Impact of a Compound Collector on the Recovery of a Low-Rank Coal by Flotation

Kabelo Nkuna, Willie Nheta

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Flotation remains the cornerstone for recovering low-rank coal leveraging on differences in mineral surface properties. However, the efficiency of standard non-ionic surfactants like kerosene and diesel oil has been suboptimal. This study investigated the impact of combining pine oil (PO) with oleic acid (OA) on low-grade coal flotation response, employing Response Surface Methodology based on a Box-Behnken matrix to design the flotation experiments, with combustible matter recovery (%) as the primary response. Chemical analysis identified the notable presence of silica and alumina, while mineralogical investigations revealed the dominance of kaolinite and anhydrite as major gangue constituents. The coal surface was characterised by roughness, irregular strips and plenty of cracks. Zeta potential studies elucidated collector adsorption states, highlighting the influence of pH on surface charge variations. Fourier-transform infrared spectroscopy analysis indicated the presence of polar functional groups on the coal surface with observed modifications after compound collector addition. Flotation results revealed that the oleic acid-pine oil mixture, particularly at a 1:1 ratio, yields an exceptional recovery of 85.46% at a slurry pH of 8.5. The optimum condition to obtain maximum combustible matter recovery of 86.48% was found to be at an oleic acid dosage of 100 g/t, a pine oil dosage of 100 g/t and a pH of 10. The study highlighted the pivotal role of slurry pH in influencing recovery with higher pH levels correlating with increased recoveries. In conclusion, fatty acids, specifically oleic acid, emerged as potential polar collectors to combine with non-ionic collectors for the recovery of low-grade coal. The findings advocate for further exploration of surface chemistry, mineralogical interactions and alternative collectors. Additionally, scaling up studies and environmental impact assessments are recommended to propel the practical applicability of the compound collector system in industrial settings.

Original languageEnglish
Title of host publicationProceedings of the 10th World Congress on Mechanical, Chemical, and Material Engineering, MCM 2024
EditorsHuihe Qiu
PublisherAvestia Publishing
ISBN (Print)9781990800443
DOIs
Publication statusPublished - 2024
Event10th World Congress on Mechanical, Chemical, and Material Engineering, MCM 2024 - Barcelona, Spain
Duration: 22 Aug 202424 Aug 2024

Publication series

NameProceedings of the World Congress on Mechanical, Chemical, and Material Engineering
ISSN (Electronic)2369-8136

Conference

Conference10th World Congress on Mechanical, Chemical, and Material Engineering, MCM 2024
Country/TerritorySpain
CityBarcelona
Period22/08/2424/08/24

Keywords

  • Compound collector
  • Flotation
  • Low-rank coal
  • Response surface methodology
  • Surfactants

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • General Chemical Engineering

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