶中,以水稀释至刻度,摇匀。
Tin bronze zinc, lead complexation titration, generally have to join the toxic chemicals cyanide to mask copper, zinc, nickel, cobalt, cadmium, iron and other elements, and then triethanolamine masking aluminum, manganese and other impurity elements, and then Chromium black T as an indicator, titration with lead EDTA, followed by the formaldehyde solution Zinc, titration with EDTA direct zinc. In order to improve operating conditions and avoid environmental pollution, many cyanide-free chemicals have been recently reported. We draw on the experience of our predecessors and make improvements. We propose a new cyanide-free rapid complexometric titration method for lead in zinc bronze, lead and lead bronze. The method is rapid, accurate and simple, and can meet production needs in time without separation procedures. A tin bronze zinc, lead analysis steps Weigh 0.5000 grams of sample in a 250 ml high beaker, add 5 ml of hydrochloric acid, 3 ml of 30% hydrogen peroxide, the sample decomposition completely (if necessary, slightly heated) after the low temperature Heat for about half a minute to decompose excess hydrogen peroxide. Rinse the inner wall of the beaker with 20-30 ml of water, cool to room temperature, transfer to a 100 ml volumetric flask, dilute to the mark with water, and shake well.