The features of classification in hydrocyclones in the course of titanium magnetite ore grinding

Abstract

Research aim is to assess the use of hydrocyclones in the closed circuit of the second stage of grinding for the conditions of EVRAZ KGOK dressing mill. Methodology. Industrial tests were carried out under various solid phase capacities of two hydrocyclones GTs-710. Industrial testing results and their discussion. Increase in the content of solid and –71 µm class in the feed of the hydrocyclone results in discharge output increase. Decrease in the content of solid and increase in the content of –71 µm class result in the increased content of –71 µm class in the discharge. When increasing the content of solid in the feed of the hydrocyclone, the extraction of all size classes into the discharge of the hydrocyclone increases. At the same time the efficiency of classification by –71 µm class reduces. 84 "Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal". No. 1. 2021 ISSN 0536-1028 Iron content values in hydrocyclone discharge and sand. The classifying hydrocyclone partially separates by density resulting in different content values of iron in discharge and sand. Under pulp high density, the content of iron in the discharge is higher than that of iron in sand. Under low density of feed pulp, there is less iron in the discharge, compared to that in sand; that is due to small particles of titanium magnetite entering the sand. Summary. The indicators of separation by size in hydrocyclone are significantly affected by the content of solid and –71 µm class in the feed. The drawback of the hydrocyclone is partial separation by density (in iron) which results in overgrinding of titanium magnetite in the closed circuit of grinding and higher losses in subsequent procedures of wet magnetic separation. The technologies which make it possible to reduce overgrinding of titanium magnetite in the closed circuit of grinding are as follows: automatic control system for classification in the hydrocyclone, the use of hydraulic screens instead of hydrocyclones, and multi-stage dressing.