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<p>The depletion of easily milled (free-milling) gold deposits has driven the mining industry to increasingly rely on refractory ores, particularly those containing arsenic (As)- and antimony (Sb)-bearing sulfides, for future gold (Au) production. Today, Au derived from refractory ores accounts for roughly one-third of global output, and this share is expected to increase further. Conventional extraction methods are often ineffective for these ores because of their complex mineralogy, where Au is encapsulated within sulfide matrices such as pyrite, arsenopyrite, and stibnite, while coexisting metal elements consume leaching reagents and hinder Au dissolution. In this review, strategies to enhance Au extraction from As/Sb-bearing refractory ores are discussed, including Ultrafine Grinding, Bio-oxidation, Pressure Oxidation, Alkaline Pretreatment, and cyanide-free leaching systems, together with the mechanistic relationships between pretreatment, sulfide decomposition, lixiviant stability, and downstream Au recovery. Among these, Ultrafine Grinding, Bio-oxidation, and Alkaline Pretreatment exhibit strong potential for liberating encapsulated Au prior to leaching. Of the alternative leaching reagents, thiosulfate systems have emerged as promising replacements for cyanide; however, significant challenges remain, including sulfide-induced reagent decomposition, passivation phenomena, high reagent consumption, and inefficient downstream Au recovery. Emerging techniques such as Au cementation using activated carbon and zero-valent aluminum from thiosulfate pregnant solutions have shown encouraging results. In addition, recent advances in selective pretreatment and improved recovery technologies indicate that integrated hydrometallurgical systems may provide more sustainable approaches for processing refractory Au ores. Future industrial implementation will depend on the development of integrated hydrometallurgical flowsheets capable of simultaneously optimizing sulfide decomposition, reagent stability, environmentally responsible management of As/Sb-bearing residues, and efficient Au recovery from cyanide-free systems.</p> Graphical abstract <p></p>

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A review of hydrometallurgical strategies for gold recovery from arsenic- and antimony-bearing refractory ores: mechanisms, challenges, and emerging trends

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年7月3日

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  • Takunda Joseph Mhandu,
  • Ilhwan Park,
  • Sanghee Jeon,
  • Walubita Mufalo,
  • Yewuhalashet Fissha,
  • Takahiko Arima,
  • Atsushi Furusaki,
  • Mayumi Ito,
  • Naoki Hiroyoshi

摘要

The depletion of easily milled (free-milling) gold deposits has driven the mining industry to increasingly rely on refractory ores, particularly those containing arsenic (As)- and antimony (Sb)-bearing sulfides, for future gold (Au) production. Today, Au derived from refractory ores accounts for roughly one-third of global output, and this share is expected to increase further. Conventional extraction methods are often ineffective for these ores because of their complex mineralogy, where Au is encapsulated within sulfide matrices such as pyrite, arsenopyrite, and stibnite, while coexisting metal elements consume leaching reagents and hinder Au dissolution. In this review, strategies to enhance Au extraction from As/Sb-bearing refractory ores are discussed, including Ultrafine Grinding, Bio-oxidation, Pressure Oxidation, Alkaline Pretreatment, and cyanide-free leaching systems, together with the mechanistic relationships between pretreatment, sulfide decomposition, lixiviant stability, and downstream Au recovery. Among these, Ultrafine Grinding, Bio-oxidation, and Alkaline Pretreatment exhibit strong potential for liberating encapsulated Au prior to leaching. Of the alternative leaching reagents, thiosulfate systems have emerged as promising replacements for cyanide; however, significant challenges remain, including sulfide-induced reagent decomposition, passivation phenomena, high reagent consumption, and inefficient downstream Au recovery. Emerging techniques such as Au cementation using activated carbon and zero-valent aluminum from thiosulfate pregnant solutions have shown encouraging results. In addition, recent advances in selective pretreatment and improved recovery technologies indicate that integrated hydrometallurgical systems may provide more sustainable approaches for processing refractory Au ores. Future industrial implementation will depend on the development of integrated hydrometallurgical flowsheets capable of simultaneously optimizing sulfide decomposition, reagent stability, environmentally responsible management of As/Sb-bearing residues, and efficient Au recovery from cyanide-free systems.

Graphical abstract