Particle size effect and migration regularity of material group in enhanced gravity separator
Firstly,the main gangue mineral quartz and representative coal were used as test materials,the response regularity of material migration to particle size properties in enhanced gravity separator was analyzed,and the particle size and classification effect were investigated. Secondly,the material migration process and the stabilisation-destabilisation mechanism in the separation zone were revealed. Finally,the spatial distribution and migration law of each narrow-grained class in the clean coal product were clarified,and the role of bi-directional medium coupling in the enhanced gravity field was explored. The results show that the material groups of different particle sizes have specific response regularity to the rotational frequency and backwash water pressure in the enhanced gravity separator. Fine particles are easily enriched in the overflow,while coarse particles are easily enriched in the underflow. The particle size effect is more significant for the spatial distribution of below 0.045 mm grain size. The classification effect in the enhanced gravity separator is obvious,the separation size ranges from 60 μm to 95 μm,and the classification size ranges from 142.44 μm to 350.62 μm. With the increases of rotational frequency and backwash water pressure,the classification size shows decreasing trend. The response regularity of classification efficiency to rotational frequency and backwash water pressure is similar for different classification sizes,but with the increase of classification size,the classification efficiency tends to decrease gradually. The migration process of materials in separation zone is divided into three stages,including deposition stage,sorting stage and retention stage. There is a stabilisation-destabilisation phenomenon in the migration process of materials in the separation zone,which is attributed to the heterogeneity of feed size and the discontinuity of sorting process. Fine-grained coal of each narrow-grained clean coal yield and ash reduce with the increase of rotational frequency,while increase with the increase of backwash water pressure,and the sorting effect of intermediate grains are significantly better. The separation characteristics of each particle size of fine coal are consistent with the grain is effect and migration rule in the separation of single material group. There is an obvious bi-directional medium coupling effect in the enhanced gravity separator,which can be used to prepare clean coal products with different requirements,such as ultra-low ash coal,etc.
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维普
