Experimental study on ash reduction of concentrate in flotation of high-ash hard-to-float fine coal

In Baotou Mining Area, the concentrate yielded through flotation of high-ash hard-to-float fine coal is excessively high in ash. To address this problem, laboratory-scale test is made on such factors as dosage of kerosene, froth scraping time, pulp conditioning time, ash reduction level of flotation column and < 0.5 mm fine coal flotation result in relation to grinding time, so as to compare the results obtained under different floatation conditions. Test result indicates that the increase of ash of concentrate is mainly attributed to the presence of high-ash fine coal and nonselective floating up of locked middlings. In comparison with other methods, grinding flotation can yield a much better result. Under test conditions, the use of this process at a grinding time of 0.50 minutes can yield a concentrate with an ash of 14.98% and a yield of 61.02%.