Method for removing trace iron and aluminum in rare earth solution in preferential precipitation mode
By adjusting the pH of the rare earth solution and combining it with ammonium bicarbonate and ammonia precipitation, the problem of removing trace amounts of iron and aluminum from the rare earth solution was solved, achieving efficient impurity removal and rare earth recovery.
Patent Information
- Application Number
- CN202411442433.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-16
- Publication Date
- 2025-01-07
AI Technical Summary
Existing technologies are ineffective at removing trace amounts of iron and aluminum from rare earth solutions, resulting in low rare earth yields and high costs. Furthermore, existing methods suffer from difficulties in controlling the extraction and separation process.
After adjusting the pH of the rare earth solution to 3-3.5, ammonium bicarbonate was added, and then adjusted to 4.5-5.5. Precipitation and filtration were carried out. The filter residue was then treated with oxalic acid to remove iron and aluminum impurities. A combination of ammonium bicarbonate and ammonia was used for preferential precipitation.
It achieves a complete removal rate of over 99% for trace iron and aluminum, low rare earth loss rate, low oxalic acid consumption, low economic cost, and high rare earth yield.
Smart Images
Figure CN119265434A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of metal recovery in rare earth solutions, and in particular relates to a method for removing trace iron and aluminum in rare earth solutions in a preferential precipitation manner. Background Art
[0002] Ionic rare earth ores are widely distributed in the southern provinces of my country. They are named because rare earths are adsorbed on minerals in the form of ions, but they also adsorb aluminum, iron, silicon, calcium and other substances. At present, the acid leaching process is generally used to treat rare earth concentrates, but in addition to rare earths, impurities such as aluminum and iron will also enter the rare earth acid leaching solution at the same time. The content of Fe2O3 in rare earth oxide products in the industry is generally not higher than 0.01% (mass fraction), and the content of Al2O3 is not higher than 0.05% (mass fraction). At present, cyclohexane acid extraction method, oxalic acid precipitation method, liquid alkali neutralization precipitation method, coordination method and other methods are generally used to deeply remove cationic impurities in rare earth feed liquid. The organic phase is prone to emulsification during cyclohexane acid extraction, which makes it difficult to smoothly carry out the extraction and separation process, resulting in a low rare earth yield and incomplete impurity removal effect; when removing impurities by liquid alkali neutralization precipitation method, it is difficult to control the pH value and the solubility product of the impurity precipitation is close to the solubility product of the rare earth, making it difficult to effectively separate. When the impurities are completely precipitated, some rare earths are precipitated or the rare earths are severely adsorbed and wrapped, resulting in a low yield; the current research on the coordination method is difficult to find a certain ligand compound that can effectively coordinate and remove iron and aluminum at the same time; oxalic acid precipitation has obvious effects on removing impurities but is costly. Therefore, a method for removing trace iron and aluminum in rare earth solutions by precipitation is needed to solve the above technical problems. Summary of the invention
[0003] In view of the above-mentioned defects in the prior art, the present invention provides a method for removing trace iron and aluminum in a rare earth solution by preferential precipitation, comprising the following steps:
[0004] Step 1, adjusting the pH value: adding a rare earth solution containing trace aluminum and iron impurities into a reactor and stirring continuously, adding ammonium bicarbonate solution during stirring to adjust the pH value of the solution in the reactor to 3-3.5, then adding ammonia water to adjust the pH value of the solution in the reactor to 4.5-5.5 and then ending the stirring;
[0005] Step 2, precipitation and filtration: the solution in step 1 is precipitated and filtered to obtain rare earth liquid and filter residue;
[0006] Step three, filter residue recovery: add oxalic acid solution to the filter residue and stir, then filter to obtain rare earth oxalate and iron and aluminum waste liquid. The mass of the oxalic acid solution added in step three is 3-5 times that of the filter residue.
[0007] Preferably, the stirring speed in step 1 is 100-500 rpm, and the reaction temperature is about room temperature 25°C.
[0008] Preferably, the concentration of the ammonium bicarbonate solution in step 1 is 0.1-1 mol / L.
[0009] Preferably, the concentration of the ammonia water in step 1 is 0.1-1 mol / L.
[0010] Preferably, the stirring time in step three is 2-3 hours.
[0011] The present invention also includes other components that enable the method for removing trace iron and aluminum in rare earth solution by preferential precipitation to be used normally, which are conventional technical means in the art. In addition, the devices or components not limited in the present invention all adopt conventional technical means and conventional equipment in the art.
[0012] The beneficial effects of the present invention are as follows: trace iron and aluminum impurities in rare earth liquid can be removed more thoroughly, with a removal rate greater than 99%, a small rare earth loss rate, a high comprehensive recovery rate, a small oxalic acid consumption, and a low economic cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention is further described below in conjunction with the accompanying drawings and embodiments.
[0014] Figure 1 The present invention is a flowchart of a method for removing trace amounts of iron and aluminum from a rare earth solution by preferential precipitation in an embodiment of the present invention. DETAILED DESCRIPTION
[0015] The present invention is described clearly below in conjunction with the drawings and specific embodiments in the embodiments of the present invention. The description herein is only used to explain the present invention, but is not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work, any modifications, equivalent substitutions, improvements, etc., should be included in the protection scope of the present invention. Example
[0016] like Figure 1 As shown, the present invention provides a method for removing trace iron and aluminum in a rare earth solution by preferential precipitation, comprising the following steps:
[0017] Step 1, adjusting the pH value: add 200L of rare earth solution (neodymium chloride) containing trace aluminum and iron impurities into the reactor and stir continuously. During the stirring process, add 0.1mol / L ammonium bicarbonate solution to adjust the pH value of the solution in the reactor to 3, then add 0.1mol / L ammonia water to adjust the pH value of the solution in the reactor to 4.5 and then stop stirring;
[0018] Step 2, precipitation and filtration: The solution in step 1 is precipitated and filtered to obtain 338L of rare earth liquid and filter residue; wherein the Nd2O3 (RE) content is 0.88mol / L, the Fe2O3 content is 1mg / L, the Al2O3 content is 3mg / L, the iron removal rate is 99.11%, the aluminum removal rate is 99.4%, and the rare earth precipitation rate is 0.85%.
[0019] Step three, filter residue recovery: add oxalic acid solution to the filter residue and stir, then filter to obtain oxalate rare earth and iron and aluminum waste liquid, the mass of the added oxalic acid solution is 3 times that of the filter residue.
[0020] The stirring speed in the step 1 is 100 rpm.
[0021] The stirring time in step 3 is 2 h. Example
[0022] like Figure 1 As shown, the present invention provides a method for removing trace iron and aluminum in a rare earth solution by preferential precipitation, comprising the following steps:
[0023] Step 1: Adjust the pH value: Add 300L of rare earth solution containing trace aluminum and iron impurities (praseodymium chloride solution, containing Pr6O 11 1mol / L, Fe2O3 content 0.75g / L, Al2O3 content 0.45g / L) was added into the reactor and stirred continuously. During the stirring process, 1mol / L ammonium bicarbonate solution was added to adjust the pH of the solution in the reactor to 3.5. Then 1mol / L ammonia water was added to adjust the pH of the solution in the reactor to 5.5 before the stirring was stopped.
[0024] Step 2, precipitation and filtration: The solution in step 1 is precipitated and filtered to obtain 525L of rare earth liquid and filter residue; the content of Pr6O 11 (RE) is 0.57 mol / L, Fe2O3 content is 3 mg / L, Al2O3 content is 3 mg / L, iron removal rate is 99.3%, aluminum removal rate is 99.2%, and rare earth precipitation rate is 0.25%.
[0025] Step three, filter residue recovery: add oxalic acid solution to the filter residue and stir, then filter to obtain oxalate rare earth and iron and aluminum waste liquid, the mass of the added oxalic acid solution is 4 times that of the filter residue.
[0026] The stirring speed in the step 1 is 300 rpm.
[0027] The stirring time in step 3 is 2.5 h. Example
[0028] like Figure 1As shown, the present invention provides a method for removing trace iron and aluminum in a rare earth solution by preferential precipitation, comprising the following steps:
[0029] Step 1, adjusting the pH value: add 250L of rare earth solution containing trace aluminum and iron impurities (yttrium chloride solution, containing 1.2mol / L Y2O3 and 0.5g / L Fe2O3) into the reactor and stir continuously. During the stirring process, add 0.5mol / L ammonium bicarbonate solution to adjust the pH of the solution in the reactor to 3.5, then add 0.5mol / L ammonia water, adjust the pH of the solution in the reactor to 5 and stop stirring;
[0030] Step 2, precipitation and filtration: The solution in step 1 is precipitated and filtered to obtain 460L of rare earth liquid and filter residue; wherein the Y2O3 (RE) content is 0.65mol / L, the Fe2O3 content is 1mg / L, the iron removal rate is 99.6%, and the rare earth precipitation rate is 0.33%.
[0031] Step three, filter residue recovery: add oxalic acid solution to the filter residue and stir, then filter to obtain oxalate rare earth and iron and aluminum waste liquid, the mass of the added oxalic acid solution is 5 times that of the filter residue.
[0032] The stirring speed in the step 1 is 500 rpm.
[0033] The stirring time in step 3 is 3 hours.
[0034] In the present invention, the data of Examples 1-3 are shown in the following table:
[0035] From the above table, it can be seen that the present invention adopts the method of sequentially adding ammonium bicarbonate and ammonia water to adjust the pH value of the solution and filtering by precipitation, and then recovering the filter residue with oxalic acid, so that the trace iron and aluminum impurities in the rare earth liquid can be removed more thoroughly, and the removal rate is greater than 99%, achieving the beneficial effects of low rare earth loss rate, high comprehensive recovery rate, low oxalic acid consumption and low economic cost.
[0036] Embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of the present invention.
Claims
1. A method for removing trace iron and aluminum from a rare earth solution by preferential precipitation, characterized in that: The steps include: Step 1, adjusting the pH value: adding a rare earth solution containing trace aluminum and iron impurities into a reactor and stirring continuously, adding ammonium bicarbonate solution during stirring to adjust the pH value of the solution in the reactor to 3-3.5, then adding ammonia water to adjust the pH value of the solution in the reactor to 4.5-5.5 and then ending the stirring; Step 2, precipitation and filtration: the solution in step 1 is precipitated and filtered to obtain rare earth liquid and filter residue; Step three, filter residue recovery: add oxalic acid solution to the filter residue and stir, then filter to obtain oxalate rare earth and iron and aluminum waste liquid, the mass of the added oxalic acid solution is 3-5 times that of the filter residue.
2. The method for removing trace iron and aluminum from a rare earth solution by preferential precipitation according to claim 1, characterized in that: The stirring speed in the step 1 is 100-500 rpm.
3. The method for removing trace iron and aluminum from a rare earth solution by preferential precipitation according to claim 1, characterized in that: The concentration of the ammonium bicarbonate solution in step 1 is 0.1-1 mol / L.
4. The method for removing trace iron and aluminum from a rare earth solution by preferential precipitation according to claim 1, characterized in that: The concentration of the ammonia water in the step 1 is 0.1-1 mol / L.
5. The method for removing trace iron and aluminum from a rare earth solution by preferential precipitation according to claim 1, characterized in that: The stirring time in step 3 is 2-3 hours.