Experimental Study On Flotation Conditioning Intensifying Of Low Rank Coal And Coal Fly Ash Based On The Ultrasonic Field

In this paper,two low-rank coal slime of M1?medium-high ash?and M2?medium ash?,and a coal fly ash sample were taken as research objects.Based on the analysis of the basic properties of the above test samples,the ultrasonic technology was applied to the flotation conditioning process,and the response of the above three test samples to the flotation conditioning process based on the ultrasound field was investigated.The ash content of M1 and M2 coal samples used in this paper is 34.35%and22.69%,respectively.The dominant particle size of the above two coal samples is-0.045 mm,and the yield of-0.045 mm in M1 and M2 coal samples is 80.09%and61.42%,respectively.Two low-rank coal slime of M1 and M2 contains rich oxygen functional groups,these hydrophilic oxygen functional groups are easy to form hydrogen bonding with water molecules and a stable hydration film is formed on the surface of coal particles,which will result in poor floatability of the low rank coal samples.The carbon distribution rate of-0.074 mm particle size in coal fly ash samples used in this paper is 71.09%;thus,the effective mineralization of unburned carbon in-0.074 mm coal fly ash is the key to improve the flotation recovery of unburned carbon.In this paper,the response of M1 and M2 low rank coal slime to the flotation conditioning process based on the ultrasound field was investigated.With the increase of ultrasonic power used in the flotation conditioning process based on ultrasonic field from 0 W to 225 W,for M1 coal samples,the flotation combustible recovery increased from 32.30%to 73.50%,the ash content in flotation concentrate decreased from 18.00%to 12.46%,and the flotation perfection increased from 18.75%to53.50%after 5 min flotation time;for M2 coal samples,the flotation combustible recovery increased from 34.75%to 82.03%,the ash content in flotation concentrate decreased from 10.65%to 7.97%,and the flotation perfection increased from 20.64%to 57.82%after 5 min flotation time.Under the test conditions,the flotation conditioning process based on ultrasonic field improved the flotation selectivity of M1 and M2 low rank slime,the cumulative ash content in the flotation concentrate for the above two low rank slime decreased with the increase of ultrasonic power used in the above conditioning process at the same cumulative combustible recovery.According to Fuerstenau upgrading curves analysis,the K value related to flotation selectivity of M1 and M2 low rank coal slime increased gradually with the increase of ultrasonic power used in the flotation conditioning process.The flotation conditioning process based on ultrasonic field improved the flotation kinetics performance of the above two low rank coal slime.For the five flotation kinetics models used in the experiment,the flotation rate constant for combustible recovery(k_cn)and the flotation rate constant for ash recovery(k_an),as well as the maximum combustible recovery(?_c?)and the maximum ash recovery in flotation concentrate(?_a?)for M1 and M2 low rank coal slime all increased with the increase of ultrasonic power used in the flotation conditioning process based on ultrasonic field from 0 W to 225 W.Moreover,the modified flotation rate constant for combustible recovery and the modified flotation rate constant for ash recovery as well as the corresponding Selectivity Index?SI?also increased gradually with the increase of ultrasonic power used in the flotation conditioning process,the gradual increase of SI indicated that the flotation selectivity was improved gradually.For coal fly ash sample,the flotation unburned carbon recovery of coal fly ash increased from 59.41%to 80.47%,the LOI?loss on ignition?of flotation concentrated carbon increased from 70.11%to 75.89%,the LOI of flotation tailing decreased from13.27%to 6.86%,and the flotation perfection increased from 50.69%to 71.67%after5 min flotation time with the increase of ultrasonic power used in the flotation conditioning process based on ultrasonic field from 0 W to 225 W.The flotation conditioning process based on ultrasonic field improved the flotation selectivity of coal fly ash,within the range of ultrasonic power studied,the cumulative LOI of flotation concentrated carbon increased with the increase of ultrasonic power used in flotation conditioning process based on ultrasonic field at the same cumulative flotation unburned carbon recovery;according to Fuerstenau upgrading curves analysis,the K value related to the flotation selectivity of coal fly ash increased gradually with the increase of ultrasonic power used in the flotation conditioning process under the studied conditions.The flotation conditioning process based on ultrasonic field improved the flotation kinetics performance of coal fly ash.For the five flotation kinetics models used in the test,the flotation rate constant and the maximum flotation unburned carbon recovery of coal fly ash increased gradually with the increase of ultrasonic power used in the flotation conditioning process based on ultrasonic field from 0 W to 225 W.This paper contains 54 figures,10 tables and 141 references.