Study On Fine Separation Method Of Fly Ash Cenospheres

Cenospheres are one of the most value-added components in fly ash.Its unique properties make it have potential application prospects in many fields,and it has become a material in great demand.Conventional ore beneficiation methods,such as gravity separation and air separation,are used to recovery cenospheres from fly ash.However,the cenospheres in fly ash have fine particle size,small density,and wide distribution range,which often results in the separation of cenospheres is bad.Based on the difference in particle shape in fly ash,this study uses a combined process of high-frequency vibrating screening,gravity sedimentation classification and particle vibration sorting to refine the fine separation of fly ash cenospheres,and explore its composition rules,and the specific results as follows:(1)Characterized the shape of particles in fly ash.Cenospheres are spherical particles with a smooth and hollow surface.Magnetic beads are solid spherical particles with a rough surface and magnetic properties.Carbon particles,ellipsoidal particles,cohesive particles,monomer particles,elongated particles,flake particles,etc.They are all particles with irregular shapes and rough surfaces.It can be seen that the cenospheres and other particulate components in fly ash have a clear degree of distinction in particle shape.(2)High-frequency vibrating screen is used to classify fly ash,and the content of cenospheres in different particle sizes is counted.The results show that the particles in+38?m fly ash are mainly carbon particles,ellipsoidal particles and cohesive particles,and almost no hollow beads.The content of hollow beads in-38+23?m,-23+13?m and-13?m particles are 27.32%,33.62%and 46.72%respectively,that is,cenospheres are mainly distributed in fine-grained pulverized coal In ash,the content of cenospheres increases with the decrease of fly ash particle size.(3)The self-built gravity sedimentation classification device is used to further refine and classify the sieved fly ash particles of different sizes.The results show that the gravity sedimentation classification can realize the fine classification of narrow-grained fly ash,and the particle size of the classification product decreases with the decrease of the density.In addition,the content of Al₂O₃in fly ash classification products of different particle sizes increases with the decrease of particle size and density,and the contents of Ca O,Ti O₂and Fe₂O₃all decrease with the decrease of particle size and density.(4)The self-built particle vibration sorting device is used to sort the products of gravity sedimentation classification,and the mechanism of interaction between cenospheres and irregular particles is explored,and the influence of amplitude,feeding amount and number of selections on the selection index of cenospheres is explored.Influence,when the amplitude is 2 mm and the number of selection is 3 times,the content of cenospheres in the separation concentrate can reach 72.43%.The composition law of cenospheres was analyzed,and the results showed that the density of cenospheres increased with the decrease of particle size.The content of Ca O,Ti O₂and Fe₂O₃increases with the increase of the density of cenospheres.The content of Ca O,Ti O₂and Fe₂O₃will affect the density of cenospheres.The wall thickness of cenospheres decreases as the particle size decreases.The viscosity of cenospheres increases with decreasing particle size.In this study,based on the difference in the shape of fly ash particles,the fine separation of fly ash cenospheres has realized the effective separation of cenospheres and revealed the composition law of different cenospheres.The deep-level,high-value-added application of cenospheres provides the foundation.