Oxide Dissolution Losses of Copper, Lead and Tin in Slags

在铜、铅或锡冶炼中，脉石矿物和杂质被浓缩到渣相中，有价金属以熔融状态回收。部分有价金属在冶炼过程中以溶出和悬浮的形式流失到炉渣中。在冶炼过程中，尽量减少有价金属对炉渣的损失是非常重要的。为了弄清矿渣成分、氧势和温度对有价金属损失的影响，在1200 ~ 1300 <s:1>℃的温度下，对这些金属与FeO-CaO-SiO_2矿渣进行了平衡实验。实验结果总结如下：1。渣中铜为单价，铅、锡为二价。金属在矿渣中的溶解度与其价有关。二元铁矾渣（FeO_x-SiO_2）和铁氧体渣（FeO_x-CaO）中铜和锡的含量相近，且远高于三元FeO_x-CaO- sio_2渣中铜和锡的含量。在含固体硅酸二钙和25%氧化铁的FeO_x-CaO-SiO_2三元渣中，铜和锡的溶解度最小。三元FeO_x-CaO-SiO_22的渣组分通过碱性cao中和酸性SiO_2形成稳定的渣溶液。氧化铅与SiO_2亲和力强，其氧化物在SiO_2活性大的铁矾渣中溶解度大。不含SiO_2的铁氧体渣能有效降低渣中氧化铅的损失。当渣中不可避免地含有SiO_2时，用CaO中和SiO_2可减少渣中铅的损失。

In copper, lead or tin smelting, gangue minerals and impurities are concentrated into slag phase and valuable metals are recovered as molten state. Some amount of valuable metal losses to slag as dissolution and suspension in the smelting step. It is very important to minimize the valuable metal loss to slag in the smelting. To clarify effects of slag composition, oxygen potential and temperature on valuable metal loss, equilibrium experiments between these metals and FeO-CaO-SiO_2 slags were carried out at the temperature of 1200 to 1300ﾟC. The experimental results are summarized as follows.1. Copper in slag was mono-valent and lead and tin in slag were di-valent. The dependence of metal solubility in slag related to its valency.2. The contents of copper and tin were similar for both binary fayalite (FeO_x-SiO_2) and ferrite (FeO_x-CaO) slag, and much higher than those in ternary FeO_x-CaO-SiO_2 slag. The minimum solubilities of copper and tin were observed in the ternary FeO_x-CaO-SiO_2 slag whose composition were close to saturation with solid di-calcium silicate and 25% iron oxide. The slag composition of the ternary FeO_x-CaO-SiO_22 forms a stable slag solution by neutralization of acidic SiO_2 with basic CaO.3. Big solubility of lead whose oxide had a big affinity with SiO_2 was observed in fayalite slag with big activity of SiO_2. Ferrite slag free from SiO_2 was effective to reduce oxide lead loss in slag. When slag contains SiO_2 inevitably, neutralization of SiO_2 with CaO reduces lead loss in slag.