OA21089A - Process for the recovery of metals from oxidic ores. - Google Patents
Process for the recovery of metals from oxidic ores. Download PDFInfo
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- OA21089A OA21089A OA1202200047 OA21089A OA 21089 A OA21089 A OA 21089A OA 1202200047 OA1202200047 OA 1202200047 OA 21089 A OA21089 A OA 21089A
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- 238000000034 method Methods 0.000 title claims abstract description 44
- 238000011084 recovery Methods 0.000 title claims abstract description 14
- 229910052751 metal Inorganic materials 0.000 title abstract description 9
- 239000002184 metal Substances 0.000 title abstract description 9
- 150000002739 metals Chemical class 0.000 title abstract description 9
- 229910052742 iron Inorganic materials 0.000 claims abstract description 40
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 40
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 29
- 238000002425 crystallisation Methods 0.000 claims abstract description 16
- 230000008025 crystallization Effects 0.000 claims abstract description 16
- 229910052802 copper Inorganic materials 0.000 claims abstract description 11
- 150000001875 compounds Chemical class 0.000 claims description 21
- 238000006386 neutralization reaction Methods 0.000 claims description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 7
- 150000004649 carbonic acid derivatives Chemical class 0.000 claims description 7
- 230000002378 acidificating effect Effects 0.000 claims description 6
- 235000011149 sulphuric acid Nutrition 0.000 claims description 5
- 125000000101 thioether group Chemical group 0.000 claims description 5
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 3
- 150000004679 hydroxides Chemical class 0.000 claims description 3
- 238000001223 reverse osmosis Methods 0.000 claims description 3
- 238000005363 electrowinning Methods 0.000 claims description 2
- 238000000605 extraction Methods 0.000 claims description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims 1
- 229910052791 calcium Inorganic materials 0.000 claims 1
- 239000011575 calcium Substances 0.000 claims 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 claims 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 abstract description 6
- 239000011572 manganese Substances 0.000 abstract description 4
- 229910000831 Steel Inorganic materials 0.000 abstract description 2
- 239000010959 steel Substances 0.000 abstract description 2
- 238000007669 thermal treatment Methods 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 64
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 42
- 239000012452 mother liquor Substances 0.000 description 10
- 238000002386 leaching Methods 0.000 description 9
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 8
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- 229910017709 Ni Co Inorganic materials 0.000 description 4
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 4
- 229910000019 calcium carbonate Inorganic materials 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- 229910052602 gypsum Inorganic materials 0.000 description 4
- 239000010440 gypsum Substances 0.000 description 4
- SQQMAOCOWKFBNP-UHFFFAOYSA-L manganese(II) sulfate Chemical compound [Mn+2].[O-]S([O-])(=O)=O SQQMAOCOWKFBNP-UHFFFAOYSA-L 0.000 description 4
- 229910000357 manganese(II) sulfate Inorganic materials 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 230000003472 neutralizing effect Effects 0.000 description 3
- HYHCSLBZRBJJCH-UHFFFAOYSA-M sodium hydrosulfide Chemical compound [Na+].[SH-] HYHCSLBZRBJJCH-UHFFFAOYSA-M 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- 239000000159 acid neutralizing agent Substances 0.000 description 2
- -1 bearing Co Substances 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- NPURPEXKKDAKIH-UHFFFAOYSA-N iodoimino(oxo)methane Chemical compound IN=C=O NPURPEXKKDAKIH-UHFFFAOYSA-N 0.000 description 2
- 238000009853 pyrometallurgy Methods 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- QKMGIVQNFXRKEE-UHFFFAOYSA-L sodium;copper(1+);3-[(n-prop-2-enyl-c-sulfidocarbonimidoyl)amino]benzoate Chemical compound [Na+].[Cu+].[O-]C(=O)C1=CC=CC(NC([S-])=NCC=C)=C1 QKMGIVQNFXRKEE-UHFFFAOYSA-L 0.000 description 2
- 239000002253 acid Substances 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 1
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 1
- 235000011130 ammonium sulphate Nutrition 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 238000009854 hydrometallurgy Methods 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000000622 liquid--liquid extraction Methods 0.000 description 1
- 239000011656 manganese carbonate Substances 0.000 description 1
- IPJKJLXEVHOKSE-UHFFFAOYSA-L manganese dihydroxide Chemical compound [OH-].[OH-].[Mn+2] IPJKJLXEVHOKSE-UHFFFAOYSA-L 0.000 description 1
- 229910000016 manganese(II) carbonate Inorganic materials 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Abstract
A process is disclosed for the recovery of valuable metals from oxidic ores, in particular from polymetallic nodules. The process is suitable for the recovery of Cu, Co, Ni, Fe, and Mn, which are the main metals of interest in such polymetallic nodules. The present process is, among others, characterized by the handling of Fe, which is dissolved and kept in solution until the step of crystallization rather than removed at an earlier stage. A mixed Mn-Fe residue is obtained, which, after thermal treatment, provides a Mn-Fe oxide that is suitable for the steel or for the manganese industry. Excellent Cu, Co and Ni yields are obtained, while Fe is leached and valorized together with Mn.
Description
PROCESS FOR THE RECOVERY OF METALS FROM OXIDIC ORES
The present disclosure concerns a process for the recovery of valuable metals from oxidic ores, in particular from polymetallic nodules. Polymetallic nodules, also called deep sea nodules or deep sea manganèse nodules, are rock concrétions formed of concentric layers of iron and manganèse oxides at the bottom of océans.
The disclosed process is suitable for the recovery of Cu, Co, Ni, Fe, and Mn, which are the main metals of interest in such polymetallic nodules.
To date, the most economically interesting nodules hâve been found in the Clarion Clipperton Fracture Zone (CCFZ). Nodules in this area typically contain 27% Mn, 1.3% Ni, 1.1% Cu, 0.2% Co, 6% Fe, 6.5% Si, and 3% Al. Other éléments of économie interest are Zn, Mo and rare earths. Other sizeable deposits hâve been found in the Penrhyn Basin near the Cook Islands, the Peru Basin in the southeast Pacific and in a région termed the Indian Océan Nodule Field (IONF).
Since the seventies, many processes hâve been investigated to treat polymetallic nodules. A recent comprehensive review of the available processes can be found in a paper by T. Abramovski et al., Journal of Chemical Technology and Metallurgy, 52, 2, 2017, 258-269. Kennecott and INCO attempted to develop industrial processes. Kennecott developed the Cuprion ammoniacal process, while several companies developed hydrometallurgy processes in sulfate, chloride and nitrate media. INCO studied pyrometallurgical processes with production of a matte. More recently, production of an alloy has been proposed. None of these processes went further than the piloting scale.
The Cuprion process faces issues with low Co recovery, slow réduction of the nodules by COgas, and low quality of the manganèse residue. Sulfate processes derived from lateritic processes making use of autoclave leaching to reject Mn and Fe in the leach residue, face technological issues in the leaching, as well as poor valorization of the Mn. Other sulfate-based processes lead to huge reagent consumption and/or production of fatal ammonium sulfate. Chloride and nitrate routes hâve high energy consumption for the régénération of the reagents by pyro-hydrolysis and pyrolysîs. Drying of nodules before pyrometallurgy processing leads also to high energy consumption.
In this context, it should be noted that US 3,906,075 discloses a single-step leaching process using SO2 and sulfuric acid. Mn, Ni, Co, and Cu are leached simultaneously. This document also illustrâtes the crystallization of manganèse as MnSO4, followed by its décomposition to oxide, thereby generating SO2 for re-use in the leaching step. MnSO4 is added to the leaching step as it is said to force Fe to remain undissolved. Cu is extracted from the single leachate stream. Liquidliquid extraction is typically used, even though the cost and complexity of this process are considérable in view of the volumes to be treated.
It has been recognized in the prior art that Fe in the leachate is undesired, as an expensive deironing step would be needed to clean up the solution. Relatively mild leaching conditions are therefore proposed, including the addition of high concentrations of MnSO4 in the leaching solution. It is assumed that the high SO4 concentrations may limit the Fe solubility; however, less than optimal recovery yields are then observed for Co and Ni.
The present process is, among others, characterized by a very different handling ofthe Fe-related issues. There is no attempt at ail to limit the leaching of Fe in the step of dissolving the ores. On the contrary, Fe is dissolved and kept in solution until the step of MnSO4 crystallization. A mixed Μη-Fe residue is then obtained, which, after thermal treatment, is susceptible to resuit in a Μη-Fe oxide that is suitable for the Steel or for the manganèse industry. Excellent Cu, Co, and Ni yields are obtained, while Fe is leached and valorized together with Mn.
Figure l provides an overview of the flowsheet, also including the optional process steps and streams. The process steps are identified in Table 1, and the streams in Table 2.
Table 1 : Identification ofthe process steps according to Fig. 1
Process step ID | Description |
Pl | Dissolving the ores |
P2 | Recovery of Cu |
P3 | Neutralization |
P4 | Précipitation of Co and Ni |
P5 | Crystallization of Mn and Fe |
P6 | Thermal décomposition |
P7 | Précipitation of Mn (in bleed) |
________P8________ | Reverse osmosis |
Table 2: Identification of product streams in Fig. 1
Stream ID | Type | Description |
RO | Feed | Ores |
RI | Residue | First residue, insoluble compounds in ores |
R2 | Residue | Second residue, when Cu is precipitated using H2S |
R3 | Residue | Third residue, when using CaCO3 as neutralizing agent |
R4 | Residue | Fourth residue, after Co and Ni are precipitated using H2S |
R5 | Residue | Fifth residue, after Mn and Fe are precipitated by crystallization |
R6 | Residue | Sixth residue, when Mn is precipitated from bleed stream |
R7 | Residue | Seventh residue, when the fifth residue is thermally decomposed |
SI | Solution | First solution, leach solution bearing Cu, Co, Ni, Fe, and Mn |
S2 | Solution | Second solution, bearing Co, Ni, Fe, and Mn |
S3 | Solution | Third solution, neutralized, Co, Ni, Fe, and Mn-bearing |
S4 | Solution | Fourth solution, Mn and Fe-bearing |
S5 | Solution | Fifth solution, mother liquor containing a minor part of the Mn and Fe |
S5a | Solution | First fraction of fifth solution, recirculated to the step of dissolving |
S5b | Solution | Second fraction of fifth solution, bleed stream |
S6 | Solution | Sixth solution, depleted sait solution |
S7 | Solution | Seventh solution, essentially H2O |
S8 | Solution | Eighth solution, essentially a concentrated sait solution |
The disclosed process suitable for the recovery of Cu, Co, Ni, Fe, and Mn from oxidic ores, comprises the steps of dissolving the ores in acidic conditions, using H2SO4 and SO2, thereby 5 obtaining a Cu, Co, Ni, Fe, and Mn-bearing first solution and a first residue, followed by S/L séparation of the first solution and of the first residue.
A suitable endpoint pH for this step would preferably be 2 or lower. Good leaching yields are then observed for the metals that are intended to be recovered, including Fe. The SO2 is directly 10 injected in the leach solution in an amount that is preferably stoichiometric with respect to the metals to be reduced.
According to a first alternative, the Cu in solution can be recovered by précipitation as a sulfide by addition of a sulfide-bearing compound, or as a métal by addition of a métal more easily 15 oxidized than Cu, thereby obtaining a Co, Ni, Fe and Mn-bearing acidic second solution and a Cu-bearing second residue and S/L séparation of the second solution and of the second residue.
According to a second alternative, the Cu can be recovered by extraction, using electrowinning or SX, thereby obtaining a Co, Ni, Fe and Mn-bearing acidic second solution and a Cu-bearing stream.
During this Cu recovery step, the pH may decrease somewhat due to the protons ffeed up, in particular when Cu is precipitated using H2S or NaHS as sulfide bearing compound. This decrease of pH has no detrimental effects other than requiring more acid-consuming compounds acting as neutralizing agents in the next process step, which is the neutralization to pH 2 to 5 of the second solution by addition of first acid-consuming compounds, thereby obtaining a Co, Ni, Fe, and Mn-bearing neutralized third solution.
In a next step, Co and Ni are precipitated by addition of a sulfide-bearing compound to the third solution, thereby obtaining a Fe and Mn-bearing fourth solution, and a Co and Ni-bearing fourth residue, which are separated.
During this Co and Ni recovery step, the pH may again decrease somewhat further due to the protons freed up. More neutralization agents may be added, to reach a pH of 2 to 7. It is indeed preferred to operate the next step, which is the crystallization of Mn and Fe, on a neutralized solution to avoid the corrosion of the equipment.
In the neutralization step, CaCO3 may be used as acid-consuming compound. This produces gypsum, a solid that should preferably be separated in an additional S/L séparation step. The production of solids requiring filtration can be avoided or minimized by using MnCO3 or Mn(OH)2 as neutralization agent. These two products can advantageously be generated in the treatment of a bleed stream, as described below.
Mn and Fe are recovered together from the fourth solution by crystallization, thereby obtaining a fifth solution (mother liquor) containing a minor part of the Mn, and a fifth residue containing the major part of the Mn and of the Fe. The crystals are separated from the mother liquor.
Crystallization of Mn and Fe can be performed by évaporation. Alternatively, crystallization can be induced by heating, as the solubility limits of Mn and Fe decrease strongly with température. A température of more than 120 °C, or even of more than 170 °C is then preferred.
The mother liquor will still contain some residual dissolved Mn and Fe, as the crystallization will not fully exhaust these éléments in the mother liquor. These metals can be recovered according to the following embodiment.
Herein, the mother liquor is split in a first and second fraction, the first fraction being recirculated to the step of dissolving. The Mn and Fe in the second fraction (bleed stream) are precipitated as carbonates or hydroxides by addition of second acid-consuming compounds such as Na2CO3 or NaOH, thereby obtaining a sixth solution depleted in Mn and Fe, and a sixth residue ri ch in Mn and Fe, which are separated. Referring to the description above, it is advantageous to recirculate these carbonates or hydroxides as acid-consuming compounds to the step of neutralization.
The bleed stream will also provide for an output to minor éléments such as Na and K, which otherwise could accumulate to undesired levels when the process is run continuously. The second acid-consuming compounds are advantageously Na or K-based, as Ca-based compounds would lead to the dilution of the Mn in gypsum.
Another embodiment concems a process comprising the steps of thennal décomposition of the fifth residue, thereby obtaining an oxidic Mn-bearing seventh residue and SO2, and the séparation and recirculation of the SO2 to the step of dissolving. The thermal décomposition in this process is achieved by heating the product to 850 to 1000 °C.
Another embodiment concems a process comprising the steps of reverse osmosis of the sixth solution, thereby obtaining essentîally pure water and a concentrated sait solution. The water can be reused in a préviens step, e.g. for washing residues, and then recirculated to the step of dissolving the ores. The concentrated sait solution can be discharged.
Another embodiment concems any of the above processes, wherein the ores are deep sea nodules.
The following examples further illustrate the invention.
Example 1: Neutralization using CaCOa kg (on dry) polymetallic nodules ground to D50 of 100 pm is blended in 3.1 L water. The siurry is continuously stirred at 500 rpm and heated to 95 °C. For 1.5 hours, a total of 510 g SO2 gas is blown into the siurry. Afterwards, 280 g H2SO4 is slowly added in 2 hours. During this addition, some SO2 is released from the solution resulting in 400 g being effectively consumed. A pH of 1.6 is reached. The siurry is separated by filtration. The solution contains 9 g/L H2SO4. The solids are washed.
The Cu in the solution is precîpitated in a first sulfide précipitation. The solution is thereby brought to 80 °C and continuously stirred at 300 rpm. Argon is blown over the liquid surface. For 2 hours, 6.2 g H2S (i.e. according to a 100% stoichiometry) is bubbled through the solution. The siurry is filtrated, and the solids washed with water and dried in a vacuum stove at 40 °C. This solution now contains 14 g/L H2SO4.
The solution needs to be neutralized to achieve a successful Ni and Co précipitation. To this end, the solution is brought to 75 °C, stirred at 300 rpm, and argon is blown over the liquid surface. 51.2 g CaCO3 is brought in suspension in 0.15 L water. This siurry is slowly added to the solution. Gypsum is formed, which is separated. The pH of the solution then reaches the target value 3.
Ni and Co are recovered from the solution using NaHS. The solution is brought to 70 °C and continuously stirred at 300 rpm. Argon is blown over the liquid surface. 264 mL NaHS solution containing 38 g S/L (i.e. according to a 120% stoichiometry) is added to the solution at a rate of 3 mL/min. The siurry is filtrated, and the solids are washed with water and dried in a vacuum stove at 40 °C.
The solution is loaded in an autoclave and brought to 176 °C. Under these conditions, the solubility of both MnSCM and FeSÛ4 decreases, resulting in their crystallization. The crystals are separated from the liquid phase using hot filtration to prevent redissolution ofthe crystals.
The amounts and compositions of the different filtrâtes and residues are given in Table 3. The yields of the dissolving (Pl) and précipitation steps (P2, P4, P5) are given in Table 4.
Table 3: Amounts and compositions (solutions in L and g/L, residues in g and wt.%)
Stream ID | Mass (g) | Volum e (L) | Mn | Ni | Co | Cu | Fe | Si | Al |
RO | 1000.0 | - | 29 | 1.3 | 0.25 | 1.2 | 6.2 | 6.3 | 2.7 |
SI | - | 3.59 | 80 | 3.6 | 0.69 | 3.2 | 12 | 0.0 | 2.2 |
RI | 300.0 | - | 0.97 | 0.04 | 0.01 | 0.16 | 6.4 | 21 | 6.4 |
S2 | - | 3.59 | 80 | 3.6 | 0.69 | 0.0 | 12 | 0.0 | 2.2 |
R2 | 17.3 | - | 0.0 | 0.0 | 0.0 | 66 | 0.0 | 0.0 | 0.0 |
S3 | - | 3.74 | 77 | 3.4 | 0.66 | 0.0 | 11 | 0.0 | 2.1 |
S4 | - | 3.74 | 77 | 0.0 | 0.0 | 0.0 | 11 | 0.0 | 1.8 |
R4 | 28.1 | - | LO | 46 | 8.8 | 0.0 | 1.5 | 0.0 | 3.9 |
S5 | - | 3.66 | 9 | 0.0 | 0.0 | 0.0 | 1.7 | 0.0 | 0.06 |
R5 | 900.45 | - | 28 | 0.0 | 0.0 | 0.0 | 4.0 | 0.0 | 0.7 |
Table 4: Métal yields (in %) per process step
Process step ID | Mn | Ni | Co | Cu | Fe | Si | Al |
Pl | 99 | 99 | 99 | 96 | 69 | 0 | 29 |
P2 | 0 | 0 | 0 | 100 | 0 | 0 | 0 |
P4 | 0.1 | 100 | 100 | 100 | 1 | 0 | 14 |
P5 | 88 | 0 | 0 | 0 | 85 | 0 | 97 |
The métal yields per process step are considered as most satisfying.
Example 2: Neutralization using MnCCh
This Example is analogous to Example 1. However, recirculated Mn and Fe carbonates are used as neutralizing agent instead of CaCO3. Consequently, no gypsum is formed, and the corresponding filtration step is eliminated.
After the Cu précipitation, the solution needs to be neutralized. To this end, a fraction of the pumpable slurry, prepared as shown below, is slowly added to the solution as acid-consuming compounds. When adding an amount containing 58.8 g of a mixture of Mn and Fe carbonates, the pH of the solution reaches the target value of 3.
Mn and Fe are then recovered by crystallization, according to Example 1.
The Mn and Fe still present in the mother liquor after the crystallization step are precipitated as carbonates by the addition of 66.8 g Na2CO3. The slurry is filtrated, and the residue is washed and dried. It contains 92.4 g of a mixture of Mn and Fe carbonates. This residue is then diluted with 0.28 L water to create a pumpable slurry. Part of this slurry is used as acid consuming compounds in the above-described step.
It should be noted that in a continuous process, it would be advantageous to perform the précipitation step on only a fraction of the mother liquor, this fraction being determined by the need for acid-consuming compounds in the neutralization step. The remaînder of the mother liquor can then be recirculated to the dissolution step.
The amounts and compositions of the different filtrâtes and residues are given in Table 5. The yields of the dissolving (Pl) and précipitation steps (P2, P4, P5) are given in Table 6.
Table 5: Amounts and compositions (solutions in L and g/L, residues in g and wt.%)
Stream ID | Mass (g) | Volum e (L) | Mn | Ni | Co | Cu | Fe | Si | Al |
RO | 1000.0 | - | 29 | 1.3 | 0.25 | 1.2 | 6.2 | 6.3 | 2.7 |
SI | - | 3.59 | 80 | 3.6 | 0.69 | 3.2 | 12 | 0.0 | 2.2 |
Rl | 300.0 | - | 0.97 | 0.04 | 0.01 | 0.16 | 6.4 | 21 | 6.4 |
S2 | - | 3.59 | 80 | 3.6 | 0.69 | 0.0 | 12 | 0.0 | 2.2 |
R2 | 17.3 | - | 0.0 | 0.0 | 0.0 | 66 | 0.0 | 0.0 | 0.0 |
S3 | - | 3.77 | 83 | 3.4 | 0.66 | 0.0 | 13 | 0.0 | 2.1 |
S4 | - | 3.77 | 82 | 0.0 | 0.0 | 0.0 | 12 | 0.0 | 1.8 |
R4 | 28.2 | - | 1.1 | 46 | 8.8 | 0.0 | 1.7 | 0.0 | 3.9 |
S5 | - | 3.67 | 10 | 0.0 | 0.0 | 0.0 | 1.9 | 0.0 | 0.06 |
R5 | 973.2 | - | 28 | 0.0 | 0.0 | 0.0 | 4.1 | 0.0 | 0.7 |
R6 | 58.8 | - | 40 | 0.0 | 0.0 | 0.0 | 7.6 | 0.0 | 0.0 |
Table 6: Métal yields (in %) per process step
Process step ID | Mn | Ni | Co | Cu | Fe | Si | Al |
Pl | 99 | 99 | 99 | 96 | 69 | 0 | 29 |
P2 | 0 | 0 | 0 | 100 | 0 | 0 | 0 |
P4 | 0.1 | 100 | 100 | 100 | 1 | 0 | 14 |
P5 | 88 | 0 | 0 | 0 | 85 | 0 | 97 |
Even though the yields per process step are equally satisfying as in Example 1, the overall Mn yield will be higher when applying the neutralization method according to Example 2. Indeed, most of the Mn in the mother liquor after crystallization will in this case be recovered and brought out in the crystallization step.
Claims (7)
- l . Process for the recovery of Cu, Co, Ni, Fe and Mn from oxidic ores, comprising the steps of:- dissolving the ores (Pl) in acidic conditions using H2SO4 and SO2, thereby obtaining a Cu, Co, Ni, Fe, and Mn-bearing first solution (SI) and a first residue (RI);- S/L séparation of the first solution and of the first residue;- recovery of Cu (P2) either by:- précipitation as a sulfide by addition of a sulfide-bearing compound, or as a métal by addition of a métal more easily oxidized than Cu, thereby obtaining a Co, Ni, Fe, and Mn- * bearing acidic second solution (S2) and a Cu-bearing second residue (R2); and,- S/L séparation of the second solution and of the second residue;or by:- extraction by electrowinning or SX, thereby obtaining a Co, Ni, Fe, and Mn-bearing acidic second solution (S 2) and a Cu-bearing stream;- neutralization (P3) to pH 2 to 5 of the second solution (S2) by addition of first acidconsuming compounds, thereby obtaining a Co, Ni, Fe, and Mn-bearing neutralized third solution (S3);- précipitation of Co and Ni (P4) by addition of a sulfide-bearing compound to the third solution, thereby obtaining a Fe and Mn-bearing fourth solution (S4) and a Co and Ni-bearing fourth residue (R4);- S/L séparation of the fourth solution and of the fourth residue;- crystallization of Mn and Fe (P5) as sulfates from the fourth solution, thereby obtaining a fifth solution containing a minor part of the Mn (S5), and a fifth residue containing the major part of the Mn and of the Fe (R5); and,- S/L séparation of the fifth solution and of the fifth residue.
- 2. Process according to claim 1, wherein, in the neutralization step, the first acidconsuming compound contains calcium, thereby obtaining a third residue (R3), and comprising the additional step of:- S/L séparation of the third solution and of the third residue.9 ‘
- 3. Process according to claim 2, wherein, in the neutralization step, the first acidconsuming compound is CaCOs.
- 4. Process according to any one of claims 1 to 3, comprising the steps of:- splitting the fifth solution (S5) in a first (S5a) and second fraction (S5b);- recirculation of the first fraction of the fifth solution to the step of dissolving (PI).- précipitation of Mn and'Fe (P7) as carbonates or hydroxides by addition of second acidconsuming compounds to the second fraction of the fifth solution, thereby obtaining a sixth solution depleted in Mn and Fe (S6), and a sixth residue rich in Mn and Fe (R6);- S/L séparation of the sixth solution and of the sixth residue; and, $- recirculation of the sixth residue to the step of neutralization (P3), as at least part of the first acid-consuming compounds.
- 5. Process according to any one of claims 1 or 4, comprising the steps of:- thermal décomposition (P6) of the fifth residue, thereby obtaining an oxidic Mn-bearing seventh residue (R7) and SO2;- séparation of the SO2; and;- recirculation ofthe SO2 to the step of dissolving the ores (PI).
- 6. Process according to claim 4, comprising the steps of:- reverse osmosis (P8) of the sixth solution, thereby obtaining water (S7) and concentrated sait solution (S8); and,- recirculation of the water to the step of dissolving the ores (PI).
- 7. Process according to any one of claims 1 to 6, wherein the ores are deep sea nodules.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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EP19190915.9 | 2019-08-09 |
Publications (1)
Publication Number | Publication Date |
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OA21089A true OA21089A (en) | 2023-11-13 |
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