Method for extracting rare earth from rare-earth-contained apatite ores

Abstract

Disclosed is a method for extracting rare earth from rare-earth-contained apatite ores. The method includes the following steps of grinding the rare-earth-contained apatite ores, adding concentrated nitric acid or hydrochloric acid, adding ammonia water, ammonium carbonate or ammonium bicarbonate solution after acid decomposition, heating, separating solid from liquid to obtain crude phosphoric acid solution and rare-earth-rich slags; adding concentrated nitric acid into the rare-earth-rich slags, roasting, leaching by adding water, separating liquid from solid to obtained leaching liquid and acidified slags, stacking and abandoning the acidified slags; heating the leaching liquid, adding solid potassium chloride, sodium chloride, ammonium chloride, potassium sulfate, sodium sulfate or ammonium sulfate, and separating liquid from solid while heating to prepare rare-earth sulfuric acid compound salt with rare-earth oxide content higher than 36%. Rare-earth recovery rate is higher than 85%. The method for extracting the rare earth from the rare-earth-contained apatite ores is a method capable of effectively reasonably separating phosphorus from the rare earth and recovering the rare earth, is simple in process and low in cost, solves the problems of high energy consumption and severe pollution and is applicable to the rare-earth-contained apatite ores with REO (rare earth oxide) content ranging from 1.0% to 5.0% and P2O5 content ranging from 25% to 35%.

Description

technical field [0001] The invention relates to a method for extracting rare earth-containing ores, in particular to a method for extracting rare earths from apatite ores containing rare earths. Background technique [0002] Rare earth-containing apatite ore refers to apatite ore containing rare earth. Mainly apatite minerals, accompanied by rare earth minerals, such as allanite, bastnaesite, monazite, etc., and gangue minerals, such as pyroxene, hornblende, feldspar, etc. The chemical formula of apatite is Ca 5 (PO 4 ) 3 (F, Cl, OH), apatite contains rare earth elements and fine-grained rare earth mineral inclusions that replace calcium in the homogeneous form, and the rare earth content generally does not exceed 5%. In the ore, apatite and rare earth minerals intergrow with each other, and the embedded particle size is fine, so it is difficult to dissociate and sort. [0003] Since the 1960s, Finland, the United States and the former Soviet Union have all studied the ...

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Problems solved by technology

[0003] Since the 1960s, Finland, the United States and the former Soviet Union have all studied the method of recovering rare earths from apatite while producing phosphoric acid or phosphate fertilizer. Single, as well as operational and cost issues, and there is no mature technology for promotion and application worldwide

Someone has studied the nitric acid method to treat rare earth-containing phosphate rocks, such as CN201010557640.4 "A Utilization Method of Rare Earth-Containing Low-Grade Phosphate Rocks" and CN201110199788.X "Decomposing Rare Earth-Containing Phosphate Rocks with Nitric Acid to Produce Highly Water-Soluble Nitrophosphate Fertilizer and Recycling Rare Earth The two methods disclosed in "The method" selects the neutralization precipitation of the leachate containing rare earths. This method produces a large amount of neutralization sedimentation residue with low rare earth content. The follow-up treatment is complicated, and the rare earth recovery rate index is not quantified. Rare earths do not have an advantage