Study of Bioleaching Processes of Technogenic Waste from Mining and Metallurgical Enterprises of Kazakhstan

This study presents an integrated approach for the processing of technogenic tailings from the Balkhash concentrator, combining hydrocyclone classification, microfluidic separation, bioleaching, and geopolymer synthesis. The tailings are characterized by a fine-dispersed silicate matrix and low concentrations of valuable metals, which limit the efficiency of conventional processing methods. Hydrocyclone classification enables effective size separation and stabilization of particle size distribution, providing suitable feed for downstream processes. Microfluidic separation demonstrated selective concentrations of copper, increasing its content in the central fraction up to 0.52–0.58% with recovery up to 70–75% under optimal flow conditions. Bioleaching experiments using acidophilic microorganisms (Acidithiobacillus ferrooxidans and A. thiooxidans) revealed strong dependence on process parameters, achieving maximum recoveries of Cu (63%), Zn (58%), and Fe (43%) at pH 1.8–1.9 and 31–32 °C. The solid residues after bioleaching, composed mainly of aluminosilicates, were successfully utilized for geopolymer synthesis. The obtained geopolymer samples exhibited low water absorption (not exceeding 9.1%) and high compressive strength, meeting the requirements of Kazakhstan standard 26633-2015 (ISO 22965-1). The production of geopolymer materials from these residues contributes to the environmental rehabilitation of tailings storage facilities. The novelty of this work lies in the integration of microfluidic separation with bioleaching for fine tailing processing, enabling both selective metal recovery and subsequent conversion of residues into functional geopolymer materials. The proposed approach provides a sustainable pathway for simultaneous resource recovery and waste valorization, contributing to circular economy strategies in the metallurgical industry.