Synthesis And Flotation Performance Of Hydroxamic Acid Collectors

Ilmenit resources is enriched in China. With fewer rich ores, recovery of low-grade ilmenite is a big problem in ilmenite utilization. The flotation reagent is the key to ilmenite flotation. The development of colloctors with high efficiency and low toxicity is of great significant for the exploitation of mineral resources.A series of hydroximic acid collectors, including cyclohexyl methy hydroximic acid, octanoic hydroximic acid, benzoyl hydroximic acid, decyl hydroximic acid and salicyl hydroximic acid, were prepared with fatty acids as the material by processes of esterification and hydroxyl-oximation. The solid-acid catalyst of Ti(SO4)2-Zr(SO4)2/SiO2prepared by the method of immersion was used in the esterification. Synthetic processes of esterification and hydroxyl-oximation were studied. For cyclohexyl methy hydroximic acid, the optimum conditions are as follow:22g solid-acid catalysts of per-mole fatty acid, methanol/cyclohexanecarboxylic acid molar ratio at6, esterification for5h, the hydroxylamine hydrochloride was reacted with sodium hydroxide under condition that the ratio of equivalent ester, hydroxylamine hydrochloride and sodium hydroxide was1:1.1:2.2,500mL water of per-mole fatty acid methyl ester, hydroximation for3hours at the temperature of45℃. Under such condition, the total yield of cyclohexyl methy hydroximic acid was86.16%. Hydroximic acids synthetized by the improved synthesis technology can be used as collectors directly, which integrates the process of synthesis and flotation.The experiments of pure minerals present that decyl hydroximic acid on ilmenite and titanaugite shows the best collecting ability, while cyclohexyl methy hydroximic acid and octanoic hydroximic acid take the second place and the collecting ability of benzoyl hydroximic acid and salicyl hydroximic acid are very weak. In terms of selectivy, the selectivity of cyclohexyl methy hydroximic acid, octanoic hydroximic acid, decyl hydroximic acid, benzoyl hydroximic acid and salicyl hydroximic acid reduce successively and benzoyl hydroximic acid and salicyl hydroximic acid can not effectively solve the separation ilmenite and titanaugite. Accordingly, the actual mineral experiments of ilmenite from Panzhihua show that the hydroximic acids synthetized by the improved synthesis technology exhibit better results than xantathate. Furthermore, using the hydroximic acids synthetized by the improved synthesis technology can obtain a recovery of about84%with a content of36%after a roughing flotation, which can be considered as a preferable combined reagent.The adsorption mechanism of the hydroximic acids on ilmenite was investigated through solution chemical analysis, Zeta-potential, adsorption amount and IR spectrum measurements. Zeta-potential and IR spectrum measurements confirmed that the interaction between hydroximic acid collertors and ilmenit must mainly be the chemical action. This paper includes68charts,6tables,93references.