Method for removing aluminum from rare earth solution by benzoate precipitation method

Abstract

The invention relates to a method for removing aluminum from a rare earth solution by a benzoate precipitation method. The method comprises the following steps: (1) preparing the raw materials: an aluminum-containing rare earth solution of which the pH is not less than 4 and a REO (rare earth oxide) is 30-300g / L, and a precipitating agent which is one or more of potassium benzoate, sodium benzoate, ammonium benzoate or benzoic acid; and (2) precipitating to remove the aluminum: adding a fixed quantity of the precipitating agent into the aluminum-containing rare earth solution to produce an aluminum benzoate precipitate, and filtering and separating to get rare earth filtrate and aluminum benzoate slag, wherein the using quantity of the precipitating agent is 100-150% of the theoretical reaction amount, and the ratio of Al2O3 in the rare earth filtrate to the REO in percentage by weight is 10-50PPM. The method has the advantages of very low production cost, simple production process, strong process operability, effects of reducing environmental pollution and eliminating environmental protection risk and excellent product quality; and the ratio of the Al2O3 to the REO in percentage by weight can be 10-50PPM.

Description

technical field [0001] The invention relates to the removal of aluminum (Al) in rare earth solution 3+ ) industrialized production methods for the purification of rare earths, especially medium and heavy rare earths such as praseodymium, neodymium, yttrium, and dysprosium, which belong to the fields of rare earth hydrometallurgy, chemical industry, and chemistry. Background technique [0002] Rare earth is known as the treasure trove of modern industrial new materials, especially in the application of high-tech methods, such as fluorescence, permanent magnetic materials, special glass, precision ceramics, superconducting materials, etc. Praseodymium and neodymium are the key and main components of permanent magnetic materials. Component. Aluminum is a harmful impurity in rare earth products, which must be removed during the production process. High-performance rare earth materials have strict requirements on the content of aluminum. The market price of rare earth products ...

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Problems solved by technology

Although the rare earth products produced by this process can reach Al 2 o 3 Less than 50PPM, this process has a large consumption of oxalic acid, 1 ton of rare earth oxide consumes 1.35 to 1.5 tons of oxalic acid, and the price of oxalic acid is expensive. Only the cost of raw material consumption is currently as high as 1.0 to 15,000 yuan per ton of rare earth oxide; in the production process A large amount of acidic wastewater containing oxalic acid is produced, oxalic acid is poisonous, and the toxic acidic wastewater produced per ton of rare earth oxides reaches 10m 3 For the above, it needs to be treated and discharged up to the standard. This method has high environmental risks and high costs.

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