A review of Preg-robbing and the impact of chloride ions in the pressure oxidation of double refractory ores

ABSTRACT

As the mining industry moves toward the extraction of increasingly complex ores to meet global demands, one of the challenges in gold processing is the treatment of preg-robbing ores. Preg-robbing occurs when gold that can be otherwise recovered is lost through adsorption, reduction, or absorption by carbonaceous compounds or other clays and minerals in the ore. This review discusses the sources and mechanisms of preg-robbing and examines several operating factors that can exacerbate losses. Historical and current techniques to mitigate preg-robbing will be critically reviewed, along with promising new approaches that are in development or have recently been commercialized, such as high-temperature caustic conditioning, with special consideration to costs and sustainability. A secondary section details the interactions between chloride and gold in minerals processing, focusing on the negative impact of chloride ions during the pressure oxidation of double refractory ores, and examines the techniques undertaken by industry to approach this issue.

KEYWORDS:

• Preg-robbing
• carbon removal
• pressure oxidation
• chloride ions

Acknowledgments

This work was supported by the Australian government through the Australian Research Council Linkage Project Grant (LP160101760) and the Zijin Mining Group. The views expressed herein are those of the authors and are not necessarily those of the Australian Government, Australian Research Council, or the Zijin Mining Group. Special thanks to our reviewers for their insightful comments in improving the quality of this review.

Disclosure statement

In accordance with Taylor & Francis policy and our ethical obligations as a researcher, we report no financial and/or business interests from the research reported in the enclosed paper.

Additional information

Funding

This work was supported by the Australian Research Council [ARC LP160101760].