Method for recovering neodymium and iron from neodymium iron boron oil sludge through two-step co-precipitation

Abstract

The invention relates to a method for recovering neodymium and iron from neodymium iron boron oil sludge through two-step co-precipitation, belonging to the technical field of recycling of neodymium iron boron oil sludge. The method comprises the following steps of: dissolving the neodymium iron boron oil sludge by using hydrochloric acid and filtering undissolved substances, and then, controlling a certain pH value and reaction temperature after oxidizing through adding hydrogen peroxide; adding oxalic acid-ammonium bicarbonate and ammonium oxalate-ammonium hydroxide precipitating agent; co-precipitating a neodymium and iron sediment mixture in two steps; and respectively roasting a filtered product at the proper decomposition temperature to obtain neodymium and iron oxides. The neodymium and iron oxides can be used for re-preparing regenerated neodymium iron boron through reducing, forming, sintering and thermal treatment. A complex wet-method process for obtaining single high-purity rare earth in recovery is avoided, and the method is a key step for forming a cycle industry.

Description

technical field [0001] The invention relates to a method for preparing regenerated NdFeB two-step co-precipitated neodymium-iron alloys from NdFeB sludge, and belongs to the technical field of recycling NdFeB sludge. Background technique [0002] Today, one out of every six new technologies is related to rare earths, which fully demonstrates the role and status of rare earths in new technologies. Rare earth is an important strategic resource in the 21st century and the "monosodium glutamate" of modern industry. The reason why rare earth elements are called "strategic elements in the 21st century" is because they have special physical and chemical properties that other elements do not have. Many new rare earth materials made based on these characteristics have excellent performance and are widely used, and are widely used in electronic information, communication technology, automobile manufacturing, energy, aerospace and other fields. Rare earths have been hailed as "materi...

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Problems solved by technology

[0006] Based on the above current rare earth recovery methods, although these processes can regain rare earths, there are still many problems: first of all, from the results, the circular chain of the above processes does not form a real cycle, and the products obtained by these processes are only Rare earth oxides, but not made into industrial products that can be used directly

Only in the extraction process, because of the need for a higher liquid-to-liquid ratio and better stripping effect, the acid consumption is more than 10 times the normal stoichiometric amount, and the acid-base waste liquid formed in these processes is very high at the end of the process. Difficult to handle; not only that, the sulfuric acid double salt precipitation method will produce SO which is very harmful to the human body in the process of iron recovery 2 and H 2 S gas

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