Study of adsorption of rare earth elements by ferric oxide gel

Abstract

A new secondary ore of rare earth was discovered in the Southwest of China. It is a kind of product of the weathered mineral. The rare earth elements (REE) in it exist probably as ionic characteristic adsorption state in manganesian and ferric oxide colloid mineral, and one bearer of REE is amorphous ferric oxide gel. It is necessary to study the binding state of rare earth elements on manganesian and ferric oxide in order to utilize comprehensively the rare earth resources and avoid latent influence on the environment resulting from the fact that high-content rare earth elements are carried into soil by the mineral efflorescence. A simulating adsorption test of rare earth ions in weak acid media is carried out with ferric oxide gel prepared by sol-gel method. The experimental results show that the characteristics of adsorption isotherm correspond well with the Flory-Huggins equation, but deviated from the Langmuir equation. The standard molar adsorption Gibbs function, standard molar adsorption entropy and standard molar adsorption enthaply are calculated. The measurements of the point of zero charge and isoelectric point show occurrence of the characteristic adsorption. It has been proved that the OH group on the skeleton of ferric oxide gel is the innate cause of the characteristic adsorption.

Keywords

ferric oxide gel / rare earth elements / characteristic adsorption

References

[1] ShiZemin. Form of Eu, Y in black earthy efflorescence existing in Mao Niuping rare earth depositand its comprehensive utilization. Xichang Geology, 1993, 4: 12-16(in Chinese)

[2] ShiZemin. Form and distribution feature of erare earth elements in rare earth deposit at north Xichuang in Sichuan. Rare Earth, 1992, 13(3): 1-9(in Chinese)

[3] ZhuJianguo, XingGuangxi, YamasakiS., et al. . Adsorption and desorption of exogenous rare earth elements in soil :I Rate and forms of rare earth elements sorbed. Pedosphere, 1993, 3(4): 299-308

[4] ZhuJianguo, XingGuangxi. Forms of rare earth elements in soil: I. Distribution. Pedosphere, 1992, 2(2): 125-134

[5] ZhuJianguo, XingGuangxi. Forms of rare earth elements in soil: I. differention of rare earth elements. Pedosphere, 1992, 2(3): 193-200

[6] ZhuJianguo, XingGuangxi. Study of continuous fractionation of rare earth elements in soil. J of Pedosphere, 1991, 5: 215-218

[7] AteyaB G, AnadouliB E El, NizamyF M El. The adsorption of thiourea on mild steel. Corrosion Science, 1984, 24(6): 509-515

[8] GuTirenSurface chemistry, 1994, Beijing, Science Press: 141142(in Chineses)

[9] PenShiwenAtlas of infred spectrogram of mineral, 1982, Beijing, Science Press: 160162(in Chinese)

[10] WenLuoInfred spectroscopy of mineral, 1988, Chong Qing, Chongqing University Press: 171172(in Chinese)

[11] ChenJinghongThermal Analysis and Application, 1985, Beijing, Science Press: 9495(in Chinese)

[12] HirotaroKThermal Analysis, 1982, Tvo Beijing, Chemical Industry Press: 106109(in Chinese)