Dispersion Behavior And Mechanism Of Micro-fine Fluorite And Quartz

Flotation separation of fine mineral is one of the difficult problems in today's mineral processing.The fineness of mineral particle dissociation results in the occurrence of fine particle encapsulation in flotation system,which directly affects the concentrate grade.The flotation of fine minerals can be effectively improved and strengthened by pre-dispersing minerals.In this paper the microgranular fluorite and quartz heterogeneous condensation problems existing in the flotation system,the effects of sodium carbonate,sodium silicate,sodium fluosilicate and sodium hexametaphosphate of fluorite and quartz mechanism and effect,comparative analysis of four different dispersants flotation characteristics,for solving the fine mineral calcium selective flotation separation problem has important theoretical guiding significance.Dispersion test results show that quartz is in good dispersion state when pH=2?12,the mixed minerals of fluorite and quartz are seriously agglomerated out of phase,and their dispersion stability is very poor.Using dispersant can dramatically improve the dispersion stability of micro-fine fluorite and mixed ore,and the dispersion ability is from large to small:sodium hexametaphosphate>Sodium fluorosilicate>Sodium carbonate>Sodium silicate.When pH=10,the combined action of sodium oleate,sodium carbonate,sodium silicate and sodium hexametaphosphate has the same dispersing ability of fluorite and quartz mixed ore,and sodium oleate has almost no influence on the dispersing ability of sodium fluosilicate mixed ore.The dispersion mechanism analysis shows that when the flotation pulp system pH=6?8.2,fluorite and quartz are different in electrical properties,and the dispersion performance is very poor,when pH>8.2,The dispersion of the mixed minerals of fluorite and quartz was improved.According to the calculation of DLVO,when pH=6,8,10,the total potential energy between fluorite and quartz particles is always negative,and the two are easy to coagulate,and the agglomeration phenomenon can be observed obviously under the microscope.The solution chemical calculation shows that sodium carbonate and sodium silicate mainly reduce the surface potential of fluorite and change the electrostatic force between fluorite and quartz particles to disperse through CO₃^2-and Si O(OH)₃^-.Sodium hexametaphosphate mainly through HPO₄^2-and Ca²⁺form a stable complex to produce steric hindrance effect to enhance the dispersion performance of mixed ore.The flotation characteristics of fluorite show that-74+38?m fluorite has good floatability when pH=5?11,and the recovery rate can reach more than 70%.Mineral size has a great influence on the flotation effect of artificial mixed ore.When pH=10.4 and sodium oleate dosage is 45mg/L,-38?m artificial mixed ore coagulates due to fine particles,resulting in that the fluorite recovery of 27.5%and Ca F₂ grade of 60%are lower than the fluorite recovery of 35.36%and Ca F₂ grade of 87.58%(-74+38?m artificial mixed ore).Sodium silicate,sodium fluosilicate and sodium hexametaphosphate have excellent dispersive properties at low dosage,but too high dosage will inhibit fluorite.All the four dispersants are easier to react with fine particles(-38?m),which can effectively improve the slurry dispersion behavior,reduce the degree of heterogeneous coagulation and improve the flotation index.