Scientific Research Geotechnological Center of Far Eastern Branch of RAS (Petropavlovsk-Kamchatsky, Russia)

Ocheretyana S. O., Senior Researcher, Candidate of Biological Sciences, blossom-so@yandex.ru
Iodis V. A., Leading Researcher, Candidate of Engineering Sciences, iodisva@mail.ru

Bacterial-chemical leaching (BCL) is a proven biotechnological method for extracting non-ferrous and rare metals from sulfide ores, utilizing acidophilic chemolithotrophic microorganisms such as Acidithiobacillus ferrooxidans. However, its efficiency is often limited by the formation of passivating oxidation films that restrict microbial access to mineral surfaces. This study investigates the impact of ultrasonic pretreatment of ore slurry, followed by screening, on the efficiency of BCL for the extraction of nickel, copper, and cobalt from low-grade sulfide ores. Ultrasonic treatment disrupts oxidation films, generates microcracks, and increases specific surface area, thereby enhancing bacterial colonization and accelerating leaching kinetics. Liquid-phase separation further facilitates downstream solid-phase processing by concentrating valuable components and reducing contamination. Experiments were conducted on sulfide ore from the Shanuch deposit (Kamchatka), containing pyrrhotite, pentlandite, chalcopyrite, and violarite. Comparative tests—one with ultrasonic pretreatment and one control—demonstrated significantly improved outcomes in the treated sample. The bioreactor with pretreated ore showed accelerated bacterial growth (up to 287 × 109 cells/ml), reduced pH (2.13–2.17), elevated redox potential (up to 290 mV), and intensified iron redox activity. Metal concentrations in the leachate reached: Ni – 4478 mg/L, Cu – 253 mg/L, and Co – 132 mg/L, all substantially exceeding the control values. The results confirm that ultrasonic pretreatment significantly enhances the performance of bacterial-chemical leaching, offering a viable method for intensifying metal recovery from refractory sulfide ores.

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