Hydrometallurgical Recycling of Copper Anode Furnace Dust for a Complete Recovery of Metal Values

Dušan Oráč,Andrea Miškufová,Tomáš Vindt,Jana Pirošková,Jakub Klimko,Dušan Klein,Pavol Liptai

doi:10.3390/met12010036

Abstract

Copper anode furnace dust is waste by-product of secondary copper production containing zinc, lead, copper, tin, iron and many other elements. Hydrometallurgical Copper Anode Furnace dust recycling method was studied theoretically by thermodynamic calculations and the proposed method was verified experimentally on a laboratory scale. The optimum condition for leaching of zinc from dust was identified to be an ambient leaching temperature, a liquid/solid ratio of 10 and H2SO4 concentration of 1 mol/L. A maximum of 98.85% of zinc was leached under the optimum experimental conditions. In the leaching step, 99.7% of lead in the form of insoluble PbSO4 was separated from the other leached metals. Solution refining was done by combination of pH adjustment and zinc powder cementation. Tin was precipitated from solution by pH adjustment to 3. Iron was precipitated out of solution after pH adjustment to 4 with efficiency 98.54%. Copper was selectively cemented out of solution (99.96%) by zinc powder. Zinc was precipitated out of solution by addition of Na2CO3 with efficiency of 97.31%. ZnO as final product was obtained by calcination of zinc carbonates.

Highlights

Copper is the third most widely used metal and total global smelter production was approximately 24.5 million metric tons in the year 2020 [1,2,3]
Electrolytical refining [10]; Various chemical elements enter the process of recycling from secondary raw materials, which are later separated from copper in refining processing steps
As and Ni were detected by atomic absorption spectrometry (AAS) method, but their content was under 0.1% and they are not further studied in followed experiments

Summary

Introduction

Copper is the third most widely used metal and total global smelter production was approximately 24.5 million metric tons in the year 2020 [1,2,3]. Copper recycling requires up to 85% less energy than primary production [5]. Around the world, it saves 100 million MWh of electrical energy and 40 million metric tons of CO2 annually [6,7,8]. Electrolytical refining [10]; Various chemical elements enter the process of recycling from secondary raw materials, which are later separated from copper in refining processing steps. This leads to the production of large amounts of waste with different chemical compositions. The most common waste are slags, which are the subject of many research papers, but in addition, dust (shown in Figure 1) is generated

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Conclusion