Study on ash reduction of low-rank fine coal using reverse flotation process wich starch as depressant

The low-rank fine coal cake product of the pressure filter of Halagou Coal Preparation Plant is taken as the object of study. The reverse flotation of this material is carried out with dodecylamine hydrochloride (DDAH) and cetyltrimethylammonium bromide (CTAB) as collectors and starch as inhibitor. Test result shows that: the two collectors can all offer a good effect in collection of minerals in the low-rank coal while the CTAB exhibits a better selectivity; starch can produce a significant inhibitory effect on low-rank coal particles; the ash of flotation tailings is increased by 6.92 percentage points while the recovery of combustible matters is reduced by 8.7 percentage points; and under the combined effect of collector and depressant, the CTAB exhibits a better selectivity.