Research On Pre-Desliming Flotation Process Of Hard-To-Float Coal Slime With High-Ash Fine Fraction

With the proportion of high-ash fine fraction in coal slime increasing, rare coal, such as coking coal and fat coal, is used for thermal coal, which caused great waste of resources. In view of the above difficult problems, the hard-to-float bituminous coal of Tangshan Kailuan mine was taken as research samples, flotation characteristics of high-ash fine fraction hard-to-float fine coal were based on wet screening-flotation under laboratory conditions; pre-desliming process of small taper angle hydrocyclone and flotation technology of the underflow were researched by the method of laboratory and intermediate test.The results of experimental study on the coal slurry characteristics show that, clay mineral is the main gangue mineral in coal slime, such as kaolinite and illite; The fine clay content of-0.045 mm is higher than the original coal slime, and a large number adheres to the surface of coal particles; when clean coal ash is 11.00%, washability of +0.045 mm coal slime is changed correspondingly, which is categorized into medium buoyant.Compared to coal slime,the collector dosage of+0.045 mm coal slime is reduced from 450 g/t to 405 g/t, pulp density is increased from 105 g/L to 125 g/L, stirring velocity is increased from 1800 r/min to 1950 r/min; the data of clean coal cumulative speed and combustible recovery show that the two finally indicators of+0.045 mm were higher than the original coal slime.The results of flotation process behavior of fine mud show that,collision probability between fine fraction slurry and bubble is low, but adhere easily and not easy to fall off; the first classical kinetic equation was used to describe the coal slime flotation process of desliming and non-desliming, and results show that k value is a function of time.The results of pre-desliming by small taper angle hydrocyclone and flotation of underflow show that, ?150 mm and ?75 mm hydraulic cyclone series connection is the best desliming process, the whole desliming efficiency of fine particles is up to 56.41%, and the clay mineral is got enriched in overflow; The content of-0.045 mm, in overflow product of ?75 mm hydroclone, is 94.76%; the process good ensures that the recovery of +0.045 mm fraction in the deslime process. Desliming branch and flotation technology process were verified from two aspects of test and mechanism, the results show that when coal slime mixing-ratio data is 3:1, flotation effect is best,and cleans ash is 11.75%, and productive rate is 61.99%. On this basis, an intermediate test of "twice desliming,once roughing, once cleaning and once scavenging" continuous flotation was studied. The results show that clean coal ash content is 50.10%, the production rate is 43.09%, and clean coal density is 276.36 g/L.