Coal mining is a thriving industry and 53% of the coal mined in SouthAfrica is used for electricity generation. Mechanization has made coalmining more efficient, but fines generation has subsequently increased. Upto 6% of the run of mine material can report to the -200 μm fraction.Common problems associated with fines handling include dust formation,storage problems, and high moisture levels. A method to turn this materialinto a saleable product instead of stockpiling it can add value to acompany.Briquetting is a pressure agglomeration method where loose material iscompacted into a dense mass (FEECO International, 2014). The briquettesmust be able to withstand rigorous handling and transport operationswithout disintegrating. This study aims to investigate the optimum binderand moisture conditions required to produce a mechanically strongbriquette using two different binders – a PVA powder (binder A) and astarch powder (binder B).It was found that for binder A the optimum moisture level was 12% to14%. At this moisture level the greatest compression strength gains wereobserved, and low amounts of fines produced in impact and abrasion tests.The minimum amount of binder added while still obtaining a strongbriquette was 0.5% binder A. For binder B the optimum moisture level wasalso 12% and the minimum amount of Binder B to be added was found tobe 1%. Briquettes that were dried outside reached their peak strength afterabout four days, whereas the briquettes that dried inside took about 20days to reach their strength plateau. Hardly any degradation took place onthe surface of the binder A film after exposure of 300 hours of artificialweathering. Thermogravimetric analysis confirmed that neither binder Anor binder B will add to the ash content of the coal fines, as both binderstotally decompose above 530°C.Binder B yielded stronger briquettes after 15 days and also generatedless fines. It is therefore superior to binder A and would be recommendedfor further use.
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