Effects of sodium hexmetaphosphate on flotation separation of diaspore and kaolinite

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 sodium hexmetaphosphate with dodecyl-amine as collector. Fourier transform infrared spectra indicate that the absorbance 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⁻¹ of the asymmetric stretching vibration of the bridge PO₂ shifts to 1 267 cm⁻¹ in the diaspore’s 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 PO₃⁻ on the surface of diaspore is about 4.7 × 10⁻⁶ mol/m², while that on the kaolinite is only about 3.5 × 10⁻⁷ mol/m² when pH value is 6.

Keywords

sodium hexmetaphosphate / flotation / depression / mechanism

References

[1] WANG En-fu, MA Chao-jian, LU Qin-fang, et al. The processing-bayer method of Chinese high siliceous bauxite to produce the Al₂O₃[J]. Light Metals, 1996, (7): 3–6, (in Chinese)

[2] HuYue-hua, JiangHao, QiuGuan-zhou, et al.. Solution chemistry of flotation separation of diasporetype bauxite[J]. The Chinese Journal of Nonferrous Metals, 2001, 11(1): 125-130(in Chinese)

[3] LiangAi-zhen, LiTing-hui. The flotation and prospect of diaspore bauxite[J]. Nonferrous Metal (Mineral Processing Partial), 1981, 33(6): 6-11(in Chinese)

[4] LiuYi-chao, YangCao-yun, ChengXue-zhi. The flotation experiments of hydromica-diaspore bauxite [J]. Nonferrous Metal, 1984, 36(1): 11-14(in Chinese)

[5] ZhangGuo-fan, FengQi-ming, LuYi-ping, et al.. Effects of sodium hexametaphosphate on flotation of bauxite[J]. Journal of Central South University of Technology (Natural Science), 2001, 32(2): 127-130(in Chinese)

[6] LiChang-gen, LuYong-xin. Selective flotation of shelties from calcium minerals with sodium oleate as a collector and phosphates as modifiers. II. The mechanism of the interaction between phosphate modifiers and minerals[J]. International Journal of Mineral Processing, 1983, 10(5): 219-235

[7] YamaguchiN, OkazakiM, HashitaniT. Proton consumption with phosphate adsorption on amorphous Fe (III) hydroxide[J]. Soil Science and Plant Nutrition, 1996, 42(4): 681-690

[8] DimirkouA, IoannouA, DoulaM. Preparation characterization and sorption properties for phosphates ofhematite, bentonite and bentonite-hematite systems [J]. Advances in Colloid and Interface Science, 2002, 97(1–3): 37-61

[9] HuH Q, LiX Y, HeJ Z, et al.. Secondary adsorption of phosphate on aluminum oxides surfaces as influenced by several organic acids[J]. Journal of Plant Nutrition, 2004, 27(4): 637-649

[10] BorrasC A, RomagnoliR, LeznaR O. In-situ spectroelectrochemistry (UV-visible and infrared) of a-nodic films on iron in neutral phosphate solutions[J]. Electrochimica Acta, 2000, 45(11): 1717-1725

[11] LefevreG. In situ fpurier-transform infrared spectroscopy studies of inorganic ions adsorption on metal oxides and hydroxides[J]. Advances in Colloid and Interface Science, 2004, 107(2–3): 109-123

[12] GongWen-qi. A real-time in situ ATR-FTIR spectroscopic study of linear phosphate on titania surfaces [J]. Int J Miner Process, 2001, 63(3): 147-165

[13] XuHong-bo, JiangXiao-jun. A new method for determination of the degree of the polymerization of the inorganic fire retardant phosphate salts[J]. Journal of Anshan Institute of I & S Technology, 1998, 21(1): 19-23(in Chinese)

[14] PerssonP, SjobergS, NilssonN. Structure and bonding of orthophosphate ions at the iron oxide aqueous interface[J]. Journal of Colloid and Interface Science, 1996, 177(1): 263-275

[15] MichelmoreA, JenkinsP, RalstonJ. The interaction of linear polyphosphates with zincite surfaces[J]. Int J of Miner Process, 2003, 68(1): 1-16

[16] PyeC C, RudolphW W. An ab initio infrared and raman investigation of phosphate ion hydration [J]. Journal of Physical Chemistry A, 2003, 107(41): 8746-8755