Synthesis And Application Of Hydroxypropyl Amine Collectors In Reverse Flotation Of Iron Ore

With the exploitation and utilization of iron ore resourse,high grade and easily separated iron ores are decreasing year by year,the exploitation and utilization of low-grade fine-grained complicated refractory iron ores are badly in need.For low-grade fine-grained complicated refractory iron ores,it is hard to separate by single magnetic or gravity separation,so the status of flotation in iron ore separation is more and more important.However,use of high-efficiency flotation collector is one of the sticking point for successful flotation.Thus,develpment and synthesis of new collectors are important theoretical and practical significance for continuous development of iron ore resources.In this paper,based on molecular design theory for flotation reagents,hydroxypropyl was induced into general amine cationic collector molecule,and two hydroxypropyl amine collectors were designed and synthesised followed by theoretical calculation and structure optimization of quantum chemistry method.Flotation performances of the two collectors were discussed by single mineral flotation and manual mixture mineral separation experiments.The adsorption mechanism of amine collectors on quartz surface was analysized by Z-potentials measurements,FT-IR spectrum tests,XPS measurements and electrostatic potential structure calculation.These researches incarnate concretely in the following aspects.(1)The structure performace of amine cationic collector was analized and two type collectors(N-dodecyl-isopropanolamine and N-dodecyl-diisopropanolamine)were screened out as new desilication collector for hematite reverse flotation.(2)N-dodecyl-isopropanolamine was synthesized by additive reaction using dodecylamine and epoxypropane as reactants when absolute ethyl alcohol was used as solvent.However,N-dodecyl-diisopropanolamine was synthesized by addition reaction at high temperature using dodecylamine and epoxypropane as reactants.The two products were represented by FT-IR sprectrum,1H-NMR and Mass Spectrometry analysis.(3)Single mineral flotation tests were conducted to investigate the collecting performance of N-dodecyl-isopropanolamine and N-dodecyl-diisopropanolamine to quartz,while dodecylamine was taking as comparison.Concluded from the results of single mineral flotation,flotation performance of the two new collectors to quartz were stronger than dodecylamine.However,the collecting performance of the two collectors to hematite was very poor.The flotation recovery of 93.12%and 7.32%for quartz and hematite was obtained respectively,when N-dodecyl-isopropanolamine dosage was 33.33 mg/L and starch dosage was 13.33 mg/L at pH 6.65.However,95.02%and 1.54%recovery of quartz and hematite was obtained when N-dodecyl-diisopropanolamine dosage was 50.00 mg/L and starch dosage was 6.67 mg/L at pH 6.65.(4)Separation of N-dodecyl-isopropanolamine and N-dodecyl-diisopropanolamine on manual mixture was investigated.And the results indicated that two novel cationic collectors had excellent separation efficiency on manual mixture minerals under weak acid or neutral pH condition.Compared with N-dodecyl-diisopropanolamine,the separation effect of N-dodecyl-diisopropanolamine on manual mixture minerals was better under the less collector dosage.(5)Surface tension experiment indicated that better collecting perfoemance of N-dodecyl-diisopropanolamine and N-dodecyl-diisopropanolamine than dodecylamine on quartz was achieved for their lower CMC.The resudial bubble measurement results showed that the two new collectors had a better defoam performace than dodecylamine.(6)Z-potentials,FT-IR spectrum,XPS and electrostatic potential structure tests revealed that electrostatic attraction and hydrogen bond adsorption were occurred between collectors and quartz surface.