A method for selectively leaching sedimentary rare earth ores

Abstract

The invention discloses a method for selectively leaching sedimentary type rare earths. The method comprises the steps that a, the sedimentary type rare earths are pulverized into powder; b, the powder is calcinated for 0.5-5 hours at the temperature of 550-850 DEG C; c, the calcinated powder is cooled down for 0.5-48 hours at room temperature to obtain cooled hydrated powder; d, the hydrated powder is put into organic acid with the concentration of 0.5-5 mol / L to be reacted for 0.5-5 hours, the liquid-solid ratio is 2-20 L / kg, the leaching temperature is 20-90 DEG C, rare earth liquid is obtained, and remaining slag is washed until neutral, and acid washing liquid is recycled; the content of rare earth oxide (REO) in the sedimentary rare earths is equal to or less that 1.6%, and rare earth elements exist in clay minerals in the form of isomorphic substitution. According to the method, the rare earth element leaching rate is higher than 90% aiming at the technical difficulty of sedimentary rare earths in Guizhou province, the leaching of impurity elements can be effectively inhibited, and the method has the advantages of low energy consumption and convenient and controllable operation.

Description

technical field [0001] The invention relates to the technical field of pyro-wet comprehensive smelting of rare earth ores, in particular to a method for selectively leaching Guizhou sedimentary rare earth ores. Background technique [0002] The rare earth resources in the Bijie-Liupanshui area of ​​Guizhou are rich in rare earth resources. The rare earth deposits are mainly the sedimentary rare earth deposits of the Upper Permian Xuanwei Formation, and some places are called the Longtan Formation. At present, 2 large-scale triple-rare deposits and 6 medium-sized triple-rare deposits have been discovered in the area. A number of rare earth mineralization sites have also been found in its periphery, and this area has been listed as an important strategic resource support base in southern my country for national key construction. The composition of this sedimentary rare earth ore is mainly composed of clay minerals, mainly kaolinite, halloysite, hydromica and chlorite, etc., and...

AI Technical Summary

Problems solved by technology

However, the above-mentioned treatment method is only for bastnaesite-type rare earth ores. The bastnaesium minerals are completely decomposed by roasting, and the valence state of cerium is controlled through the test conditions, and the rare earth elements are enriched by utilizing the characteristics of hydrochloric acid that can preferentially leach trivalent rare earths. The leaching process has no selectivity for impurity elements, and its overall process treatment object, principle and control conditions are completely unsuitable for Guizhou sedimentary rare earth ores where rare earth elements are present in kaolinite in the form of similar quality and isomorphism