Kinetics and Mechanisms of Chalcopyrite Dissolution at Controlled Redox Potential of 750 mV in Sulfuric Acid Solution

Yubiao Li,Gujie Qian,Zhenlun Wei,Andrea Gerson,Jun Li

doi:10.3390/min6030083

Yubiao Li, Gujie Qian + Show 3 more

Open Access

https://doi.org/10.3390/min6030083

Copy DOI

Abstract

To better understand chalcopyrite leach mechanisms and kinetics, for improved Cu extraction during hydrometallurgical processing, chalcopyrite leaching has been conducted at solution redox potential 750 mV, 35–75 °C, and pH 1.0 with and without aqueous iron addition, and pH 1.5 and 2.0 without aqueous iron addition. The activation energy (Ea) values derived indicate chalcopyrite dissolution is initially surface chemical reaction controlled, which is associated with the activities of Fe3+ and H+ with reaction orders of 0.12 and −0.28, respectively. A surface diffusion controlled mechanism is proposed for the later leaching stage with correspondingly low Ea values. Surface analyses indicate surface products (predominantly Sn2− and S0) did not inhibit chalcopyrite dissolution, consistent with the increased surface area normalised leach rate during the later stage. The addition of aqueous iron plays an important role in accelerating Cu leaching rates, especially at lower temperature, primarily by reducing the length of time of the initial surface chemical reaction controlled stage.

Highlights

Chalcopyrite is the Earth’s most abundant Cu-bearing mineral [1]
Chalcopyrite dissolution has been conducted at 750 mV, 35–75 ̋ C and pH 1.0 and pH 1.5 and 2.0 without iron addition
The Ea values derived indicate that chalcopyrite dissolution is initially controlled by surface chemical reaction which is associated with the activities of solution speciation of Fe3+ and H+ with reaction orders of 0.12 and0.28

Summary

Introduction

Chalcopyrite is the Earth’s most abundant Cu-bearing mineral [1]. Improved knowledge of chalcopyrite dissolution kinetics and mechanisms is of both geochemical and industrial interest [2,3,4,5].Chalcopyrite is one of the most difficult minerals to process economically [6] with Cu primarily produced pyrometallurgically. Chalcopyrite is the Earth’s most abundant Cu-bearing mineral [1]. Improved knowledge of chalcopyrite dissolution kinetics and mechanisms is of both geochemical and industrial interest [2,3,4,5]. Chalcopyrite is one of the most difficult minerals to process economically [6] with Cu primarily produced pyrometallurgically. A great deal of attention has been paid to the development of hydrometallurgical processing routes [5,6,7,8,9,10,11,12,13,14,15,16,17] due to the potentially attractive economics, especially when chalcopyrite is present at a low grade, and reduced environmental impact [18,19]. Chalcopyrite is frequently associated with pyrite (FeS2 ), the predominant contributor to the serious environmental issue of acid and metalliferous drainage (AMD), but understanding of the contribution of chalcopyrite to AMD is incomplete

Objectives

Methods

Results

Conclusion