Arsenic removal from acid extraction solutions of copper smelting flue dust

Multi-metal extraction of flue dust from copper smelting is being pursued to meet the increasingly appealing environmental requirements of our modern life. In this paper, the thermodynamic analysis of acid leaching solution was carried out. Ferric arsenate deposits were found in the range of pH = 0-11.63, in the form of FeAsO4 and FeAsO4 center dot 2H(2)O center dot Cu2AsO4OH, CuHAsO4, and Cu5H2(AsO4)(4) forms of Cu2AsO4 were produced in the range of pH = 0.98-2.33. Zn-3(AsO4)(2), Zn2AsO4OH, ZnHAsO4, and Zn5H2(AsO4)(4) forms of zinc arsenate were produced in the range of pH = 1.40-4.85. Theoretically, when pH = 0.98 -2.33, copper arsenate salt was produced; however, when the actual experimental results were at pH >= 1.2, a small amount of copper co-settling occurred. Theoretical results were verified by single factor experiments. Strictly controlling the pH value of the reaction system can effectively separate arsenic (As) from copper (Cu) and zinc (Zn). Through single factor experimentation, optimal process parameters of iron salt and calcium salt combined with As removal were as follows: reaction time, 5 h; reaction temperature, 85 degrees C; pH value, 1.2; Fe-As molar ratio, 1.5; no H2O2 added. Under these conditions, the precipitation rate of As was 89.12%, while Cu and Zn did not precipitate. Through XRD analysis, As element was removed from acid leaching solution in the form of scorodite (FeAsO4 center dot 2H(2)O). This has laid a theoretical foundation for the effective removal of As in acid leaching solution and the reduction of As content. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study focused on the multi-metal extraction of flue dust from copper smelting, conducting thermodynamic analysis to identify ferric arsenate deposits and various forms of copper and zinc arsenate in acid leaching solution. Single factor experiments were used to verify the research findings, showing that controlling the pH value of the reaction system can effectively separate arsenic from copper and zinc.