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本文改进了及滴定法测定高含量黄金样品中金的方法,在样品溶解后,加入过量的氯化钠溶液,控制砂浴温度,蒸发至近干,省去中和调节酸度等步骤。加水溶解Na[AuCl_4],加入过量硫酸亚铁铵标准溶液,以重铬酸钾标准溶液回滴:低含量黄金样品是以加入大量固体氯化钾、硝酸及盐酸,在较高温度下加热,使样品快速溶解,蒸发至近干,加入适量水溶解K[AuCl_4]等,同样以硫酸亚铁铵-重铬酸钾间接容量法滴定之,银、铜、铅等不干扰,测定的绝对误差≤±0.2%,金可以回收,方法快速,准确,适合于高含量(≥90%)及低含量(58.5～90%)黄金饰品的日常分析。
In this paper, the titration method for the determination of gold in high-content gold samples is improved. After the sample is dissolved, an excess of sodium chloride solution is added to control the temperature of the sand bath, evaporated to near dryness, and the steps of neutralizing and adjusting acidity are eliminated. Add water to dissolve Na [AuCl_4], add excess ferrous ammonium sulfate standard solution to potassium dichromate standard solution drop: the low content of gold sample is added by a large amount of solid potassium chloride, nitric acid and hydrochloric acid, heated at higher temperatures, So that the sample quickly dissolved, evaporated to near dry, add the appropriate amount of water dissolved K [AuCl_4], the same ammonium ferrous sulfate - potassium dichromate indirect capacity titration of silver, copper, lead and other interference, the determination of the absolute error ≤ ± 0.2%, gold can be recovered, the method is fast and accurate, suitable for daily analysis of high content (≥90%) and low content (58.5 ~ 90%) gold jewelry.