Effect Of Microbubble Generation Methods On Mineral Flotation

The purpose of this paper is to explore the effect of two micro-nano bubble generation methods,electrolytic micro-bubble method and mechanical shear micro-bubble method,on the flotation effect of pure minerals and Tunlan coal,in order to improve the flotation effect of fine and coarse minerals,and to provide reference for the next micro-nano bubble flotation research and gradually move towards industrial tests.In the study of pure minerals,hydrophobic mineral graphite and hydrophilic mineral quartz are taken as research objects,and the effects of two micro-nano bubble generation modes on the flotation effect of coarse and fine minerals are studied.The influence of micro-nano bubbles on the flotation of Tunlan coal with different particle sizes was further investigated.The electrolytic microbubble flotation method combines an external direct current power supply with a flotation machine,and sodium chloride,sodium sulfate and sodium acetate are introduced as electrolytes to carry out flotation tests on hydrophilic and hydrophobic minerals and coarse and fine minerals.According to the principle of mineral flotation and combined with the data of p H change,Zeta potential,conductivity test and test results,the mechanism of action can be preliminarily analyzed.Relevant experimental studies are as follows:The electrolytic microbubble method has a certain inhibitory effect on graphite flotation,and the inhibitory effect on coarse graphite flotation is stronger than that on fine graphite.It is inferred that electrolysis causes the local p H of ore pulp to increase.For graphite,too high p H is not conducive to graphite flotation,resulting in poor graphite electrolytic flotation effect.When the cationic collector dodecylamine is used for flotation of quartz,the electrolytic microbubble method has a strong inhibitory effect on the flotation of quartz,and has a stronger inhibitory effect on coarse quartz.Among the three electrolytes,sodium chloride has the strongest inhibitory effect on the electrolytic flotation,and the recovery of coarse quartz is the lowest of 1.29%.The influence mechanism of electrolysis is inferred as follows:on the one hand,electrolysis causes a sharp increase in the p H of the area near the electrode,causing dodecylamine to mainly exist in the form of RNH₂ molecules and RNH₂precipitates,affecting the flotation effect of dodecylamine;On the other hand,electrolysis activated inevitable metal cations in tap water and Na⁺in sodium salt,and various cations competed with RNH³⁺of collector for adsorption on the surface of quartz,resulting in a sharp drop in the electrolytic flotation recovery of quartz.When the anionic collector sodium oleate is used for flotation of quartz,the recovery of electrolytic flotation is much lower than that of conventional flotation under the suitable flotation conditions of adding p H regulator and activator.Under the flotation condition of natural p H and no activator,the electrolytic microbubble method significantly improves the flotation recovery of quartz.Among the three electrolytes,sodium chloride has the best electrolytic flotation effect,the highest recovery was increased by 59.86%.Under suitable sodium oleate flotation conditions,electrolysis causes the local p H of ore pulp to be too high,and high concentration of OH^-crowding oleate ions are adsorbed on the mineral surface,resulting in deterioration of originally suitable flotation conditions.At natural p H,the p H increase caused by electrolysis and the activation of inevitable metal cations in water make the originally sodium oleate flotation conditions more suitable,thus improving the flotation recovery of quartz.Among the three electrolytes,sodium chloride has the strongest effect in the electrolytic flotation process.On the one hand,the amount of sodium chloride is the largest under the same mass and the ion concentration is higher after dissolution.On the other hand,Cl^-participates in the electrolytic reaction,further increasing the p H of ore pulp.Under the combined action of various factors,sodium chloride has a stronger effect on electrolytic flotation.The mechanical shearing microbubble method combines a micro-nano bubble generator with a flotation machine,and uses sec-octyl alcohol,terpineol and MIBC as foam stabilizing agents.The flotation test results of two pure minerals,quartz and graphite,show that the mechanical shearing microbubble method is helpful to improve the flotation effect of pure minerals.The promotion of hydrophobic mineral graphite is stronger than hydrophilic mineral quartz,the promotion of coarse-grained graphite is stronger than fine-grained graphite,and the promotion of coarse-grained quartz is stronger than fine-grained quartz.The promotion effect is the best under the conditions of secondary octanol and 1L/min air inlet flow rate,under this suitable conditions,the mechanical shearing microbubble method is used to conduct flotation research on Tunlan coal.The flotation results show that the microbubble treatment has a better promotion effect on the Tunlan coal with coarser particle size,and the recovery of combustible substance can be increased by up to 13.31%,while the effect on the fine Tunlan coal is not obvious,and the flotation effect is better when the dosage of collector is deficient.The mechanism of mechanical shear microbubble method may be that after micro-nano bubbles are adsorbed on the surface of coarse minerals,they can act as secondary collectors to improve the adhesion stability with conventional bubbles and improve the flotation effect of coarse minerals.