Research On Flocculation Flotation Of Low-ash And Fine Coal Slime

With the development of mechanization in process of coal mining and reduction of lower size limit of dense-medium separation and improvement of separation of coarse slime, the content of ultra-fine particles in the flotation feed has increased rapidly, so it has an effect on process of flotation. On the one hand, for the coal slime mainly consisted of ultra-fine particles, its flotation speed is slow and flotation time is long because the fine coal slime is hard to mineralize and float in a short time, and is easy to loss in the tailings, which causes the decline of concentrate yield; On the other hand, the ultra-fine cola slime can absorb lots of reagents in the process of flotation because of its large specific area, which results in high consumption of reagents. So it is meaningful to research on the separation of micro-fine coal slime. The subject of study in this paper was low-ash and fine coal slime sampled from a coal preparation plant located in Shanxi province. Through this paper, the basic properties of this coal slime were analyzed, the conventional flotation behavior of coal slime was studied, the possibility and process of flocculation flotation of coal slime to reinforce the recovery of ultra-fine particles were discussed deeply, and finally the flocculation flotation was researched in industrial flotation system, which proved its practical significances.This paper focused on low-ash and fine coal slime, which its ash content was about 13.5 % and the yield of grain size under 0.045 mm was about 70 %. The yield of intermediate density of coal slime was small, so its dissociation was good. The mineral matters in coal slime were mainly composed of kaolinite and halloysite which were the sort of clay minerals. The coal slime contained more hydrophobic groups and fewer hydrophilic groups.In conventional flotation test of coal slime, the type and dosage of frothers had a more significant impact on separation performance than collectors involved in this paper. Using the 2-Octanol as frother can get the highest yield and ash content of clean coal. Flotation speed test on whole and narrow particle size of coal slime proved that the more fine particles coal slime had, the slower flotation rate and longer flotation time it would have. In free air condition, the higher speed of flotation cell was, the higher yield and ash content of clean coal were.When dosage of diesel oil was 200 g/t, 2-Octanol was 100 g/t and stirring speed of flotation machine was 1800 r/min, the growth of yield and ash content of clean coal of flocculation flotation was max in comparison with conventional flotation, reaching to 4.32 % and 1.30 % respectively, which the consumption of X in the process of flocculation flotation was 20 g/t. Compared with conventional flotation, flocculation flotation could increase flotation speed in some extent.Flocculation flotation was more proper to apply to separation of coal slime which was mainly consisted of ultra-fine particles. As for flocculation flotation, its perfect index had declined to some extent compared with conventional flotation, because of non-selective flocculation of fine slime and entrainment of water flow enhanced in process of flocculation flotation.The industrial flotation test proved that compared with conventional flotation,the growth rate of yield of clean coal of flocculation flotation,which consumpation of X was 30 g/t,was up to 7.84 % on the basis of meeting the ash content requirement when the separation condition was the same. The optimal dosage of flocculant X was 30 g/t. The screening test proved that compared with conventional flotation, flocculation flotation could enhance the recovery of grain size under 0.045 mm of coal slime obviously. The separation environment would be improved in process of flocculation flotation when flow rate of feed was about 450 m3/h and frequency of circulating pump was 41 Hz.