Flotation Collector Molecular Design And Mechanism Of Industrial Minerals In Xinhua Molybdenum Tailings

The huge amount of tailings are existed in China,which pollutes the environment and cause potential safety hazard,but the industrial minerals are valuable and nonrenewable mineral resources.Industrial minerals recovery and purification from the tailings is an effective way of tailings resource recovery and efficient utilization.It's of great significance to conducting research on flotation collector molecular design and meschanism,aiming at the specific industrial minerals in tailings.Taking the main industrial minerals in Xinhua molybdenum tailings as the research object,as the problemof large flotation collectors dosage,inconvenience and complex floatation agents scheme on the early components separation and enrichment technological research,flotation collector molecular design,synthesis,preparation and application are needed to solve the problem.In this work,according to first principle calculation,Materials Studio 7.0 modeling package was employed to build the series of crystal structural model of albite,phlogopite,diopside,calcite and dolomite.Crystal chemistry was calculated to speculate and validate the active site of chemisorption on the surface of different minerials,and select the bound atom to design the polar group stucture,including the nonpolar group.New collector called sodium dodecylglycinate(SD)and 2,2'-(dodecylazanediyl)diacetate(SDD)were synthesized and characterized,and both electronic structural properties were analyzed also.Flotability differences of the monomineral and actual tailings were validated with different flotation collector by flotation tests.In neutral pH aqueous solution,the infrared spectrum features on monomineral with different collectors were tested,and the adsorption mechanism of SD on the surface of each monomineral was investigated using molecular simulation,the major findings of this study are as follows:Crystal chemical properties of monominerals were analyzed,and the active site of monominerals were determined.The band structure,density of states,electron density and charge distribution analysis of monominerals show that,the absolute value of all the atomic net charge in different monomineral crystal cell are significantly less than the formal charge,and the oxygen atom are negatively charged with high activity,aluminum atoms in the albite,calcium and magnesium atom in the diopside and dolomite,calcium atom in the calcite are the active sites of chemisorption.According to the active site of different monomineral on the crystal surface,the new type of collectors were designed and synthesized.Taking oxygen atom as the bound atom,the glycine polar group was designed,and its electronegativity value is 4.07.With the acid of the glycine polar group,the new collector of sodium dodecylglycinate(SD)and 2,2'-(dodecylazanediyl)diacetate(SDD)were synthesized and the yield are 82.5%and 57.33%,respectively.IR pattern indicated that the synthetic product and the major functional groups of SD,SDD are consistent.Using dodecylamine(DDA),sodium oleate(NaOl),combination of DDA and NaOl,SD and SDD as the collector respectively,flotation effect of different monomineral under neutral pH value condition were tested.The point of zero charge(PZC)of different monomineral is low and close.In neutral pH aqueous solution,using DDA as the collector,dosage of 16 mg/L,the flotation recovery of different monomineral both follows the order:calcite?dolomite>albite>phlogopite>diopside.Using NaOl as the collector,dosage of 150 mg/L,the flotation recovery of different monomineral both follows the order:calcite?dolomite>phlogopite>albite>diopside.Using DDA and NaOl combination as the collector,dosage of 16 mg/L and 150 mg/L respectively,the flotation recovery of different monomineral both follows the order:calcite?dolomite>phlogopite>albite>diopside,using sodium silicate as inhibitor,DDA and NaOl combination as the collector,dosage of 120 mg/L and 15 mg/L respectively,the flotation recovery of calcite and dolomite are higher than 90%,with the dosage of DDA and NaOl increase,the flotation order is phlogopite>albite>diopside.Using SD as the collector,dosage of 80 mg/L,the flotation recovery of different monomineral both follows the order:calcite?dolomite>phlogopite>diopside>albite.Using SDD as the collector,dosage of 80 mg/L,the flotation recovery of different monomineral both follows the order:calcite?dolomite>phlogopite?diopside>albite.The actual flotation test of industrial mineral in Xinhua molybdenum tailings shows that comparing with DDA and NaOl as the combination collector,the flotation indexes of different monomineral is better by using SD as the collector,while the dosage of SD decrease by 20.65%,using SDD as the collector,the flotation recovery of albite and phlogopite is lower than the conditions by using DDA and NaOl combination,while other three monominerals are still better than the conditions by using DDA and NaOl combination,and the dosage of SD decrease by 32.60%,compared with using NaOl.This conclusion provides theoretical reference to flotation reagents optimization.IR spectrum analysis of monomineral with different collectors indicates that with pH of 6.5,the adsorption form of DDA and NaOl on the surface of different monominerals respectively are physical adsorption with weak intensity and chemisorption,the adsorption form of SD on the surface of different silicate monominerals include physical adsorption and chemisorption,but only chemisorption for different carbonate monominerals,the adsorption form of SDD on the surface of different monominerals is chemisorption.Flotation collector of SD has higher synthetic productivity,excellent collecting performance and selectivity,it also has good application prospect.Molecular simulation of SD on the cleavage plane of different monomineral indicates that,the adsorption form of SD on the(001)cleavage plane of albite is chemisorption,and aluminum atom is the adsorption site,chemisorption for SD on the(110)cleavage plane of diopside,calcium atom and magnesium atom are adsorption sites,and chemisorption for SD on the(101),(104)cleavage plane of calcite,calcium atom is the adsorption site,while the adsorption energy of SD on the(104)cleavage plane is larger,chemisorption for SD on the(101)cleavage plane of dolomite also,the calcium atom and magnesium atom are the adsorption sites,and calcium atom is the priority adsorption site,the adsorption form of SD on the(001)cleavage plane of phlogopite is physisorption,not chemisorption.The adsorption energy calculation results of SD on the cleavage plane of monominerals are consistent with the corresponding molecular simulation results,which explaine the chemisorption characteristics of SD on the cleavage plane of monominerals under neutral pH value condition,and verify the feasibility of SD used to the major industrial minerals flotation separation in molybdenum tailings,and provide the practice basis.All the researches above,provide the basis in theory and practice for highly efficient flotation separation and enrichment of Xinhua molybdenum tailings.