(昆明理工大学 冶金与能源工程学院,昆明 650093)
摘 要: 湿法炼锌过程中产生的窑渣含有大量的有价金属。锌冶炼污酸具有成分复杂、酸度高、含有大量的砷及其他重金属离子的特点。根据锌窑渣和污酸的理化性质,将二者进行联合浸出处理,考察反应时间、反应温度、液固比、H2O2加入量、窑渣粒径对锌窑渣与污酸联合浸出行为的影响。结果表明:在反应时间3 h、反应温度50 ℃、液固比(mL/g) 10:1、H2O2加入量为16 mL、窑渣粒径75~106 μm条件下进行二段逆流浸出,铜、铁、锌的浸出率均高于90%。浸出后液的酸度从172.48 g/L降至20 g/L左右,砷浓度达9 g/L左右,为后续沉砷处理提供了条件。另外,对浸出渣进行分析,可知浸出渣中主要物相为CaSO4?2H2O、SiO2和焦炭,其中银品位最高达484.7 g/t,可作为提银原料。
关键字: 锌窑渣;污酸;联合浸出;湿法炼锌
(Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China)
Abstract:Large amount of valuable metals are contained in kiln slag produced in zinc hydrometallurgy. The waste acid in zinc metallurgy has the characteristics of complex composition, high acidity and large amount of arsenic and other heavy metal ions. The zinc kiln slag and waste acid were leached combined according to the physical and chemical properties. The effect of the combined leaching behavior on kiln slag and waste acid was investigated by the conditions, including reaction time, reaction temperature, solid-liquid ratio, the addition of H2O2, and particle size of kiln slag. The experimental results show that after the two stages reflux leaching, the leaching rates of copper, iron, zinc are higher than 90% for 50 g kiln slag, 3 h reaction time, 50 ℃ reaction temperature, 10:1 mL/g liquid-solid ratio, 16 mL H2O2, 75-106 μm kiln slag particle size, respectively. The acidity of leach solution decreases from 172.48 g/L to about 20 g/L and the arsenic concentration reaches about 9 g/L, which provide conditions for subsequent arsenic treatment. The main phases of residue are CaSO4?2H2O, SiO2 and coke according to the analysis of leaching residue. The silver grade is up to 484.7 g/t, which can be used as raw material for extracting silver.
Key words: zinc kiln slag; waste acid; combined leaching; zinc hydrometallurgy