KR102041294B1 - Method for recovering covalt from solution comprising covalt, nickel and iron - Google Patents

Abstract

The present invention relates to a method for recovering cobalt from the filtrate remaining in the process of recovering nickel from the ore with high purity, wherein the precipitated filtrate generated in the process of recovering nickel from low-grade nickel ore is applied to the cation exchange resin to cobalt and nickel A cation exchange step of obtaining a solution comprising a, a decarburization step of removing iron from the solution containing the cobalt and nickel to obtain a iron removal solution, by adding a cation extractant to the iron removal solution to obtain an extract solution containing cobalt and Recovering nickel from low-grade nickel ores, including solvent extraction and stripping to obtain a cobalt solution in the aqueous phase by removing cobalt from the extraction solution, and a concentrated crystallization step of concentrating and crystallizing the solution containing the cobalt. From the precipitated filtrate that occurs during the process It provides a method for recovering a bit.

Description

Cobalt recovery method from precipitated filtrate in nickel smelting process {METHOD FOR RECOVERING COVALT FROM SOLUTION COMPRISING COVALT, NICKEL AND IRON}

The present invention relates to a method for recovering cobalt with high purity from the precipitated filtrate remaining in the process of recovering nickel from the ore.

Due to the depletion of high-grade ores including nickel, there is a growing interest in techniques for recovering cobalt from ores containing low-grade nickel, and the development of these technologies is in progress or some technologies are commercially available.

The related art is a method of extracting cobalt from low-grade nickel ores at high temperature and high pressure (HPAL Process, High Pressure Acid Leaching Process). However, since this technology proceeds under high temperature and high pressure, there are many difficulties in operation and maintenance.

As another technique, a technique for recovering nickel from low grade nickel oxide ore has been developed (Korean Patent Application No. 2010-0128249), which is produced in the previous process after reducing low grade nickel oxide ore with hydrogen and leaching with hydrochloric acid. Part of the reduced light is used as seed light to go through the precipitation process. After the precipitation process, the solid solution is separated into the precipitate cake and the precipitate filtrate.

At this time, the precipitation filtrate after the precipitation process contains an excessive amount of iron, and contains a trace amount of nickel and cobalt not precipitated. Therefore, there is a demand for the development of a technique for recovering cobalt with high purity from a precipitate filtrate containing a small amount of cobalt.

As a technique for this, conventionally, as shown in FIG. 1, cobalt is extracted into the organic phase by solvent extraction with respect to a mixed solution of cobalt, nickel, and iron, and includes washing to remove nickel extracted together. Thereafter, a technique of back extracting cobalt from an organic phase to obtain an aqueous phase has been applied. However, this conventional technique requires the step of cleaning the nickel before back-coating the cobalt of the organic phase into the water phase.

The present invention seeks to provide a technique for effectively recovering cobalt from a low grade nickel oxide ore having a low cobalt content.

Specifically, it is to provide a method for recovering a high concentration of the cobalt remaining in the precipitate filtrate without precipitation in the precipitation process according to the nickel wet smelting process from the precipitation filtrate.

Furthermore, the present invention is to provide a method that can simplify the process by eliminating the washing step for the removal of Ni in the solvent extraction process.

The present invention relates to a method for recovering cobalt from the precipitated filtrate generated in the process of recovering nickel from a low-grade nickel ore, according to an embodiment of the present invention, by applying to a cation exchange resin solution containing cobalt and nickel Obtaining cation exchange step, the iron removal step to remove the iron from the solution containing the cobalt and nickel to obtain a iron removal solution, a cation extractant is added to the iron removal solution to obtain an extraction solution containing cobalt, from the extraction solution Solvent extraction and stripping step of removing the cobalt by the stripping solution to obtain a cobalt solution of the water phase and a concentrated crystallization step of concentrating and crystallizing the solution containing the cobalt.

The cation extractant may be 0.2M bis (2,4,4-trimethylpentyl) phosphinic acid (CYANEX 272), 0.2M bis (2,4,4-trimethylpentyl) phosphinic acid (CYANEX 272) and It may be to include a 0.8M saponifier.

The cationic extractant is preferably added so that the volume ratio of the organic phase and the aqueous phase is 4: 1 or more ratio.

The stripping solution may be at least 0.3% sulfuric acid solution.

The concentrated crystallization step is preferably carried out at 30 to 40 ℃ temperature, 44 to 67 mbar vacuum conditions.

The low quality nickel ore may be limonite.

The precipitate filtrate may be produced after hydrogen reduction, leaching, neutralization and precipitation of nickel laterite ore.

The iron removal step may be performed by maintaining and maintaining a nitrogen atmosphere to adjust and maintain the pH of the precipitate filtrate in the range of 3 to 5.

The pH of the precipitate filtrate can be adjusted by the addition of a neutralizing agent selected from the group consisting of sodium hydroxide, magnesium hydroxide, calcium hydroxide, magnesium oxide and calcium oxide.

According to the present invention, there is provided a method for recovering high-purity cobalt sulfate from a precipitate filtrate having a small amount of cobalt, as well as eliminating the need for removing nickel in the stripping process after solvent extraction, eliminating the cleaning process to remove nickel. The process can be simplified.

1 is a view schematically showing a process for recovering cobalt from the precipitate filtrate according to the prior art.
2 is a view schematically showing a process for recovering cobalt from the precipitate filtrate according to the present invention.
3 is an XRD result showing a crystal phase of a cobalt crystal obtained by the crystallization process.

A precipitation step of precipitating nickel into the seed light from the leachate obtained in hydrochloric acid by using a portion of the reduced light prepared in the reduction step by washing with water, after reducing low-grade nickel oxide ore with hydrogen and leaching with hydrochloric acid. Illustrating a representative composition of the precipitate filtrate generated after recovering the nickel by the Table 1 below.

Precipitation Filtrate (ppm) Fe Co Ni No. One 97,670 302 275 No. 2 94,863 368 55

The present invention is to provide a method for recovering cobalt with high purity from a mixed solution such as precipitated filtrate containing a large amount of iron and a small amount of nickel and cobalt as shown in Table 1.

The cobalt recovery method according to the present invention includes an ion exchange step, a degassing step, a solvent extraction step, and a crystallization step. Hereinafter, the present invention will be described in more detail with reference to the drawings.

(1) ion exchange step

The ion exchange process of the present invention can be carried out by a conventional ion exchange process, but is not particularly limited, but includes, for example, adsorption, backwashing, desorption, and washing.

The adsorption process is a adsorption process (Servicing) for adsorbing cobalt and nickel ions to the ion exchange resin by passing the precipitated filtrate through the ion exchange column filled with the ion exchange resin.

As a method for selectively recovering cobalt and nickel from the precipitate filtrate as shown in Table 1, first, an ion exchange process (Ion exchange process, IX process) is performed. The ion exchange process may selectively recover cobalt and nickel from the precipitate filtrate.

It is important to select the ion exchange resin to be used in the ion exchange process of the present invention. For the selective recovery of cobalt and nickel by the ion exchange process, it is important to select an appropriate ion exchange resin. Suitable ion exchange resins for the selective recovery of cobalt and nickel may be chelate exchange resins capable of adsorbing cobalt and nickel, for example bis-picolylamine or multi-dentate amine ligands ( multi-dendate amine ligand). Specifically, the chelate exchange resin may be Lanxess's TP 220 (Lewatit® MonoPlus TP 220), TP207 or TP227, Purolite's S957 or S950, DOW's DOWEX M4195 or PFA600, preferably TP 220.

Since the residual iron content is high in the solution remaining after the ion exchange process, it is preferable to recover the iron in the form of iron oxide through crystallization and roasting. Therefore, as the ion exchange resin to be applied to the ion exchange process of the present invention, it is more preferable to use an ion exchange resin which can be carried out under conditions without loss of iron components. Such an ion exchange resin may be, for example, TP200.

The ion exchange resin as described above adsorbs metal ions in the order of Cu ^{2 +} > Pb ^{2 +} > Ni ^{2 +} > Fe ^{3 +} > Zn ^{2 +} > Co ^{2 +} > Cd ^{2 +} > Fe ^{2 +} > Cr ³⁺ . . There is low - grade waste liquid generated during the process of recovery of nickel, cobalt, nickel and iron-containing nickel from the ore, in the case of the iron due to the presence of most of the ions Fe ^{2 +} in solution form, which is not adsorbed, partially oxidized Fe ³⁺ When cobalt and nickel are adsorbed, a high concentration of Fe ²⁺ is adsorbed.

If the filtrate is precipitated nopeunde the content of Fe, Fe ^{+ 2} is oxidized to Fe ^{+ 3} is because the amount of the iron ion to be adsorbed on the ion exchange resin is increased, it is preferable to avoid this. Thus, the reactor and lines in the process are preferably maintained in a nitrogen atmosphere. Nitrogen gas may be purged into the reactor and the line to maintain the atmosphere.

In adsorbing cobalt and nickel ions from the precipitate filtrate, the precipitate filtrate preferably has a pH in the vicinity of pH 4, specifically, in the range of 3 to 5. Cobalt and nickel ions are adsorbed because the leaching filtrate recovered through the leaching process is raised to pH 4 using a neutralizing agent such as Mg (OH) ₂ , CaO, Fe (OH) ₂ , and removes impurities such as Al and is used in the precipitation process. Precipitation filtrate used in the process can be maintained near pH 4. When the pH of the precipitated filtrate has such conditions, the adsorption rate of Co and Ni ions increases.

In addition, the precipitation filtrate may range from 40 to 65 ℃. The precipitated filtrate is usually formed after the precipitation process with the remaining filtrate after the precipitation process is a temperature of 60 ℃ level is formed. Lowering or increasing the temperature of a large amount of precipitated filtrate may be expensive and may cause an increase in manufacturing cost. Therefore, it is preferable to use the incoming precipitated filtrate as it is without cooling or heating. It is preferable to use the precipitation filtrate.

The adsorption process may be performed by passing the precipitated filtrate through an ion exchange resin. The precipitated filtrate may vary depending on the flow rate and the bed volume (Bed volume, Bv), is not particularly limited. For example, when the bed volume in which the adsorption process is performed is 0.3 m3, the adsorption process may set the supply flow rate of the precipitated filtrate to 10 to 15 Bv / hr. Therefore, as an embodiment, the precipitate filtrate may be supplied at a flow rate of 3.6 m 3 / hr.

The backwashing process is a process of washing the precipitated filtrate from the ion exchange resin after adsorbing cobalt and nickel to the ion exchange resin. The backwashing process may be washed using distilled water.

The desorption process is a process of desorbing the adsorbed cobalt and nickel ions from the ion exchange resin. For example, the desorption may pass 6% of HCl through the ion exchange resin to desorb the ions adsorbed on the ion exchange resin.

Further, the cleaning process may be a cleaning process (Rinsing) to remove the desorption liquid. After the desorption, it can be washed with distilled water.

B. Deferring

Precipitating the filtrate is higher that the concentration of Fe ^{2 +} ions. The iron ions are adsorbed to the ion exchange resin adsorption rate is very low, but, in the step of adsorption by the cobalt and nickel ions from the filtrate to precipitate the ion exchange resin, and Fe ^{3 +} Fe ^{2 +} ions are adsorbed together. These iron ions are adsorbed at a content similar to the combined content of cobalt and nickel ions. Therefore, the proportion of iron ions in the solution obtained by ion exchange is high. Therefore, in order to recover high purity cobalt ions, it is preferable to remove iron ions.

After oxidizing the Fe ^{2 +} ions contained in the solution obtained in the ion exchange step, the Fe ^{3 +} compound having a low solubility may be generated through neutralization, and then removed through a filtration process. This decarburization step is a conventional process in the process of extracting expensive metal components, and is not particularly limited.

For example, for the oxidation of Fe ^{2 +} in the solution to Fe ^{+ 3,} it may be used sodium hypochlorite (NaOCl) or hydrogen peroxide. The oxidizing agent may be used in an amount of 1 to 1.5 equivalents, preferably 1.1 equivalents, relative to the amount of Fe contained in the solution containing cobalt and nickel, and the reaction time is 10 minutes to 60 minutes, preferably 20 minutes to 40 minutes. Minutes, most preferably 30 minutes.

Next, Fe ^{+ 3} in the solution may be precipitated in the form of Fe (OH) _3. To this end, the pH of the solution containing cobalt and nickel can be adjusted in the range of 3.0 to 4.5. For the adjustment of the pH, bases such as sodium hydroxide, magnesium hydroxide, calcium hydroxide, magnesium oxide, calcium oxide can be used. For example, 10% of sodium hydroxide may be used to precipitate Fe, and the iron component precipitated by solid-liquid separation may be removed to obtain a deironed filtrate.

On the other hand, the iron removal filtrate obtained by the iron removal step is an alkali metal or alkaline earth metal which is mainly a Co and Ni ions and a neutralizer component used in the iron removal process. Since these alkali metals or alkaline earth metals have a difference in precipitation pH ranges with hydroxides of Co and Ni, the alkali metals or alkaline earth metals can be removed using the same.

C. Solvent Extraction Step

The solvent extraction step is performed using the cobalt nickel-containing solution obtained in the de-ironing step as a raw material solution. In the solvent extraction step, a cation extracting solvent may be used as a step of extracting a metal ion existing as a cation in a raw material solution through an exchange reaction.

As the cation extracting solvent, one commonly used may be applied to the present invention. For example, Cyanex 272 may be used.

Cationic extraction solvents are usually used after dilution to a specific concentration through a diluent, such diluents include, for example, kerosene. The extractant by the cation extracting solvent and the diluent usually has a specific gravity lower than that of water and thus floats in water and is commonly referred to as an organic phase.

The extraction reaction of the solvent extractant has an equilibrium reaction, and the reaction formula is shown in the following reaction formula.

M ²⁺ + 2 (HA) ₂ ↔ MA ₂ (AH) ₂ + 2H ⁺ (A = R ₂ PO ₂ )

M: metal ion, HA: cationic extraction solvent

As shown in the above scheme, when the metal ion is extracted with the cation extraction solvent, H ⁺ ions are generated, and thus the pH of the solution is lowered. The extraction rate of the solvent extraction process varies depending on the pH.

In general, the organic phase is mixed with the aqueous phase in which the metal ions are present to extract the metal ions of the aqueous phase into the organic phase (extraction process) or the reverse extraction (scrubbing process and stripping process). Will go through.

The ratio of the concentration of a specific element present in the organic phase to the concentration of a specific metal present in the water phase is called a distribution coefficient, and the ratio of the distribution coefficient between two specific metals is called a separation factor. The solvent extraction process is usually purified by using a counter-current multi-stage mixed settler (Mixer-settler) using the difference in the separation coefficient.

However, process factors such as the type of extractant, the mixing ratio of the aqueous phase and the organic phase (mixing ratio of the aqueous phase and the organic phase: A / O ratio), the concentration of the aqueous phase, the concentration of the organic phase, and the degree of saponification and the pH after extraction, Therefore, the degree of extraction (extraction rate) varies for each metal ion. For this reason, a washing process is required in order to remove the unwanted nickel after solvent extraction.

The present inventors have conducted research on this, by mixing the saponification agent in a predetermined range by adding an extraction solvent and adding the organic phase after the saponification in a volume ratio of 4 or more (ie, O / A ratio 4 or more) with respect to the volume of the aqueous phase. It was confirmed that cobalt can be recovered as an aqueous phase by selectively extracting the desired cobalt from the nickel and cobalt present in the raw material solution into the organic phase, and then controlling the concentration of the stripping solution. As a result, most of the nickel can be recovered from the extracted organic phase by remaining in the organic phase.

Preferably, the extraction solvent is subjected to a saponification process using a saponification agent to reduce the change of solvent extraction according to pH. The extraction solvent which has undergone the saponification process is present in the form of monomer and participates in the extraction reaction.

The reaction formula of the saponified extractant is subjected to the reaction as shown in the following scheme, and the change in pH is less than when not saponified.

^{Mi 2 + + A - + 2} (HA) 2 ↔ MiA 2 · (HA) 3 + H +

Saponification of the solvent extractant behavior for the saponification reaction can maintain the extraction rate in the solvent extraction. That is, the pH of each extraction stage can be kept constant, and the distribution coefficient and separation coefficient of the saponified extractant can be improved.

Examples of the saponifying agent include NaOH. When using the saponification agent, the saponification agent and the extraction solvent is preferably mixed to have a molar ratio of 0.6 to 0.9: 0.4 to 0.1. Preferably 0.7 to 0.9: 0.3 to 0.1, most preferably the saponification agent and the extraction solvent may have a molar ratio of 0.8: 0.2.

The saponification process in the solvent extraction process is a process necessary to improve the performance of the solvent extraction, but can not increase the performance of the solvent extraction agent by increasing the saponification rate. This is due to the micelle and solidification. Depending on the mixing ratio of the saponification rate or the saponification agent (NaOH) and the organic phase as the solvent extractant, the organic phase is mixed into the aqueous phase or the Michel phenomenon or the solidification of the extractant is mixed. If the degree of saponification is low, the pH of the aqueous phase may be lowered and the extraction rate may be lowered. Therefore, it is preferable to supply a saponifier in the above range.

After saponifying the above extraction solvent, the organic phase of the extraction solvent may be mixed with the aqueous phase in a volume ratio of at least 4: 1 (O / A ratio 4/1) to recover cobalt from the aqueous phase as a whole organic phase. When the O / A ratio is less than 4: 1, the cobalt extraction rate from the water phase to the organic phase is low, which is not preferable. More preferably, the O / A ratio may be in the range of 4 to 10: 1, for example, 4: 1 or more, 5: 1, 6: 1, 7: 1, 8: 1 or 10: 1 or less. .

After performing solvent extraction using the above extraction solvent or saponified extraction solvent, the organic phase may be separated and recovered, and the cobalt may be recovered as an aqueous phase by removing the extraction solvent without a washing process.

According to the present invention, when stripped using 0.3% or more sulfuric acid, it can be recovered from the organic phase obtained by solvent extraction, wherein a small amount of nickel present in the extracted organic phase is not recovered as an aqueous phase. Therefore, a separate washing step for removing nickel can be omitted, and the process can be simplified. More preferably sulfuric acid having a concentration of 0.3 to 0.35% can be used.

D. Crystallization Step

The crystallization step is a step of evaporating a highly purified CoSO ₄ solution through ion exchange, Fe removal, and solvent extraction to form a supersaturated solution, and crystallizing it in the form of a hydrate of CoSO ₄ · xH ₂ O using a difference in solubility according to temperature. .

The solution containing cobalt, ie CoSO ₄ solution, can be concentrated using a reduced pressure evaporator, and the concentrated solution is gradually lowered to obtain a crystalline state, i.e., CoSO ₄ · 7H ₂ O, by solubility difference. Can be.

The crystallization step may obtain cobalt sulfate crystals by lowering the temperature of the solution from 60 to 90 ℃ to 30 to 40 ℃, vacuum evaporation crystallization at 44 to 67 mbar vacuum conditions.

The process diagram for performing the method according to the present invention as described above is schematically shown in FIG. As can be seen from FIG. 2, according to the present invention, cobalt can be recovered with high purity by performing a stripping process immediately after solvent extraction, and thus, a washing step for cleaning nickel can be omitted.

Example

Hereinafter, an Example is given and this invention is demonstrated more concretely. The following examples are examples of the present invention, and the present invention is not intended to be limited thereby.

1. Ion Exchange

The precipitation filtrate of Table 1 was maintained in a N ₂ gas atmosphere to maintain a pH of 4.5.

In order to recover Co and Ni in the precipitated filtrate, the precipitated filtrate was loaded at a rate of 3.6m 3 / hr for 40 minutes in two towers filled with 15 L of TP 220 (Lewatit® MonoPlus TP 220) ion exchange resin per tower. And Ni was adsorbed onto the resin (adsorption step).

Thereafter, distilled water was washed at a rate of 3.6 m 3 / hr for 10 minutes to wash the resin (backwashing step).

Then, 6% of HCl was passed for 20 minutes at a rate of 2.7 m 3 / hr per hour to desorb the ions adsorbed on the resin (desorption step).

The desorption solution was washed by passing distilled water through the desorption solution at a rate of 3.6 m 3 / hr for 30 minutes (washing).

As a result of analyzing the components of the desorption solution after washing, it was confirmed that Fe, Ni and Co components were contained as shown in Table 2.

Fe Co Ni Desorbent (ppm) 2,744 2,149 441

2. Decarrying

Sodium hyperchlorite (NaOCl; 1.1 equivalent to Fe content in the solution) was added to the desorption solution of Table 2 and stirred for 30 minutes. Then, the pH was adjusted to 4.0 by adding 10% NaOH. When the pH was stabilized, the mixture was stirred for 1 hour at room temperature.

When the reaction was completed, the solid-liquid separation to remove iron in the form of Fe (OH) ₃ cake, to obtain a de-iron filtrate.

As a result of analyzing the iron removal filtrate recovered through the iron removal process, it was confirmed that the Fe, Ni, Co components are contained as shown in Table 3.

Fe Co Ni Final pH Decarburization aftertreatment (ppm) <10 1,610 448 5.5

3. Solvent Extraction

(1) saponification process

The solution shown in Table 3 was used as a raw material solution, and Cyanex 272 was used as an extraction solvent, and the solvent extraction was carried out at a concentration ratio as shown in Table 4 (the remainder of 1M is NaOH as a saponification agent) to a volume ratio of O / A ratio 1. Was performed.

The concentrations of cobalt and nickel present in the aqueous phase thus obtained were analyzed, and the results are shown in Table 4.

Solution composition cobalt nickel Remarks Raw material solution Awards 1610 448 - Extraction Solvent (Cyanex 272)
Input condition 0.2M Organic phase 730 68 Example 1 Awards 880 380 0.3M Organic phase 1610 444 Example 2 Awards <1 4.3 0.4M Organic phase 1610 446 Example 3 Awards <1 1.7 0.5M Organic phase 1610 338 Example 4 Awards <1 <1

As can be seen from Table 4, it was confirmed that the highest solvent extraction results when the concentration of the extraction solvent is 0.2M, through which the concentration of the extractant Cyanex272 was selected to 0.2M.

(2) extraction process

Extractant mixing conditions were selected from the results of Table 4, saponified NaOH 0.8M and extraction solvent Cyanex272 0.2M.

As shown in Table 5 below, the desulfurization solution of Table 3 was mixed with an extractant to obtain a volume ratio (O / A ratio) of the organic phase and the aqueous phase, and solvent extraction was performed.

After solvent extraction, the content of Co and Ni in the aqueous phase was analyzed, and the results are shown in Table 5.

Input condition Award (ppm) Extraction rate (%) Remarks Co Ni Co Ni O / A = 1 880 380 45.3 15.2 Example 5 O / A = 2.5 655 425 59.3 5.1 Example 6 O / A = 3 530 429 67.1 4.2 Example 7 O / A = 4 183 424 88.6 5.4 Example 8

As can be seen from Table 5, when the O / A ratio is 4, the ratio of cobalt in the organic phase to high conversion is high, whereas nickel is hardly converted into the aqueous phase.

Therefore, the ratio of O / A was selected to four.

(3) cleaning / removal process

The organic phase obtained in Example 8 of Table 5 was stripped using a sulfuric acid solution. At this time, sulfuric acid having a concentration as shown in Table 6 was used as the stripping solution.

The aqueous phase thus obtained was analyzed and the results are shown in Table 6.

Cleaning solution Award (ppm) Extraction rate (%) Remarks Co Ni Co Ni H ₂ SO ₄ 0.15% 1009 <10 66.3 - Example 9 H ₂ SO ₄ 0.30% 1521 <10 About 100 - Example 10

As can be seen from Table 6, Co was almost 100% stripped by the sulfuric acid stripping solution, it can be seen that the nickel is hardly stripped. From these results, it can be seen that in the case of using sulfuric acid with a concentration of 0.3% or more, Ni can be selectively recovered in the aqueous phase while remaining in the organic phase.

Therefore, according to the present invention, it can be seen that the removal process can be performed immediately after the extraction is omitted.

(4) crystallization

The solution obtained in the stripping process using 0.3% or more sulfuric acid of Example 10 was subjected to vacuum evaporation crystallization at 40 ° C. and 67 mbar vacuum degree using a rotary evaporator to obtain high-purity cobalt sulfate crystals.

The crystals thus obtained were analyzed and the results are shown in Table 7 below.

Na Ni Co decision (%) 0.020 0.038 20.9

In addition, the analysis result of the crystal phase by XRD about the obtained crystal is shown in FIG.

Claims (10)

A cation exchange step of applying a precipitate filtrate generated in the process of recovering nickel from a low-grade nickel ore to a cation exchange resin to obtain a solution containing cobalt and nickel;
A iron removal step of removing iron from the solution containing cobalt and nickel to obtain a iron removal solution;
A saponified cation extractant was added to the de-iron solution such that the volume ratio of the organic phase and the aqueous phase was 4: 1 to 10: 1 to obtain an extract solution containing cobalt, and the sulfuric acid solution having a concentration of 0.3% or more from the extract solution without washing. Solvent extraction and stripping step of removing the cobalt by the stripping solution to obtain a cobalt solution of the water phase; And
Concentrated crystallization step of concentrating and crystallizing the solution containing the cobalt
A method for recovering cobalt from the precipitated filtrate generated in the process of recovering nickel from a low-quality nickel ore comprising a. delete 2. The method of claim 1 wherein the saponified cation extractant comprises nickel from low quality nickel ores comprising 0.2 M bis (2,4,4-trimethylpentyl) phosphinic acid (CYANEX 272) and 0.8 M saponification agent. A method for recovering cobalt from the precipitated filtrate generated during the recovery process. delete delete The method of claim 1, wherein the concentrated crystallization step is performed at a temperature of 30 to 40 ° C. and 44 to 67 mbar vacuum conditions to recover cobalt from the precipitated filtrate generated in the process of recovering nickel from the low quality nickel ore. The method of claim 1, wherein the cobalt is recovered from the precipitate filtrate generated in the process of recovering nickel from the low grade nickel ore, wherein the low grade nickel ore is limonite. The method of claim 1, wherein the precipitated filtrate is produced after hydrogen reduction, leaching, neutralization, and precipitation of nickel laterite ore. The method of recovering cobalt from the precipitated filtrate generated in the process of recovering nickel from a low quality nickel ore. The method of claim 1, wherein the iron removal step is performed by maintaining and maintaining a nitrogen atmosphere to adjust and maintain the pH of the precipitate filtrate in the range of 3 to 6 cobalt from the precipitated filtrate generated in the process of recovering nickel from the low quality nickel ore How to recover. 10. The method of claim 9, wherein the pH of the precipitated filtrate is adjusted by the addition of a neutralizing agent selected from the group consisting of sodium hydroxide, magnesium hydroxide, calcium hydroxide, magnesium oxide and calcium oxide. A method for recovering cobalt from the precipitated filtrate generated.

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