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钨的络合滴定法国内已有报导,有钙盐法、钡盐法和铅盐法,但在实际中应用不多。我们在前人工作的基础上,对钨络合滴定的有关条件进行了摸索,并拟定了简便的分析方法,应用于钨矿和钨精矿中钨的测定。其结果与重量法和差示法相符,测定误差在±0.5％以内。在有硝酸铵存在时,高达20毫克钼仍无影响。3—40毫克三氧化钨的回收率为97.5—99.9％。方法基于矿样以盐酸-硝酸溶解,析出钨酸与大部分元素分离,以氢氧化钠溶解钨酸,所得钨酸钠溶液经调整酸度
Tungsten complexometric titration has been reported in China, there are calcium salt method, barium salt method and lead salt method, but in practice is not much used. Based on our predecessors’ work, we have explored the relevant conditions of tungsten complex titration and developed a simple and convenient analytical method for the determination of tungsten in tungsten and tungsten concentrates. The result is in accordance with the gravimetric method and the differential method, and the measurement error is within ± 0.5%. In the presence of ammonium nitrate, up to 20 mg of molybdenum still has no effect. The recovery of 3-40 mg tungsten trioxide was 97.5-99.9%. The method is based on the mineral sample dissolved in hydrochloric acid-nitric acid, the tungstate is separated from most of the elements and the tungstic acid is dissolved in sodium hydroxide. The resulting sodium tungstate solution is adjusted in acidity