Effects of sodium hexmetaphosphate on flotation separation of diaspore and kaolinite^①

来源期刊：中南大学学报(英文版)2005年第4期

论文作者：陈湘清 胡岳华 王毓华 熊道陵

文章页码：420 - 424

Key words：sodium hexmetaphosphate; flotation; depression; mechanism

Abstract: In order to offer high grade concentrate to produce alumina by Bayer, the reverse-flotation technology of bauxite was investigated. The results show that sodium hexmetaphosphate has different depression on the flotation of diaspore and kaolinite. The recoveries of diaspore decrease markedly with the increase of the concentration of so-dium hexmetaphosphate with dodecyl-amine as collector. Fourier transform infrared spectra indicate that the absor-bance band 875 cm^-1 of the asymmetric stretching vibration of bridge oxygen P—O—P shifts to 880 cm^-1, and the 1 264 cm^-1of the asymmetric stretching vibration of the bridge PO₂shifts to 1 267 cm^-1in the diaspores spectra. This demonstrates that sodium hexmetaphosphate interacts through bridging PO₂ groups with the Al atoms exposed on the diaspore and kaolinite surfaces to form P—O—Al bond. Adsorption measurements also testify that sodium hexmetaphosphate adsorbs easily on the surface of diaspore. The adsorption density of PO^-₃on the surface of diaspore is about 4.7×10^-6mol/m², while that on the kaolinite is only about 3.5×10^-7mol/m²when pH value is 6.