Processing method of rare earth chloride solution

Abstract

The invention relates to a rare earth chloride solution processing method, which relates to the technical field of rare earth chemistry, and comprises the following steps: activating and refining monazite ore, destroying the structure of the surface of the monazite ore by an alkaline solution, enhancing the internal fluidity and activity of the monazite ore, and roasting the monazite ore mixed with carbon powder at high temperature in a smelting furnace to obtain the rare earth chloride solution. The method comprises the following steps of: performing water quenching and solid-liquid separation on roasted ore for multiple times, adding hydrochloric acid into filter residues for optimal dissolution, adding hydrogen peroxide for assisting dissolution in the optimal dissolution process, performing impurity treatment on filtrate to obtain a rare earth chloride solution, and adding deionized water into the rare earth chloride solution to adjust different concentrations. The process of filter pressing and crystallization of the rare earth chloride solution is removed, diversified requirements of manufacturers are met, the preparation process of the rare earth chloride solution is optimized, modular continuous production is achieved, and good economic benefits are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of rare earth chemistry, in particular to a rare earth chloride solution processing method. Background Art

[0002] Monazite mines are mostly formed in coastal placer mines and alluvial placer mines, and can be used for the extraction and preparation of rare earth elements. Rare earth chloride is the main form of rare earth resources.

[0003] At present, the chemical processes for extracting rare earths from monazite mainly include concentrated sulfuric acid roasting process and caustic soda decomposition-hydrochloric acid leaching process. The concentrated sulfuric acid roasting process will produce a large amount of "three wastes" environmental pollutants during the production process. The caustic soda decomposition-hydrochloric acid leaching process requires a higher grade of monazite ore, and the preparation process is complicated and costly.

[0004] In the prior art, there is an oxidative roasting-hydrochloric acid leaching process for extracting rare earths from monazite mines. However, this chemical process has the problems of high monazite adaptability, low rare earth leaching rate, and more product impurities. At the same time, most of the existing extraction methods can only obtain rare earth chloride solids containing impurities, which cannot meet the needs of some manufacturers for rare earth chloride solutions. How to prepare rare earth chloride solutions of different concentrations simply, efficiently and environmentally friendly is a problem that needs to be solved urgently in the current rare earth chemistry field. Summary of the invention

[0005] In order to improve the problems in the process of extracting rare earth from monazite ore in the above background technology, the present invention provides a method for processing rare earth chloride solution.

[0006] The present invention provides a rare earth chloride solution processing method using the following technical solutions: A method for processing a rare earth chloride solution comprises the following steps: Step 1, the activated and refined monazite ore powder is mixed with carbon powder and roasted at high temperature in a furnace to obtain roasted ore; Step 2, the roasted ore is subjected to multiple water quenching and solid-liquid separation to obtain filter residue; Step 3, adding hydrochloric acid to the filter residue to obtain a soluble residue and a filtrate after solid-liquid separation; Step 4, treating the filtrate for impurities to obtain a rare earth chloride solution; Step 5: Add deionized water to the rare earth chloride solution to prepare different concentrations. The different concentrations are prepared according to the manufacturer's needs and transported in barrels.

[0007] Preferably, in step 1, the activation refining treatment is to soak the monazite ore powder in a low concentration alkaline solution for alkali activation, keep it at a temperature below 60° C. for 6-10 h and filter it.

[0008] Preferably, an alcohol amine activator is added during the alkaline excitation process.

[0009] Preferably, the alkaline solution is a calcium hydroxide or sodium hydroxide solution with a concentration lower than 15%, and the filtered filtrate is recycled and further used for alkali excitation, thereby reducing costs and waste of raw materials.

[0010] Preferably, in step 1, the average particle size of the monazite ore powder is less than 80 μm.

[0011] Preferably, in step 1, the calcination temperature is 450° C. to 600° C., and the calcination time is 1 to 2 h.

[0012] Preferably, in step 3, hydrogen peroxide is added during the dissolution process to aid dissolution, and the solution is dissolved at 60 to 90° C. for 0.5 to 1.5 hours.

[0013] Preferably, in step 3, the molten slag is subjected to metal recovery, mainly recovering thorium metal.

[0014] Preferably, in step 4, the impurity treatment is to add ammonia water and barium chloride to the filtrate to filter out the radium residue impurities.

[0015] In summary, the present invention has the following beneficial technical effects: 1. The present invention removes phosphorus from monazite ore powder through activation refining and roasting, thereby reducing environmental pollution. The roasted ore after phosphorus removal is dissolved in hydrochloric acid and treated with impurities to obtain a rare earth chloride solution and prepare different concentrations. The present invention optimizes the preparation process of the rare earth chloride solution, realizes modular continuous production, has fewer impurities in the product, and has good economic benefits.

[0016] 2. The present invention performs activation and refining treatment on monazite ore powder, immerses the monazite ore powder in a low-concentration alkaline solution for a long time, and the alkaline solution destroys the surface structure of the monazite ore powder, enhances the internal fluidity and activity of the monazite ore powder, adapts to the processing requirements of monazite ore powder with lower grade, and accelerates the subsequent reaction process.

[0017] 3. The present invention eliminates the filter pressing and crystallization process of the rare earth chloride solution, and directly prepares and mixes rare earth chloride solutions of different concentrations, thereby meeting the diverse needs of manufacturers and reducing the complexity and energy consumption of the operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a process flow chart of a rare earth chloride solution processing method according to Example 1 of the present invention. DETAILED DESCRIPTION

[0019] The following combination Figure 1 The present invention is described in further detail.

[0020] Invention Example 1 discloses a method for processing a rare earth chloride solution, referring to Figure 1, a rare earth chloride solution processing method, comprising the following steps: Step 1, the activated and refined monazite ore powder is mixed with carbon powder and roasted at high temperature in a furnace to obtain roasted ore, the monazite ore powder is mixed with carbon powder and a binder to solidify into a mass, and the roasted ore is roasted at high temperature in a furnace to remove phosphorus to obtain the roasted ore, the roasting temperature is 450°C to 600°C, the roasting time is 1-2 hours, and the polluted gas generated during the high-temperature roasting process is passed into a spray box for recovery.

[0021] Reference Figure 1 The activation and refining treatment is that the monazite ore powder is immersed in a low-concentration alkaline solution for alkaline activation, wherein the alkaline activation is that the monazite ore powder is immersed in a low-concentration alkaline solution, the monazite ore powder and the low-concentration alkaline solution are mixed and placed in a closed reactor, kept warm at below 60°C for 6-10 hours and filtered, the alkaline solution destroys the surface structure of the monazite ore powder, allows the alkaline medium and water molecules to penetrate, enhances the fluidity and activity of the particles inside the monazite ore powder, and adapts to the processing needs of monazite ore powder with lower grade. At the same time, the alkaline activation also has a dispersing effect, which accelerates the subsequent reaction process, and the monazite ore powder is mixed with carbon powder and adhesive for more thorough calcination; in the alkaline activation, the monazite ore powder reacts with a small amount of alkaline solution to generate soluble salts and acid salts, thereby improving the recovery rate of rare earths; the alkaline solution is a calcium hydroxide or sodium hydroxide solution with a concentration of less than 15%, and the filtered filtrate is recycled and treated, and can be further used for alkaline activation after impurity removal and enrichment.

[0022] Monazite is a phosphate mineral. During the high-temperature roasting process, the phosphorus in the monazite ore powder is reduced to elemental phosphorus by carbon. The elemental phosphorus burns to produce phosphorus pentoxide, which is recovered in the gas recovery device at the top of the furnace. Adding carbon powder can also increase the roasting temperature.

[0023] Step 2: The roasted ore after cooling is ball-milled in a ball mill, the roasted ore is water-quenched for multiple times, and solid-liquid separation is performed in a filter press to obtain filter residue.

[0024] Step 3, adding hydrochloric acid to the filter residue, dissolving it in a reactor, the hydrochloric acid concentration is 4-12 mol / L, the solid-liquid ratio is 6-10, and after dissolving, using a filter press to separate the solid and liquid to obtain a dissolved residue and a filtrate; adding hydrogen peroxide to assist dissolution during the dissolution process, dissolving at 60-90° C. for 0.5-1.5 h, and recovering metal from the dissolved residue, which is mainly thorium slag. The thorium slag is acid-dissolved in nitric acid and filtered, and the filtrate is used to recover thorium metal.

[0025] Step 4: The filtrate contains a small amount of impurities and mixed acid solution. The filtrate is treated for impurities. Ammonia water and barium chloride are added to the filtrate for secondary impurity removal and neutralization. The filtrate is fully reacted at 50-70° C. in a reactor. The radium residue is filtered out using a filter press to obtain a rare earth chloride solution. The pH range of the rare earth chloride solution is 7-9. The filtered rare earth chloride solution enters a storage tank.

[0026] Step 5: Add deionized water to the rare earth chloride solution to prepare different concentrations. The different concentrations are prepared according to the manufacturer's needs and transported in barrels. Inventive Example 1 also designs an automated PLC control system. By setting up signal-connected sensors and PLC controllers, the sensors are set in containers during the preparation process to accurately control parameters such as reaction temperature, pressure, and time during the entire preparation process, thereby improving the stability and efficiency of the preparation. It is also beneficial to reduce energy consumption and ensure the smooth progress of the reaction.

[0027] The implementation principle of a rare earth chloride solution processing method in Example 1 of the invention is as follows: monazite ore is mined in open-pit coastal sand mines and alluvial sand mines, and the monazite ore is crushed and transported to a processing plant; monazite ore powder is immersed in a low-concentration alkaline solution for activation and refining treatment, the activated and refined monazite ore powder is mixed with carbon powder and roasted at high temperature in a furnace to remove the phosphorus element in the monazite ore powder, the roasted ore is subjected to multiple water quenching and solid-liquid separation, hydrochloric acid is added to the filter residue for dissolution, metal is recovered from the dissolved slag after solid-liquid separation, and impurity treatment is performed on the filtrate, and deionized water is added to the obtained rare earth chloride solution to prepare different concentrations to achieve modular continuous production.

[0028] Invention Example 2 discloses a method for processing a rare earth chloride solution, referring to Figure 1 , a rare earth chloride solution processing method, comprising the following steps: Step 1, the activated and refined monazite ore mixed with carbon powder is roasted at high temperature in a furnace to obtain roasted ore; Step 2, the roasted ore is subjected to multiple water quenching and solid-liquid separation to obtain filter residue; Step 3, adding hydrochloric acid to the filter residue to obtain a soluble residue and a filtrate after solid-liquid separation; Step 4, treating the filtrate for impurities to obtain a rare earth chloride solution; Step 5: Add deionized water to the rare earth chloride solution to prepare different concentrations.

[0029] Reference Figure 1 The activation and refining treatment is that the monazite ore is immersed in a low concentration alkaline solution for alkaline activation, kept below 60°C for 6-10 hours and filtered. After the alkaline activation is completed, the filtered monazite ore is ball-milled in a ball mill; an alcohol amine activator is added during the alkaline activation process; the alkaline solution is a calcium hydroxide or sodium hydroxide solution with a concentration of less than 15%, and the filtered filtrate is recycled and further used for alkaline activation.

[0030] The implementation principle of a rare earth chloride solution processing method of Invention Example 2 is as follows: monazite ore is mined in open-pit coastal sand mines and alluvial sand mines, and the monazite ore is directly transported to a processing plant after simple crushing; the monazite ore is immersed in a low-concentration alkaline solution for activation and refining treatment, and after the activation and refining treatment, the monazite ore is crushed, and the crushed monazite ore powder is mixed with carbon powder and calcined at high temperature in a furnace to remove the phosphorus element in the monazite ore powder.

[0031] Inventive Example 2, after the alkali excitation is completed, the monazite ore is ball-milled. During the alkali excitation process, the low-concentration alkali solution infiltrates the monazite ore for a long time. At the same time, the alkali molecules and alcoholamine activators added during the alkali excitation process can be used as grinding catalysts, so that the particles of the monazite ore after ball milling are more uniform and fine. The average particle size of the monazite ore powder after activation, refining and screening is less than 80μm.

[0032] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for processing a rare earth chloride solution, characterized in that: The steps include: Step 1, the activated and refined monazite ore powder is mixed with carbon powder and roasted at high temperature in a furnace to obtain roasted ore; Step 2, the roasted ore is subjected to multiple water quenching and solid-liquid separation to obtain filter residue; Step 3, adding hydrochloric acid to the filter residue to obtain a soluble residue and a filtrate after solid-liquid separation; Step 4, treating the filtrate for impurities to obtain a rare earth chloride solution; Step 5: Add deionized water to the rare earth chloride solution to prepare different concentrations.

2. A method for processing a rare earth chloride solution according to claim 1, characterized in that: In step 1, the activation refining treatment is to soak the monazite ore powder in a low concentration alkaline solution for alkali activation, keep it at below 60° C. for 6-10 hours and filter it.

3. A method for processing a rare earth chloride solution according to claim 2, characterized in that: An alcohol amine activator is added during the alkaline activation process.

4. A method for processing a rare earth chloride solution according to claim 2, characterized in that: The alkaline solution is a calcium hydroxide or sodium hydroxide solution with a concentration lower than 15%, and the filtered filtrate is recycled and further used for alkaline excitation.

5. A method for processing a rare earth chloride solution according to claim 1, characterized in that: In step 1, the average particle size of the monazite powder is less than 80 μm.

6. A method for processing a rare earth chloride solution according to claim 1, characterized in that: In step 1, the calcination temperature is 450° C. to 600° C., and the calcination time is 1 to 2 h.

7. A method for processing a rare earth chloride solution according to claim 1, characterized in that: In step 3, hydrogen peroxide is added to aid dissolution during the dissolution process, and the solution is dissolved at 60 to 90° C. for 0.5 to 1.5 h.

8. The method for processing a rare earth chloride solution according to claim 1, characterized in that: In step 3, the molten slag is subjected to metal recovery.

9. A method for processing a rare earth chloride solution according to claim 1, characterized in that: In step 4, the impurity treatment is to add ammonia water and barium chloride to the filtrate to filter out the impurities.

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