Experimental study on flotation of power plant flyash with a high loss on ignition

Study is made on flotation of flyash for recovery of coal particles with a certain calorific value,with the power plant flyash containing a high proportion of unburnt coal particles in Ningxia area as the object of study.The study is made with an aim to reducing loss of the flyash on ignition.Result of study shows that: under the optimum flotation conditions: concentration of collector-440 μL,concentration of frother-80 μL,density of flyash-50 g/L,aeration quantity per unit area-0.40 m3/（m~2·min）,a product with a yield of 20.49%,an ash of 28.81% and a perfection index of up to 46.12% can be obtained after primary flotation; through re-flotation of the product with timed-release process,a concentrate with an ash of as low as 8.27%,a yield of 4.52% and a calorific value of 29.22 MJ/kg can be produced; after scavenging of the flotation tailings,the loss of flyash on ignition can be lowered down to13.87%,making it possible for the flyash to be used as a Grade-III ash.