Bio-Physiochemical Beneficiation of Low Grade Coal from Lakhra Mine, (Sindh) Pakistan

Abstract

Low grade coal of Lakhra mines was beneficiated using bioleaching technology. This technique has more advantages over their counterparts such as chemical and physical techniques due to its easy processing, simplicity, having no environmental pollution, economic feasibility and maximum removal of contamination like sulfur and ash present in coal composition. Presently bacterial strain of Thiobacillus ferrooxidans was isolated and purified from indigenous sources i.e. Coal mine drainage, hot spring water and soil adjacent to sulphide mineral ore, using simple screening, serial dilution and growth culturing. Isolated microorganisms were applied on low grade reduced size/powdered coal collected from mines site. Chemical evolution of coal revealed that this sample has 44.45% of ash and 7.03% of sulfur along with 2.3% of Iron. Microbial processing was continued for maxim 36 days which successfully reduced up to 57.33% of sulfur, 75.21% ash and 87.7% iron. Optimization of parameters such as pH, grain size, aeration time and pulp density were also been optimized. The results were confirmed by 100, 50 and 20 magnification of scanning electron microscope (SEM) fallowed by Fourier transform infrared spectroscopy (FTIR). Contribution/ Originality: This study contributes in existing literature about the bio desulphurization of low grade coal having high contaminations. Presently we have selected the sample from Lakhra mines with high percentage of sulfur, ash and associated minerals for bioleaching process. It is found successful for beneficiation of such type of coals. 1. INTRODUCTION Need of energy is the basic requirement of every living body; various sources are available for fulfillment like solar, wind, electrical, and coal sources. All other sources of energy are comparably neat & clean, however use of coal for energy purpose have adverse effects for our environment, animal health, plants and damaging of solid structures. This behavior is due to presence of contaminations in coal composition such as high sulfur, minerals and burden of ash; on combustion of coal it produces sulfur dioxide, sulfur trioxide and also producing high ash burden