Method for preparing solid spherical rare earth oxide in one-step spraying thermal decomposition mode

Abstract

The invention belongs to the field of rare earth metallurgy, and in particular relates to a method for preparing a solid spherical rare earth oxide in a one-step spraying thermal decomposition mode. The method comprises the following steps of: firstly, controlling the temperature of a roasting furnace to 400-1700 DEG C, subsequently mixing a solution containing 10-350g / L rare earth oxide and 0.1-500g / L carboxylic acid additive with a carrier compressed gas with a flowing speed of 5-8,000L / h, subsequently spraying into the roasting furnace, roasting for 1-60 seconds, and naturally cooling down the roasting slag so as to obtain a solid spherical powder product of which the rare earth oxide content is greater than 90wt%. As a trivalent rare earth chloride solution is used as the raw material, ammonium bicarbonate and toxic oxalic acid are not used in the production process, carbon dioxide emitted in the roasting process in the conventional process is not generated, and the pollution on the environment is greatly reduced. Solid spherical powder can be prepared through one-step thermal decomposition.

Description

technical field [0001] The invention belongs to the field of rare earth metallurgy, and in particular relates to a method for preparing solid spherical rare earth oxides through one-step spray thermal decomposition. Background technique [0002] With the development of science and technology, rare earth oxides, as one of the basic materials for preparing new materials, have been more and more widely used. Rare earth oxides are the most common intermediate products in rare earth production, which can be further used to produce rare earth metals, alloys and functional materials, etc. At present, the preparation of rare earth oxides is developing in the direction of special physical and chemical properties, such as the preparation of rare earth oxides and rare earth composite powders with different particle sizes and specific surface areas. [0003] Rare earth oxides can be obtained by oxidizing rare earth metals in air, burning rare earth hydroxides and rare earth salts conta...

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Problems solved by technology

It is worth noting that oxalic acid has certain toxicity, and it exists in wastewater, polluting the environment

At the same time, regardless of the oxalic acid precipitation method or the ammonium bicarbonate precipitation method, a large amount of carbon dioxide will be emitted during the burning rare earth precipitation process, which will increase the carbon emissions of the enterprise

In addition, the filtrate after precipitation by this method contains a large amount of chloride radicals, which cannot be utilized and will also cause environmental pollution.

[0005] Chinese patent application, application number 200410036484.1 discloses a method for preparing rare earth oxides, which solves the problems of high labor intensity, large equipment loss and serious pollution in the process of preparing rare earth oxides by oxalate precipitation method or ammonium bicarbonate precipitation method , unbalanced decomposition, poor consistency, and affecting product quality, etc., a technical scheme that can continuously burn and decompose rare earth carbonate or oxalate to prepare rare earth oxides was proposed, and the burning equipment was designed

Xu Huarui and others used the method of adding oxalate to cerium chloride solution to prepare solid spherical cerium oxide by thermal decomposition, but the method has the following problems. The first thermal decomposition process is divided into two stages, and the first stage is roasting. into cerium oxalate, and then carry out the second stage of roasting to decompose cerium oxalate to prepare cerium oxide, which leads to complex process control and equipment structure of this method, resulting in increased cost

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