CA2413207C - Dissolution method of co precipitate with acid - Google Patents
Dissolution method of co precipitate with acid Download PDFInfo
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- CA2413207C CA2413207C CA2413207A CA2413207A CA2413207C CA 2413207 C CA2413207 C CA 2413207C CA 2413207 A CA2413207 A CA 2413207A CA 2413207 A CA2413207 A CA 2413207A CA 2413207 C CA2413207 C CA 2413207C
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- precipitate
- processing solution
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- acid
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B23/00—Obtaining nickel or cobalt
- C22B23/04—Obtaining nickel or cobalt by wet processes
- C22B23/0453—Treatment or purification of solutions, e.g. obtained by leaching
- C22B23/0461—Treatment or purification of solutions, e.g. obtained by leaching by chemical methods
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Removal Of Specific Substances (AREA)
Abstract
A dissolution method for Co precipitate containing at least Co and Fe hydroxides using acid, wherein the pH of the processing solution is kept in the range between 0.5 and 2.0, so that the Co dissolves into the processing solution together with the Fe, after which the pH of the processing solution is raised to the range between 2.0 and less than 3.0 to distribute the Fe preferentially into the precipitate.
Description
Title of the Invention Dissolution Method of Co Precipitate with Acid Background of the Invention Field of the Invention This invention relates to a dissolution method of dissolving Co precipitate, mainly comprised of Co and Fe hydroxides, with acid in nickel and cobalt refining.
Description of the Related Art Generally, in nickel refining, nickel matte having concentrated Ni is obtained from raw ore, and the metallic components such as Ni, Co and Fe are leached from this matte into a leaching liquid, then Co and Fe are removed as hydroxides from the obtained leaching liquid by an oxidation-neutralization method, and nickel is produced as pure nickel solution by electrolytic refining.
The Co precipitate mainly comprised of Co and Fe hydroxides that are removed by an oxidation-neutralization method from the leaching liquid is dissolved in sulfuric acid or hydrochloric acid, and then the obtained solution is used as the raw material for electrolytic cobalt or cobalt chemical products.
Recently, a solvent extraction method is widely used in the separation and refinement of cobalt from this solution, however, much of the organic solvent used industrially extracts Fe easier than Co. Accordingly, when processing the solution as is in the solvent extraction process, there is a problem occurring such as insufficient Co extract, the cobalt being the target metal, or having Fe concentrated in the organic solvent. Therefore, as shown in Fig. 4, normally there is an Fe removal process performed in the stage before the solvent extraction process, to remove the Fe from the solution by an oxidation-neutralization method.
As described above, the Fe removal process is indispensible in the stage before the solvent extraction process for separating and refining Co from the solution of Co precipitate. However, the amount of necessary equipment increases when setting up the Fe removal process. In addition, a neutralizing agent is necessary for removing Fe by the oxidation-neutralization method, so this brings about an increase in the cost of equipment as well as in operating costs.
Summary of the Invention An aspect of this invention relates to a method of processing the Co precipitate solution directly in the solvent extraction process without using the Fe removal process.
Brief Description of the Drawings Fig. 1 is a flowchart to show a selective solvent extraction process for cobalt precipitate solution with pH adjusted according to the present invention.
Fig. 2 is a graph to show a relationship between a dissolution pH and Fe concentration in a cobalt precipitate solution.
Fig. 3 is a graph to show a change in Co leaching ratio in a cobalt precipitate solution.
Fig. 4 is a flowchart to show the conventional process of cobalt solvent extraction for cobalt precipitation solution including a Fe-removal step.
Description of the Preferred Embodiments In the dissolution processing method of this invention for Co precipitate, Co precipitate containing at least Co and Fe hydroxides is dissolved by acid, wherein the pH of the processing solution is kept in the range between 0.5 and 2.0, and wherein the Co is dissolved by the processing solution together with the Fe, after which the pH of the processing solution is raised to the range between 2.0 and 3.0 to distribute the Fe first into a precipitate.
That is, it is desirable that the pH of the processing solution is once kept in the range between 0.5 and 2.0 by adding sulfuric acid or hydrochloric acid (plus reducing agent), and then after Fe and Co have been dissolved into the processing solution, Co precipitate, Co carbonate or Ni carbonate is added to raise the pH of the processing solution to the range between 2.0 and 3.0, to deposit the Fe in a precipitate. In this disclosure, the terms 'Dissolve' and 'Deposit' will be for the all or part of the Fe or Co depending on conditions.
With the process described above, Fe is, in effect, left remaining in the precipitate in a solid state, and part or substantially all of the Co is dissolved in the processing solution.
The Co and Fe in the Co precipitate exist as trivalent hydroxides. The reactions for dissolving these hydroxides are given in Equations 1 and 2.
Equation 1:
2Co (OH) 3+ 6H + + 2e - = 2Co 2+ + 6H,O
Equation 2:
Fe (OH) 3+ 3H += Fe 3+ + 3H2O
From these equations it can be seen that for Co it is possible to dissolve its hydroxide by lowering the pH and combining the equation with a reductive reaction, on the other hand, for Fe, it is possible to control its dissolution by exactly adjusting the pH.
Description of the Related Art Generally, in nickel refining, nickel matte having concentrated Ni is obtained from raw ore, and the metallic components such as Ni, Co and Fe are leached from this matte into a leaching liquid, then Co and Fe are removed as hydroxides from the obtained leaching liquid by an oxidation-neutralization method, and nickel is produced as pure nickel solution by electrolytic refining.
The Co precipitate mainly comprised of Co and Fe hydroxides that are removed by an oxidation-neutralization method from the leaching liquid is dissolved in sulfuric acid or hydrochloric acid, and then the obtained solution is used as the raw material for electrolytic cobalt or cobalt chemical products.
Recently, a solvent extraction method is widely used in the separation and refinement of cobalt from this solution, however, much of the organic solvent used industrially extracts Fe easier than Co. Accordingly, when processing the solution as is in the solvent extraction process, there is a problem occurring such as insufficient Co extract, the cobalt being the target metal, or having Fe concentrated in the organic solvent. Therefore, as shown in Fig. 4, normally there is an Fe removal process performed in the stage before the solvent extraction process, to remove the Fe from the solution by an oxidation-neutralization method.
As described above, the Fe removal process is indispensible in the stage before the solvent extraction process for separating and refining Co from the solution of Co precipitate. However, the amount of necessary equipment increases when setting up the Fe removal process. In addition, a neutralizing agent is necessary for removing Fe by the oxidation-neutralization method, so this brings about an increase in the cost of equipment as well as in operating costs.
Summary of the Invention An aspect of this invention relates to a method of processing the Co precipitate solution directly in the solvent extraction process without using the Fe removal process.
Brief Description of the Drawings Fig. 1 is a flowchart to show a selective solvent extraction process for cobalt precipitate solution with pH adjusted according to the present invention.
Fig. 2 is a graph to show a relationship between a dissolution pH and Fe concentration in a cobalt precipitate solution.
Fig. 3 is a graph to show a change in Co leaching ratio in a cobalt precipitate solution.
Fig. 4 is a flowchart to show the conventional process of cobalt solvent extraction for cobalt precipitation solution including a Fe-removal step.
Description of the Preferred Embodiments In the dissolution processing method of this invention for Co precipitate, Co precipitate containing at least Co and Fe hydroxides is dissolved by acid, wherein the pH of the processing solution is kept in the range between 0.5 and 2.0, and wherein the Co is dissolved by the processing solution together with the Fe, after which the pH of the processing solution is raised to the range between 2.0 and 3.0 to distribute the Fe first into a precipitate.
That is, it is desirable that the pH of the processing solution is once kept in the range between 0.5 and 2.0 by adding sulfuric acid or hydrochloric acid (plus reducing agent), and then after Fe and Co have been dissolved into the processing solution, Co precipitate, Co carbonate or Ni carbonate is added to raise the pH of the processing solution to the range between 2.0 and 3.0, to deposit the Fe in a precipitate. In this disclosure, the terms 'Dissolve' and 'Deposit' will be for the all or part of the Fe or Co depending on conditions.
With the process described above, Fe is, in effect, left remaining in the precipitate in a solid state, and part or substantially all of the Co is dissolved in the processing solution.
The Co and Fe in the Co precipitate exist as trivalent hydroxides. The reactions for dissolving these hydroxides are given in Equations 1 and 2.
Equation 1:
2Co (OH) 3+ 6H + + 2e - = 2Co 2+ + 6H,O
Equation 2:
Fe (OH) 3+ 3H += Fe 3+ + 3H2O
From these equations it can be seen that for Co it is possible to dissolve its hydroxide by lowering the pH and combining the equation with a reductive reaction, on the other hand, for Fe, it is possible to control its dissolution by exactly adjusting the pH.
Also, to adjust the pH, it is possible to use hydrochloric acid or sulfuric acid as a pH regulator. However, when sulfuric acid is used as a pH regulator, a reducing agent such as SO2 gas or sodium sulfite must be added to cause the Co dissolution reaction to progress. On the other hand, when hydrochloric acid is used as the pH regulator, chlorine ions are oxidized to be chlorine gas, so there is no need to add a reducing agent.
It is difficult to fix the Fe in the Co precipitate only by adding acid to simply lower the pH, because Fe is dissolved together with the Co. Therefore, the pH
is lowered once in the range from 0.5 to 2.0, and after the Co and Fe are dissolved, the pH is adjusted again using cobalt carbonate, nickel carbonate or Co precipitate in the range from 2.0 to 3Ø In doing this, the Co remains dissolved and the Fe is re-deposited. Utilizing the difference in the stability of Fe and Co hydfrooxides in this way is effective in preferentially to Fe in the precipitate first.
The ratio of leaching the cobalt does not become high even when the pH is kept between 2.0 and 3.0 without lowering it once to between 0.5 and 2Ø
The reactions above are given by Equations 3 to 6.
Equation 3:
M3++3CoCO3+3H+=M(OH)3+3CO2+3Co 2+
Equation 4:
M 3+ + 3NiCO3 + 3H += M(OH)3 + 3C02 + 3Ni `'+
Equation 5:
M 3+ + 3Ni (OH) 2+ 3H += M(OH)3 + 3Ni 2+ + 3H20 Equation 6:
MZ++Ni(OH)3 =M(OH)3+Niz+
Equation 3 shows the case of adjusting the pH with cobalt carbonate, Equation 4 shows the case of adjusting the pH with nickel carbonate, and Equations 5 and 6 shows the case of adjusting the pH with Co precipitate. In all of the equations, M is Fe or Co.
Using Co precipitate itself as the pH regulator has the objective of lowering the operating cost when compared to a method of adding new chemicals for regulating the pH. However, in this case, as shown in Equation 5 and Equation 6, it is necessary to include Ni divalent hydroxide and/or Ni trivalent hydroxide in the Co precipitate.
The nickel ions that are leached into the solution can be separated from cobalt in a solvent extraction process.
Example Co precipitate was made into a 400 g/L repulped slurry and hydrochloric acid was added to the slurry to adjust the pH. The Fe concentration in the slurry or solution is shown in Fig. 2 (plot 0). Also, the leaching ratio of Co is shown in Fig. 3 (plot =).
Also, Fig. 2 shows the change in Fe concentration of the slurry or solution when the pH was raised with Co precipitate (Co-ppt) after lowering the pH to 1.5 once (plot ^). Moreover, Fig. 3 shows the change in the Co leaching ratio (plot ^ shows the measurement results, and the dotted line represents the tendency of the change).
Furthermore, Fig. 2 shows the change in Fe concentration of the slurry or solution when the pH was raised with nickel carbonate (NiCO3) after lowering the pH to 1.5 once (plot 0). Moreover, Fig. 3 shows the change in the Co leaching ratio (plot L shows the measurement results, and the dotted line represents the tendency of the change).
As can be seen in Fig. 2, by adjusting the pH to 2.0 or higher, the Fe concentration becomes 0.1 g/L or less. Furthermore, by adjusting the pH to 2.5 or higher, the Fe concentration becomes 0.01 g/L or less. In this way, no matter what pH adjustment is performed, the Fe concentration takes a value that depends mainly on the pH, and it is seen that nearly all of the Fe is fixed in the precipitate.
However, it was not possible to obtain a sufficient dissolution rate in the pH
range of 2.0 to 3.0 only by adjusting the pH in this pH range by just adding acid, as it can be seen in Fig. 3 that the Co leaching ratio is about 20% at a pH of 2.0, and 5% or less at a pH of 2.5.
On the other hand, when the pH was adjusted in the range from 2.0 to 3.0 using Co precipitate (Co-ppt) after lowering the pH once in the range from 0.5 to 2.0 (plot ^), the Co leaching ratio was about 50% at a pH of 2.5.
Also, when the pH was adjusted to be in the range from 2.0 to 3.0 using nickel carbonate (NiCO3) after lowering the pH once in the range from 0.5 to 2.0 (plot A),the Co leaching ratio was about 90% at pH of 2.5. In comparison with the case of simply adding hydrochloric acid to adjust the pH to 2.5, a very good Co leaching ratio was obtained.
With the method of this invention, it becomes possible to easily remove Fe from a solution in which Co precipitate is dissolved, and thus it is possible to economically produce electrolytic Cobalt and Cobalt chemicals.
It is difficult to fix the Fe in the Co precipitate only by adding acid to simply lower the pH, because Fe is dissolved together with the Co. Therefore, the pH
is lowered once in the range from 0.5 to 2.0, and after the Co and Fe are dissolved, the pH is adjusted again using cobalt carbonate, nickel carbonate or Co precipitate in the range from 2.0 to 3Ø In doing this, the Co remains dissolved and the Fe is re-deposited. Utilizing the difference in the stability of Fe and Co hydfrooxides in this way is effective in preferentially to Fe in the precipitate first.
The ratio of leaching the cobalt does not become high even when the pH is kept between 2.0 and 3.0 without lowering it once to between 0.5 and 2Ø
The reactions above are given by Equations 3 to 6.
Equation 3:
M3++3CoCO3+3H+=M(OH)3+3CO2+3Co 2+
Equation 4:
M 3+ + 3NiCO3 + 3H += M(OH)3 + 3C02 + 3Ni `'+
Equation 5:
M 3+ + 3Ni (OH) 2+ 3H += M(OH)3 + 3Ni 2+ + 3H20 Equation 6:
MZ++Ni(OH)3 =M(OH)3+Niz+
Equation 3 shows the case of adjusting the pH with cobalt carbonate, Equation 4 shows the case of adjusting the pH with nickel carbonate, and Equations 5 and 6 shows the case of adjusting the pH with Co precipitate. In all of the equations, M is Fe or Co.
Using Co precipitate itself as the pH regulator has the objective of lowering the operating cost when compared to a method of adding new chemicals for regulating the pH. However, in this case, as shown in Equation 5 and Equation 6, it is necessary to include Ni divalent hydroxide and/or Ni trivalent hydroxide in the Co precipitate.
The nickel ions that are leached into the solution can be separated from cobalt in a solvent extraction process.
Example Co precipitate was made into a 400 g/L repulped slurry and hydrochloric acid was added to the slurry to adjust the pH. The Fe concentration in the slurry or solution is shown in Fig. 2 (plot 0). Also, the leaching ratio of Co is shown in Fig. 3 (plot =).
Also, Fig. 2 shows the change in Fe concentration of the slurry or solution when the pH was raised with Co precipitate (Co-ppt) after lowering the pH to 1.5 once (plot ^). Moreover, Fig. 3 shows the change in the Co leaching ratio (plot ^ shows the measurement results, and the dotted line represents the tendency of the change).
Furthermore, Fig. 2 shows the change in Fe concentration of the slurry or solution when the pH was raised with nickel carbonate (NiCO3) after lowering the pH to 1.5 once (plot 0). Moreover, Fig. 3 shows the change in the Co leaching ratio (plot L shows the measurement results, and the dotted line represents the tendency of the change).
As can be seen in Fig. 2, by adjusting the pH to 2.0 or higher, the Fe concentration becomes 0.1 g/L or less. Furthermore, by adjusting the pH to 2.5 or higher, the Fe concentration becomes 0.01 g/L or less. In this way, no matter what pH adjustment is performed, the Fe concentration takes a value that depends mainly on the pH, and it is seen that nearly all of the Fe is fixed in the precipitate.
However, it was not possible to obtain a sufficient dissolution rate in the pH
range of 2.0 to 3.0 only by adjusting the pH in this pH range by just adding acid, as it can be seen in Fig. 3 that the Co leaching ratio is about 20% at a pH of 2.0, and 5% or less at a pH of 2.5.
On the other hand, when the pH was adjusted in the range from 2.0 to 3.0 using Co precipitate (Co-ppt) after lowering the pH once in the range from 0.5 to 2.0 (plot ^), the Co leaching ratio was about 50% at a pH of 2.5.
Also, when the pH was adjusted to be in the range from 2.0 to 3.0 using nickel carbonate (NiCO3) after lowering the pH once in the range from 0.5 to 2.0 (plot A),the Co leaching ratio was about 90% at pH of 2.5. In comparison with the case of simply adding hydrochloric acid to adjust the pH to 2.5, a very good Co leaching ratio was obtained.
With the method of this invention, it becomes possible to easily remove Fe from a solution in which Co precipitate is dissolved, and thus it is possible to economically produce electrolytic Cobalt and Cobalt chemicals.
Claims (3)
1. A dissolution method for Co precipitate containing at least Co and Fe hydroxides, comprising the step of dissolving the Co precipitate with acid to form a processing solution, wherein the pH of the processing solution is kept in the range between 0.5 and 2.0, so that Fe and Co are dissolved into the processing solution, and then the pH of the processing solution is raised to the range between 2.0 and 3.0 to deposit the Fe.
2. A dissolution method for Co precipitate containing at least Co and Fe hydroxides comprising the step of dissolving the Co precipitate with acid to form a processing solution, wherein the pH of the processing solution is kept in the range between 0.5 and 2.0 by adding sulfuric acid plus a reducing agent or by adding hydrochloric acid, so that Fe and Co are dissolved into the processing solution, and one of Co precipitate, Co carbonate or Ni carbonate is added to raise the pH of the processing solution to the range between 2.0 and 3.0 to deposit the Fe.
3. The dissolution method of claim 2, wherein the Co precipitate added to raise the pH of the processing solution to the range between 2.0 and 3.0 further comprises at least one of Ni divalent hydroxide and Ni trivalent hydroxide.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001-364006 | 2001-11-29 | ||
| JP2001364006A JP4035985B2 (en) | 2001-11-29 | 2001-11-29 | Method for dissolving Co precipitate with acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2413207A1 CA2413207A1 (en) | 2003-05-29 |
| CA2413207C true CA2413207C (en) | 2010-07-27 |
Family
ID=19174254
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2413207A Expired - Fee Related CA2413207C (en) | 2001-11-29 | 2002-11-28 | Dissolution method of co precipitate with acid |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP4035985B2 (en) |
| AU (1) | AU2002308793B2 (en) |
| CA (1) | CA2413207C (en) |
| GB (1) | GB2382573B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6760793B2 (en) * | 2016-08-03 | 2020-09-23 | Ｊｘ金属株式会社 | How to recover valuable metals from cobalt / tungsten raw materials |
| CN107881341A (en) * | 2017-12-08 | 2018-04-06 | 上海产业技术研究院 | Method of comprehensive utilization based on hydrometallurgical processes middle and high concentration sodium sulfate wastewater |
| CN111826523B (en) * | 2020-06-28 | 2022-07-15 | 广东邦普循环科技有限公司 | Method for refining nickel hydroxide cobalt |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU1332830A1 (en) * | 1985-07-23 | 1992-08-07 | Государственный проектный и научно-исследовательский институт "Гипроникель" | Method of ferrocobaltic hydrate cakes |
| RU2041276C1 (en) * | 1988-11-30 | 1995-08-09 | Институт металлофизики АН Украины | Cobalt cake reprocessing method |
| JP3385997B2 (en) * | 1999-02-12 | 2003-03-10 | 大平洋金属株式会社 | Method of recovering valuable metals from oxide ore |
-
2001
- 2001-11-29 JP JP2001364006A patent/JP4035985B2/en not_active Expired - Fee Related
-
2002
- 2002-11-28 CA CA2413207A patent/CA2413207C/en not_active Expired - Fee Related
- 2002-11-28 GB GB0227732A patent/GB2382573B/en not_active Expired - Fee Related
- 2002-11-28 AU AU2002308793A patent/AU2002308793B2/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| JP2003166022A (en) | 2003-06-13 |
| GB2382573B (en) | 2005-09-14 |
| GB0227732D0 (en) | 2003-01-08 |
| JP4035985B2 (en) | 2008-01-23 |
| GB2382573A (en) | 2003-06-04 |
| CA2413207A1 (en) | 2003-05-29 |
| AU2002308793B2 (en) | 2007-10-04 |
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| EEER | Examination request | ||
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Effective date: 20201130 |