A Study Of Highly-efficient And Clean Flotation Separation Mechanism Of Ilmenite In Panxi

Considering the difficulties in the Panxi ilmenite flotation,such as the complex chemical properties in the solid-liquid interface,large consumption of reagents,as well as difficult flotation separation,this paper used kinds of modern testing coupled with analysis techniques,combining theoretical and experimental results to obtain the highly-efficient and clean flotation separation of ilmenite from titanaugite.Through enhancing adsorption ability of flotation reagents and surface dissolved ions modification,this paper determined four kinds of enhanced separation methods including mixed collectors of NaOL-DAA,organic depressant of corn dextrin,Pb-BHA complexes collectors,and ultrasonic pretreatment.Secondly,their adsorption mechanism at the solid-liquid interface was explored and a highly-efficient and clean flotation mechanism on ilmenite in Panxi was determined.The main results are as follows:?1?A study on influence factors of efficient and clean flotation separation of ilmeniteThe flotation tests were used to compare the separation effects of various flotation reagents and interfacial ion control methods.As a result,the reagents and control measures with good separation ability were determined.Therefore,the optimal conditions affecting the efficient and clean flotation separation of ilmenite were achieved.We found that single reagents barely achieved the separation of ilmenite from titanaugite,while mixed collectors NaOL-DAA had better flotation capacity than single collectors.The best separation conditions are molar rate of 10:1 and pH=5-7.Small molecule depressant?citric acid?and organic depressant?xanthan gum?have strong inhibitory effect on two minerals,while flotation separation could be feasible with the dosage of corn dextrin 10 mg/L and pH=10.Pb²⁺showed stronger activation performance than Ca²⁺and Mg²⁺.The Pb-BHA complexes exhibited better performance than sequentially added Pb?II?and BHA species.The optimal separation of the minerals could be obtained by using complexes with the molar ratio of Pb?II?:BHA=1:3 at pH=6.0.In addition,ultrasonic pretreatment promoted the ilmenite floatability,but depressed titanaugite floatability within pH=4—6.When ultrasonic time and power were 5 min and 500W,the best separation conditions were determined.Synthetic mineral mixture flotation results showed that the above four enhanced separation methods could obtain higher TiO₂ grade and TiO₂ recovery.Among them,the best separation effect was the mixed collector NaOL-DAA.A TiO₂ concentrate assaying 43.18%was obtained at a TiO2 recovery of 82.23%.?2?A study on the interfacial chemistry mechanism of the enhanced flotation separation of ilmenite from titanaugite through reagentsThe zeta potential,FTIR,microcalorimetry,XPS analysis and other methods were used to study the selectivity and synergistic adsorption mechanism of the mixed collector on the ilmenite mineral at the solid-liquid interface.Furthermore,the selective depression mechanism of the environmentally-friendly organic depressant corn dextrin was studied,too.The NaOL-DAA mixed collector exhibited a synergistic effect and could be co-adsorbed on the surface of ilmenite,which not was only the higher adsorption of NaOL that leaded to the higher recovery of ilmenite.FTIR analysis showed that the NaOL-DAA collectors might be mainly adsorbed on the ilmenite surface by chemical and physical adsorption,while NaOL-DAA was weakly and physically adsorbed on the titanaugite surface.In the presence of NaOL and corn dextrin,ilmenite recovery was not affected.However,corn dextrin impeded the adsorption of NaOL on the surface of titanaugite.XPS results showed that after treated with corn dextrin,a chemical adsorption occurred on the ilmenite surface with Fe?OH?₂/Fe?OH?₃ and Mg?OH?₂,while a chemical adsorption occurred on the titanaugite surface with Ca?OH?₂,Fe and Si.?3?A study on the mechanism of enhanced flotation separation of ilmenite based on the regulation of selective migration of interfacial metal ionsThrough modern analytical techniques,the adsorption products,adsorption heat,adsorption sites,and adsorption configurations of metal ions and reagents were investigated,which determined the assembly behavior and activation mechanism of metal ions at the mineral interface.Moreover,ultrasonic surface modification measures were used to investigate the behavior of selective migration and transformation of dissolved ions and the selective adsorption behavior between reagents and mineral particles.Finally,the ultrasonic surface modification control mechanism for ilmenite and titanaugite was proposed.The Pb-BHA complexes exhibited stronger chemical adsorption capacity on the surface of ilmenite but lower adsorption on titanaugite surface.Since complexes with BHA are easier to generate when using Pb?II?than Ca²⁺and Fe²⁺ions,and the Pb-BHA complexes preferred to adsorb on the active sites of ilmenite(e.g.Fe²⁺or Fe³⁺)rather than titanaugite(e.g.Ca²⁺),indicating that Pb-BHA released more heat resulting in stronger chemical adsorption occurred on the surface of ilmenite.Ultrasonic treatment changed the surface morphology on ilmenite and titanaugite,which strengthened the dissolution of Ca and Mg,increased the relative contents of Fe on ilmenite but decreased the Fe,Ca,Mg relative contents of titanaugite.Ultrasound could increase the relative content of Fe³⁺on the ilmenite surface,which is beneficial to the chemisorption of NaOL.Furthermore,after ultrasonic treatment,the relative content of Ca?OL?₂,Ca?OH?₂,and Mg?OH?₂ on titanaugite surface decreased.These species are the main adsorbed component for titanaugite.Thus,the adsorption between NaOL and titanaugite is poor.