Carbon Dioxide as a Catalyst to Improve the Grinding Efficiency of a Chalcopyrite-Bearing Ore

Abstract

In response to the challenge of high energy consumption in grinding, this study proposed a novel technology that employs carbon mineralization to reduce ore hardness and thus improve the grinding efficiency of chalcopyrite-bearing ore. The effects of solid concentration, reaction duration, and CO₂ pressure during ex-situ treatment on the performance of carbon mineralization-assisted grinding were thoroughly investigated. Additionally, a suite of analytical techniques, such as inductively coupled plasma-mass spectrometry (ICP-MS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), was used to analyze the ion dissolution behavior, phase transformation process, and micromorphological changes of the chalcopyrite-bearing ore after ex-situ CO₂ treatment to elucidate the grinding aid mechanism. The results of grinding tests indicated that the optimal grinding aid effect was achieved at a solid concentration of 50%, a treatment duration of 5 h, and a CO₂ partial pressure of 100 psi. Correspondingly, the bond work index of the chalcopyrite-bearing ore decreased from 11.72 to 10.66 kWh/t with a reduction of 9.04%, and the carbon mineralization capacity of the chalcopyrite-bearing ore reached 2850 g of CO₂/t. The mechanistic studies revealed that during the ex-situ CO₂ treatment, hydrogen ions released from dissolved CO₂ promoted the dissolution of certain silicate minerals within the chalcopyrite-bearing ore, resulting in the formation of H₄SiO₄ and the development of fractures. Concurrently, generated CO₃^2– reacted with silicate minerals containing Ca, Mg, and Fe, converting them into carbonate minerals with lower hardness, leading to reduced mechanical strength and enhanced grindability of the ore. Overall, carbon mineralization demonstrates significant potential for improving ore grindability in mineral processing applications.