Quality improvements for South African coal fines by flotation with montenol and agglomeration

Abstract: Coal is an important fossil fuel and as a source of energy for South Africa and globally. Fine coal has been since an unattractive product because of problems associated but not limited to handling and transportation. With the depreciation of coal quality, better coal products are reserved for the export market leaving the poor quality coal products for domestic electricity generation. Based on the latter, this has resulted in interest and advancement in the coal processing techniques and progressive technologies. With these recent developments, fines can be processed, prepared and sold for profit. The current work focused of flotation of discards with the aim to upgrade the quality of coal. Flotation with Montenol 800 and 505 produced a clean coal product with high ash reduction with a very good combustibles recovery after 30 and 35 minutes milling of the fine coal sample, but this has proven to be over milling as coal is soft. This is supported by the sampled milled for only one minute where there was consistency over 40% separation efficiency over all different times employed. The ash rejections were over 40% and 45% for Montenol 505 and 800 respectively with the very high combustible recovery higher than 95% for Montenol 505. The results showed that fine coal cleaning using Montenol is possible to increase the quality of coal. The sample was further agglomerated using different binders; all binders considered yielded bigger pellets with only a small fraction of particles that were less than 5mm. In addition, it was found that the final product was of a better quality in terms of reduced moisture, CV and ash content

Quantitative XRD analysis of different coal samples to understand their ashing process during the initial stages of combustion

Abstract: Coals in general have very complex chemistry and depending on the intended usage, further challenges are experienced. Such challenges vary from the methods mining and cleaning that should be employed to yield the best quality coal for the specified usage and the final products which are produced from coal use. It is therefore very important to understand the chemistry of raw coal and the ashing properties of such coals and the information from this work can also assist in highlighting the environmental and health aspects that are linked to processing and usage of coal. This work focused on a qualitative studies using XRD to analyze five different coal samples and the chemistry change during the ashing process which takes place during the coal combustion process. An ashing process was conducted on the five samples at 350⁰C, 500⁰C, 750⁰C and 1000⁰C and their results where compared to the composition of the raw coal. The results from this work showed that there are a total of up to 40 major phase-mineral compositions found in the samples analyzed, of which some of them are one phase-mineral composition that appears as different phases/forms in the coal ash

Recent developments in beneficiation of fine and ultra-fine coal - Review paper

Abstract: Generation of fines and ultra-fine is concept that mining and metallurgical sector can never shy away from since exploration coal commodity began. These coal fines and ultra-fines are what coal mines regard(ed) as waste material without economic value until present moment. Poor technologies in the past lead to stockpiling of large quantity of fines and ultra-fines and again increase in mechanization in mining has led to the generation what is considered as waste in large quantities making it thus difficult to treat the coal. This paper reviews recent developments in minerals processing beneficiation technologies of coal fines and coal ultra-fines

Coal mining and the environmental impact of Acid Mine Drainage(AMD): A review

In spite of the growing global initiatives towards achieving clean energy, coal remains a dominant source of electricity generation, a fuel for iron and steel production, an important entity among road construction materials and a commodity for foreign exchange earnings for many nations. Coal mining from old and active sites remains a source of an environmental problem described as acid mine drainage (AMD). AMD is produced when sulfide present in waste rocks or tailings in coal mines reacts with air and water in a microbes facilitated oxidation to form solutions with high acidity. The acids formed by these chemical and biological conditions further release heavy metals present in the host rock in concentrations higher than are acceptable by environmental standards (pb;0.01, Zn;5, Cu;2, Fe;0.3 mg/l as prescribed by WHO and Encyclopedia of Environmental Science,2000) such that soils, surface and underground waters are contaminated. Consequently, the human population which derives her livelihood in the mine zones, in form of crop production and fishing/modern aquaculture is endangered by terminal health diseases. This article aims at bringing forth, the urgent need to work towards achieving goal six of the United Nations Sustainable Development Goals, 2030 (SDGs-6) which is clean water and sanitation while enriching the knowledge repository of the environmental problem for the purpose of teaching, research, community services and policy making. An overview of AMD menace, variables which influence its formation, selected areas that have been impacted, and a brief analysis of its treatment cost have been discussed with a list of concluding remarks in the paper. Keywords: Coal, Mining, Environmental , AM