KR20220140396A - Method for recovering and manufacturing crude lithium carbonate from the battery meterial raffinate - Google Patents

Abstract

Disclosed is a method for recovering and manufacturing crude lithium carbonate from a battery material raffinate. According to the present invention, fluorine entering a raffinate during a process of recovering batteries is removed by using a zirconium-based fluorine remover, sodium sulfate products are acquired through evaporation and separation, lithium is precipitated by evaporating a circulation mother liquid and adding carbonate, and the sodium content in lithium carbonate products is reduced by using a manner of multi-drop dispersion and addition of a pre-lithium precipitation liquid during a process of precipitating lithium. Accordingly, the method provides features such as a short process, low impurities in a product, realization of internal circulation and use of lithium precipitation mother liquid, and low production cost. In addition, the content of lithium-sodium carbonate produced by the method is less than 0.1%, the main content of lithium carbonate is greater than 98.50%, and the fluorine content is less than 0.020%, and each indicator satisfies the required level of industrial grade lithium carbonate. The method comprises a fluorine removal step, a phosphorus removal step, a heavy metal precipitation step, an acid-alkaline control step, an evaporation concentration step, and a lithium precipitation step.

Description

Method for recovering and manufacturing prepared lithium carbonate from the battery material raffinate

The present invention belongs to the field of hydrometallurgical technology, and specifically, it is a method of preparing and extracting crude lithium carbonate of low-sodium low-fluorine at low cost from a raffinate of a battery material of low-lithium high-sodium. it's about how

In recent years, the country has been supporting the new energy industry with electric power, and the lithium-ion battery is the most popular secondary battery, showing a good development trend. Currently, the power battery is in the period of being discarded, and a large amount of discarded batteries are flowing into the market. A big plan that can be

Since the high-temperature dry method has characteristics such as high pollution and low resource utilization, valuable metals such as nickel, cobalt, and manganese in battery materials are usually recovered and used by wet methods such as leaching and extraction. Lithium, a light metal, is difficult to recover through extraction, but due to the property of forming a precipitate when lithium metal is combined with carbonate, lithium metal in the residue can be recovered and extracted by adding carbonate.

The lithium content in the discarded lithium-ion power battery is 5% to 7%, and after pre-treatment, leaching and extraction to recover cobalt, nickel and manganese, the lithium content that finally enters into the extraction residue is very small, and the amount of sodium The content is very high, and the ratio of sodium to lithium is as high as 18-22:1, so the extraction residue with low-lithium high-sodium content cannot be directly used for lithium carbonate precipitation method.

The invention with Chinese Patent Publication No. CN108002410B discloses a recycling method for extracting lithium recovered from tailwater in a low content and extracting tailwater, and the invention relates to lithium extraction from tailwater and a technology for recycling industrial wastewater. will be. This patent realizes lithium recovery by adding calcium to the extraction residue, removing fluorine, evaporating the crystals, precipitating and sedimenting lithium. In this patent, the fluoride removal agent selects calcium and the fluorine removal efficiency is low, the amount of residues from the fluorine removal is large, there is no phosphorus removal method (the phosphorus contained in the extraction residue is relatively large), and first, After removing impurities by forming crystals, a method of precipitating lithium is selected, which has disadvantages in that the amount of impurities in sodium sulfate is high, and the sodium content in lithium carbonate products is high and the main content is low.

The present invention was created to solve the problems existing in the prior art, and its purpose is to prepare low-sodium low-fluorine crude lithium carbonate in a low-lithium high-sodium battery material raffinate. It aims to improve lithium sedimentation efficiency by providing a manufacturing and extraction method, and to effectively reduce the production cost of lithium extraction to realize the cyclic use of lithium in the battery material balance.

In order to achieve the above object, the present invention provides a method for recovering and manufacturing prepared lithium carbonate from a battery material raffinate using the following technical method, the method comprising:

1) A fluorine removal step of removing fluoride by adding a zirconium-based fluoride removal agent to the battery material balance solution to obtain a liquid after removal of fluoride with a fluorine content of less than 3 mg/L;

2) a phosphorus removal step in which phosphorus is removed from the liquid after fluorine removal through a phosphorus remover, and the obtained residue is discarded after being stirred, washed, extruded and filtered;

3) precipitating heavy metals by adding a liquid auxiliary to the liquid after phosphorus has been removed, precipitating heavy metals, and then precipitating heavy metals to obtain heavy metal precipitation mother liquor and heavy metal precipitation residues through extrusion filtration and separation;

4) an acid-alkaline control step of adjusting the pH to acidity by adding an acidic solution to the heavy metal precipitation mother liquor, and adding an alkaline solution to neutralize the pH after removing the residual carbonic acid;

5) an evaporation concentration step of increasing the lithium concentration while precipitating sodium sulfate through double-effect circulation evaporation of the battery material raffinate after acid-alkaline control;

6) lithium precipitation step of adding carbonate to the concentrated mother liquor obtained in step 5), performing lithium precipitation, filtration and separation, and obtaining a crude lithium carbonate product;

In the battery material balance, the Li content is 0.5-5 g/L, the sodium content is 30-80 g/L, the heavy metal content is 0.5-2 g/L, the fluorine content is 50-150 mg/L, and the phosphorus content is 30 to 60 mg/L.

Furthermore, in step 1), the zirconium-based fluoride scavenger reaches the upper limit of adsorption, and then proceeds through a regeneration cycle to be used.

Furthermore, in step 1), the concentration of sodium hydroxide in the regeneration liquid used in the regeneration process of the zirconium-based fluoride removal agent is 0.1-2 mol/L, and the mass ratio of the regeneration liquid and the zirconium-based fluorine remover is 2-8:1, The temperature is room temperature, and the regeneration time is 30 to 60 min.

Furthermore, in step 2), the heavy metal sedimentation residue recovers valuable metals through a leaching method.

Furthermore, in step 1), the added mass of the zirconium-based fluorine remover is 1% to 10% of the mass of the battery material raffinate, and the pH is controlled to 3 to 8 in the process of removing fluorine, the temperature is room temperature, The time is 10-90 min.

Furthermore, in step 1), the main content of the zirconium-based defluorination agent is ZrO ₂ +TIO ₂ ≥33%.

Further, in step 2), the phosphorus scavenger uses one or a mixture of one or more of iron sulfate, calcium hydroxide, and aluminum sulfate, and is used after mixing the mass concentration of 10% to 30%, and The added mass is 0.01% to 0.02% of the mass of the battery material raffinate, the pH to remove phosphorus is 3 to 10, the temperature is room temperature, and the reaction time is 10 to 90 min.

Further, in step 3), the liquid auxiliary material is a lithium precipitation mother liquor containing a carbonic acid group, and the ratio of the lithium precipitation mother liquor to the liquid after phosphorus removal is 1/5 to 1:1, and the reaction temperature is 50° C. to 70° C. , the reaction time is 50 to 120 min, and the reaction pH is 8.5 to 13.

Further, in step 4), the acidic solution used is 95%-98% sulfuric acid solution, the alkaline solution used is 30%-32% liquid sodium hydroxide, the acidic control pH is 3-6, and the alkaline control pH is 6-9.

Further, in step 5), the evaporation concentration ratio is 3 to 10 times, the lithium concentration in the evaporation mother liquor is 10 to 20 g/L, and the sodium concentration is 90 to 125 g/L.

Further, in step 6), the carbonate selected is sodium carbonate, the mass concentration is 25% to 32%, and the multi-drop dispersion method used in the process of precipitating lithium is to add a concentrated mother liquor (i.e., liquid before lithium precipitation) and , the lithium precipitation temperature is higher than 80 ° C, the lithium precipitation time is 0.5 to 3 h, and the amount of pure alkali added is 1.05 to 1.15 times the theoretical amount.

The present invention achieves the following technical effects.

The present invention uses a zirconium-based fluoride removal agent in the process of extracting lithium from a battery material for the first time, and the fluorine removal rate is high.

In the present invention, the lithium extraction process to be selected is short, the phosphorus removal agent is iron-based, calcium-based, and aluminum-based one or a mixture of several selected and used, and the phosphorus removal rate is high.

Based on the low-lithium high-sodium properties of the battery material raffinate, the present invention is a method of first producing sodium sulfate by cyclic evaporation, improving the lithium concentration of the raw material, and then precipitating lithium using carbonate By selecting , the one-time recovery rate of lithium metal in the battery material balance is greatly improved, and the recovery cost of lithium metal in the weight balance of the battery material is lowered.

The present invention effectively lowers the probability of sodium enveloping lithium carbonate products in the sodium sulfate system by adding them using multi-drop dispersion during the addition process of the concentrated mother liquor, and the sodium content in the industrial grade lithium carbonate products produced is less than 0.1%. low.

The present invention utilizes the property of containing carbonic acid groups in the lithium precipitation mother liquid to precipitate heavy metals in the battery material raffinate liquid, thereby realizing the carbonic acid group cycle utilization of the lithium precipitation mother liquid and reducing the amount of use of auxiliary materials for precipitating heavy metals.

The lithium carbonate content produced by the present invention is less than 0.1%, the mass content of lithium carbonate is higher than 98.50%, the fluorine content is less than 0.020%, and each indicator meets the level requirements of industrial grade lithium carbonate make it

1 is a process flow chart for recovering lithium from a battery material raffinate according to an embodiment of the present invention.

Hereinafter, the technical solution of the present invention will be further described in conjunction with the drawings and specific implementation methods. Those skilled in the art should understand that the above examples only aid in understanding the present invention, and should not be viewed as limiting the present invention in detail.

Example 1

At room temperature, usually 3% of a fluoride removal agent is added to the raffinate of the battery material, stirred, the fluorine removal pH is controlled to 4.5, and after reacting for 0.5 h, the fluorine-removed slurry is extruded and filtered And, the fluoride removal agent containing fluorine is regenerated through 0.5 mol/L sodium hydroxide solution to remove fluorine, and the fluoride removal agent after being regenerated is recycled and returned to the fluoride removal process step after slurrying the battery material raffinate solution. become; After removal of fluorine obtained by extrusion, filtration, and separation, a phosphorus remover solution having a mass concentration of 15% was added to the liquid, the pH was controlled to 3.99, the phosphorus removal time was 30 min, and the phosphorus removal operation was performed. It is separated by extrusion and filtration. Lithium precipitation mother liquid (mass ratio of liquid and lithium precipitation mother liquid after phosphorus removal is 3:1) is added to the liquid after phosphorus is removed, extruded and filtered to adjust the pH to 10.0, the temperature is 60° C., and after reacting for 60 minutes The precipitated heavy metal slurry is extruded and filtered, and heavy metal residues containing nickel are recovered through leaching.

After the precipitated heavy metal is extruded and filtered, 98% sulfuric acid is added to the liquid to adjust the pH to 4.0, then 32% liquid sodium hydroxide is added to adjust the pH to 7.0, and the liquid after acid-alkaline adjustment is double Evaporation through the effect circulation evaporator, the concentration ratio is controlled 4 times during the evaporation process, the evaporation mother liquid is 1.1 times the theoretical amount, 30% sodium carbonate solution is added to precipitate lithium, and the lithium precipitation temperature is 80 ° C. , the lithium precipitation time is 2 h, and the mother liquor is added to the lithium precipitation vessel through multi-drop dispersion. The produced lithium carbonate reaches the national industrial grade lithium carbonate standard (GB/T11075-2013).

Table 1 Battery material weight balance composition table

Table 2 Composition Table of Liquids after Fluoride Removal Phosphorus Removal Extrusion Filtration

Table 3 Lithium Carbonate Composition Table

Table 4 Sodium Sulfate Ingredients Table

Example 2

At room temperature, typically, 5% of a fluoride removal agent is added to the battery material weight balance, stirring is performed, the fluorine removal pH is controlled to 5.0, and after reacting for 1 h, the slurry from which fluorine has been removed is extruded and filtered, and fluorine is removed The contained fluorine scavenger is recycled through 1 mol/L sodium hydroxide solution to remove fluorine, and the regenerated fluorine scavenger is recycled and returned to the fluorine removal process step after slurrying the battery material raffinate; After removal of fluorine obtained by extrusion, filtration and separation, a phosphorus remover solution having a mass concentration of 10% was added to the liquid, the pH was controlled to 4.12, and the phosphorus removal time was 50 min. It is separated by extrusion and filtration. Lithium precipitation mother liquid (mass ratio of liquid and lithium precipitation mother liquid after phosphorus removal is 3:1) is added to the liquid after phosphorus is removed, extruded and filtered to adjust the pH to 11.0, the temperature is 50° C., and after 90 minutes of reaction The precipitated heavy metal slurry is extruded and filtered, and heavy metal residues containing nickel are recovered through leaching.

After the precipitated heavy metal is extruded and filtered, 98% sulfuric acid is added to adjust the pH to 3.5, then 32% liquid sodium hydroxide is added to adjust the pH to 7.5, and the liquid after acid-alkaline adjustment is double. Evaporation through the effect circulation evaporator, the concentration ratio is controlled 5 times in the evaporation process, the evaporation mother liquid is 1.05 times the theoretical amount, 28% sodium carbonate solution is added to precipitate lithium, and the lithium precipitation temperature is 85 ° C. , the lithium precipitation time is 1 h, and the mother liquor is added to the lithium precipitation vessel through multi-drop dispersion. The produced lithium carbonate reaches the national industrial grade lithium carbonate standard (GB/T11075-2013).

Table 5 Battery material weight balance composition table

Table 6 Composition Table of Liquids after Fluoride Removal Phosphorus Removal Extrusion Filtration

Table 7 Lithium Carbonate Composition Table

Table 8 Sodium Sulfate Ingredients Table

Although the above embodiment has described some details of carrying out the present invention, it should not be understood as a limitation on the present invention, and those skilled in the art should understand the scope of the present invention under the premise that does not depart from the principle and spirit of the present invention Changes, corrections, substitutions, and transformations can be made within it.

Claims (10)

In the method for manufacturing by recovering the prepared lithium carbonate from the battery material raffinate,
the following steps,
1) A fluorine removal step of removing fluoride by adding a zirconium-based fluoride removal agent to the battery material purifying liquid to obtain a liquid after removal of fluoride with a fluorine content of less than 3 mg/L;
2) a phosphorus removal step of removing phosphorus from the liquid after fluorine removal through a phosphorus removal agent, and discarding the resulting residue after stirring, washing, extrusion and filtration;
3) precipitating heavy metals by adding a liquid auxiliary to the liquid after phosphorus has been removed, precipitating heavy metals, and then precipitating heavy metals to obtain heavy metal precipitation mother liquor and heavy metal precipitation residues through extrusion filtration and separation;
4) an acidic-alkaline control step of adjusting the pH to acidity by adding an acidic solution to the heavy metal precipitation mother liquor, and adjusting the pH to neutral by adding an alkaline solution after removing the residual carbonic acid;
5) an evaporation and concentration step of precipitating sodium sulfate through double-effect circulation evaporation of the battery material raffinate after acid-alkaline control, and at the same time improving lithium concentration;
6) lithium precipitation step of adding carbonate to the concentrated mother liquor obtained in step 5), performing lithium precipitation, filtration and separation, and obtaining a crude lithium carbonate product;
In the battery material balance, the Li content is 0.5-5 g/L, the sodium content is 30-80 g/L, the heavy metal content is 0.5-2 g/L, the fluorine content is 50-150 mg/L, and the phosphorus content is A method for recovering and manufacturing the prepared lithium carbonate from the battery material weight balance, characterized in that it is 30-60 mg/L. According to claim 1,
In step 1), the zirconium-based fluoride scavenger reaches the upper limit of adsorption, and then proceeds through a regeneration cycle to recover and manufacture the crude lithium carbonate from the battery material raffinate solution. According to claim 1,
In step 1), the concentration of sodium hydroxide in the regeneration liquid used in the regeneration process of the zirconium-based fluoride removal agent is 0.1 to 2 mol/L, the mass ratio of the regeneration liquid to the zirconium-based fluorine remover is 2 to 8:1, and the regeneration temperature is room temperature , and the playing time is 30 to 60 min; The main content of the zirconium-based fluoride removal agent is ZrO ₂ +TIO ₂ A method for recovering and manufacturing the prepared lithium carbonate from the battery material raffinate, characterized in that ≥33%. 3. The method of claim 1 or 2,
In step 2), the heavy metal sedimentation residue is a method of recovering and manufacturing crude lithium carbonate from the battery material raffinate, characterized in that the valuable metal is recovered through a leaching method. 3. The method of claim 1 or 2,
In step 1), the added mass of the zirconium-based fluoride removal agent is 1 to 10% of the mass of the battery material raffinate, and in the process of removing fluorine, the pH is controlled to 3 to 8, the temperature is room temperature, and the time is 10 to A method for recovering and manufacturing the prepared lithium carbonate from the battery material weight balance, characterized in that it is 90 min. 3. The method of claim 1 or 2,
In step 2), the phosphorus remover is one or a mixture of iron sulfate, calcium hydroxide, and aluminum sulfate, and is used after mixing the mass concentration of 10% to 30%, and the added mass of the phosphorus remover solution is the weight of the battery material. 0.01% to 0.02% of the mass of the balance, the phosphorus removal pH is 3 to 10, the temperature is room temperature, and the reaction time is 10 to 90 min. 3. The method of claim 1 or 2,
In step 3), the liquid auxiliary material is a lithium precipitation mother liquor containing a carbonic acid group, the addition ratio of the lithium precipitation mother liquid and the liquid after phosphorus removal is 1/5 to 1:1, the reaction temperature is 50 ° C to 70 ° C, the reaction The time is 50 ~ 120 min, and the reaction pH is 8.5 ~ 13. 3. The method of claim 1 or 2,
In step 4), the acidic solution used is 95%-98% sulfuric acid solution, the alkaline solution used is 30%-32% liquid sodium hydroxide, the acidic control pH is 3-6, and the alkaline control pH is 6-9 A method for recovering and manufacturing the prepared lithium carbonate from the battery material weight balance, characterized in that 3. The method of claim 1 or 2,
In step 5), the evaporation concentration ratio is 3 to 10 times, and the lithium concentration of the evaporation mother liquid is 10 to 20 g/L. 3. The method of claim 1 or 2,
In step 6), the selected carbonate is sodium carbonate, the mass concentration is 25% to 32%, the multi-drop dispersion method used in the process of precipitating lithium is to add a concentrated mother liquor, the lithium precipitation temperature is higher than 80 ° C., lithium precipitation The time is 0.5 to 3 h, and the amount of pure alkali added is 1.05 to 1.15 times the theoretical amount.

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