New Carboxyl Hydroxamic Acids Fishing Income Synthesis And Flotation Separation Behavior Of Al-si Minerals

In order to solve the problem in alumina production, it is important to develop new collectors for improving the Al/Si (mass ratio of Al2O3 to SiO2) of diasporic bauxite by fotation in China. In this paper, three novel carboxyl hydroxamic acids including OCB, OHB and OTB, were synthesized by the oximate reaction; the prepared carboxyl hydroxamic acids were charicterized by elemental analysis and FT-IR spectrum and tested as collectors for the flotation of diaspore, kaolinite and illite contained in diasporic bauxite from China. Subsequently, their flotation mechanism to diaspore and aluminosilicate minerals was investigated by zeta potential, adsorption amount and FT-IR spectrum measurements.The results of flotation experiments for single minerals show that by using carboxyl hydroxamic acid as collectors, the pulp pH value has significant influence on their collecting performance as the floatability of either diaspore or aluminosilicates varies sharply with their change. The appropriate pH value for the flotation of diaspore gets close to neutral condition where diaspore presents good floatability while kaolinite and illite exhibits poor performances. Additionally, the floatability of diaspore and aluminosilicates is in the descending order of diaspore, kaolinite, and illite in the presence of three collectors, and their collecting capacity to three minerals is in the ascending order of OTB, OHB and OCB. The results of flotation experiments for artifially mixed minerals indicate that, of the three synthesized carboxyl hydroxamic acids, OCB has the strongest collecting capability to diaspore while relatively weak to aluminoscilicate minerals, and the flotation speration of diaspore and aluminosilicate minerals is completely feasible. Meanwhile, through the comparison with traditional collector oleate, OCB is characteristic of lower consumption and higher selectivity, and probably suited for direct flotation desilication of diasporic bauxite.The study of zeta potentials and adsorption amount shows that OCB has a higher adsorption on diaspore than kaolinite and illite. The adsorption amount associated with FT-IR spectrum and zeta potentials indicate that the adsorption interaction between OCB and diaspore is dominantly a kind of chemical bonding one. Such bonds are possibly in the form of three cycle chelate rings due to the coordination of carboxyl and hydroxamate to the metal aluminum atoms, where the oxygen atoms contained in carboxyl and hydroxamate of the polar group have the stereo conditions to form five to seven membered rings. By contrast, the adsorption interactions of OCB on the surfaces of aluminosilicate minerals are mainly dominated by means of hydrogen bonds.