Regular Article

Enrichment of a Nigerian chromite ore for metallurgical application by dense medium flotation and magnetic separation

¹ Department of Industrial Chemistry, University of Ilorin, P.M.B.1515, Ilorin 240003, Nigeria
² CSIR–Institute of Minerals and Materials Technology, Bhubaneswar 751013, India

^* e-mails: ibkuranga@gmail.com; alafara@unilorin.edu.ng

Received: 11 July 2018
Accepted: 13 September 2018

Abstract

This study, focused on the beneficiation of a Nigerian complex chromite ore sourced from Tunga-Kaduka, Anka Local Government of Zamfara State, Nigeria, assaying 45.85% Cr₂O₄ and 54.15% mineral impurities, was enriched concurrently through sink floatation and magnetic separation techniques. The chromite ore initially analyzed to contain silicate impurities was found not suitable for metallurgical purposes. Thus, enrichment was examined through gravity separation studies using organic liquid with different specific gravities at 2.8, 3.3, and 4.0. The separation of chromite ore with lowest particle size fraction was done using Mozley mineral separator followed by the magnetic separation of the sink product by magnetic separator. The results obtained revealed about 77% of the total material containing 300 μm particle size, 52% ˂ 212 μm and 17% below 75 μm. Subsequent analysis of the beneficiated ore was carried out by wet chemical analysis and atomic absorption spectrophotometer. The results showed that Cr₂O₄ content increased to 78.34% from initial 45.83% with maximum Cr:Fe ratio of 3.2:1, representing 84.27% of chromium metal present in the ore. The enrichment of Cr₂O₄ obtained in this study could be found metallurgically applicable in the electro-deposition and ferro-chromium alloy production practices.