Recovery of precious and non-ferrous metals from the rebellious complex of mineral raw materials

The results of comprehensive researches aimed to develop the advanced technology of rebellious refractory minerals and ore processing are given in this paper. Some ways in solving the most challenging technological problems associated with complex ores enrichment and hydrometallurgical processing to recover precious and non-ferrous metals, biochemical leaching inclusive, as well as recommendations on processing of leaching solutions aimed at valuable components recovery are proposed. Effects of reagent X on dissolving the non-ferrous and precious metals as well as the associated elements from refractory ore, concentrates and metallurgical production wastes are shown. Reagent X promotes metal leaching through a control of oxygen regime of leaching process. Reagent X, capable to form readily soluble metals hetero-complexes, plays a prominent part. Beneficial effects of reagent X on the mineral polarizing processes in alkali-cyanides media were found. Reagent X pretreatment enhances metals recovery into solution by 20-30 % depending on the process time. Process of Au, Cu, Zn etc., dissolving from rebellious gold-bearing raw materials was studied through the use of unique microorganisms strain; there are identified chemo-physical regularities of chemical leaching process, and the innovation technology of chemical leaching of gold-containing materials was developed

Study of Electroflotation Beneficiation of Low-Sulphide and Refractory Gold-Bearing Raw Materials

The paper presents the results of experiments with electroflotation beneficiation of gold-bearing raw materials. Three variants of ore samples with 0.56, 1.2 and 5.9 g/t gold grades, which also have different mineralogical and phase composition, were taken as objects of study. Based on the ionization effects, as well as changes in electrostatic and electrokinetic properties of the flotation pulp components, different electrode locations in the flotation chamber were considered. Experiments have shown that for electroflotation processing of raw materials with weakly acidic and neutral medium, positive electric potential of pulp, as well as raw materials with complex mineralogical composition, the negative electrode (cathode) should be placed at the surface of foaming and concentrate assembly, and the positive electrode (anode) in the pulp flow. For electroflotation of raw materials with neutral, alkaline pH and negative electric potential of the pulp, the anode is placed at the surface of the concentrate formation and the cathode is placed in the pulp flow. Thus, additional electrolytic treatment of mineral slurry in the flotation process can increase the gold recovery in the flotation concentrate by an average of 20–30%

Harnessing Microwave Technology for Enhanced Recovery of Zinc from Industrial Clinker

This article presents a cutting-edge approach to microwave-assisted processing aimed at enhancing the efficiency of zinc extraction from materials characterized by a high degree of processing complexity. The described technique encompasses two sequential phases: phase transformation under microwave irradiation and leaching in sulfuric acid at ambient temperature. During the phase transformation, implemented through the application of microwave energy, insoluble zinc phases undergo a controlled transition. The experimental results confirm that microwave calcination at 600 °C for 5–7 min is effective for converting ZnS to ZnO without the formation of ZnO∙Fe2O3. Zinc extraction from the clinker reached 46.47% after treatment with microwave radiation at a power of 25 kW for the specified duration. Thus, this study opens up prospects for environmentally friendly zinc extraction from challenging-to-process resources

The Novel Use of Microalgae in the Greening of the Metallurgical Industry

The application of biotechnological methods in the metallurgical industry has the potential to provide an environmentally friendly and cost-effective direction of development. Thiobacillus ferrooxidans, a thionic bacterium, and the microalga Chlamydomonas reinhardtii TN-72 CH were used as complex reagents for extracting gold from sulfide mineral raw materials. The sorption properties of modal and productive multicomponent gold-bearing solutions were studied. The sorption characteristics of the biosorbents were compared with those of sorbents currently used in gold production – the synthetic resin AM2B and GoldCarb activated carbon. The conducted research studying the sorption properties and survival ability of the microalga C. reinhardtii TN-72 CH will make it possible to develop an industrial technology for extracting metal in the hydrometallurgical cycle of gold production. The use of microorganisms in gold hydrometallurgy as an alternative to cyanide methods will reduce the load on the environment while reducing the cost of the technology. In the process of leaching gold-bearing raw materials by microorganisms, even submicroparticles of gold are released, which makes the processing of poor and refractory ores promising. Preliminary biooxidation increases the effectiveness of thiosulfates in terms of both time and gold recovery