烷基羧基羟肟酸合成及铝硅浮选性能研究

【作者】 殷志刚；

【导师】 蒋玉仁；

【作者基本信息】 中南大学 ， 有机化学， 2010， 硕士

【摘要】 开发低品位铝土矿高效正浮选捕收剂以提高我国一水硬铝石型铝土矿的铝硅比,对解决我国氧化铝生产中存在的问题具有重大意义。本文研究了烷基羧基羟肟酸系列捕收剂的合成方法及其对一水硬铝石、高岭石和伊利石的浮选性能,通过吸附量、zeta电位和红外光谱分析等手段,探讨了烷基羟肟酸类捕收剂与矿物的作用机理。用羟胺与相应的酸酯为原料合成了CMCA、CDHA和CTHA三种捕收剂,并通过红外光谱和元素分析等手段对化合物进行表征。单矿物浮选实验结果表明：对一水硬铝石,CTHA、CDHA和CMCA的捕收能力相当强,明显高于对高岭石和伊利石的捕收能力；其中CTHA的捕收能力稍微强于CDHA,但远大于CMCA。在pH5-9,药剂浓度为2×10-4 mol/L时,CTHA和CDHA对一水硬铝石的浮选回收率均大于90%,对高岭石和伊利石的浮选回收率均小于30%。因此,在pH5-9范围内,采用CTHA和CDHA有可能实现一水硬铝石与高岭石和伊利石的有效分离。人工混矿试验表明,CTHA能有效分离一水硬铝石与铝硅酸盐矿物；氧化铝回收率均大于85%,同时精矿铝硅比也有显著提高,所以CTHA很可能成为一种新型的高效铝土矿捕收剂。矿粒扫描电镜(SEM)照片(×10,000)表明：一水硬铝石颗粒为椭圆形,高岭石和伊利石颗粒为不规则的形状。吸附量曲线表明,CTHA在一水硬铝石表面的吸附量远大于在高岭石和伊利石表面的吸附量,与浮选实验结果一致。Zeta电位和红外光谱分析表明,捕收剂在一水硬铝石表面通过-COOH、-NHOH与矿物表面的铝离子(Al3+)形成双环螯合物的化学吸附,而在高岭石和伊利石表面主要是物理吸附。更多还原

【Abstract】 In order to solve the problem in alumina production, it is important to develop new collectors of direct flotation for improving the Al/Si (mass ratio of Al2O3 to SiO2) of diasporic bauxite in China. In this paper, the synthesis of novel alkyl carboxyl hydroxamic acids and their flotation properties to diaspore, kaolinite and illite have been studied. The adsorption mechanism of the new collectors on the minerals has been investigated through adsorption amount, zeta potential, SEM and IR spectrum measurements.Three carboxyl hydroxamic acids, CMCA, CDHA and CTHA were synthesized by reaction of hydroxylamine hydrochloride with relevant ester. The molecular structures of synthesized products have been identified by IR spectrum and element analysis.The results of flotation tests for single minerals indicate that the collecting ability of carboxyl hydroxamic acids for diaspore, kaolinite and illite is in the order of CTHA > CDHA> CMCA, the collecting ability and selectivity of CTHA are better than those of CDHA and CMCA. Using CTHA and CDHA as collector in the pH range of 5-9, diaspore have good flotation recovery; However, kaolinite and illite still keep a relatively low flotation recovery. At the dosage of 2×10-4 mol/L, both CDHA and CTHA show excellent collecting abilities for diaspore with the recoveries over 90%, but for kaolinite and illite the recoveries were less than 30%. Therefore, it is possible to separate the diaspore from such silicate minerals as kaolinite and illite using CTHA and CDHA as collector in the pH range of 5-9. So, CTHA may become a new type of selective collectors for direct flotation to remove aluminosilicate minerals from bauxite. The results of separation of artificially mixed minerals present that the mass ratio of Al2O3 to SiO2 was increased to a high level, and the recovery of Al2O3 is more than 85%.SEM (×10,000) shows that diaspore takes oval shape, kaolinite and illite takes irregular appearance. The adsorption measurement indicates that the adsorption on diaspore is lager than that on kaolinite and illite, which is generally consistent with the flotation tests. Zeta potential and IR spectrum measurements approve that the interaction of the collector on the diaspore surface is mainly a chemical adsorption, while the adsorption on kaolinite and illite is mainly dominated by physical adsorption. The chemical adsorption of chelator ion on diaspore may take place through-COOH,-NHOH and the Al3+ on the surface of mineral to form double rings.更多还原