铜阳极泥复合浸出渣选择性分离硒过程热力学分析

铜阳极泥复合浸出渣是铜阳极泥采用复合浸出砷锑铋后的产物，采用硫酸化焙烧选择性分离硒。针对其含硒物质在选择性分离过程中的反应历程不明晰，本文利用Factsage数据库中相关热力学数据及Equilib平衡计算模块对含硒物质在不同温度时反应的■及反应过程平衡分析，明晰反应过程中的物相变化规律。结果表明：Cu₂Se与H₂SO₄在低温下反应生成固态Se、CuSO₄·H₂O、SO₂及H₂SO₄吸水形成H₂SO₄·H₂O；然后固态Se融化变成液态Se，同时与H₂SO₄·H₂O反应生成SeO₂、SO₂和H₂O；高温下CuSO₄·H₂O会脱水生成CuSO₄和H_2...

Thermodynamic analysis on selective separation of Selenium from compound leaching slag of copper anode slime

The compound leaching slag of copper anode slime is the product of compound leaching of arsenic, antimony and bismuth from copper anode slime, and Selenium (Se) is selectively separated by sulfated roasting. In view of the unclear reaction process of the selenium-containing substances in the selective separation process, relevant thermodynamic data in Factsage and Equilib equilibrium calculation module were used to analyze the ΔGθ of selenium-containing substances reacting at different temperatures and reaction process balance, to clarify the law of phase change in reaction process. The results show that at low temperature Cu₂Se reacts with H₂SO₄ to generate solid Se, CuSO₄·H₂O, SO₂ and H₂SO₄ absorbs water to form H₂SO₄·H₂O. Solid Se then melts into liquid Se and simultaneously reacts with H₂SO₄·H₂O to form SeO₂, SO₂ and H₂O. At high temperature, CuSO₄·H₂O will be dehydrated to produce CuSO₄ and H₂O, and CuSO₄ will be further decomposed to produce CuSO₄·CuO and SO₃. Ag₂Se reacts with H₂SO₄ to generate solid Se, Ag₂SO₄, SO₂ and H₂SO₄ absorbs water to form H₂SO₄·H₂O, and then solid Se melts into liquid Se and reacts with H₂SO₄·H₂O to form SeO₂, SO₂ and H₂O. In addition, Ag₂SO₄ will change form at high temperature, and Se reacts with H₂SO₄ to generate SeO₂, SO₂ and H₂O. Therefore, the Se evaporation rates of compound leaching slag of copper anode slime at different roasting temperatures, with different sulfuric acid dosages and for different roasting time were analyzed. Under the roasting condition of temperature at 500 ℃, the added quantity of H₂SO₄ of 0.2 mL/g, the warming rate 10 ℃/min and the reacting time 30 min, Se evaporation rate reached 95.4%.