Experimental Study On Heterogeneous Coagulation During The Oil Agglomeration Process Of Cryptocrystalline Graphite

In this dissertation,cryptocrystalline graphite was used as the research object.Oil agglomeration sorting method was used to investigate the segregation of cryptocrystalline graphite.Combined with the method of particle size distribution and zeta potential distribution method,the heterogeneous coagulation of graphite and gangue mineral quartz affecting the effect of oil agglomeration was studied.The DLVO theory was finally used to explain the mechanism of the heterogeneous coagulation of graphite and gangue mineral quartz The main research results are as follows:Among the three neutral oils of kerosene,diesel oil and transformer oil,the transformer oil has obvious advantages in increasing the yield of cryptocrystalline graphite concentrate and reducing the concentrate ash content;Under acidic conditions,the agglomeration sorting effect is poor,and the effect of agglomeration sorting is greatly improved under alkaline conditions;the hexametaphosphate can reduce the ash content of cryptocrystalline graphite concentrates;Too little time for agglomeration is not conducive to the formation of cryptocrystalline graphite flocs but too long to break the floc The best time for agglomeration was 10 min;The stirring intensity affected the ash and yield of the agglomerated graphite oil agglomerates.with the stirring strength increasing,the ash and the yield of concentrates sorted by agglomerated graphite oils are reduced.The results of the particle size distribution method and the zeta potential distribution method show that:graphite and quartz are prone to heterophasic agglomeration under acidic conditions;Heterogeneous coalescence is less likely to occur under alkaline conditions.The addition of sodium hexametaphosphate can effectively reduce the degree of heterogeneous coagulation of graphite and quartz.The DLVO forces between graphite and quartz particles at different pH and different concentrations of sodium hexametaphosphate were calculated.The results show that when the pH is 2,the total interaction energy between quartz and graphite particles is negative,indicating that the total force between quartz particles and graphite particles is attractive.At pH 7 and 12,the total interaction energy between quartz and graphite particles is positive,indicating the total force between quartz particles and graphite particles.Therefore,Graphite and quartz tend to coagulate under acidic conditions,and are not easily agglomerated under alkaline conditions.The sodium hexametaphosphate was added to the solution,the total interaction between the quartz particles and the graphite particles was always positive,and the total force between the graphite and the quartz particles was a repulsive force on the surface.Graphite and quartz were not easily agglomerated.