DEVELOPING TECHNOLOGICAL PRINCIPLES FOR OBTAINING ZINC CONCENTRATES FROM OXIDISED ORES BY THE GRINDING AND FLOTATION METHODS

Abstract

The continuing depletion of limited reserves of sulphide zinc-bearing polymetallic ores makes it difficult to meet the growing demand for metallic zinc. Therefore, the use of oxidised, difficult-to-process ores and their effective processing to extract zinc compounds, with due consideration for the environmental issues that arise in the process, is considered an important scientific and technical task.

Research has been conducted and technological principles have been established for the deep sulphidation of the surface layers of particles of oxidised zinc-bearing polymetallic ore, which is subjected to desliming with an aqueous solution of sodium metasilicate Na₂SiO₃ followed by grinding with partial sulphidation,  and the effective and controlled flotation process to  ensure the final and complete sulphidation. The sulphidation of zinc-containing oxidised ore was carried out using sodium sulphide Na₂S.

The grinding of oxidised ore in an aqueous medium was carried out to increase the contact surface area of the particles with the introduced sulphidising agent Na₂S . To increase the efficiency of sulphidation in the flotation process and neutralise the undesirable influence of various compounds present in the ore, ammonium nitrate NH₄NO₃ was used, which made it possible to increase the extraction of zinc-containing components upto 80%.

Based on the results of comprehensive studies, the optimal parameters and conditions for grinding processes were determined, ensuring the stable production of the -0.074 mm fraction and final sulphide flotation. At the same time, the consumption of flotation reagents was optimised: a collector in the form of sodium isoamyl xanthate  NaIX, an activator in the form of copper sulphate CuSO4, and a frother, for which pine oil was used. A mandatory condition for a high-quality sulphide flotation process was to maintain a pH of 10.

Based on the results obtained, technological principles and a scheme for obtaining high-quality zinc concentrates from oxidised polymetallic ores of Armenian deposits were developed using deep sulphidation in the grinding and flotation processes.