Zircon Concentrate Enrichment by Dry Magnetic Separation and Centrifugal Air Separation

Abstract

The possibility of enrichment and radioactivity reduction of zirconium concentrate obtained at the Obukhovsky mining and processing plant, located in the North Kazakhstan region, was investigated. The zircon concentrate was enriched and deactivated by dry magnetic separation and centrifugal air separation. The elements distribution over the grain surface of the obtained fractions was studied and the particle size distribution was determined by energy dispersive X-ray spectroscopy. The characteristics of the initial zircon concentrate were determined. The average particle size was 70 µm, the bulk density was 2.21 g/cm3, the true density was 4.05 g/cm3, the activity was 10.3 ± 0.6 kBq/kg, and the ZrO2 content was 44.85 wt.%. Dry magnetic separation was carried out at a magnetic induction value of 1.3 T in the separator working area and a feed rate of 5 g/min. Centrifugal air separation was carried out using a rotary classifier at rotor speeds of 3000, 980, and 600 rpm, consuming 2000 Nm3 of air per hour and a concentrate flow of 20 kg/h. The scheme of zircon concentrate processing to produce three final products was proposed. The first is the zircon concentrate having a low activity (ZrO2 content = 55.4 wt.%, P = 5.8 ± 0.6 kBq/kg). The second is the titanium-containing fraction having a low zirconium content (ZrO2 content = 17.7 wt.%, P = 14.2 ± 0.6 kBq/kg). The third is the concentrate having a considerable zirconium content and high activity (ZrO2 content = 23.5 wt.%, P = 12.8 ± 0.6 kBq/kg).