Flotation performance of anisic hydroxamic acid as new collector for tungsten and tin minerals

一种新型茴香羟肟酸捕收剂对钨、锡矿物的浮选性能研究

In order to improve the recovery of tungsten ores containing tin minerals,anisic hydroxamic acid(p-methoxy benzohydroxanic acid,PMOB)was synthesized and introduced as novel collector in the flotation of scheelite,wolframite and cassiterite.The flotation performance and adsorption mechanism were investigated by micro/batch flotation,zeta potential measurements and density functional theory(DFT).The micro flotation results showed that the recoveries of scheelite,wolframite and cassiterite using PMOB as collector are 97.45%,95.77% and 90.08%,respectively,and the corresponding recoveries are 91.00%,84.30% and 84.67% for benzohydroxamic acid(BHA).The batch flotation results revealed that the collector dosage could be reduced by about 45% for PMOB compared with BHA,in the case of similar flotation indicators.Zeta potential measurements indicated that PMOB could be adsorbed on the mineral surfaces by chemisorption.Moreover,density functional theory(DFT)calculation results showed that the substituent group—OCH_(3)endues PMOB stronger electron donation ability and hydrophobicity compared with benzohydroxamic acid(BHA),pmethyl benzohydroxamic acid(PMB)and p-hydroxyl benzohydroxamic acid(PHB).

为了提升钨锡矿物的浮选回收,本文研究了一种新型羟肟酸捕收剂——对甲氧基苯甲羟肟酸(茴香羟肟酸,PMOB)对白钨矿、黑钨矿和锡石的浮选性能。以茴香酸乙酯为原料与盐酸羟胺通过肟化反应制备PMOB,采用质谱与核磁共振光谱对产物结构进行表征。单矿物浮选试验结果表明,在适宜的浮选pH条件下,PMOB对白钨矿、黑钨矿和锡石的回收率分别为97.45%、95.77%和90.08%,而苯甲羟肟酸(BHA)对三者的回收率分别为91.00%、84.30%和84.67%;根据黑白钨混合矿实际矿石浮选结果,获得相近的浮选指标时PMOB的用量比BHA降低约45%,浮选研究表明PMOB的捕收能力强于BHA。Zeta电位测试研究证实,在浮选pH区间,PMOB的吸附导致三种矿物的表面电性发生不同程度的负移,PMOB在矿物表面发生了化学吸附。此外,采用密度泛函理论(DFT)方法研究了取代基—OCH_(3)的电子效应,DFT计算结果表明,与苯甲羟肟酸、对甲基苯甲羟肟酸和对羟基苯甲羟肟酸相比,取代基团的引入提高了PMOB的给电子能力,增强了PMOB与矿物表面的结合能力,另一方面,甲氧基同时也提高了PMOB的疏水性能,对其捕收性能的提升起到促进作用。