Process Factors for Preparing Ultra-low-ash Low-rank Coal Using Oily Bubble Flotation

摘要

Ultra-low-ash low rank coal is an important raw material for chemical industry. In order to utilize the fine-grained low rank coal effectively and solve the problems of poor floatability, severe entrainment, and high consumption of oil collectors in flotation, the oily bubble flotation method was introduced. Based on the atomization and flash evaporation method, the new oil bubble generation device was designed. Then, it was used for the oily bubble flotation test of the Cuner coal samples, Shendong Mining Area. Therefore, the optimum process conditions for the oil bubble floatation were explored. The results showed that the best ultra-low-ash concentrate with ash content of 3.02% and combustible matter recovery of 94.47% was obtained at the pulp concentration of 66.7g/L, the frother dosage of 0.77 kg/L and the collector dosage of 0.90 kg/L. It seems that the selectivity of flotation concentrate is improved and the consumption of flotation reagents is reduced by oily bubble flotation. These works could contribute to the preparation of ultra-low-ash low rank coal and the expansion of coal flotation method.