Improving low-rank coal flotation using a mixture of oleic acid and dodecane as collector

Mineral Processing and Technology Research Centre, Department of Metallurgy, School of Mining, Metallurgy and Chemical Engineering, Faculty of Engineering and the Built Environment, University of Johannesburg, Doornfontein Campus, 55 Beit St, Johannesburg 2028, South Africa.

^* Corresponding Author: Tel: +27 84 216 9346 Email Address: nbaloyi@uj.ac.za

Abstract

Low-rank coals (LRC) are abundant but underutilized due to their hydrophilic nature and high oxygen content, which hinder flotation efficiency. Traditional single-collector systems often result in low recovery rates and high reagent consumption. This study investigates the use of a mixed collector system comprising oleic acid (OA) and dodecane (D) to improve LRC flotation. Response Surface Methodology (RSM) was employed to optimize the dosing ratio of OA to D. Laboratory-scale flotation tests demonstrated that mixed collectors significantly enhance flotation efficiency, achieving recovery rates up to 65.5% and reducing ash values from 55.6% to 16.7%. Optimal conditions were identified at a dodecane dosage of 300 g/t and an oleic acid dosage of 255.5 g/t. The findings underscore the potential of mixed collectors to enhance coal hydrophobicity, thereby improving recovery and separation from gangue minerals. This approach offers a sustainable solution for LRC beneficiation, minimizing waste and enhancing economic viability.