DETERMINATION OF THE EFFECT OF SEQUENTIAL CLASSIFICATION ON THE EFFICIENCY OF PRIMARY CLASSIFICATION IN THE GRINDING OF MAGNETITE QUARTZITES

Abstract

In modern mineral processing, the beneficiation of mineral raw materials is a key stage that determines the economic feasibility and efficiency of further processing. Hydraulic classification methods, which enable the separation of mineral pulp by particle size and density, are of particular importance. Among these methods, hydrocyclones play a leading role, offering high throughput at relatively low energy consumption. Hydrocyclones are widely used at processing plants for preliminary classification and separation of fine materials, pulp preparation for magnetic or flotation beneficiation, removal of waste in wet processing circuits, and sometimes for product thickening prior to feeding thickeners or filters. The main advantages of hydrocyclones include simple design, absence of moving parts, high reliability, and the ability for continuous operation in automated systems. However, alongside these advantages, hydrocyclones also exhibit several significant drawbacks: low classification efficiency in the presence of narrow size fractions, high sensitivity to variations in feed pressure and pulp density, limited ability to separate particles of similar density or size, and the formation of a turbulent core that reduces separation selectivity. These limitations lead to inefficient classification, increased circulating loads, decreased overall process productivity, excessive overgrinding, and elevated energy consumption. These challenges are particularly evident when processing complex mineralogical compositions or when fine fraction separation is required. An important approach to improving classification efficiency is the implementation of sequential (multi-stage or circulating) classification, involving multiple stages of material treatment with re-classification of misclassified fractions.