Experimental study on enhancement of flotation of jig middling through in-depth grinding liberation and use of compound reagent

Recleaning of liberated coking coal middling is of great significance for the recovery of scarce coking coal resource. The jig middling produce by a coking coal preparation plant under Hebi Coal and Electricity Co. Ltd. is taken as the object to conduct the experimental study on enhancement of flotation of the middling through in-depth grinding liberation and use of compound reagents. As shown by study results, with the middling crushed down to a size of < 0.5 mm, it contains a higher proportion of interlocked grains and lower proportion of suitable sizes of particles; at an optimum grinding time of 3 minutes, a maximum corresponding yield of flotation concentrate can be obtained while the yield of the < 0.074 mm sizes in the ground product is as high as 66.22%; with the use of 1600 ternary collector and Q7 frother at a respective dosage of 500 g/t and 150 g/t, the optimal flotation indices can be expected; and through one roughing and one cleaning processes, the concentrate with a yield of 53.83% and an ash of 10.25% can be produced, well demonstrating the effectiveness of recleaning of jig middling after it is thoroughly liberated through deep grinding.