KR101773439B1 - Manufacturing method of lithium carbonate from waste solution containing lithium - Google Patents

Abstract

Provided is a method for manufacturing solid lithium carbonate from a waste solution containing lithium, comprising the following steps: preparing a mixture in which a material containing phosphorus is added to a waste solution containing lithium (step 1); adding a basic solution to the prepared mixture and controlling pH (step 2); raising the temperature of the pH-controlled mixture, filtering the mixture and collecting lithium phosphate (step 3); preparing an acid lithium solution in which purified water and acid are added to the collected lithium phosphate (step 4); evaporating and concentrating the acid lithium solution and collecting solid lithium salt (step 5); adding the purified water and basic solution to the collected solid lithium salt and controlling pH (step 6); and adding a carbonate to the pH-controlled solution and preparing solid lithium carbonate (step 7).

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing a solid lithium carbonate from a lithium-containing waste liquid,

TECHNICAL FIELD The present invention relates to a process for producing solid lithium carbonate from a lithium-containing waste liquid, and more particularly, to a method for finally producing lithium carbonate after forming a lithium-containing waste liquid from an intermediate product of lithium phosphate and lithium sulfate.

The process of recycling the waste batteries is divided into a dry process and a wet process. The dry process for recycling spent batteries is a process in which spent lithium is charged into a high-temperature furnace to recover valuable metals. The dry process is relatively simple, but it has the disadvantage that the lithium is slaked and the lithium is difficult to recover, the initial investment amount is high, the recovery of the valuable metal is low, and the gas treatment cost is high.

The wet process for recycling waste batteries is a process of dissolving spent batteries in sulfuric acid and extracting valuable metals using solvents. The wet process is advantageous in that the initial cost is low, the recovery rate of the metal is high, and the high-purity valuable metal can be produced. However, the wet process has a high disposal cost for the waste liquid used for solvent extraction. Domestic waste batteries are estimated at 20,000 tons / year, and a large amount of lithium waste liquid is generated through a solvent extraction process in which cobalt, nickel, and manganese are recovered from waste batteries.

Korean Patent Laid-Open No. 10-2015-0002963 discloses a method of recovering lithium from a lithium-containing waste liquid by mixing a lithium-containing waste liquid with an extractant diluted with a diluent by a method of recovering lithium from a lithium-containing waste liquid using a solvent extraction method, An extraction process step; And a stripping process step in which the organic phase obtained by the extraction process is mixed with a stripping agent and stripped and the lithium is concentrated.

At present, the recycling of lithium is performed only for an alloy containing lithium metal. There have been many researches and developments of lithium recovery in the waste secondary battery, but there is no commercially available technology due to economical efficiency. Further, in the case of a lithium waste solution, not only the amount of the generated lithium waste is large, but also the concentration of contained lithium is as high as about 3000 ppm, and development of a technology capable of recovering lithium is urgently required. However, the conventional lithium recovery process using adsorption-desorption condensation-solvent extraction or evaporation-solvent extraction technology has a very high process cost of 5,000,000 W / ton, which is difficult to apply.

Korean Patent Publication No. 10-2015-0002963

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art described above, and it is an object of the present invention to provide a method of manufacturing lithium carbonate which can lower the process cost, increase the reuse ratio of lithium, I have to.

According to an aspect of the present invention, there is provided a method of manufacturing a lithium-containing waste liquid comprising the steps of: (1) preparing a mixture containing a phosphorus-containing material in a lithium-containing waste liquid; Adjusting the pH by adding a basic solution to the prepared mixture (step 2); Raising the pH-adjusted mixture to react, and recovering lithium phosphate by filtration (step 3); (Step 4) of producing an acid lithium solution to which distilled water and an acid are added to the recovered lithium phosphate; Concentrating the acid lithium solution by evaporation to recover the solid lithium salt (step 5); Adding distilled water and a basic solution to the recovered solid lithium salt to adjust the pH (step 6); And adding a carbonate to the pH-adjusted solution to produce a solid lithium carbonate (Step 7). The method comprises the steps of:

In one embodiment, the phosphorus-containing material of step 1 may comprise a phosphoric acid (H ₃ PO ₄₎ or a phosphate.

In one embodiment, the phosphorus-containing material addition ratio in step 1 may be 0.8 to 1.2 times the equivalent of lithium in the lithium-containing waste liquid.

In one embodiment, the basic solution of step 2 is sodium hydroxide (NaOH), potassium hydroxide (KOH), magnesium hydroxide (Mg (OH) _2), calcium hydroxide (Ca (OH) ₂₎ and barium hydroxide (Ba (OH ) ₂ ). ≪ / RTI >

In one embodiment, the addition of the basic solution of step 2 may be performed such that the pH of the mixture is from 10 to 12. [

In one embodiment, the temperature of the step 3 may be raised to a temperature of 70 ° C to 90 ° C and maintained for 30 minutes to 90 minutes after the temperature is raised.

In one embodiment, the production of the acid lithium solution in step 4 may be performed by adding 2.5 to 4.5 times the weight of distilled water to the recovered lithium phosphate and 0.75 to 1.75 times the weight of the recovered lithium phosphate. have.

In one embodiment, the acid of step 4 may include at least one member selected from the group consisting of sulfuric acid, nitric acid, hydrochloric acid, acetic acid, oxalic acid, citric acid and formic acid.

In one embodiment, the evaporation concentration of step 5 may be performed one to five times.

In one embodiment, filtration is performed after the evaporation concentration in step 5, and the filtrate resulting from the filtration can be used as the phosphorus-containing material in step 1 above.

In one embodiment, washing the recovered lithium salt in step 5 (step 5a) may be further included.

In one embodiment, the washing of step 5a may be carried out with 10 wt% to 40 wt% of distilled water relative to the recovered lithium salt.

In one embodiment, the wash liquid resulting from the washing of step 5a may be used to prepare the acid lithium solution of step 4 above.

In one embodiment, the amount of distilled water added in step 6 may be 2 to 20 times the weight of the recovered solid lithium salt.

In one embodiment, the basic solution of step 6 is aqueous sodium hydroxide (NaOH), potassium hydroxide (KOH), magnesium hydroxide (Mg (OH) _2), calcium hydroxide (Ca (OH) _2), barium hydroxide (Ba (OH ) ₂ ), and a carbonate.

In one embodiment, the pH adjustment of step 6 can be adjusted to a pH of 9-11.

In one embodiment, the pH adjustment of step 6 may be performed at a temperature of 60 ° C to 90 ° C for 30 minutes to 90 minutes.

In one embodiment, step 6 may be followed by filtration after the pH adjustment, and the filtrate from the filtration may be used to prepare the acid lithium solution of step 4 above.

In one embodiment, the carbonate of the step 7 is sodium carbonate (Na ₂ CO _3), sodium bicarbonate (NaHCO _3), potassium carbonate (K ₂ CO _3), potassium bicarbonate (KHCO _3), calcium carbonate (CaCO _3), may be at least one member selected from the group consisting of magnesium carbonate (MgCO _3), barium carbonate (BaCO ₃₎ and dolomite _{(CaMg (CO 3) 2)} .

In one embodiment, step 7 is followed by filtration after the addition of the carbonate, and the filtrate resulting from the filtration may be used to prepare the mixture of step 1 above.

In one embodiment, step 7 performs the post-filtration wash, and the wash liquid resulting from the wash may be used to prepare the mixture of step 1 above.

According to another aspect of the present invention, there is also provided a method for manufacturing a lithium ion secondary battery, comprising the steps of: (i) preparing a mixture of a waste solution of a lithium-containing lithium battery and phosphoric acid added thereto; Adding a basic solution to the prepared mixture to adjust the pH to 10 to 12 (step ii); Raising the temperature of the pH-adjusted mixture to a temperature of 70 ° C to 90 ° C for reaction, and recovering lithium phosphate by filtration (step iii); Preparing a lithium sulfate solution to which distilled water and sulfuric acid are added to the recovered lithium phosphate (step iv); Concentrating the lithium sulfate solution by evaporation to recover solid lithium sulfate (step v); Adding distilled water and a basic solution to the recovered solid lithium sulfate to adjust the pH (step vi); And adding a carbonate to the pH-adjusted solution to produce solid lithium carbonate (step vii). The method comprises the steps of: preparing a solid lithium carbonate from a waste solution of a spent lithium battery;

Further, in order to achieve the above object, another aspect of the present invention is to provide a waste solution of a lithium battery containing lithium at a concentration of 1.5 g / L to 6.0 g / L in an amount of 0.8 to 1.2 times, To prepare a mixture (step a); Adding sodium hydroxide solution to the prepared mixture to adjust the pH to 10 to 12 (step b); Raising the temperature of the pH-adjusted mixture to 70 ° C to 90 ° C, reacting for 30 minutes to 90 minutes, and recovering lithium phosphate by filtration (step c); Adding distilled water and lithium sulfate to the recovered lithium phosphate in an amount of 2.5 to 4.5 times the weight of the lithium phosphate and 0.75 to 1.75 times the weight of the lithium phosphate, and then filtering the lithium phosphate to prepare a lithium sulfate solution (step d); The lithium sulfate solution is concentrated by evaporation and filtration to recover and wash the solid lithium sulfate, and the evaporation and filtration is performed 2 to 5 times (step e); Adding distilled water having a weight of 2 to 20 times the weight of the recovered solid lithium sulfate to the lithium sulfate, adjusting the pH to 9 to 11 by adding a sodium hydroxide solution, and then filtering (step f); And a step (g) of adding a sodium carbonate solution with a concentration of 5 wt% to 50 wt% to the filtrate, filtering and washing to prepare solid lithium carbonate (step g). A method for producing lithium carbonate is provided.

In order to achieve the above object, another aspect of the present invention is a process for producing a lithium-containing waste liquid, comprising the steps of: preparing a solid phase containing lithium in an amount of 90 wt% to 95 wt% And the phosphoric acid used in the production of lithium phosphate can be recovered and reused, thereby reducing the processing cost.

According to an aspect of the present invention, it is possible to recover 90 wt% to 95 wt% of lithium relative to lithium in the lithium-containing waste liquid, minimize lithium to be disposed of in the process, It can be recovered and reused.

It should be understood that the effects of the present invention are not limited to the above effects and include all effects that can be deduced from the detailed description of the present invention or the configuration of the invention described in the claims.

Fig. 1 is a flowchart showing an example of a method for producing solid lithium carbonate from a lithium-containing waste liquid according to an embodiment of the present invention.
2 is a flowchart schematically showing an example of a method for producing solid lithium carbonate from a lithium-containing waste liquid according to an embodiment of the present invention.
FIGS. 3 to 5 are graphs showing the results of XRD analysis of the recovered lithium compounds (lithium phosphate, lithium sulfate, and lithium carbonate).
FIG. 6 is a schematic diagram showing recovery rates of the lithium byproducts in the respective stages when the lithium byproducts are introduced into the previous stage.
7 is a graph showing the recovery rate of lithium in each example and comparative example.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving it will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings.

It should be understood, however, that the present invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. To fully inform the inventor of the category of invention. Further, the present invention is only defined by the scope of the claims.

Further, in the following description of the present invention, if it is determined that related arts or the like may obscure the gist of the present invention, detailed description thereof will be omitted.

According to an aspect of the present invention,

(Step 1) (S10) of preparing a mixture containing a phosphorus-containing substance in a lithium-containing waste liquid;

Adjusting the pH by adding a basic solution to the prepared mixture (step 2) (S20);

(Step S30) of raising the pH-adjusted mixture to react, and recovering lithium phosphate by filtration (step 3);

(Step 4) (S40) of producing an acid lithium solution to which distilled water and an acid are added to the recovered lithium phosphate;

(Step S 5) of recovering the solid lithium salt by concentrating the acid lithium solution by evaporation (step S 50);

Adding distilled water and a basic solution to the recovered solid lithium salt to adjust the pH (step 6) (S60); And

And adding carbonates to the pH-adjusted solution to produce solid lithium carbonate (Step 7) (S70). The solid-state lithium carbonate is prepared from a lithium-containing waste liquid.

Hereinafter, a method for producing a solid lithium carbonate from a lithium-containing waste liquid according to one aspect of the present invention will be described in detail for each step.

In the method for producing a solid lithium carbonate from a lithium-containing waste liquid according to an aspect of the present invention, the step 1 (S10) comprises preparing a mixture containing a phosphorus-containing substance in a lithium-containing waste liquid.

The lithium-containing waste solution of step 1 may be a waste solution of a spent lithium battery.

The lithium concentration of the lithium-containing waste solution in the step 1 may be 1.5 g / L to 6.0 g / L, and preferably 1.5 g / L to 3.5 g / L. When the lithium concentration is less than 1.5 g / L, the recovery rate of lithium may decrease in the filtration step to be described later. When the lithium concentration is more than 6.0 g / L, it is economical to recover lithium carbonate by evaporation .

The phosphorus-containing material in step 1 may include phosphoric acid (H ₃ PO ₄ ) or phosphate, and the phosphate may be selected from the group consisting of potassium phosphate, sodium phosphate, aluminum phosphate, zinc phosphate, ammonium polyphosphate and sodium hexametaphosphate , And preferably a phosphorus-containing substance containing phosphoric acid can be used.

The phosphorus-containing material addition ratio in step 1 may be 0.8 to 1.2 times the equivalent of lithium in the lithium-containing waste solution, and preferably 0.9 to 1.1 times the equivalent. If the phosphorus-containing material is added in an amount equivalent to less than 0.8 times the lithium of the lithium-containing waste liquid, there is a risk that the recovery rate of lithium is lowered in the filtration step described below. When the phosphorus- Times more than the equivalent amount, the use of excessive phosphorus-containing materials can result in economic waste and increased waste water treatment costs.

In step (S20), a basic solution is added to the prepared mixture to adjust the pH of the solid lithium carbonate from the lithium-containing waste solution according to one aspect of the present invention.

A basic solution of step 2 is the group consisting of sodium hydroxide (NaOH), potassium hydroxide (KOH), magnesium hydroxide (Mg (OH) _2), calcium hydroxide (Ca (OH) ₂₎ and barium hydroxide (Ba (OH) ₂₎ , And the like.

The basic solution of step 2 may be added so that the pH of the mixture is 10 to 12, preferably 10.5 to 11.5. If the pH of the mixture is less than 10, there may be a problem that the lithium recovery rate is lowered. If the pH of the mixture is more than 12, the lithium recovery rate may be lowered. If the basic solution of step 2 is sodium hydroxide and the pH is more than 12, it can be produced with a very small amount of lithium hydroxide due to the addition of a large amount of sodium hydroxide, and due to the solubility of the lithium hydroxide produced, The lithium concentration may be increased. In addition, when the amount of sodium hydroxide used for raising the pH is 12 or higher is 5.25 times as high as pH 13, and 10 times as high as that of sodium hydroxide is used at pH 13.5, there is a problem of increase in process cost Also, there is a problem that the cost of wastewater treatment due to excessive use of sodium hydroxide and the cost of waste treatment increase due to increase of process sludge.

In the method for producing a solid lithium carbonate from a lithium-containing waste liquid according to an aspect of the present invention, in the step 3 (S30), the pH-adjusted mixture is heated to react and filtered to recover lithium phosphate.

The temperature of the step 3 may be elevated to a temperature of 70 ° C to 90 ° C and maintained for 30 minutes to 90 minutes after the temperature rise. At this time, reaction of lithium phosphate solid component can be easily performed.

The filtration in step 3 above can recover the solid lithium phosphate produced in the reaction and the remaining filtrate can be treated with wastewater.

The filtration in step 3 can recover lithium phosphate containing lithium in an amount of 86 wt% to 95 wt% relative to lithium in the lithium-containing waste solution in step 1, preferably 93 lithium phosphate containing from about 96 wt% to about 96 wt% of lithium can be recovered.

The step 3 may further include washing the lithium phosphate recovered by the filtration.

In step (S40), the acid lithium solution is prepared by adding distilled water and an acid to the recovered lithium phosphate in the step (S40) in the solid-state lithium carbonate production process from the lithium-containing waste liquid according to one aspect of the present invention.

The acid lithium solution prepared in step 4 may be prepared by adding distilled water having a weight of 2.5 to 4.5 times the recovered lithium phosphate and an acid having a weight of 0.75 to 1.75 times the weight of the recovered lithium phosphate, Distilled water of 3 to 4 times the weight of the recovered lithium phosphate and 1 to 1.5 times of the weight of the recovered lithium phosphate relative to the recovered lithium phosphate. If distilled water less than 2.5 times the weight of the recovered lithium phosphate is added, the slurry agitation may become difficult due to the viscosity of the phosphoric acid after the substitution reaction of phosphoric acid and sulfuric acid. This may cause the possibility that the lithium phosphate is not completely decomposed have. If more than 4.5 times the weight of distilled water is added to the recovered lithium phosphate, the process time and energy consumption may be increased in the following evaporation concentration step. Further, if an acid of less than 0.75 times the weight of the recovered lithium phosphate is added, there may occur a problem that the recovery rate of lithium sulfate is lowered during the evaporation concentration proceeding in the next step, and an acid exceeding 1.75 times the weight of the recovered lithium phosphate , The amount of the basic solution may increase when the lithium phosphate is recovered due to excess sulfate ions in the phosphoric acid solution after the lithium sulfate recovery by evaporation and concentration.

The acid in step 4 may include at least one member selected from the group consisting of sulfuric acid, nitric acid, hydrochloric acid, acetic acid, oxalic acid, citric acid and formic acid, preferably sulfuric acid.

The step 4 may further include a step of adding the distilled water and the acid, followed by filtration. At this time, the residue generated in the filtration may include an organic substance and a partially precipitated lithium salt, and lithium may be recovered through water washing and the organic residue may be discarded. The water-washed lithium solution and the remaining filtrate can be used as the acid lithium solution for the post-processing.

In the method for producing solid lithium carbonate from a lithium-containing waste liquid according to an aspect of the present invention, in step 5 (S50), the lithium lithium salt is evaporated and concentrated to recover the solid lithium salt.

The evaporation concentration in step 5 may be performed 1 to 5 times, preferably 2 to 5 times, more preferably 2 to 3 times.

Filtration can be performed after the evaporation concentration in step 5, and the filtrate generated in the filtration can be used as the phosphorus-containing material in step 1 above. For example, as shown in FIG. 2, filtration is performed after evaporation concentration, and the resulting lithium salt solid phase is used in the subsequent step. The remaining filtrate is again concentrated by evaporation and filtration to obtain a lithium salt solid phase And the remaining filtrate contains a large amount of phosphoric acid, so that it can be used as the phosphorus-containing material of step 1 above.

The evaporation concentration in step 5 may be performed by evaporating 50 to 90% by weight of the water contained in the acid lithium solution.

The method for producing solid lithium carbonate from a lithium-containing waste liquid according to an aspect of the present invention may further include washing the lithium salt recovered in step 5 (step 5a).

The washing of step 5a may be carried out with 10 wt% to 40 wt% of distilled water relative to the recovered lithium salt.

The washing of the step 5a may be carried out for the purpose of removing the phosphorus component of the recovered lithium salt, and the resulting washing liquid may be used for the production of the acid lithium solution of the step 4 above.

In step 6 (S60), distilled water and a basic solution are added to the recovered solid lithium salt to adjust the pH of the solid lithium carbonate from the lithium-containing waste liquid according to one aspect of the present invention. At this time, the main purpose of the pH adjustment is to remove phosphorus remaining in the lithium salt after washing, and the pH of the lithium salt solution of the lithium salt solution is precipitated as lithium phosphate, which can be used in step 4.

The amount of distilled water added in step 6 may be 2 to 20 times by weight, preferably 2 to 10 times by weight, based on the weight of the recovered solid lithium salt. If the added amount of the distilled water is less than 2 times the weight of the recovered solid lithium salt, the solubility of the lithium salt may not be enough to completely dissolve. If the added amount of the distilled water is 20 If it is added in an excess of the weight, there may be a problem of lowering the recovery rate and increasing the wastewater.

A basic solution of step 6 with sodium hydroxide (NaOH), potassium hydroxide (KOH), magnesium hydroxide (Mg (OH) _2), calcium hydroxide (Ca (OH) _2), barium hydroxide (Ba (OH) ₂₎ and carbonate And may include at least one selected from the group consisting of sodium hydroxide, and preferably sodium hydroxide.

The concentration of the basic solution in step 6 may be 10 wt% to 30 wt%, but is not limited thereto.

The pH of the step 6 may be adjusted to a pH of 9 to 11 by adding the basic solution. If the pH is less than 9, there is a problem that the phosphorus in the lithium salt solution can not be completely removed. If the pH is more than 11, there is an increase in the cost due to the use of the unnecessary basic solution and a problem of loss due to the co- Lt; / RTI > Of course, the precipitated lithium phosphate can be utilized in step 4, but the unnecessary increase in the process cost is obvious.

The pH adjustment of step 6 may be performed at a temperature of 60 to 90 캜 for 30 to 90 minutes, preferably at a temperature of 70 to 90 캜 for 45 to 75 minutes.

The step 6 may be followed by filtration after the pH adjustment, and the residue resulting from the filtration may be used to prepare the acid lithium solution of step 4 above. That is, the residue resulting from the filtration may remain as lithium phosphate and the lithium salt of step 5, and the filtrate may be used in the subsequent step.

In step 7 (S70), carbonate is added to the pH-adjusted solution to produce solid lithium carbonate in the method of preparing lithium carbonate containing lithium from the lithium-containing waste liquid according to an aspect of the present invention.

Carbonates of the step 7 is sodium carbonate (Na ₂ CO _3), sodium bicarbonate (NaHCO _3), potassium carbonate (K ₂ CO _3), potassium bicarbonate (KHCO _3), calcium carbonate (CaCO _3), magnesium carbonate (MgCO ₃₎ , it may be a barium carbonate (BaCO ₃₎ and dolomite (CaMg (CO _{3) 2)} be at least one member selected from the group consisting of and, preferably, sodium carbonate.

The carbonate solution of step 7 may be added in a concentration of 5 wt% to 50 wt%, but is not limited thereto.

After the addition of the carbonate of step 7, the reaction can be carried out at a temperature of 80 ° C to 90 ° C for 1 hour to 2 hours.

The step 7 may be performed after adding the carbonate, and the filtrate generated in the filtration may contain a small amount of lithium. Therefore, the filtrate may be used for preparing the mixture of step 1 above.

The step 7 may perform washing of the lithium carbonate solid phase after the filtration, and the washing liquid generated by the washing may also contain a small amount of lithium, so that it can be used in the preparation of the mixture of step 1 above.

The lithium carbonate produced through the above-described method (steps 1 to 7, S10 to S70), when performing the above-described method once, is characterized in that 60 wt% to 80 wt% of lithium relative to the lithium content of the lithium waste solution of step 1 , And when the above method is continuously performed and stabilized, only 3 wt% to 8 wt% of lithium relative to the lithium content of the lithium waste solution in the step 1 can be used without being used .

According to an aspect of the present invention, there is provided a filtration method comprising the steps of filtration resulting from the final filtration in step 5, a washing liquid generated in the washing step in step 5a, residues generated in filtration in step 6, It is possible to recycle the filtrate and the washing liquid generated in the washing, and thus it is possible to utilize the lithium contained in the lithium-containing waste liquid as the starting material as much as possible.

According to another aspect of the present invention,

A step of preparing a mixture in which a phosphoric acid is added to a waste solution of a waste lithium battery containing lithium (step i);

Adding a basic solution to the prepared mixture to adjust the pH to 10 to 12 (step ii);

Raising the pH-adjusted mixture to react, and recovering lithium phosphate by filtration (step iii);

Preparing a lithium sulfate solution to which distilled water and sulfuric acid are added to the recovered lithium phosphate (step iv);

Concentrating the lithium sulfate solution by evaporation to recover solid lithium sulfate (step v);

Adding distilled water and a basic solution to the recovered solid lithium sulfate to adjust the pH (step vi); And

And adding carbonates to the pH-adjusted solution to produce solid lithium carbonate (step vii). The method comprises the steps of: preparing a solid lithium carbonate from a waste solution of a spent lithium battery;

In the method for producing a solid lithium carbonate from a waste solution of a spent lithium battery according to an aspect of the present invention, the step i) comprises preparing a waste solution of a waste lithium battery containing lithium by adding phosphoric acid to the waste solution.

The lithium concentration of the waste solution of the spent lithium battery of step i may be the same as the lithium concentration of the lithium containing waste solution of step 1. [

The phosphoric acid addition ratio of step i may be the same as the phosphorus containing material addition ratio of step 1 above.

In the method for producing a solid lithium carbonate from a waste solution of a spent lithium battery according to an aspect of the present invention, the pH of the prepared mixture is adjusted to 10 to 12 by adding a basic solution to the prepared mixture.

The kind of the basic solution of step ii may be the same as that of the basic solution of step 2 above.

The basic solution of step ii may be added so that the pH of the mixture is 10 to 12, preferably 10.5 to 11.5. If the pH of the mixture is less than 10, there may be a problem that the lithium recovery rate is lowered. If the pH of the mixture is more than 12, the lithium recovery rate may be lowered. If the basic solution is sodium hydroxide and the pH is more than 12, lithium hydroxide may be produced in a very small amount due to the addition of a large amount of sodium hydroxide, and the lithium concentration in the lithium recovery filtrate is increased due to the solubility of the lithium hydroxide Gt; In addition, when the amount of sodium hydroxide used for raising the pH is 12 or higher is 5.25 times as high as pH 13, and 10 times as high as that of sodium hydroxide is used at pH 13.5, there is a problem of increase in process cost Also, there is a problem that the cost of wastewater treatment due to excessive use of sodium hydroxide and the cost of waste treatment increase due to increase of process sludge.

In the method for producing a solid lithium carbonate from a waste solution of a spent lithium battery according to an aspect of the present invention, in the step iii, the pH-adjusted mixture is heated to a temperature of 70 to 90 ° C to react, Recall.

The reaction holding time after the heating in the step iii may be the same as the step 3.

The filtration of step iii above can recover the solid lithium phosphate produced in the reaction and the remaining filtrate can be treated with wastewater.

The lithium phosphate recovered in relation to the lithium content of the spent lithium battery waste solution, which is the starting material in the filtration of step iii, may be the same as the lithium phosphate recovered relative to the lithium content of the waste solution of step 3 above.

The step iii may further comprise washing the lithium phosphate recovered by the filtration.

In the method for producing a solid lithium carbonate from a waste solution of a spent lithium battery according to an aspect of the present invention, the step iv is a step of preparing a lithium sulfate solution to which distilled water and sulfuric acid are added to the recovered lithium phosphate.

The added weight of distilled water and sulfuric acid added in preparing the lithium sulfate solution of step iv above may be the same as the weight of the distilled water and the acid added in step 4 above.

The step iv may further include a step of adding the distilled water and the acid, followed by filtration. At this time, the residue generated in the filtration may include organic matter and partially precipitated lithium sulfate, and lithium may be recovered through water washing and the organic residue may be discarded. The water-washing lithium solution and the remaining filtrate can be used as the lithium sulfate solution for the post-treatment.

In the method for producing lithium carbonate in solid phase from a waste solution of a spent lithium battery according to an aspect of the present invention, in step (v), the lithium sulfate solution is evaporated and concentrated to recover lithium sulfate in solid phase.

The evaporation concentration of the step v may be performed 1 to 5 times, preferably 2 to 5 times, more preferably 2 to 3 times.

Filtration can be carried out after evaporation concentration of step v above, and the filtrate resulting from the filtration can be used in the preparation of the mixture of step i above. For example, as shown in FIG. 2, the lithium sulfate solid phase produced by performing filtration after evaporation and concentration is used for the subsequent step, and the remaining filtrate is subjected to evaporation concentration and filtration to obtain a lithium sulfate solid phase And the remaining filtrate contains a large amount of phosphoric acid, so that it can be used in the preparation of the mixture of step i.

The evaporation concentration of step (v) may be performed by evaporating 50 to 90% by weight of the water contained in the lithium sulfate solution.

The method for producing a solid phase lithium carbonate from a lithium-containing waste liquid according to an aspect of the present invention may further comprise washing the recovered lithium sulfate solid in the step (v +).

The washing of the step v + can be carried out by adding 10 wt% to 40 wt% of distilled water to the recovered lithium sulfate solid phase.

The washing of the step v + can be performed for the purpose of removing the phosphorus component of the recovered lithium sulfate solid phase, and the washing liquid generated at this time can be used for preparing the lithium sulfate solution of the step iv.

In the method for producing a solid lithium carbonate from a waste solution of a spent lithium battery according to an aspect of the present invention, the step vi regulates the pH by adding distilled water and a basic solution to the recovered solid lithium sulfate.

The amount of distilled water added in step vi may be the same as the amount of distilled water added in step 6 above.

The concentration of the basic solution in step vi may be the same as the concentration of the basic solution in step 6 above.

The pH adjustment in step vi may be the same as the pH adjustment in step 6 above.

The temperature and the holding time during the pH adjustment of step vi may be the same as the temperature and holding time of step 6 above.

The step vi may be followed by filtration after the pH adjustment, and the residue resulting from the filtration may be used to prepare the lithium sulfate solution of step iv. That is, the residue resulting from the filtration may be lithium phosphate and the lithium sulfate solid phase in step v, and the filtrate may be used in the subsequent step.

In the method for producing lithium carbonate in solid phase from a waste solution of a spent lithium battery according to an aspect of the present invention, in step vii, carbonate is added to the pH-adjusted solution to prepare solid carbonate lithium.

The carbonate of step vii may be the same as the carbonate of step 7 above.

The addition of the carbonate of step vii may be performed by adding a carbonate solution having a concentration of 5 wt% to 50 wt%, but the present invention is not limited thereto.

After the addition of the carbonate of the step vii, the reaction can be carried out at a temperature of 80 ° C to 90 ° C for 1 hour to 2 hours.

The step vii may be followed by filtration after the addition of the carbonate, and the filtrate generated from the filtration may contain a small amount of lithium, so that it may be used for preparing the mixture of step i.

The step vii can perform washing of the lithium carbonate solid phase after the filtration and the washing liquid generated by the washing may also contain a small amount of lithium and can be used in the preparation of the mixture of step i.

The lithium carbonate produced through the above-described method (step i to step vii), when carrying out the above-described process once, may be produced by adding carbonic acid containing lithium of 60 wt% to 80 wt% to the lithium content of the lithium waste solution of step i If the above method is continuously performed and stabilized, only 3 wt% to 8 wt% of lithium relative to the lithium content of the lithium waste solution of step i can be used without being used.

Further, according to an aspect of the present invention, there is provided a method for purifying an aqueous solution comprising filtration resulting from the final filtration of the step v, a washing liquid generated in the washing step v +, a residue resulting from filtration in the step vi, It is possible to recycle the filtrate and the washing liquid generated in the washing, and thus it is possible to utilize the lithium contained in the lithium-containing waste liquid as the starting material as much as possible.

According to another aspect of the present invention,

Preparing a waste solution of a waste lithium battery containing lithium at a concentration of 1.5 g / L to 6.0 g / L by adding phosphoric acid in an amount of 0.8 to 1.2 times the lithium relative to the lithium (step a);

Adding sodium hydroxide solution to the prepared mixture to adjust the pH to 10 to 12 (step b);

Raising the temperature of the pH-adjusted mixture to 70 ° C to 90 ° C, reacting for 30 minutes to 90 minutes, and recovering lithium phosphate by filtration (step c);

Adding distilled water and lithium sulfate to the recovered lithium phosphate in an amount of 2.5 to 4.5 times the weight of the lithium phosphate and 0.75 to 1.75 times the weight of the lithium phosphate, and then filtering the lithium phosphate to prepare a lithium sulfate solution (step d);

The lithium sulfate solution is concentrated by evaporation and filtration to recover and wash the solid lithium sulfate, and the evaporation and filtration is performed 2 to 5 times (step e);

Adding distilled water having a weight of 2 to 20 times the weight of the recovered solid lithium sulfate to the lithium sulfate, adjusting the pH to 9 to 11 by adding a sodium hydroxide solution, and then filtering (step f); And

Adding a sodium carbonate solution at a concentration of 5 wt% to 50 wt% to the filtrate, filtering and washing to prepare a solid lithium carbonate (step g); removing solid carbon dioxide from the waste solution of the spent lithium battery, A method for producing lithium is provided.

The sodium hydroxide added in step b) may be added so that the pH of the mixture is 10 to 12, preferably 10.5 to 11.5. If the pH of the mixture is less than 10, there may be a problem that the lithium recovery rate is lowered. If the pH of the mixture is more than 12, the lithium recovery rate may be lowered. This can be produced with a very small amount of lithium hydroxide due to the addition of a large amount of sodium hydroxide, and the solubility of the produced lithium hydroxide may result in an increase in the lithium concentration in the lithium recovery filtrate. In addition, when the amount of sodium hydroxide used for raising the pH is 12 or higher is 5.25 times as high as pH 13, and 10 times as high as that of sodium hydroxide is used at pH 13.5, there is a problem of increase in process cost Also, there is a problem that the cost of wastewater treatment due to excessive use of sodium hydroxide and the cost of waste treatment increase due to increase of process sludge.

The filtration in step c) can recover the solid lithium phosphate produced in the reaction and the remaining filtrate can be treated with wastewater.

The lithium phosphate recovered in relation to the lithium content of the spent lithium battery waste solution, which is the starting material in the filtration in step c), may be the same as the recovered lithium phosphate content relative to the lithium content of the waste solution in step 3 above.

The step c may further include washing the lithium phosphate recovered by the filtration.

The added weight of distilled water and sulfuric acid added in the preparation of the lithium sulfate solution of step (d) may be the same as the weight of the distilled water and the acid added in step 4 above.

The step d may further include a step of adding the distilled water and the acid, followed by filtration. At this time, the residue generated in the filtration may include organic matter and partially precipitated lithium sulfate, and lithium may be recovered through water washing and the organic residue may be discarded. The water-washing lithium solution and the remaining filtrate can be used as the lithium sulfate solution for the post-treatment.

The evaporation concentration of the step e may be performed 2 to 5 times, more preferably 2 to 3 times.

The filtrate resulting from the final filtration of step e above can be used in preparing the mixture of step a above. For example, as shown in FIG. 2, the lithium sulfate solid phase produced by performing filtration after evaporation and concentration is used for the subsequent step, and the remaining filtrate is subjected to evaporation concentration and filtration to obtain a lithium sulfate solid phase And the remaining filtrate contains a large amount of phosphoric acid, so that it can be used in the preparation of the mixture of step a).

The evaporation concentration of the step e may be performed by evaporating 50 to 90% by weight of the water contained in the lithium sulfate solution.

The washing of step e may be performed by adding 10 wt% to 40 wt% of distilled water to the recovered lithium sulfate solid phase.

The washing of step e may be performed for the purpose of removing the phosphorus component of the recovered lithium sulfate solid phase, and the washing liquid generated at this time may be used for preparing the lithium sulfate solution of step d above.

The concentration of the sodium hydroxide solution in step f may be the same as the concentration of the basic solution in step 6 above.

The temperature and the holding time during the pH adjustment of step f may be the same as the temperature and holding time of step 6 above.

The residue resulting from the filtration of step (f) may be used to prepare the lithium sulfate solution of step (d). That is, the residue resulting from the filtration may be lithium phosphate and the lithium sulfate solid phase in step e, and the filtrate may be used in the subsequent step.

After the addition of the sodium carbonate solution of step g), the reaction can be carried out at a temperature of 80 ° C to 90 ° C for 1 hour to 2 hours.

The filtrate generated in the filtration of step g may contain a small amount of lithium, and thus may be used for preparing the mixture of step a.

The washing liquid resulting from the washing of step g may also contain a small amount of lithium and may be used in the preparation of the mixture of step a.

The lithium carbonate produced through the above method (step a to step g) can be obtained by carrying out the above-described process once, and there is provided a lithium carbonate solution containing 60 wt% to 80 wt% lithium relative to the lithium content of the lithium waste solution of step a And when the above method is continuously performed and stabilized, only 3 wt% to 8 wt% of lithium relative to the lithium content of the lithium waste solution of the step a) can not be used and can be discarded.

Further, according to an aspect of the present invention, there is provided a method for purifying a filtrate, which comprises filtration resulting from the final filtration of the step e, washing liquid resulting from washing of the step e, residue resulting from filtration of the step f, And a washing solution generated in washing can be recycled and used. Thus, it is possible to utilize lithium contained in a lithium-containing waste liquid as an initial starting material to the maximum extent.

According to another aspect of the present invention,

A solid phase carbonate comprising 90 wt% to 95 wt% of lithium relative to lithium in the waste solution of step 1, i, a, which is prepared in the above method (steps 1 to 7, steps i to vii, Lithium.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples. However, the following examples and experimental examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

≪ Example 1 > Solid phase lithium carbonate production step 1

Step 1: 63 kg of lithium waste solution (lithium concentration: 3 g / L) of a spent lithium secondary battery was provided. Phosphoric acid was added to the waste solution at 1 molar equivalent to lithium.

Step 2: The pH was adjusted to 11 by adding sodium hydroxide (25% concentration) to the phosphoric acid-added waste solution.

Step 3: The pH-adjusted waste solution was heated to 80 ° C, reacted for 1 hour, and filtered to collect 1 kg of solid lithium phosphate, which was washed with distilled water.

Step 4: 3.5 times weight (3.5 kg) of distilled water and 1.25 times weight (1.25 kg) of sulfuric acid (95%) were added to the solid lithium phosphate and filtered to prepare 5.75 kg of lithium sulfate solution.

Step 5: The lithium sulfate solution was subjected to primary evaporation and filtration to separate a primary lithium sulfate solid (1.18 kg) and a primary filtrate (2.2 kg), and the primary filtrate was subjected to secondary evaporation and filtration to obtain secondary The lithium sulfate solid phase (0.32 kg) and the final filtrate (0.60 kg) were separated and the final filtrate was used for the phosphoric acid addition step of step 1 above.

Step 5a: 20 wt% of distilled water (0.30 kg) was added to the separated lithium sulfate solid phase (1.18 + 0.32 = 1.5 kg), and the washing solution (0.38 kg) Respectively.

Step 6: To the washed lithium sulfate solid (1.42 kg), the pH was adjusted to 10 by adding 2.5 times by weight of distilled water and a 25 wt% sodium hydroxide solution, maintained at 80 ° C for 1 hour, and then filtered . The filtrate (lithium phosphate, 0.01 kg) produced in the filtration was used for preparing the lithium sulfate solution of step 4 above, and the filtrate (5 kg) was used for the post-treatment.

Step 7: A sodium carbonate solution (7.13 kg) having a concentration of 15 wt% was added to the filtrate (5 kg), and the mixture was reacted at 80 ° C to 90 ° C for 1 hour to form lithium carbonate, followed by filtration. The filtrate (11.29 kg) generated during the filtration was used as the lithium waste solution in step 1, and the lithium carbonate solid phase as a residue in the filtration was washed by adding distilled water, and the washing solution was utilized as the lithium waste solution in step 1, Lithium solid phase (0.78 kg) was obtained.

Example 2 Preparation of Solid Phase Lithium Carbonate, Step 2 pH 10

A lithium carbonate solid was prepared in the same manner as in Example 1, except that in Step 2 of Example 1, the pH was adjusted to 10.

≪ Example 3 > Preparation process of solid phase lithium carbonate, step 2 pH 12

A lithium carbonate solid phase was prepared in the same manner as in Example 1, except that in Step 2 of Example 1, the pH was adjusted to 12.

Example 4 Solid phase lithium carbonate production step, step 3 70 ° C

A lithium carbonate solid phase was prepared in the same manner as in Example 1 except that the temperature was raised to 70 캜 in the step 3 of Example 1.

Example 5 Solid phase lithium carbonate production step, step 3 90 ° C

A lithium carbonate solid phase was prepared in the same manner as in Example 1 except that the temperature was raised to 90 ° C in the step 3 of Example 1.

≪ Comparative Example 1 > Preparation process of solid phase lithium carbonate, step 2 pH 9

A lithium carbonate solid was prepared in the same manner as in Example 1, except that in Step 2 of Example 1, the pH was adjusted to 9.

≪ Comparative Example 2 > Preparation of solid phase lithium carbonate, step 2 pH 13

A lithium carbonate solid was prepared in the same manner as in Example 1 except that in Step 2 of Example 1, the pH was adjusted to 13.

≪ Comparative Example 3 > Preparation process of solid phase lithium carbonate, step 2 pH 13.5

A lithium carbonate solid phase was prepared in the same manner as in Example 1, except that in Step 2 of Example 1, the pH was adjusted to 13.5.

≪ Comparative Example 4 > Solid phase lithium carbonate production step, step 3 50 < 0 > C

A lithium carbonate solid phase was prepared in the same manner as in Example 1 except that the temperature was raised to 50 캜 in the step 3 of Example 1.

≪ Comparative Example 5 > Solid phase lithium carbonate production step, step 3 100 DEG C

A lithium carbonate solid was prepared in the same manner as in Example 1, except that the temperature was raised to 100 ° C in the step 3 of Example 1.

≪ Comparative Example 6 > Preparation of solid phase lithium carbonate, step 2 pH 8

A lithium carbonate solid phase was prepared in the same manner as in Example 1, except that in Step 2 of Example 1, the pH was adjusted to 8.

≪ Comparative Example 7 > Preparation process of solid phase lithium carbonate, step 2 pH 7

A lithium carbonate solid phase was prepared in the same manner as in Example 1, except that in Step 2 of Example 1, the pH was adjusted to 8.

≪ Comparative Example 8 > Solid phase lithium carbonate production step, step 3 60 ° C

A lithium carbonate solid phase was prepared in the same manner as in Example 1 except that the temperature was raised to 60 ° C in the step 3 of Example 1.

≪ Comparative Example 9 > Solid phase lithium carbonate production step, step 3 25 C

A lithium carbonate solid was prepared in the same manner as in Example 1, except that the temperature was raised to 25 ° C in the step 3 of Example 1.

<Experimental Example 1> Measurement of lithium recovery rate under each condition

In Examples 1 to 5 and Comparative Examples 1 to 10, the lithium content of the lithium carbonate prepared in the early stage of lithium waste solution versus lithium was measured. The results are shown in Table 1.

division Condition Primary lithium recovery (%) Example 1 standard 76.52 Example 2 Step 2 pH 10 70.84 Example 3 Step 2 pH 12 76.52 Example 4 Step 3 70 ° C 75.35 Example 5 Step 3 90 ° C 76.52 Comparative Example 1 Step 2 pH 9 53.72 Comparative Example 2 Step 2 pH 13 75.64 Comparative Example 3 Step 2 pH 13.5 70.84 Comparative Example 4 Step 3 50 ° C 62.72 Comparative Example 5 Step 3 100 ° C 76.52 Comparative Example 6 Step 2 pH 8 42.37 Comparative Example 7 Step 2 pH 7 38.26 Comparative Example 8 Step 3 60 ° C 70.84 Comparative Example 9 Step 3 25 ° C 39.92

As shown in Table 1, in Examples 1 to 3, in which the pH was adjusted to 10 to 12 through sodium hydroxide in Step 2, the lithium content of the lithium carbonate prepared with respect to the waste lithium was 72 wt% or more, Was found to exhibit the best lithium recovery rate. On the other hand, Comparative Example 1 in which the pH was adjusted to 9 exhibited a lower value, Comparative Examples 2 and 3 in which the pH was adjusted to 13 and 13.5 were lower than those in Example 1, and the sodium hydroxide usage was lower than that in Example 1 Over 10 to 10 times of the increase in the cost of the process resulted in an increase in the cost of wastewater treatment. The reason why the recovery rates of Comparative Examples 2 and 3 are lowered is that as a part of lithium is produced as lithium hydroxide due to an excessive amount of sodium hydroxide as described above and lithium is dissolved again due to the solubility of lithium hydroxide, Resulting in an increase in lithium concentration in the filtrate.

In Examples 1, 4 and 5, in which the temperature rise temperature of Step 3 was adjusted to 70 to 90 캜, the lithium content of lithium carbonate prepared in comparison with 77 wt% or more of waste lithium was shown, and in Comparative Example 5 at 100 캜, It shows a similar recovery rate as in Example 1, but shows poor results in terms of the energy cost to be charged for the temperature rise. In Comparative Example 4, in which the temperature was elevated to 50 ° C, it was confirmed that the lithium recovery was lowered because the solubility of lithium phosphate was lowered as the temperature increased and increased as the temperature decreased.

<Experimental Example 2> Measurement of lithium recovery rate

In Example 1, the entire process was repeated from 2 to 5 times, and the relative weights and lithium recovery rates of the respective materials with respect to the total weight of the lithium waste solution were measured according to the respective turns. Respectively.

As shown in FIG. 6, the recovery rate of lithium from the lithium of the first lithium waste solution was 76.5%. As shown in FIG. 6, the recovery rate increased as the repetition degree was increased. It was confirmed that lithium recovery was possible.

<Experimental Example 3> XRD analysis of product in each step

In Example 1, X-ray diffraction analysis of lithium phosphate, lithium sulfate and lithium carbonate produced in each step was carried out, and the results are shown in FIG. 3 to FIG.

As shown in FIGS. 3 to 5, it was confirmed that lithium phosphate recovered in step 3, lithium sulfate recovered in step 5, and lithium carbonate finally produced were easily formed.

Although the concrete embodiments of the method for producing solid lithium carbonate from the lithium-containing waste liquid according to one aspect of the present invention have been described so far, it is apparent that various modifications can be made within the scope of the present invention without departing from the scope of the present invention.

Therefore, the scope of the present invention should not be construed as limited to the embodiments described, but should be determined by the scope of the appended claims, as well as the claims.

It is to be understood that the foregoing embodiments are illustrative and not restrictive in all respects and that the scope of the present invention is indicated by the appended claims rather than the foregoing description, It is intended that all changes and modifications derived from the equivalent concept be included within the scope of the present invention.

Claims (24)

A step of preparing a mixture in which a phosphorus-containing substance is added to a lithium-containing waste liquid (step 1);
Adjusting the pH by adding a basic solution to the prepared mixture (step 2);
Raising the pH-adjusted mixture to react, and recovering lithium phosphate by filtration (step 3);
A step (step 4) of preparing a lithium sulfate solution to which distilled water and sulfuric acid are added to the recovered lithium phosphate;
Concentrating the lithium sulfate solution by evaporation to recover solid lithium sulfate (step 5);
Washing the recovered lithium sulfate in step 5 (step 5a);
Adding distilled water and a basic solution to the cleaned solid lithium sulfate to adjust pH and then filtering (step 6); And
Adding carbonate to the filtered filtrate, filtering and washing to produce solid lithium carbonate (Step 7)
The washing solution generated by the washing of the step 5a is utilized as the lithium sulfate solution of the step 4,
The lithium phosphate generated in the filtration in the step 6 is utilized as the lithium phosphate in the step 4,
Wherein the filtrate generated in the filtration in step 7 and the washing liquid generated in the washing are utilized in the preparation of the mixture of step 1, from the lithium-containing waste liquid.
The method according to claim 1,
The phosphorus-containing material in step (1)
Containing waste liquid characterized by comprising phosphoric acid (H ₃ PO ₄ ) or phosphate.
The method according to claim 1,
The phosphorus-containing material addition ratio in the above step (1)
Containing waste liquid is added in an amount of 0.8 to 1.2 times the equivalent of lithium in the lithium-containing waste liquid.
The method according to claim 1,
The basic solution of step 2,
Hydroxide including sodium (NaOH), potassium hydroxide (KOH), magnesium hydroxide (Mg (OH) _2), calcium hydroxide (Ca (OH) ₂₎ and barium hydroxide at least one selected from the group consisting of (Ba (OH) ₂₎ By weight based on the weight of the lithium-containing waste liquid.
The method according to claim 1,
The addition of the basic solution of step 2,
Wherein the pH of the mixture is adjusted so that the pH is 10-12.
The method according to claim 1,
The temperature rise in step 3 is,
Containing waste liquid from a lithium-containing waste liquid, wherein the temperature is raised to a temperature of 70 ° C to 90 ° C and maintained for 30 minutes to 90 minutes after the temperature rise.
The method according to claim 1,
The production of the acid lithium solution in the step 4,
Wherein the distillated water is prepared by adding 2.5 to 4.5 times as much weight of distilled water to the recovered lithium phosphate and 0.75 to 1.75 times as much weight of the recovered lithium phosphate as the lithium phosphate.
delete The method according to claim 1,
The evaporation concentration in step 5 is carried out,
Containing waste liquid is performed 1 to 5 times.
10. The method of claim 1 or 9,
Wherein the filtration is performed after the evaporation concentration in the step 5, and the filtrate generated in the filtration is used as the phosphorus-containing material in the step 1.
delete The method according to claim 1,
The washing of step 5a,
Wherein the recovered lithium salt is carried out through 10 wt% to 40 wt% of distilled water relative to the recovered lithium salt.
delete The method according to claim 1,
The amount of distilled water added in step 6 is,
Wherein the weight of the recovered solid lithium salt is 2 to 20 times the weight of the recovered solid lithium salt.
The method according to claim 1,
The basic solution of the step 6 is,
Sodium hydroxide (NaOH), potassium hydroxide (KOH), magnesium hydroxide (Mg (OH) _2), calcium hydroxide (Ca (OH) _2), barium hydroxide (Ba (OH) ₂₎ and at least one member selected from the group consisting of carbonate Containing waste liquid from a lithium-containing waste liquid.
The method according to claim 1,
The pH adjustment in step 6 is carried out,
and the pH is adjusted to be 9 to 11. The method for producing lithium carbonate according to claim 1,
The method according to claim 1,
The pH adjustment in step 6 is carried out,
Wherein the reaction is carried out at a temperature of 60 DEG C to 90 DEG C for 30 minutes to 90 minutes.
delete The method according to claim 1,
The carbonates of step 7,
Sodium carbonate (Na ₂ CO _3), sodium bicarbonate (NaHCO _3), potassium carbonate (K ₂ CO _3), potassium bicarbonate (KHCO _3), calcium carbonate (CaCO _3), magnesium carbonate (MgCO _3), barium carbonate (BaCO ₃ ) And dolomite (CaMg (CO ₃ ) ₂ ). 2. A process for producing lithium carbonate, comprising:
delete delete A step of preparing a mixture in which a phosphoric acid is added to a waste solution of a waste lithium battery containing lithium (step i);
Adding a basic solution to the prepared mixture to adjust the pH to 10 to 12 (step ii);
Raising the temperature of the pH-adjusted mixture to a temperature of 70 ° C to 90 ° C for reaction, and recovering lithium phosphate by filtration (step iii);
Preparing a lithium sulfate solution to which distilled water and sulfuric acid are added to the recovered lithium phosphate (step iv);
Concentrating the lithium sulfate solution by evaporation to recover solid lithium sulfate (step v);
Washing the recovered lithium sulphate in step v (step v +);
Adding distilled water and a basic solution to the washed solid lithium sulfate to adjust the pH and then filtering (step vi); And
Adding a carbonate to the filtered filtrate, filtering and washing to produce solid lithium carbonate (step vii)
The washing solution generated by the washing of the step v + is utilized as the lithium sulfate solution of the step iv,
The lithium phosphate generated in the filtration in the step vi is utilized as the lithium phosphate of the step iv,
Wherein the filtrate generated in the filtration of the step vii and the washing liquid generated in the washing are used in the preparation of the mixture of the step i.
Preparing a waste solution of a waste lithium battery containing lithium at a concentration of 1.5 g / L to 6.0 g / L by adding phosphoric acid in an amount of 0.8 to 1.2 times the lithium relative to the lithium (step a);
Adding sodium hydroxide solution to the prepared mixture to adjust the pH to 10 to 12 (step b);
Raising the temperature of the pH-adjusted mixture to 70 ° C to 90 ° C, reacting for 30 minutes to 90 minutes, and recovering lithium phosphate by filtration (step c);
Adding distilled water and lithium sulfate to the recovered lithium phosphate in an amount of 2.5 to 4.5 times the weight of the lithium phosphate and 0.75 to 1.75 times the weight of the lithium phosphate, and then filtering the lithium phosphate to prepare a lithium sulfate solution (step d);
The lithium sulfate solution is concentrated by evaporation and filtration to recover and wash the solid lithium sulfate, and the evaporation and filtration is performed 2 to 5 times (step e);
Adding distilled water of 2 to 20 times the weight of the lithium sulfate to the washed solid lithium sulfate, adjusting the pH to 9 to 11 by adding sodium hydroxide solution, and then filtering (step f); And
Adding sodium carbonate solution at a concentration of 5 wt% to 50 wt% to the filtrate, filtering and washing to prepare solid lithium carbonate (step g)
The washing liquid generated by the washing of the step e is utilized as the lithium sulfate liquid of the step d,
The lithium phosphate generated in the filtration of the step (f) is utilized as the lithium phosphate of the step (d)
Wherein the filtrate generated in the filtration in step g and the washing liquid generated in the washing are used in the preparation of the mixture in step a) from the waste liquid of the spent lithium battery.
23. A process for the preparation of a compound according to any one of claims 1, 22 and 23,
A solid lithium carbonate comprising 90 wt% to 95 wt% lithium relative to the lithium content of the waste solution.

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