A method for recovering nickel and cobalt from a mixture of compounds of these metals from spent lithium-ion batteries

Abstract

The invention relates to a method for recovering nickel and cobalt from a mixture of compounds of these metals from the recycling of spent lithium-ion batteries, comprising the following steps: a) digestion of a mixture of nickel and cobalt compounds in a solution containing hydrochloric acid having a concentration of more than 25 mass %, in case the mixture of nickel and cobalt compounds is solid; or bringing the mixture of nickel and cobalt compounds to a hydrochloric acid concentration of more than 25 mass %, in case the mixture of nickel and cobalt compounds is a solution; b) activation of ion-exchange resin in a column using hydrochloric acid; c) passing the solution from step a) through the column filled with the ion-exchange resin activated in step b); d) washing the column with hydrochloric acid having a concentration of more than 25 mass % in order to wash out the remaining solution containing nickel ions; e) washing the column with hydrochloric acid having a concentration of less than 10 mass % in order to wash out cobalt ions; f) extraction distillation of the nickel ion solution obtained in step d) in hydrochloric acid using sulfuric(VI) acid; phase separation in a spent liquid; recycling of a filtrate to distillation; dissolution of nickel sulfate(VI) and electrolysis in order to recover metallic nickel; g) extraction distillation of the cobalt ion solution obtained in step e) in hydrochloric acid using sulfuric(VI) acid; phase separation in a spent liquid; recycling of a filtrate to distillation; dissolution of cobalt sulfate(VI) and electrolysis in order to recover metallic cobalt; h) extraction distillation of the solution of diluted hydrochloric acid with nickel and cobalt ions obtained after the activation of the ion-exchange resin in step b), using sulfuric(VI) acid; phase separation in a spent liquid; recycling of a filtrate to distillation; recycling of a mixture of the formed cobalt sulfate(VI) and nickel sulfate(VI) to digestion in step a); i) rectification of diluted hydrochloric acid having a concentration below the azeotropic concentration (approx. 20.2 mass % at atmospheric pressure) formed in extraction distillation processes in steps f)-h) in order to concentrate hydrochloric acid and recover and recycle of water; recycling of concentrated hydrochloric acid to extraction distillation in steps f)-h).

Description

[0001] A method for recovering nickel and cobalt from a mixture of compounds of these metals from spent lithium-ion batteries

[0002] Description of the Invention

[0003] The invention relates to a method for recovering nickel and cobalt from a mixture of compounds of these metals from recycling of spent lithium-ion batteries. The invention enables the effective recovery of valuable elements from spent lithium-ion batteries in a manner that is environmentally safe and characterized by high yield of recovery and high purity of recovered elements.

[0004] Background art

[0005] Because lithium-ion batteries have a limited number of charge cycles, these batteries are expected to become a significant source of waste. As soon as many devices, such as electric vehicles or cell phones, reach the end of their life, it is expected that the quantity of spent lithium-ion batteries will increase significantly. The recycling of such spent batteries has a potential to reduce the volume of waste of this kind and will contribute to reduced output of valuable elements, such as lithium, nickel and cobalt.

[0006] In the face of increasing demand for production of lithium-ion batteries, the use of recycling of metals, such as cobalt and nickel, in the process for the production of new batteries could significantly reduce the demand for new raw materials. The process for the output and processing of these metals typically involves a significant environmental impact, unlike recycling. The recovery of valuable raw materials from spent lithium-ion batteries has a beneficial effect on environmental protection and reduced energy consumption. In addition, owing to the reuse of recovered metals, this may contribute to a reduced manufacturing cost of new batteries. The process for the separation of nickel and cobalt ions, which is also highly cost intensive and material intensive, is one of the particularly important challenges in the recycling of lithium-ion batteries. Currently, multistage solvent extraction (SX) is a commonly used method. The advantages of SX include high selectivity toward respective elements.

[0007] Publication KR102548398B 1 discloses a process for the separation of cobalt and nickel from a reaction mixture formed within the processing of lithium-ion batteries using bis(2,4,4- trimethylpentyl)dithiophosphinic acid (Cyanex 301). Two successive stages of solvent extraction can be carried out in this method. First, cobalt and nickel are extracted using Cyanex 301 dissolved in kerosene. Subsequently, by a separation process involving Cyanex 272, both metals are separately crystallized after being previously treated with acid, in particular hydrochloric or sulfuric(VI) acid, in order to obtain solution containing nickel and cobalt. Publication EP3945068A1 discloses a process for using Cyanex 272 (bis(2,4,4- trimethylpentyl)phosphinic acid) in an extraction process of cobalt and manganese as well as certain other impurities extracted using an organic extracting agent. Cobalt and manganese were extracted from the organic extracting agent using sulfuric(VI) acid solution. An alternative method is to use ion-exchange (IX) resins whose advantage over SX is their ease of application, automation and really simple process scaling. In addition, the use of IX resins reduces raw materials consumption, including expensive and frequently toxic organic solvents. Furthermore, chelating ion-exchange resins and resins impregnated with compounds used in SX are commercially available, so that the advantages of both methods can be combined.

[0008] Publication WO201226061 Al discloses a process for the recovery of lithium ions and transition metal ions, including cobalt and nickel, from lithium-ion batteries. The process involves leaching metal ions in an acidic environment followed by separation of metals from the resulting solution using a basic anion-exchange resin.

[0009] The inventors of present invention previously developed a solution wherein an anionic ionexchange resin was used for the separation of Ni(II) ions from Co(II) ions. The concept of the process is related to the formation of cobalt(II) chlorocomplexes in the hydrochloric acid environment and lack of formation of anionic complexes with nickel(II). As a result, both ions can be separated using readily available ion-exchange (IX) resins. According to this solution, a product in the form of nickel(II) oxalate and cobalt(II) oxalate is obtained, both of them are not typically commercially available compounds. Preparation of oxalates involves the use of additional reagents in the recycling process. According to this solution, problematic waste is generated in the form of liquid sewage containing chlorides.

[0010] In addition, a process for the production of hydrogen chloride gas and concentration of hydrochloric acid is known in the art, through variable pressure distillation or extraction distillation, including using sulfuric(VI) acid, magnesium and calcium chlorides and the like. The use of nickel and / or cobalt for this purpose is not known. In addition, use of this process in the recycling technology for lithium-ion batteries is not known.

[0011] The methods for the recovery of valuable metals reported in the prior art are characterized by a high level of complexity as well as material and cost intensity, which significantly limits their application on the industrial scale. The objective of this invention is to eliminate these disadvantages.

[0012] Summary of the invention

[0013] The present invention relates to a method for recovering nickel and cobalt from a mixture of compounds of these metals from the recycling of spent lithium-ion batteries, comprising the following steps: a) digestion of a mixture of nickel and cobalt compounds in a solution containing hydrochloric acid having a concentration of more than 25 mass %, in case the mixture of nickel and cobalt compounds is solid; or bringing the mixture of nickel and cobalt compounds to a hydrochloric acid concentration of more than 25 mass %, in case the mixture of nickel and cobalt compounds is a solution; b) activation of ion-exchange resin in a column using hydrochloric acid; c) passing the solution from step a) through the column filled with the ion-exchange resin activated in step b); d) washing the column with hydrochloric acid having a concentration of more than 25 mass % in order to wash out the remaining solution containing nickel ions; e) washing the column with hydrochloric acid having a concentration of less than 10 mass % in order to wash out cobalt ions; f) extraction distillation of the nickel ion solution obtained in step d) in hydrochloric acid using sulfuric(VI) acid; phase separation in a spent liquid; recycling of a filtrate to distillation; dissolution of nickel sulfate(VI) and electrolysis in order to recover metallic nickel; g) extraction distillation of the cobalt ion solution obtained in step e) in hydrochloric acid using sulfuric(VI) acid; phase separation in a spent liquid; recycling of a filtrate to distillation; dissolution of cobalt sulfate(VI) and electrolysis in order to recover metallic cobalt; h) extraction distillation of the solution of diluted hydrochloric acid with nickel and cobalt ions obtained after the activation of the ion-exchange resin in step b), using sulfuric(VI) acid; phase separation in a spent liquid; recycling of a filtrate to distillation; recycling of a mixture of the formed cobalt sulfate(VI) and nickel sulfate(VI) to digestion in step a); i) rectification of diluted hydrochloric acid having a concentration below the azeotropic concentration (approx. 20.2 mass % at atmospheric pressure) formed in extraction distillation processes in steps f)-h) in order to concentrate hydrochloric acid and recover and recycle of water; recycling of concentrated hydrochloric acid to extraction distillation in steps f)-h).

[0014] Preferably, the digestion of the mixture of nickel and cobalt compounds in step a) is carried out in a solid to liquid ratio of 1:3-1:50 g / mL.

[0015] Preferably, the activation of the ion-exchange resin in step b) is carried out until an eluate from the column is a solution containing HC1 having a concentration of at least 20 mass %. Preferably, the column for separating nickel from cobalt ions in steps b)-e) contains basic anion-exchange resin.

[0016] Preferably, the bed for separating nickel from cobalt ions in steps b)-e) has dimensions in which the ratio of diameter to height is 1:2-1:20. Preferably, the separation of cobalt from nickel in each of steps c)-e) is carried out in a manner that ensures contact between the solution and the bed for a time of 1-90 min.

[0017] Preferably, the HC1 solution recycled from the process in step d) is used for digestion the mixture of nickel and cobalt compounds in step a).

[0018] Preferably, digestion of the mixture of nickel and cobalt compounds in step a), activation in step b) and washing the column in step d) are carried out using the solution of HC1 having a concentration of 25-38 mass %.

[0019] Preferably, the solution of HC1 having a concentration of 25-38 mass % is recovered in steps f)-i).

[0020] Preferably, the diluted solution of HC1 having a concentration of 0.01-10 mass % is recovered in steps f)-i), which solution is used in step e).

[0021] Preferably, the extraction distillation in steps f)-h) is carried out with an addition of sulfuric(VI) acid having a concentration of 10-98 mass % in the mixture submitted to the distillation.

[0022] Preferably, the extraction distillation in steps f)-h) is carried out in the presence of nickel and cobalt ions having total concentration of at least 0.1 mass % in the mixture submitted to the distillation.

[0023] In addition, the steps in items f)-i) may be optionally replaced by continuous rectification and extraction distillation systems for nickel and cobalt solutions and solution after bed activation. Therefore, concentrated hydrochloric acid and water streams can be obtained directly.

[0024] In addition, the streams leaving the column can be separated as appropriate and selectively directed to selected process steps.

[0025] In addition, the distillate streams obtained in the extraction distillation can be separated as appropriate and selectively directed to selected process steps.

[0026] Such separation of the streams may contribute, inter alia, to a reduced quantity of streams to be recirculated, to a reduced quantity of streams to be submitted to extraction distillation, to no need for performing extraction distillation for solution after bed activation, to no need for performing rectification, and to obtaining products with increased purity.

[0027] The mixture of nickel and cobalt compounds is defined as a mixture that contains any mixture of ions, oxides, salts, hydroxides or oxyhydroxides of these metals at oxidation states II and III, in particular nickel(II) hydroxide, cobalt(II) hydroxide, nickel(II) carbonate, cobalt(II) carbonate, nickel(II) oxalate, cobalt(II) oxalate and the like. The mixture may also contain other metals, in particular alkaline metals, including in particular sodium, potassium, lithium, which have not been removed during previous process steps.

[0028] The method of the present invention allows for separation of nickel and cobalt as well as it yields high-purity products. The products may include nickel and cobalt sulfates(VI) or nickel and cobalt in metallic form. In addition, the method is characterized by the use of readily available reagents and does not require any organic solvents. The method of the present invention does not result in the formation of any problematic waste containing chloride. In addition, the method ensures complete recovery of hydrochloric acid which is recycled to the process. An additional advantage of the method according to the present invention is the use of nickel and cobalt ions in the extraction distillation process. These metals contribute to improved efficiency of hydrochloric acid stripping, because their action is similar to that of alkaline earth metals known in the art.

[0029] Examples of the invention

[0030] The invention is illustrated by the following examples.

[0031] Example 1

[0032] 30 g of a mixture of nickel and cobalt compounds containing 24.8 mass % Ni and 20.4 mass % Co was dissolved in 300 mL of 37 mass % HC1 (solid-liquid ratio of 1:10 g / mL) and it was stirred until the sediment was completely digested. A column filled with ion-exchange resin (strongly basic, substituted with CT ions) was activated with 150 mL of 37 mass % HC1 in order to ensure effective binding of cobalt ions, and, as a result, 135 mL of 21.4 mass % HC1 for concentration was obtained. The eluate from the column after activation was a solution containing 25 mass % HC1. Subsequently, the solution containing Ni and Co was applied on the bed. A bed with dimensions in which the diameter to height ratio was 1:2 was used. Cobalt ions were retained in the bed, and nickel ions were eluted from the column first. 300 mL of 37 mass % HC1 was applied in order to wash the bed and remove Ni ions. The solution was obtained which was recycled to digest another portion of a mixture of Ni and Co compounds. Subsequently, 500 mL of diluted HC1 having a concentration of 0.01 mass % HC1 was applied on the bed in order to recover cobalt ions. The flow rate of the solutions through the bed was adjusted to achieve their mean residence time of 5 min. In the subsequent step, extraction distillation of 498 mL of the solution containing cobalt (HC1 concentration of 8.4 mass %) was carried out. In a 1000 mL flask, 98 mL of 98% H2SO4 was placed and cobalt solution was gradually added (the mixture comprises 25 mass % of H2SO4; the total Ni and Co concentration was 0.9 mass % of the mixture). 100 mL of diluted HC1 having a concentration of 0.01 mass % was added to two scrubbers each. As a result of the process, HC1 concentrations of 4.1 mass % and 0.9 mass %, respectively, were obtained in the scrubbers, and 475 mL of distillate having a concentration of HC1 of 7.9 mass %. The scrubbers were used in the subsequent step, i.e. extraction distillation of 302 mL of solution containing nickel (HC1 concentration of 34.2 mass %; the total Ni and Co concentration was 1.3 mass % of the mixture). In a 500 mL flask, 67 mL of 98% H2SO4 was placed and nickel solution was gradually added (the mixture comprises 25 mass % of H2SO4). After the process, the scrubbers contained solutions with HC1 concentrations of 30.3 mass % and 15.5 mass %, respectively, and 257 mL of distillate had a HC1 concentration of 23.1 mass %. Extraction distillation of the mixture after activation was carried out similarly (HC1 concentration of 21.4 mass %). In the subsequent step, rectification of the mixture of streams in which HC1 concentration was lower than 20.2 mass % (azeotrope) was carried out. In this manner, 320 mL of water was recovered and 270 mL of HC1 azeotrope was obtained. As it was the first process in a series, an additional extraction distillation step was carried out in order to concentrate the acid, using a spent liquid after distilling the mixture after activation. Finally, 320 mL of water, 216 mL of distillate having a concentration of 4 mass % HC1 which was used in the subsequent process in scrubbers, as well as 560 mL of 30 mass % HC1 which was recycled to activation and washing the bed in the subsequent step, were obtained. The water recovered in extraction distillation of the solution containing nickel, the solution containing cobalt and the mixture after activation as well as in rectification, was used to recover cobalt ions from the bed. Spent liquids from both processes were subjected to phase separation after cooling. Cobalt sulfate(VI) was digested in water and the solution was obtained having a concentration of cobalt ions of 100 g / L and subjected to electrolysis at constant current (current density of 180 A / m2). The electrolysis was carried out using a lead anode and stainless steel as a cathode at 60-70°C in an acidic environment with a pH of 3.0 and with addition of 5 vol. % boric acid. Current efficiency was 97% and 4.0 g metallic Co with 99.3% purity was obtained. Nickel sulfate(VI) was digested in water and the solution was obtained with a concentration of cobalt ions of 160 g / L and subjected to electrolysis at constant current (current density of 200 A / m2). The electrolysis was carried out using a lead anode and copper as a cathode at 60°C in an acidic environment with a pH of 3.5 and with addition of 5 vol. % boric acid. Current efficiency was 91% and 4.9 g metallic Ni with 99.5% purity was obtained.

[0033] Example 2

[0034] 20 g of a mixture of nickel and cobalt compounds containing 21.8 mass % Ni and 27.3 mass % Co was dissolved in 100 mL (solid-liquid ratio of 1:10 g / mL) of the solution after nickel ion washing in the previous example (fraction 1 / 2). It was stirred until the sediment was completely digested. A column filled with ion-exchange resin (strongly basic, substituted with Cl’ ions) was activated. A bed with dimensions in which the diameter to height ratio was 1:10 was used. 185 mL of eluate from the column after the previous activation (fraction 3 / 3, 21.4 mass % HC1) and 115 mL of acid concentrated after distillation (29.6 mass % HC1) was successively used for activation. Three fractions were obtained: 100 mL of solution for washing out cobalt ions (3.6 mass % HC1); 50 mL of solution for the extraction distillation of cobalt (15.2 mass % HC1) and 160 mL of solution for subsequent activation (24.2 mass % HC1, eluate from the column after activation). Subsequently, solutions were applied on the bed in order to retain cobalt ions in the following sequence: 195 mL of solution after washing nickel ions in the previous example (fraction 2 / 2); 160 mL of solution containing a digested nickel and cobalt sediment after passing through the bed in the previous process and 110 mL of solution containing a digested nickel and cobalt sediment. 350 mL of solution purified from cobalt ions was collected from the column for extraction distillation and 115 mL of solution containing a digested nickel and cobalt sediment was collected from the column in order to be purified in the subsequent process. In order to wash the bed and remove nickel ions, the following were successively applied: 80 mL of solution after washing out cobalt ions in the previous example (fraction 1 / 3) and 220 mL of acid concentrated after distillation (29.6 mass % HC1). 100 mL of solution (fraction 1 / 2) was collected from the column for digesting another portion of the mixture of Ni and Co compounds and 205 mL of solution (fraction 2 / 2) to be purified in the subsequent process. Subsequently, diluted hydrochloric acid was applied on the beds in order to recover cobalt ions: 170 mL of solution after washing out cobalt ions in the previous example (fraction 3 / 3); 90 mL of solution after activation in the previous example (fraction 1 / 3); 240 mL of diluted acid after distillation (2.2 mass % HC1). Three fractions were collected from the column: 100 mL of solution for washing the bed in the subsequent process; 200 mL of purified cobalt ion solution for distillation and 195 mL of solution for washing out cobalt ions in the subsequent process. The flow rate of the solutions through the bed was adjusted to achieve their mean residence time of 1 min. In the subsequent stage, extraction distillation of 350 mL of solution purified from cobalt ions (23.8 mass % HC1) was carried out. In a 500 mL flask, 100 mL of 98 mass % H2SO4 was placed and nickel solution was gradually added (the mixture comprises 31 mass % of H2SO4; the total Ni and Co concentration was 1.0 mass % of the mixture). 100 mL of diluted HC1 having a concentration of 0.01 mass % was added to two scrubbers each. As a result of the process, the acid having concentrations of 30.8 mass % and 2.6 mass %, respectively, were obtained in the scrubbers. Two distillate fractions were collected: the first one was collected at a vapor temperature of 108.3°C (125 mL, 30.1 mass % HC1); the second one was collected at a vapor temperature of 103.3°C (200 mL, 3.3 mass % HC1). Diluted HC1 solutions were used for the extraction distillation of cobalt solution. 102 mL of acid having a concentration of 2.6 mass % HC1 and 100 mL of acid having a concentration of 3.2 mass % HC1, respectively, was placed in the scrubbers. The purified solution of cobalt ions (200 mL) and the solution after bed activation (50 mL, fraction 2 / 3) were submitted for extraction distillation. In a 500 mL flask, 100 mL of 98 mass % H2SO4 was placed and cobalt solution was gradually added (the mixture comprises 39 mass % of H2SO4; the total Ni and Co concentration was 1.3 mass % of the mixture). After the process, the solutions in the scrubbers had HC1 concentrations of 10.1 mass % and 3.2 mass %, respectively. Two distillate fractions were collected: the first one was collected at a vapor temperature of 108.1°C (90 mL, 28.1 mass % HC1); the second one was collected at a vapor temperature of 103.0°C (140 mL, 2.1 mass % HC1). Streams of concentrated acid of above 25 mass % HC1 were collected together and 340 mL of acid having a concentration of 29.2 mass % HC1 was obtained, which was used in the subsequent process (activation and washing out nickel ions from the bed). Diluted acid streams with a concentration of below 10 mass % HC1 were collected in a volume of 250 mL (2.6 mass % HC1) and used in the subsequent process (washing out cobalt ions from the bed). The other streams after extraction distillation of nickel and cobalt solutions, 205 mL of diluted acid (6.3 mass % HC1) were used in subsequent distillation for acid scrubbers. In this process variant, extraction distillation of the mixture after activation as well as rectification was not needed. Spent liquids from both processes were subjected to phase separation after cooling. After washing, 16.0 g cobalt(II) sulfate(VI) with purity of 99.0% and 15.2 g nickel(II) sulfate(VI) with purity of 99.9% was obtained. A further electrolysis process was not performed in this example.

[0035] Example 3

[0036] 300 mL of solution containing nickel ions having a concentration of 45 g / L, cobalt ions having a concentration of 30 g / L and HC1 having a concentration of 15 mass % was evaporated to 80% volume, and then 120 mL of 37 mass % HC1 was added. The resulting solution (containing HC1 having a concentration of 25.2 mass %) was applied on an activated ion-exchange bed and, following a similar procedure as in Example 2, 29.8 g cobalt(II) sulfate(VI) with purity of 98.8% and 38.4 g nickel(II) sulfate(VI) with purity of 99.8% was obtained. A further electrolysis process was not performed in this example.

[0037] Industrial application

[0038] The invention is applicable for the recycling of spent lithium-ion batteries.

Claims

Claims1. A method for recovering nickel and cobalt from a mixture of compounds of these metals from the recycling of spent lithium-ion batteries, characterized in that it comprises the following steps: a) digestion of a mixture of nickel and cobalt compounds in a solution containing hydrochloric acid having a concentration of more than 25 mass %, in case the mixture of nickel and cobalt compounds is solid; or bringing the mixture of nickel and cobalt compounds to a hydrochloric acid concentration of more than 25 mass %, in case the mixture of nickel and cobalt compounds is a solution; b) activation of ion-exchange resin in a column using hydrochloric acid; c) passing the solution from step a) through the column filled with the ion-exchange resin activated in step b); d) washing the column with hydrochloric acid having a concentration of more than 25 mass % in order to wash out the remaining solution containing nickel ions; e) washing the column with hydrochloric acid having a concentration of less than 10 mass % in order to wash out cobalt ions; f) extraction distillation of the nickel ion solution obtained in step d) in hydrochloric acid using sulfuric(VI) acid; phase separation in a spent liquid; recycling of a filtrate to distillation; dissolution of nickel sulfate(VI) and electrolysis in order to recover metallic nickel; g) extraction distillation of the cobalt ion solution obtained in step e) in hydrochloric acid using sulfuric(VI) acid; phase separation in a spent liquid; recycling of a filtrate to distillation; dissolution of cobalt sulfate(VI) and electrolysis in order to recover metallic cobalt; h) extraction distillation of the solution of diluted hydrochloric acid with nickel and cobalt ions obtained after the activation of the ion-exchange resin in step b), using sulfuric(VI) acid; phase separation in a spent liquid; recycling of a filtrate to distillation; recycling of a mixture of the formed cobalt sulfate(VI) and nickel sulfate(VI) to digestion in step a); i) rectification of diluted hydrochloric acid having a concentration below the azeotropic concentration (approx. 20.2 mass % at atmospheric pressure) formed in extraction distillation processes in steps f)-h) in order to concentrate hydrochloric acid and recover and recycle of water; recycling of concentrated hydrochloric acid to extraction distillation in steps f)-h).

2. The method of claim 1, characterized in that the digestion of the mixture of nickel and cobalt compounds in step a) is carried out in a solid to liquid ratio of 1:3-1:50 g / mL.

3. The method of claims 1-2, characterized in that the activation of the ion-exchange resin in step b) is carried out until an eluate from the column is a solution containing HC1 having a concentration of at least 20 mass %.

4. The method of claims 1-3, characterized in that the column for separating nickel from cobalt ions in steps b)-e) contains basic anion-exchange resin.

5. The method of claims 1-4, characterized in that the bed for separating nickel from cobalt ions in steps b)-e) has dimensions in which the ratio of diameter to height is 1:2-1:20.

6. The method of claims 1-5, characterized in that the separation of cobalt from nickel in each of steps c)-e) is carried out in a manner that ensures contact between the solution and the bed for 1-90 min.

7. The method of claims 1-6, characterized in that the HC1 solution recycled from the process in step d) is used for digestion the mixture of nickel and cobalt compounds in step a).

8. The method of claims 1-7, characterized in that digestion of the mixture of nickel and cobalt compounds in step a), activation in step b) and washing the column in step d) are carried out using the solution of HC1 having a concentration of 25-38 mass %.

9. The method of claims 1-8, characterized in that the solution of HC1 having a concentration of 25-38 mass % is recovered in steps f)-i).

10. The method of claims 1-9, characterized in that the diluted solution of HC1 having a concentration of 0.01-10 mass % is recovered in steps f)-i), which solution is used in step e).

11. The method of claims 1-10, characterized in that the extraction distillation in steps f)-h) is carried out with an addition of sulfuric(VI) acid having a concentration of 10-98 mass % in the mixture submitted to the distillation.

12. The method of claims 1-11, characterized in that the extraction distillation in steps f)-h) is carried out in the presence of nickel and cobalt ions having total concentration of at least 0.1 mass % in the mixture submitted to the distillation.