NaPO3 用于粗锑火法精炼过程除铅

针对传统粗锑精炼工艺中除铅的难题,提出用NaPO3 作为除铅剂,生成磷酸盐渣浮于锑液表面除去的方法. 用热重-差热法和X射线衍射技术研究反应机理并进行粗锑除铅的条件实验. 研究发现,PbO与NaPO3 在590℃时即开始吸热反应,在850℃以下主要形成NaPb4 ( PO4 ) 3 ,而在850℃以上主要形成NaPbPO4 ,反应彻底. PbO、Sb2 O3 和NaPO3 混合物的反应表明:在NaPO3 量不足时,优先与PbO反应,只有当NaPO3 足量时才会与Sb2 O3 生成锑的非晶态玻璃. 用NaNO3 作为氧化剂,在氮气保护下进行了除铅单因素实验,考察反应时间和温度、NaPO3 和NaNO3 加入量对结果的影响. 在最优条件下精锑含铅0. 047%,除铅率98. 90%.

Lead removal from crude antimony in the pyrometallurgical refining process by using NaPO3

In order to solve the problem of lead removal from crude antimony in the traditional antimony refining process, NaPO3 was introduced as a lead elimination reagent to generate phosphate slag and the slag was removed by floating on the surface of liquid antimony. The reaction mechanisms were clarified by thermogravimetric-differential thermal analysis and X-ray diffraction analysis and removal of Pb from crude Sb was investigated by condition experiment. It is found that PbO and NaPO3 begin an endothermic reaction at 590℃ and mainly form NaPb4 ( PO4 ) 3 and NaPbPO4 below 850℃ and above 850℃, respectively. The reaction products of the mixture of PbO, Sb2O3 and NaPO3 show that NaPO3 preferentially reacts with PbO when NaPO3 is insufficient, and amorphous antimo-ny glass will generate only with enough NaPO3 . Single-factor experiments were taken with NaNO3 as an oxidizing agent under nitrogen. Reaction time, temperature, NaPO3 and NaNO3 amounts were considered for smelting results. Under the optimal condition, the con-tent of lead in refined antimony is 0. 047% and 98. 90% of lead is removed.