Study On Flotation Experiment And Mechanism Of Strengthening Graphite Flotation By Inorganic Salt Ions

The rapid development of new energy vehicles promotes the rapid expansion of graphite industry chain,which is the raw material for batteries.Therefore,the rational development of upstream graphite resources has become the focus of attention at home and abroad.In order to obtain high purity graphite,flotation has always been the most effective means of graphite enrichment.Salt solution flotation has been studied more and more extensively since the 1930s.Inorganic salt ions do not have surface activity,and can not reduce the surface tension of liquid phase in water.However,the existence of inorganic salt ions can effectively inhibit foam merger phenomenon in flotation system,which has a great impact on flotation concentrate index.Therefore,the flotation behavior of graphite under the action of inorganic salts was studied.The effects of inorganic cations(K⁺,Mg²⁺,Al³⁺)on graphite flotation were investigated by adding inorganic cations in the single mineral experiment.Taking flake graphite in Jixi of Northeast China as the research object,the open circuit flowsheet test under the action of inorganic salts was carried out,and the flotation test results were compared with those of traditional reagent system.The mechanism of action was analyzed by contact angle test,Zeta surface potential test,flotation solution chemical analysis,foam performance test and surface tension test.The main research contents and conclusions are as follows:?1?The pure graphite mineral experiment shows that when the concentration of inorganic salts is 0.09mol/L,three inorganic salts with different valences?KCl,MgCl2,AlCl3?have certain influence on graphite flotation.The recovery rates are 84.54%,94.82% and 95.89% respectively.The ability of three inorganic salts to strengthen graphite flotation is:Al³⁺>Mg²⁺>K⁺.K⁺ion is the least affected by pulp pH and has a better flotation effect on graphite;Mg²⁺ion has a better flotation index when pulp pH is acidic or weak alkaline;Al³⁺ion has a better flotation index when pulp pH is acidic or alkaline;compared with flotation behavior of traditional reagent system,it is found that inorganic salt can promote graphite flotation and alkaline flotation.The flotation rate can be improved obviously,and the amount of kerosene and 2^#oil can be reduced at the same time.?2?The actual ore beneficiation test shows that after adding inorganic salt MgCl₂,the fixed carbon content of final concentrate is 94.77% and the recovery rate is 69.71% under the open process of five times grinding and six times concentrating.Moreover,under the same flotation conditions,the fixed carbon content of the final graphite concentrate increased by 1.80% and the recovery of the concentrate increased by 8.85% with the addition of inorganic salts,indicating that the addition of inorganic salts can enhance the flotation effect of graphite.?3?The mechanism of flotation of graphite by inorganic salts was studied.The results of foam performance test and surface tension test showed that in the flotation process of inorganic salt,a large number of stable small bubbles were generated in the solution due to the hydration of inorganic salt ions and the difference of ion migration rate.The results of contact angle test and Zeta potential test show that the presence of inorganic salt cations compresses the electric double layer between graphite particles and bubbles,graphite particles and particles,reduces the absolute value of zeta potential on graphite surface,reduces the long-range repulsion between graphite particles and bubbles,reduces the degree of hydration on graphite surface,and thus enhances the hydrophobicity of graphite surface.The co-existence of these two effects increases the collision probability between the bubble and the graphite particle,thus achieving the purpose of improving the recovery rate of graphite flotation.