Leaching Chalcopyrite Concentrate with Oxygen and Sulfuric Acid Using a Low-Pressure Reactor

Josué Cháidez,José Parga,Raúl Carrillo,Jesús Valenzuela,Isaías Almaguer

doi:10.3390/met9020189

Abstract

This article presents a copper leaching process from chalcopyrite concentrates using a low-pressure reactor. The experiments were carried out in a 30 L batch reactor at an oxygen pressure of 1 kg/cm2 and solid concentration of 100 g/L. The temperature, particle size and initial acid concentration were varied based on a Taguchi L9 experimental design. The initial and final samples of the study were characterized by chemical analysis, X-ray diffraction and particle size distribution. The mass balance showed that 98% of copper was extracted from the chalcopyrite concentrate in 3 h under the following experimental conditions: 130 g/L of initial sulfuric acid concentration, temperature of 100 °C, oxygen pressure of 1 kg/cm2, solid concentration of 100 g/L and particle size of −105 + 75 μm. The ANOVA demonstrated that temperature had the greatest influence on copper extraction. The activation energy was 61.93 kJ/mol. The best fit to a linear correlation was the chemical reaction equation that controls the kinetics for the leaching copper from chalcopyrite. The images obtained by SEM showed evidence of shrinking in the core model with the formation of a porous elemental sulfur product layer.

Highlights

Chalcopyrite is the most abundant sulfide copper mineral in the Earth’s crust
Hydrometallurgical processes have a series of advantages in comparison to pyrometallurgical processes, for example, the required plant capacity is smaller (
Thermodynamics required to carry out the decomposition of chalcopyrite

Summary

Introduction

Chalcopyrite is the most abundant sulfide copper mineral in the Earth’s crust. Generally, it is associated with other compounds such as galena, sphalerite, pyrite, arsenic, antimony or bismuth sulfides; it is often bonded with valuable metals such as silver and gold.From an environmental and economic perspective, further technological developments for obtaining high-grade copper in an efficient and cost-effective manner are desirable. Chalcopyrite is the most abundant sulfide copper mineral in the Earth’s crust. It is associated with other compounds such as galena, sphalerite, pyrite, arsenic, antimony or bismuth sulfides; it is often bonded with valuable metals such as silver and gold. From an environmental and economic perspective, further technological developments for obtaining high-grade copper in an efficient and cost-effective manner are desirable. Today, companies such as Beijing Nonferrous Metal, JX Nippon Mining & Metals, Freeport McMoran, Freeport Minerals, Phelps Dodge, Outotec, BHP Billiton, etc. Hydrometallurgical pilot plant projects such as Outotec, Galvanox, Activox and AAC/UBC have implemented some of the latest technology for mineral leaching, and several demo plants have Companies such as Beijing Nonferrous Metal, JX Nippon Mining & Metals, Freeport McMoran, Freeport Minerals, Phelps Dodge, Outotec, BHP Billiton, etc. are investing in hydrometallurgical research because of the potential associated economic benefits [1].

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