A method for extracting rare earth from ion adsorption type rare earth ore

Abstract

The invention discloses a method for extracting rare earth from ion adsorption type rare earth ores. The method comprises the following steps: leaching the ion adsorption type rare earth ores by a leaching agent to obtain rare earth leachate; then adding a calcium-alkali compound in the rare earth leachate to remove impurities; adding at least one of magnesium chloride, sodium chloride and potassium chloride in impurity removal mother liquor; and controlling the chloride ion concentration, the temperature and the pH in a precipitation process of the calcium-alkali compound to achieve the purpose of increasing solubility of calcium sulfate and reduce generation of the calcium sulfate in the precipitation process. Meanwhile, under the related conditions of high salinity and the like, the migration speeds of rare earth ions and hydroxyl ions in a precipitation system of the calcium-alkali compound are reduced, the degree of supersaturation of rare earth hydrate is controlled effectively, and crystal precipitates of the rare earth hydrate is facilitated. By the method, ammonia nitrogen pollution is eliminated, formation of the calcium sulfate in the precipitation process of the calcium-alkali compound is reduced, the production cost is reduced, and meanwhile, the product with qualified purity is obtained.

Description

technical field [0001] The invention relates to the field of rare earth hydrometallurgy, in particular to a method for extracting rare earth from ion-adsorption type rare earth ore. Background technique [0002] Rare earth (Rare Earth, referred to as RE) is the 15 lanthanide elements with atomic numbers from 57 to 71 in the third subgroup of the periodic table of chemical elements, namely lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd ), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb ), lutetium (Lu), plus scandium (Sc) and yttrium (Y), which are similar in electronic structure and chemical properties, a total of 17 elements. Due to their unique 4f sublayer electronic structure, large atomic magnetic moment, strong spin-orbit coupling, and variable coordination numbers, the compounds formed by rare earth elements have very rich magnetic, optical, electrical,...

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Problems solved by technology

In response to this problem, experts have also proposed related solutions (CN103436720, CN102190325, CN104152693), but they all have problems and cannot be implemented; CN101475202 uses calcium oxide or a mixture of calcium oxide and seed crystals as a precipitant to precipitate rare earth rare earths in solution

As for the calcium oxide precipitant, it is a slightly soluble substance, and the precipitation reaction is fast and the effect is good. However, there are sulfates in the leaching agent of the ion-adsorption rare earth ore, which causes a large amount of sulfate radicals to be contained in the leaching solution. Calcium oxide is used alone as the Precipitating agent, which will produce a large amount of calcium sulfate precipitation in the process of precipitating ion ore leachate, also greatly reduces the purity of rare earth concentrate products, and cannot obtain qualified products

At the same time, hydroxide precipitation has poor crystallization performance, resulting in poor filtration performance and low production efficiency.

[0005] In summary, how to provide an extraction method for ion-adsorption type rare earth ores to remove ammonia nitrogen pollution and solve the problem of unqualified product purity caused by calcium sulfate precipitation in the calcium oxide precipitation process has become a technical problem to be solved urgently

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