Material composition and technological evaluation of lead–zinc ore

The relevance of this study is driven by the worsening challenges of the mineral resource base at mines. Reserves of ores containing 6% lead and 3% zinc, processible by a direct selective scheme, are being depleted. Under these conditions, active efforts are underway to involve technologically refractory ores, characterized by complex mineral dissemination patterns and an unfavorable ratio of valuable component contents, in processing. A comprehensive study of the material composition and technological properties of lead–zinc ore from the upper horizon of the Main Ore Body at the Gorevskoe deposit was conducted. It was found that metamorphism and accompanying metasomatism led to the remobilization of ore minerals, fine sulfide dissemination, and to the complex intergrowths sulfides with nonmetallic minerals. The main technological challenges for beneficiation were identified: uneven distribution of galena, close association of sulfides with each other and with quartz, and the presence of oxidized mineral forms. It is demonstrated that the low efficiency of the current selective flotation scheme for the studied ore is a direct consequence of its material composition and microstructural features, resulting in a zinc recovery of 49.75%. A bulk flotation scheme with two-stage grinding was developed and optimized, based on the existing circuit of equipment and list of reagents. Testing the scheme in a closed cycle showed its high efficiency: recovery into bulk concentrate reached 85.52% Pb and 86.79% Zn. It is determined that the main metal losses (~68% Pb and ~53% Zn of total losses) are concentrated in -0.040 mm size fraction, which defines the direction for the further optimization of flotation technology for fine sludge.