Abstract: Carboxyl hydroxidoxime (COBA), a new cheap chelating collector, was synthesized and characterized. Its collecting effect on oxide minerals such as diaspore and kaolinite, structure—activity relationship were studied, and collecting mechanism was also investigated. Carboxyl anhydride, hydroxylamine and sodium hydroxide were mixed in mixture solvent of methanol and water, stirred at 40~45 ℃ for 6~8 h, and separated by distillation, acidification and recrystallation to obtain COBA in 86.2% yield with purity of 97.8%. The flotation tests show that the collecting ability of COBA is strong for diaspore than for kaolinite, and it possesses higher selectivity of collecting on comparison with o-hydroxyl benzohydroxidoxime (HOBA) as a collector. The reason of which is that COBA has higher group electronegativity, larger topological connectivity index, larger polar group diameter and stronger hydrophobility comparing to HOBA. Furthermore, some evidence indicates that double ring chelating compound is formed by chemical adsorption between the three oxygen atoms in COBA and the aluminium atom on the surface of diaspore. Thus, COBA may become a new type of selective collector for obverse flotation to remove Al-Si minerals from bauxite.
Synthesis and structure-activity relationships of carboxyl hydroxidoxime in bauxite flotation
Abstract:
Carboxyl hydroxidoxime (COBA) , a new cheap chelating collector, was synthesized and characterized. Its collecting effect on oxide minerals such as diaspore and kaolinite, structure-activity relationship were studied, and collecting mechanism was also investigated. Carboxyl anhydride, hydroxylamine and sodium hydroxide were mixed in mixture solvent of methanol and water, stirred at 40~45?℃ for 6~8?h, and separated by distillation, acidification and recrystallation to obtain COBA in 86.2% yield with purity of 97.8%. The flotation tests show that the collecting ability of COBA is strong for diaspore than for kaolinite, and it possesses higher selectivity of collecting on comparison with o hydroxyl benzohydroxidoxime (HOBA) as a collector. The reason of which is that COBA has higher group electronegativity, larger topological connectivity index, larger polar group diameter and stronger hydrophobility comparing to HOBA. Furthermore, some evidence indicates that double ring chelating compound is formed by chemical adsorption between the three oxygen atoms in COBA and the aluminium atom on the surface of diaspore. Thus, COBA may become a new type of selective collector for obverse flotation to remove Al Si minerals from bauxite.