Single Carboxyl Hydroxamic Acid Were Designed And Synthesized A Diaspore And Al-si Minerals Collector Performance

From the viewpoint of molecular design, electronic structure of flotation collector detailly studied by quantum chemistry methods, combining with determination of surface charge, infrared spectrum, adsorption quantity and flotation tests. Screening and designing of collector for bauxite flotation was carried out in order to improve the flotation selectivity and recovery. An efficient and practical chelated collector, HCDA, was developed.Based on the heteropolarity requirment of the collector structure, the heteropolar molecular structure models containing both hydroxamino group and carboxyl group were designed, finally the collector named HCDA was confirmed. The molecular structure is as below:it owns a nonpolar group of eight carbon lengths and a polar group containing two hydroxamino groups and carboxyl group. Consequently, the performance prediction of this collector molecular was executed with the comparison of the collector named COBA which was explored by our team formerly. The results of the quantum chemistry calculation—the analysis result of every index indicates that HCDA will be a excellent collector (such as the molecular extreme orbits energy, charges distribution, the bonding atom distances, the delocalization state and the molecular LOMO and LUMO location picture), and its collecting ability will be much stronger than that of COBA; the performance criterion results—the collector performance indexes (the solubility product, the CMC, the HLB and group negativity etc.) were compared between the two collectors mentioned above, the results revealed that HCDA will have better collecting ability and selectivity than COBA.The synthetic routine of collector HCDA molecular is suggested and carried out. The object product HCDA was synthesized by using methyl malonate and methyl chloroformate as raw materials through four steps. Meanwhile, the influence of the reaction time, temperature and the material addition on the yield was observed.The results of flotation tests with single minerals showed that the diaspore has a striking result when HCDA as a collector was applied in the flotation of these three minerals. At the HCDA concentration of 2×10-4 mol/L and pH7, the recovery of diaspore reached 96%, while the recovery of kaolinite and illite are only 20% and 10%, respectively. The recovery of diaspore can be affected significantly by the change of the pulp pH value and the reagent concentration; however, the influence of the pulp pH value and the reagent concentration on the other two alumiosilicate minerals are very little. The results of flotation tests with artificial mixture of minerals reveal that the ultimate condition for separating diaspore from the aluminosilicate minerals is at pH7 when the concentration of collector HCDA is 2×10-4mol/L. The ratio of aluminum to silicon of artificial mixture of minerals flotation revealed that diaspore can be separated from aluminosilicate minerals.The interaction mechanism of the collector HCDA with the three mineral was investigated by adsorption amount, FTIR spectra and zeta potential measurements. The results of adsorption amount were in agreement with that of the flotation test. The change of solution pH has an apparent influence on the adsorption amount of the reagent while has a very little one on that of the aluminosilicate minerals, where the adsorption amount came to maximum at pH7.The results of zeta potential measurements showed that the IEP of diaspore, kaolinite and illite are pH6.0, pH3.6 and pH3.0, respectively. The surface electrical property of diaspore was affected largely by the change of solution pH. After diaspore being conditioned by HCDA, its IEP moved from pH 6 down to pH 4, and its zeta potential value shifted apparently in the range of pH5～pH9. At the pH7, the largest shift can be observed. At the same time, no obvious change of zeta potential can be found on the two aluminoslicate minerals surface; the infrared spectra disclosed that HCDA mainly chemisorbed on the diaspore surface while mainly physically adsorbed on the kaolinite and illite surface. According to the conclusion, a polycyclic chelated model between HCDA and diaspore was suggested.