Study On Hydrophobic Agglomeration Of Vitrinite In Low Rank Bituminous Coal

Based on the advantages of hydrophobic agglomeration for fine particle separation,the hydrophobic agglomeration enrichment method for vitrinite in low-rank bituminous coal was proposed.Based on the difference of the interfacial properties between the coal macerals,experimental research on coal macerals separation was carried out by oil agglomeration separation and liquid CO₂ separation in respective.The influences of the process conditions such as slurry concentration,stirring system and reagent system on the effect and mechanism of separation were investigated.Through proximate and ultimate analysis,fourier transform infrared spectroscopy and wetability analysis,it is found that the ash content of test coal sample is lower and the volatile content is high,and the vitrinite content was 53.92%.Analysis of vitrain and fusain,it is indicated that the content of ash and carbon in the fusain are high,the volatile and elements of hydrogen and oxygen in the vitrain are high.The vitrain contains more cationic functional groups such as-NH and alkyl side,the fusain contains more oxygen-containing functional groups.The contact angle of vitrain is75°,and the contact angle of the fusain is 58.3°,the hydrophobicity of vitrain is better than the fusain.In oil agglomeration separation of coal macerals,through single factor experiment on slurry concentration,stirring system and reagent system,the influence law and mechanism of different process conditions on the separation effect were analysised.The addition of certain agent can improve the separation effect of coal macerals.The orthogonal test was designed and found that the influence order of the key factors on the content of vitrinite was the dosage,oil dosage,stirring speed,slurry concentration and stirring time.The optimum separation conditions were as follows:150mg/L of aluminum chloride,0.5kg/t of sodium lauryl sulfate,20%of diesel,40g/L of slurry concentration,stirring speed of 2100 r/min and stirring for 15 min,then the content of vitrinite reach 76.87%.In the liquid CO₂ separation of coal macerals,through single factor experiment on slurry concentration,stirring system and reagent system,the influence law and mechanism of different process conditions on the separation effect were analysised.When the slurry concentration is 40g/L,aluminum chloride is 300mg/L,SDS is1.25kg/t,the stirring speed is 1400r/min and stirring time is 25min,the good process index was obtained.The vitrinite content in the agglomerated product reached 79.81%,and the vitrinite recovery rate was 42.60%.In the separation process of coal macerals by hydrophobic agglomeration,the function of agitation is to provide energy to overcome energy barrier and to promote the dispersion of coal macerals and agglomerating agents,and to improve the effective collision efficiency to ensure the agglomeration.The mixing time and agglomerating agent have an important influence on the agglomerate size and structure.The adjusting agent can affect the the surface potential of the coal macerals,and the adsorption layer by the collector can improve the hydrophobic property,which can influence the total interaction potential energy between the coal macerals component and the agglomerating agent,improving the separation effect.There are 33 figures,27 tables and references 93 in the paper.