A process and equipment for decomposing monazite rare earth ore by alkaline method

Abstract

The invention discloses a technique and facility for decomposing monazite rare earth ore through an alkaline method. In the process of decomposing the monazite rare earth ore through the alkaline method, accurate and automatic feeding of monazite ore powder, solid caustic soda and alkali liquor is achieved through a metering type screw feeder and a flowmeter, and after the monazite ore powder, the solid caustic soda and the alkali liquor enter a multi-stage reaction tank, a far-infrared heating mode is adopted to heat the reaction tank. Solid sodium hydroxide and recovered caustic soda liquid are used for proportioning and feeding, and therefore automatic preparation of the alkali liquor concentration can be achieved. According to the technological process, the dust pollution problem generated by batched proportioning in traditional production is solved; meanwhile, the reaction process is conducted in a full-closed system, and the pollution problem caused by radioactive dust is avoided; through the far-infrared heating mode, the heating area is large, and the effect that the temperature in a kettle is controlled according to the upper section, the middle section and the lower section can be achieved; and the heating mode is safe and reliable, the service life is long, noise is avoided during operation, and energy consumption is reduced by 30%-50% compared with an original conduction oil heating mode and a steam heating mode.

Description

technical field [0001] The invention relates to a process and equipment for decomposing monazite rare earth ore by alkali method, in particular to a process and equipment for decomposing monazite rare earth ore by alkali method using far-infrared heating, belonging to the field of rare earth smelting and production. Background technique [0002] Monazite is an industrial rare earth phosphate mineral, which is generally easy to sort, and the monazite mineral content in the obtained concentrate can reach more than 95%. In industry, the caustic soda decomposition method is generally used to treat monazite concentrate. ("Rare Earth", Volume 1 of the first edition, Metallurgical Industry Press 1978, P221-237.) [0003] In industry, the traditional process is to use caustic soda liquid and concentrate to be prepared in proportion to enter the decomposition tank, and the decomposition tank is heated by a steam jacket to make the reaction proceed at a higher temperature. Continuou...

AI Technical Summary

Problems solved by technology

[0004] The process of traditional monazite decomposition reaction equipment is relatively long, and the steam heating method has disadvantages: it is not easy to be automatically controlled. When the steam pressure is insufficient or unstable, the decomposition rate fluctuates, and the decomposition consumes more energy. The decomposition rate of industrial monazite is not high. High (generally about 96%), and unstable, causing rare earth loss

In recent years, heat conduction oil reaction tanks have been gradually used in the monazite decomposition process. Patent CN201110358861.3 discloses a heat conduction oil heating reaction tank system. The material of the heat transfer oil has a limited effect on the temperature increase, and the heat transfer oil needs to add a biphenyl mixture, and when the oil gas leaks at high temperature, it is poisonous and easy to explode.

[0005] The traditional monazite decomposition reaction system fails to solve the problem of decomposition reaction process control. Generally, the decomposition reaction time is greatly extended to achieve the highest possible decomposition efficiency, which brings problems such as increased energy consumption and low equipment utilization.

[0006] The traditional alkaline decomposition method has the problem that the system production is not airtight, which is easy to cause radioactive dust pollution

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