Study On The Quantum Chemistry Calculation Of Hydroxamic Acid With Different Structure And Their Flotation Performance On Bastnaesite

Rare earth is an important mineral resource in my country,among which the selection of bastnaesite is particularly important.Flotation is a commonly used method for separation of bastnaesite in industry.The superiority of flotation reagents determines the separation effect of bastnaesite to a certain extent.Therefore,the use of quantitative calculations to study the molecular structure and properties of flotation reagents will greatly contribute to the research and development of new flotation reagents.The molecular models and their corresponding CaOH⁺/CeOH²⁺chelation models were established,including octyl hydroxamic acid(OHA),benzhydroxamic acid(BHA)and salicylic hydroxamic acid(SHA)by Gaussian and Gauss View.Their geometric structures optimization,natural layout analysis(NPA),frontline trajectory analysis and interaction energy analysis were conducted by DFT/B3LYP method,6-31+G(d)basis set and SDD pseudopotential basis,presenting the effects of non-polar group on the flotation performance of hydroxamic acid collector.Moreover,the calculation results were verified by flotation test and Zeta potential detection.The quantitative calculation results suggested the O atom is activity center in hydroxamic acid group,the chemical reaction activity of hydroxamic acid collector anion is stronger than that of hydroxamic acid collector molecule,and OHA^-has stronger electron donating ability and chemical reaction activity.Those hydroxamic acid collectors are readily interacted with CeOH²⁺than CaOH⁺.In addition,OHA presented the best performance as to complex with CeOH²⁺;and BHA presented an obvious difference as to complex with CaOH⁺/CeOH²⁺.The flotation tests and Zeta potential detections presented that OHA?BHA?SHA in descending order according to the collecting ability.Moreover,the selectivity to bastnaesite and fluorite is satisfactory by OHA,BHA whereas poor by SHA.The electronic effect of the non-polar group will affect the flotation performance of the hydroxamic acid collector.The explanation was that electron-donating group(e.g.octyl group)enhances the collecting ability while electron-withdrawing group(e.g.benzene)abated it,especially the substitution of the hydroxyl group in SHA.Therefore,the predictions by quantitative calculation were consistent with the experimental results.The flotation performance of hydroxamic acid collectors was predicted properly by quantitative calculation,prociding a novel path to develop a more efficient products.