Sulfuric acid leaching for capturing value from copper rich converter slag

Muhammad Kamran Khalid,Joseph Hamuyuni,Vivek Agarwal,Jouni Pihlasalo,Mika Haapalainen,Mari Lundström

doi:10.1016/j.jclepro.2019.01.083

Muhammad Kamran Khalid, Joseph Hamuyuni + Show 4 more

Open Access

https://doi.org/10.1016/j.jclepro.2019.01.083

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Abstract

In this research, a hydrometallurgical method for recovery of copper from copper rich converter slag is investigated. The main copper containing phases of the slag are cuprite (Cu2O), delafossite (CuFeO2) and metallic copper (Cu). The study investigates the effect of particle size, temperature, acid concentration, agitation and leaching time under oxidizing conditions. The results showed that at optimized conditions (40 °C, 2 M H2SO4, 60 min leaching time, 0.26 kW/m3 mixing power, and 2000 mL/min oxygen flow rate), ca. 100% extraction of copper from slag into the solution was obtained. X-ray diffraction (XRD) analysis consolidated the experimental results by confirming that no Cu containing phases were present in the leach residue. Results also showed that temperature ≤40 °C had the larger influence on Cu and Fe yield, whereas higher temperature (>40 °C) favored Ni and Zn dissolution. The acid consumption of the optimized leaching process was found to be 23.7 mol of H2SO4 per kg of copper.

Highlights

Copper is among one of base metals which has high economic importance in today's technological world
The results showed that every ton of this copper rich slag carries ca. 500 kg of copper, which is notably higher than copper concentration present in any typical slags as documented in the literature (Schlesinger et al, 2011)
When compared with copper smelting slags produced in the state-of-art refineries, an estimated 98% recovery of copper metal from the investigated raw material would bring the copper level in the residue 1% copper (Forsen et al, 2017). This copper rich slag was shown to be very low in silica

Summary

Introduction

Copper is among one of base metals which has high economic importance in today's technological world. Over 80% of copper slag is land filled with or without treatment (Guo et al, 2018a, 2018b), which is a major industrial concern over space availability and copper slag management (Sarfo et al, 2017). Dumping of such large volumes of slag is the waste of resources and has an adverse effect to the ecological environment (Gorai and Jana, 2003; Zhou et al, 2018)

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