硫氰酸盐分光光度法测定高铜钨精矿中三氧化钨含量

采用硫氰酸盐分光光度法测定浮选过程中高铜钨精矿时,铜对钨测定干扰严重。实验考察了硫酸联氨、甲醛、PAN指示剂(1-(2-吡啶偶氮)-2-萘酚)、DDTC(二乙氨基二硫代甲酸钠)、硫脲5种试剂对铜的掩蔽效果,其中硫酸联氨、甲醛、硫脲掩蔽效果好,因硫脲毒性低,价廉易得,实验选择作为铜掩蔽剂。实验还考察了还原剂SnCl2或TiCl3单独使用和联合使用的效果,单独使用SnCl2作为还原剂,即使在70℃水浴加热10 min后显色,其灵敏度也低于室温下单独使用TiCl3。单独使用TiCl3与联合使用TiCl3-SnCl2作为还原剂灵敏度无差异,但后者稳定性更好,因此实验选择了联合使用TiCl3-SnCl2作为还原剂。钨含量低(w(WO3)<1%)的样品也可以选择单独使用TiCl3作为还原剂。

Determination of Tungsten Trioxide in High Copper Tungsten Concentrate by Thiocyanate Spectrophotometry

Copper interferes with tungsten determination when thiocyanate spectrophotometry is used to determine high copper tungsten concentrate in flotation process.The masking effect of hydrazine sulfate,formaldehyde,PAN,DDTC and thiourea on copper was investigated.Among them,hydrazine sulfate,formaldehyde and thiourea had good masking effect.Thiourea was chosen as copper masking agent because of its low toxicity and low price.The experiment also examined the effect of using SnCl2 or TiCl3 alone and in combination.Using SnCl2 alone as reducing agent,the sensitivity of using TiCl3 alone is lower than that of using TiCl3 alone at room temperature even after heating in 70℃water bath for 10 min.There is no difference in sensitivity between using TiCl3 alone and using TiCl3-SnCl2 in combination as reducing agent,but the latter is more stable,so the test chose to use TiCl3-SnCl2 in combination as reducing agent.For samples with low tungsten content w(WO3)<1%,TiCl3 can also be used as reducing agent.