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过去,在分析三氧化钨、钨坯等中钍时,多采用重量法,手续烦琐,费时较长,且又要应用铂器皿溶样等,不能满足生产的需要。我们用焦性硫酸钾熔融样品,以氢氧化钠溶液沉淀钍并和大量钨分离,然后在pH4.5-5.5的介质中,以PAN为指示剂,用铜盐为回滴剂,络合滴定法测定钍(亦可在pH2-2.5 时,以二甲酚橙为指示剂,用EDTA直接滴定法测定钍)。分析步骤较简便于1克WO_3中,加入15-30毫克ThO_2的回收率为100-97％,方法的准确度能满足生产要求。分析方法: 准确称取试样约1克,置于50毫升磁坩埚中,加8-12克焦性硫酸钾熔融。冷却后,移入300毫升烧杯中。用50毫升2NNaOH溶液浸取。洗净坩埚后,将烧杯置于温热处静置。待Th(OH)_4
In the past, in the analysis of tungsten trioxide, tungsten billet and other thorium, the more use of gravimetric method, cumbersome procedures, time-consuming, but also the application of platinum containers and other samples, can not meet the production needs. We use focal potassium sulfate to melt the sample, precipitated thorium hydroxide solution and a large number of tungsten precipitation and separation, and then in pH4.5-5.5 medium, PAN as an indicator, with copper salt as the drop-off, complex titration Determination of thorium (also available at pH2-2.5, with xylenol orange as an indicator, with EDTA direct titration thorium). The analysis procedure is simpler to 1g WO_3, the recovery rate of adding 15-30mg ThO_2 is 100-97%, the accuracy of the method can meet the production requirements. Analysis: Accurately weighed sample about 1 g, placed in 50 ml magnetic crucible, plus 8-12 g coke potassium sulfate melting. After cooling, move into a 300 ml beaker. Leach with 50 mL 2N NaOH solution. After cleaning the crucible, place the beaker in a warm place. Be Th (OH) _4