CA1060219A - Process for leaching raw sea nodules - Google Patents
Process for leaching raw sea nodulesInfo
- Publication number
- CA1060219A CA1060219A CA222,914A CA222914A CA1060219A CA 1060219 A CA1060219 A CA 1060219A CA 222914 A CA222914 A CA 222914A CA 1060219 A CA1060219 A CA 1060219A
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- Canada
- Prior art keywords
- manganese
- values
- process according
- nodules
- carbonate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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Abstract
ABSTRACT OF THE DISCLOSURE
A process for extracting metal values from sea nodules, is provided in which nickel, cobalt and copper values are selectively extracted by leaching raw sea nodules in an aqueous ammoniacal medium in the presence of a reducing agent for tetravalent manganese and carbonate to precipitate the reduced manganese as manganous carbonate.
A process for extracting metal values from sea nodules, is provided in which nickel, cobalt and copper values are selectively extracted by leaching raw sea nodules in an aqueous ammoniacal medium in the presence of a reducing agent for tetravalent manganese and carbonate to precipitate the reduced manganese as manganous carbonate.
Description
PC-l 1060Z19 This invention relates to a l~ydromc~;lliur(Jic;l]
process for extracting metal values from manganiferous oxidc ores containing a major amount of manganese and iron and a minor amount of nonferrous metal values such as nickel, cobalt~
copper and molybdenum, and more particularly to a process for selectively extracting and separating nickel, cobalt and copper from such ores.
Althougll the process in accordance with the present invention is applicable generally to manganiferous oxide ores 1~ that contain a major amount of manganese in the tetravalent state and iron and a minor amount of nonferrous metals including at least one of the metals nic]cel, cobalt or copper, it will be described herein in conjunction with deep sea nodules. The nodular deposits contain substantial amounts of manganese and iron, and the nonferrous values can be present in a total amount of up to 10%. The physical and chemical nature of these deposits vary depending on their location. Typical deposits can contain, for example, up to about 2% nick.el, up to about
process for extracting metal values from manganiferous oxidc ores containing a major amount of manganese and iron and a minor amount of nonferrous metal values such as nickel, cobalt~
copper and molybdenum, and more particularly to a process for selectively extracting and separating nickel, cobalt and copper from such ores.
Althougll the process in accordance with the present invention is applicable generally to manganiferous oxide ores 1~ that contain a major amount of manganese in the tetravalent state and iron and a minor amount of nonferrous metals including at least one of the metals nic]cel, cobalt or copper, it will be described herein in conjunction with deep sea nodules. The nodular deposits contain substantial amounts of manganese and iron, and the nonferrous values can be present in a total amount of up to 10%. The physical and chemical nature of these deposits vary depending on their location. Typical deposits can contain, for example, up to about 2% nick.el, up to about
2% copper, up to about l~ cobalt, up to about 25~ iron and up to about 40~ manganese.
BACKGROUND OF THE INVENTION
The nodular deposits are found in large ~uantities on the ocean floor and they are a potential source of metals.
However, since the components are tied in intimate and complex association they are not amenable to separation by conventional beneficiation procedures. For the same reason extraction of the valuable metals is difficult.
~ ' q~
- . . .
~060Z19 Numerous methods have been proposed for extracting metal values from sea nodules. Among them are processes which include the use of sulfur dioxide, mainly in neutra]
or acidic media. U.S. Patent No. 3,169,856, for example, uses sulfur dioxide or nitrogen dioxide to preferentially dissolve the values in the manganese phase leaving the iron phase in the residue for subsequent treatment. Similarly, German Patent No. 2,150,785 leaches the ores, preferably in the presence of added MnSO4, with SO2 to preferentially dissolve the manganese phase leaving the iron phase in the residue for further acid treatment. In U.S. Patent No.
BACKGROUND OF THE INVENTION
The nodular deposits are found in large ~uantities on the ocean floor and they are a potential source of metals.
However, since the components are tied in intimate and complex association they are not amenable to separation by conventional beneficiation procedures. For the same reason extraction of the valuable metals is difficult.
~ ' q~
- . . .
~060Z19 Numerous methods have been proposed for extracting metal values from sea nodules. Among them are processes which include the use of sulfur dioxide, mainly in neutra]
or acidic media. U.S. Patent No. 3,169,856, for example, uses sulfur dioxide or nitrogen dioxide to preferentially dissolve the values in the manganese phase leaving the iron phase in the residue for subsequent treatment. Similarly, German Patent No. 2,150,785 leaches the ores, preferably in the presence of added MnSO4, with SO2 to preferentially dissolve the manganese phase leaving the iron phase in the residue for further acid treatment. In U.S. Patent No.
3,810,827, nodules are treated with SO2 in a fluid bed in the absence of oxygen to preferentially sulfate the manganese content of the nodules. Leaching the sulfated nodules dissolves manganese leaving the remaining nonferrous values in the residue for dissolution in a subsequent treatment.
In each of these processes, most of the manganese content of the nodules is dissolved in a weakly acidic liquor containing at least a portion of the copper, nickel, or cobalt present in the nodules. Separation and recovery of the valuable nonferrous metals and manganese from these solutions may be complex and expensive.
Other processes are known to utilize leaching `in ammoniacal solutions to extract the valuable nonferrous metals leaving manganese and iron in the residue. Among these are processes such as U.S. Patent No. 3,471,285 which involve high temperature selective reduction of the nodules prior to leaching in the ammoniacal medium. These processes are becoming less attractive because of the large energy requirement to dry and heat the nodules. Another process, . . .
..
.
`~ 1060219 .S. Patent No. 3,728,105, leaches the nodules in ammoniacal media at temperatures between 100 and 300C. under atmospheres containing H2 and/or CO at 300 to 1000 psig total pressure to reduce the Mn and selectively extract the Cu, Ni, and Co. The cost of pressure vessels to withstand such high temperatures and pressures in addition to the large energy require-ment for heating a slurry makes this process unattractive.
It is an object of the present invention to provide an improved method for treating manganese oxide ores, expecially manganiferous sea nodules in which copper, nickel and cobalt are selectively separated from manganese. Another object is to provide a method in which neither thermal pretreatment nor drying of the ore is required. A further object is to provide a hydrometallurgical method in which leaching of the ore is carried out under essentially atmospheric pressures. It is a still further object to provide a process for extracting metal values from manganese oxide ores in which early separation of metals including copper, nickel and/or cobalt from manganese is effected, thereby avoiding complex separation procedures.
It is a further object to provide a leach residue from which manganese recovery can be achieved by a simple procedure.
These and other objects will become apparent from the following 20 description taken in conjunction with the accompanying drawing.
THE INVENTION -The present invention may be generally defined as a process for extracting metal values from a manganiferous ore containing a major amount of manganese and iron, manganese being present in tetravalent form, and a lesser amount of at least one of the nonferrous metals nickel, cobalt and B ::
. ` . . `. . ~
~060Zl9 copper. The novel process comprises leaching said ore in an aqueous ammonia-cal medium maintained at a pH of not less than 8, in the presence of a re-ducing agent which is a member of the group S02 and N02, at reaction conditions to convert tetravalent manganese to the divalent state and in the presence of a carbonate capable of forming substantially insoluble manganous carbonate in the ammoniacal medium, whereby at least one of the nonferrous metal values nickel, cobalt and copper is extracted into the leach solution and the manganese and iron values are separated into the leach residue.
Suitable reducing agents are charac~erized in that they are capable of reducing tetravalent manganese to the divalent state in an ammoniacal medium under essentially atmospheric pressure or relatively low pressures, and they permit extraction of desired metal values such as copper, nickel and cobalt into the leach solution. Examples of the reducing agents are S02, N02, H2S, elemental sulfur, and metallic iron. S02 is preferred because it is efficient, commonly available, economical, and in its oxidized form as SO4= can be disposed of with minimum environmental impact.
The ammoniacal medium contains in addition to the reducing agent and NH4+, a carbonate which will precipitate the reduced manganese as manganous carbonate. The carbonate precipitant is for example C02, (NH4)2C03, or an alkali metal carbonate. C02 and ~NH4)2C03 are preferred reagents Manganous carbonate is precipitated in a crystalline form which may be recovered from the leach residue by well-known flotation technology. In the absence of carbonate, non-crystalline manganous hydroxide is precipitated which would require more complex techniques. Also, it is desirable to obtain less than 50 ppm. manganese in the leach solution, and LV
1060Zl~
it has been found that this low value is readily achieved in ammoniacal media if carbonate is present. In the absence of carbonate, manganese hydroxide is formed which precipitates more slowly.
In the preferred embodiment in which SO2 is the reducing agent and NH3 and CO2 are tne reagents, it is believed that the follo~ing overall reaction occurs ~Jith respect to the tetravalent manganese:
~5no2 + SO2 + (~IH4)2CO3 ~_ MnC03 + (NEl4)2SO4 The Ni, Co, Cu and ~lo values are extracted as ammine complexes.
The leaching conditions and reagent additions are controlled to ensure that the residue is substantially free of ammonia compounds so as to realize maximum economy of ammonia consumption and minimum harmful environmental impact. In general, the reducing agent is added in an amount substantially , stoichiometric to the amount of manganese, and it may be in-troduce~d into the leaching medium at the start of the leach or adcled in stages or continuously throughout the leaching step. The plI of the leaching medium is maintained at not less than about 8 and, preferably, the pH is maintained at about 8.5 to about 9. At a pH below about 8, the nickel, cobalt and copper tend to precipitate from the leach solution.
When too low, the pEI is suitably adjusted with NH3. ~t a p~i above about 9, the solubility of manganese in the leach sc)lution increases. ~'hen too high, the pH is suitably adjusted with CO2.
In general, the leaching medium is provided with from about 60 to about 200 grams per liter NH3 and about ~0 to about 150 grams per liter of CO2 (or its equivalent of CO3=) and in suitable propor~ions to maintain the pl~ in the range of about ~060219 ~.5 to about 9. A sufficient amount of ~i3 is required to complex all the nonferrous metal values to be extracted, such as Cu, Ni, and Co. However, in the presence of the required amount of CO3=, i.e. at least stoichiometric, and preferably in excess of the amount required to precipitate all of the manganese in the nodules as manganous carbonate, and at a pH
no lower than about 8.5, more than sufficient NH3 is present to complex the nonferrous metals to be extracted.
The temperature of the leaching slurry is maintained at about 25 to about 100C., preferably abou-t 50 to about 80C. The leaching step is carried out essentially at atmospheric pressure. However, the pressure may range to about 50 psig, depending on the partial pressure of the gaseous components at the reaction temperature. Preferably, the reaction is effected at atmospheric pressure.
Preferably, the slurry is maintained under reactin~ -conditions until solubilization of the nonferrous metals such ~-as Ni, Cu or Co and the precipitation of the manganese and iron values are substantially maximized. Suitably, a slurry containing SO2, NH3 and CO2 and/or (NH4)2CO3 is maintained under reacting conditions for about 4 to 10 hours.
The leach residue can be treated to recover the manganese and/or iron and the nonferrous metal can be recovered from the leach solution by known methods.
TH~ DRAWING
The accompanying figure is a schematic flo~ sheet showing the process for treating raw sea nodules according to a preferred embodiment of this invention.
As illustrated in the Figure, raw sea nodules are subjected directly to a reductive leach undcr rclatively mild .
- : ~
conditions. Prior to the leaching step, it is advantageous to reduce the particle size of the nodules. The nodules are crushed, ground or otherwise reduced to a fine particle size, e.g. 95% ~ 48 mesh (TSS), and preferably 95% lO0 mesh.
Although the nodules are porous and have a relatlvely large surface area, the great tortuosity of the pores in the nodules hinders diffusion of reactants and products. Therefore, it is advantageous to reduce the size of the nodules, thereby making the nodules receptive to complete and rapid reactions.
It will be noted that it is not necessary to dry the nodules before they are subjected to reductive leaching. The wet raw nodules are ground and fed directly to an aqueous medium and reduction and precipitation of the manaanese is achieved in the leaching medium.
Referring to the drawing, raw ocean nodules, ground to about minus lO0 mesh (TSS), are mixed with water to provide a slurry containing about lO~ to 30% solids. NH3 and CO2 are bubbled into the slurry to provide approximately 150 grams per liter of N~13 and lO0 grams per liter of CO2. The tempera-ture is maintained at about 50 to 80C. and the pH at about 8.5 to 9. SO2, the reducing agent is fed to the slurry to provide an amount of about 30% to 50~ by weight, e.g. about 45~, based on the weight of the sea nodules. The atmosphere is neutral or mildly reducing, air being excluded to prevent the oxidation of SO2. The total leach time is approximately
In each of these processes, most of the manganese content of the nodules is dissolved in a weakly acidic liquor containing at least a portion of the copper, nickel, or cobalt present in the nodules. Separation and recovery of the valuable nonferrous metals and manganese from these solutions may be complex and expensive.
Other processes are known to utilize leaching `in ammoniacal solutions to extract the valuable nonferrous metals leaving manganese and iron in the residue. Among these are processes such as U.S. Patent No. 3,471,285 which involve high temperature selective reduction of the nodules prior to leaching in the ammoniacal medium. These processes are becoming less attractive because of the large energy requirement to dry and heat the nodules. Another process, . . .
..
.
`~ 1060219 .S. Patent No. 3,728,105, leaches the nodules in ammoniacal media at temperatures between 100 and 300C. under atmospheres containing H2 and/or CO at 300 to 1000 psig total pressure to reduce the Mn and selectively extract the Cu, Ni, and Co. The cost of pressure vessels to withstand such high temperatures and pressures in addition to the large energy require-ment for heating a slurry makes this process unattractive.
It is an object of the present invention to provide an improved method for treating manganese oxide ores, expecially manganiferous sea nodules in which copper, nickel and cobalt are selectively separated from manganese. Another object is to provide a method in which neither thermal pretreatment nor drying of the ore is required. A further object is to provide a hydrometallurgical method in which leaching of the ore is carried out under essentially atmospheric pressures. It is a still further object to provide a process for extracting metal values from manganese oxide ores in which early separation of metals including copper, nickel and/or cobalt from manganese is effected, thereby avoiding complex separation procedures.
It is a further object to provide a leach residue from which manganese recovery can be achieved by a simple procedure.
These and other objects will become apparent from the following 20 description taken in conjunction with the accompanying drawing.
THE INVENTION -The present invention may be generally defined as a process for extracting metal values from a manganiferous ore containing a major amount of manganese and iron, manganese being present in tetravalent form, and a lesser amount of at least one of the nonferrous metals nickel, cobalt and B ::
. ` . . `. . ~
~060Zl9 copper. The novel process comprises leaching said ore in an aqueous ammonia-cal medium maintained at a pH of not less than 8, in the presence of a re-ducing agent which is a member of the group S02 and N02, at reaction conditions to convert tetravalent manganese to the divalent state and in the presence of a carbonate capable of forming substantially insoluble manganous carbonate in the ammoniacal medium, whereby at least one of the nonferrous metal values nickel, cobalt and copper is extracted into the leach solution and the manganese and iron values are separated into the leach residue.
Suitable reducing agents are charac~erized in that they are capable of reducing tetravalent manganese to the divalent state in an ammoniacal medium under essentially atmospheric pressure or relatively low pressures, and they permit extraction of desired metal values such as copper, nickel and cobalt into the leach solution. Examples of the reducing agents are S02, N02, H2S, elemental sulfur, and metallic iron. S02 is preferred because it is efficient, commonly available, economical, and in its oxidized form as SO4= can be disposed of with minimum environmental impact.
The ammoniacal medium contains in addition to the reducing agent and NH4+, a carbonate which will precipitate the reduced manganese as manganous carbonate. The carbonate precipitant is for example C02, (NH4)2C03, or an alkali metal carbonate. C02 and ~NH4)2C03 are preferred reagents Manganous carbonate is precipitated in a crystalline form which may be recovered from the leach residue by well-known flotation technology. In the absence of carbonate, non-crystalline manganous hydroxide is precipitated which would require more complex techniques. Also, it is desirable to obtain less than 50 ppm. manganese in the leach solution, and LV
1060Zl~
it has been found that this low value is readily achieved in ammoniacal media if carbonate is present. In the absence of carbonate, manganese hydroxide is formed which precipitates more slowly.
In the preferred embodiment in which SO2 is the reducing agent and NH3 and CO2 are tne reagents, it is believed that the follo~ing overall reaction occurs ~Jith respect to the tetravalent manganese:
~5no2 + SO2 + (~IH4)2CO3 ~_ MnC03 + (NEl4)2SO4 The Ni, Co, Cu and ~lo values are extracted as ammine complexes.
The leaching conditions and reagent additions are controlled to ensure that the residue is substantially free of ammonia compounds so as to realize maximum economy of ammonia consumption and minimum harmful environmental impact. In general, the reducing agent is added in an amount substantially , stoichiometric to the amount of manganese, and it may be in-troduce~d into the leaching medium at the start of the leach or adcled in stages or continuously throughout the leaching step. The plI of the leaching medium is maintained at not less than about 8 and, preferably, the pH is maintained at about 8.5 to about 9. At a pH below about 8, the nickel, cobalt and copper tend to precipitate from the leach solution.
When too low, the pEI is suitably adjusted with NH3. ~t a p~i above about 9, the solubility of manganese in the leach sc)lution increases. ~'hen too high, the pH is suitably adjusted with CO2.
In general, the leaching medium is provided with from about 60 to about 200 grams per liter NH3 and about ~0 to about 150 grams per liter of CO2 (or its equivalent of CO3=) and in suitable propor~ions to maintain the pl~ in the range of about ~060219 ~.5 to about 9. A sufficient amount of ~i3 is required to complex all the nonferrous metal values to be extracted, such as Cu, Ni, and Co. However, in the presence of the required amount of CO3=, i.e. at least stoichiometric, and preferably in excess of the amount required to precipitate all of the manganese in the nodules as manganous carbonate, and at a pH
no lower than about 8.5, more than sufficient NH3 is present to complex the nonferrous metals to be extracted.
The temperature of the leaching slurry is maintained at about 25 to about 100C., preferably abou-t 50 to about 80C. The leaching step is carried out essentially at atmospheric pressure. However, the pressure may range to about 50 psig, depending on the partial pressure of the gaseous components at the reaction temperature. Preferably, the reaction is effected at atmospheric pressure.
Preferably, the slurry is maintained under reactin~ -conditions until solubilization of the nonferrous metals such ~-as Ni, Cu or Co and the precipitation of the manganese and iron values are substantially maximized. Suitably, a slurry containing SO2, NH3 and CO2 and/or (NH4)2CO3 is maintained under reacting conditions for about 4 to 10 hours.
The leach residue can be treated to recover the manganese and/or iron and the nonferrous metal can be recovered from the leach solution by known methods.
TH~ DRAWING
The accompanying figure is a schematic flo~ sheet showing the process for treating raw sea nodules according to a preferred embodiment of this invention.
As illustrated in the Figure, raw sea nodules are subjected directly to a reductive leach undcr rclatively mild .
- : ~
conditions. Prior to the leaching step, it is advantageous to reduce the particle size of the nodules. The nodules are crushed, ground or otherwise reduced to a fine particle size, e.g. 95% ~ 48 mesh (TSS), and preferably 95% lO0 mesh.
Although the nodules are porous and have a relatlvely large surface area, the great tortuosity of the pores in the nodules hinders diffusion of reactants and products. Therefore, it is advantageous to reduce the size of the nodules, thereby making the nodules receptive to complete and rapid reactions.
It will be noted that it is not necessary to dry the nodules before they are subjected to reductive leaching. The wet raw nodules are ground and fed directly to an aqueous medium and reduction and precipitation of the manaanese is achieved in the leaching medium.
Referring to the drawing, raw ocean nodules, ground to about minus lO0 mesh (TSS), are mixed with water to provide a slurry containing about lO~ to 30% solids. NH3 and CO2 are bubbled into the slurry to provide approximately 150 grams per liter of N~13 and lO0 grams per liter of CO2. The tempera-ture is maintained at about 50 to 80C. and the pH at about 8.5 to 9. SO2, the reducing agent is fed to the slurry to provide an amount of about 30% to 50~ by weight, e.g. about 45~, based on the weight of the sea nodules. The atmosphere is neutral or mildly reducing, air being excluded to prevent the oxidation of SO2. The total leach time is approximately
4 to lO hours.
Using the above reagents and conditions up to 90%
of Cu, Co, and Ni can be extracted into virtually Mn and Fe free solutions.
1060Zl9 After separating the leach solution from the residue, the Ni, Co, and Cu values can be recovered from the leach solution by known techniques. For example, free ~H3 can be distilled from the solution to cause Cu, Ni, and Co to pre-cipitate as basic carbonates. After solid/liquid separation and washing, the basic carbonate precipitate can be redis- -solved with H2SO4. This solution can then be treated to separate and recover the Cu, Ni, and Co by several well-known techniques including, for example, solvent extraction, ion exchange, hydrolysis, sulfide precipitation, and electrolysis.
After separating the barren solution from the basic carbonate precipitate, the SO~ in solution is precipitated as gypsum with, for example, lime and the NH3 and CO2 are recovered by distillation.
The leach residue can be treated, for example, to recover a high grade manganous carbonate concentrate by well-known flotation techniques. This concentrate could then be treated to recover manganese by pyrometallurgical techniques or by dissolving and electrowinning.
The following illustrative examples are given for the purpose of enabling those skilled in the art to have a better understanding of the invention.
E~LE 1 In a series of tests, raw sea nodules ground to pass lO0 mesh (TSS) are added to an enclosed vessel containing an aqueous ammoniacal medium to provide a pulp density of about 15% solids. The nodules contain 1.22% Ni, 0.97~ Cu, 0.20% Co, 25.0% Mn and 5.35% Fe, the composition of the aqueous ammoniacal medium for each of the tests is given in TABLE I.
After raising the temperature of the slurry to 60C., SO2 is .
' . ' .' ' ~ ~ :
bubbled into the baths at a rate of 300 milli]itcrs pcr minute for l to 3 hours and the leach ~olution is analyæcd for Cu, Ni, Co and Mn. The results of typical tests are tabulated in TABLE I. Tests C and D are duplicate runs.
Comparison of the data in Tests A, s, C and D of TABLE I shows that leaching with NH40H and SO2 in the presence of (NH4)2SO4 or CO2 is more effective for extracting nickel and copper than leaching with N114O1-I and SO2 alone. Further comparison of Test B with Tests C and D show that CO2 is more effective than (NH4)2SO4 for extracting nickel and copper. In addition, very low manganese concentrations in the leach solution are more readily attained in the presence of a carbonate. Other advantages of a carbonate precipitate were indicated previously.
~XAMPLF, 2 In a series of three tests, raw sea nodules qround to pass l00 mesh (TSS) are added to an enclosed vessel containing an aqueous ammonium medium at 75C. to provide a pulp density of about 15% solids. The nodules contain l.22%
Ni, 0.97% Cu, 0.20% Co, 25.0% Mn, and 5.35% Ee. The aqueous ammoniacal medium contains 150 y. NH3/l, l00g. CO2/l, and 30, 36, or 42% SO2 by weight of nodules added. The slurry`is agitated and maintained at 75C. for 6 hours. After filtra-tion and washing the residue and solution are analyzed. The results are summarized in TABLE II.
The results of these tests show the variations in Cu, Ni, and Co extractions with the amount of SO2 added. As the S2 is increased from 30 to ~2% extraction of the Cu~ Ni, and Co increased, 10~0219 o\ OoOO~1o _ o u~ C~ O ~ ~ u~ ~ ~ ~r ..
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Although the present invention has been de.scribed in conjunction ~ith preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.
Using the above reagents and conditions up to 90%
of Cu, Co, and Ni can be extracted into virtually Mn and Fe free solutions.
1060Zl9 After separating the leach solution from the residue, the Ni, Co, and Cu values can be recovered from the leach solution by known techniques. For example, free ~H3 can be distilled from the solution to cause Cu, Ni, and Co to pre-cipitate as basic carbonates. After solid/liquid separation and washing, the basic carbonate precipitate can be redis- -solved with H2SO4. This solution can then be treated to separate and recover the Cu, Ni, and Co by several well-known techniques including, for example, solvent extraction, ion exchange, hydrolysis, sulfide precipitation, and electrolysis.
After separating the barren solution from the basic carbonate precipitate, the SO~ in solution is precipitated as gypsum with, for example, lime and the NH3 and CO2 are recovered by distillation.
The leach residue can be treated, for example, to recover a high grade manganous carbonate concentrate by well-known flotation techniques. This concentrate could then be treated to recover manganese by pyrometallurgical techniques or by dissolving and electrowinning.
The following illustrative examples are given for the purpose of enabling those skilled in the art to have a better understanding of the invention.
E~LE 1 In a series of tests, raw sea nodules ground to pass lO0 mesh (TSS) are added to an enclosed vessel containing an aqueous ammoniacal medium to provide a pulp density of about 15% solids. The nodules contain 1.22% Ni, 0.97~ Cu, 0.20% Co, 25.0% Mn and 5.35% Fe, the composition of the aqueous ammoniacal medium for each of the tests is given in TABLE I.
After raising the temperature of the slurry to 60C., SO2 is .
' . ' .' ' ~ ~ :
bubbled into the baths at a rate of 300 milli]itcrs pcr minute for l to 3 hours and the leach ~olution is analyæcd for Cu, Ni, Co and Mn. The results of typical tests are tabulated in TABLE I. Tests C and D are duplicate runs.
Comparison of the data in Tests A, s, C and D of TABLE I shows that leaching with NH40H and SO2 in the presence of (NH4)2SO4 or CO2 is more effective for extracting nickel and copper than leaching with N114O1-I and SO2 alone. Further comparison of Test B with Tests C and D show that CO2 is more effective than (NH4)2SO4 for extracting nickel and copper. In addition, very low manganese concentrations in the leach solution are more readily attained in the presence of a carbonate. Other advantages of a carbonate precipitate were indicated previously.
~XAMPLF, 2 In a series of three tests, raw sea nodules qround to pass l00 mesh (TSS) are added to an enclosed vessel containing an aqueous ammonium medium at 75C. to provide a pulp density of about 15% solids. The nodules contain l.22%
Ni, 0.97% Cu, 0.20% Co, 25.0% Mn, and 5.35% Ee. The aqueous ammoniacal medium contains 150 y. NH3/l, l00g. CO2/l, and 30, 36, or 42% SO2 by weight of nodules added. The slurry`is agitated and maintained at 75C. for 6 hours. After filtra-tion and washing the residue and solution are analyzed. The results are summarized in TABLE II.
The results of these tests show the variations in Cu, Ni, and Co extractions with the amount of SO2 added. As the S2 is increased from 30 to ~2% extraction of the Cu~ Ni, and Co increased, 10~0219 o\ OoOO~1o _ o u~ C~ O ~ ~ u~ ~ ~ ~r ..
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Although the present invention has been de.scribed in conjunction ~ith preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.
Claims (11)
1. A process for extracting metal values from a manganiferous ore containing a major amount of manganese and iron, manganese being present in tetravalent form and a lesser amount of at least one of the nonferrous metals nickel, cobalt and copper comprising leaching said ore in an aqueous ammoniacal medium maintained at a pH of not less than 8 in the presence of a reducing agent which is a member of the group SO2 and NO2 at reaction conditions to convert tetravalent manganese to the divalent state and in the presence of a carbonate capable of forming substantially insoluble manganous carbonate in the ammoniacal medium, whereby at least one of the nonferrous metal values nickel, cobalt and copper is extracted into the leach solution and the manganese and iron values are separated into the leach residue.
2. A process according to claim 1 wherein the man-ganiferous ore comprises sea nodules and said nodules are introduced in the raw condition into the leaching medium.
3. A process according to claim 1 wherein the car-bonate is provided by a reagent selected from the group CO2, (NH4)2CO3, and an alkali metal carbonate.
4. A process according to claim 1 wherein the re-ducing agent is SO2.
5. A process according to claim 1 wherein the leach-ing reactants are maintained at a temperature of about 50°
to 80°C. and substantially atmospheric pressure for a period of time sufficient to maximize said extraction of nickel, cobalt and copper values into solution and separation of manganese and iron values into the residue.
to 80°C. and substantially atmospheric pressure for a period of time sufficient to maximize said extraction of nickel, cobalt and copper values into solution and separation of manganese and iron values into the residue.
6. A process according to claim 1 wherein the am-moniacal leaching medium is maintained at a pH between 8 and about 9.
7. A process according to claim 2 wherein the reduc-ing agent is SO2 provided in the total amount of about 30%
to about 50% based on the weight of the sea nodules.
to about 50% based on the weight of the sea nodules.
8. A process according to claim 2 wherein the solids content of the slurry is in the range of about 10% to about 30%.
9. A process according to claim 2 wherein NH3 and CO2 provide the ammoniacal medium and the carbonate reagent, and said NH3 is supplied to the leaching medium in an amount to provide about 60 to about 200 gpl, and said CO2 in an amount to provide about 40 to about 150 gpl.
10. A process for extracting metal values from raw sea nodules containing a major amount of manganese and iron, manganese being present in tetravalent state, and a lesser amount of at least one of the nonferrous metals nickel, cobalt and copper comprising leaching said raw sea nodules in an aqueous ammoniacal medium maintained at a pH of not less than 8 in the presence of a reducing agent for tetra-valent manganese selected from SO2 and NO2 in the presence of a manganous carbonate precipitant selected from CO2, (NH4)2CO3, and an alkali metal carbonate, at a temper-ature in the range of about 50°C. to about 80°C. and pres-sure of atmospheric to about 50 psig, to convert tetravalent manganese to the divalent state, extract nickel, cobalt and copper values into the leach solution and to separate manganese and iron values into the leach residue, said leaching reaction condition being maintained for a period of time sufficient to maximize said extraction of nickel, cobalt and copper values into solution and separation of manganese and iron values into the leach residue.
11. A process according to claim 10 wherein the reduc-ing agent is SO2 and the carbonate and ammoniacal values are provided to the medium as CO2 and NH3, said SO2 being pro-vided in the amount of 30 to 50% based on the weight of the sea nodules, and said CO2 and NH3 being supplied in an amount to provide about 60 to about 200 gpl NH3 and about 40 to about 150 gpl CO2, and wherein the sea nodules are leached at a temperature in the range of about 50° to about 80°C., at substantially atmospheric pressure to about 50 psig and a pH of about 8.5 to about 9 for about 4 to about 10 hours.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA222,914A CA1060219A (en) | 1975-03-24 | 1975-03-24 | Process for leaching raw sea nodules |
| US05/664,752 US4085188A (en) | 1975-03-24 | 1976-03-08 | Reduction leaching of raw sea nodules with sulfides |
| AU11959/76A AU499800B2 (en) | 1975-03-04 | 1976-03-12 | Leaching raw sea nodules |
| JP51032406A JPS5912732B2 (en) | 1975-03-24 | 1976-03-24 | Method for leaching seabed nodule material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA222,914A CA1060219A (en) | 1975-03-24 | 1975-03-24 | Process for leaching raw sea nodules |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1060219A true CA1060219A (en) | 1979-08-14 |
Family
ID=4102629
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA222,914A Expired CA1060219A (en) | 1975-03-04 | 1975-03-24 | Process for leaching raw sea nodules |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5912732B2 (en) |
| CA (1) | CA1060219A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114207160A (en) * | 2019-08-09 | 2022-03-18 | 尤米科尔公司 | Method for recovering metals from oxidized ores |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4274866A (en) * | 1978-07-24 | 1981-06-23 | Kennecott Copper Corporation | Flotation and sintering of synthetic manganese carbonate |
| JPS56114804A (en) * | 1980-02-07 | 1981-09-09 | Kyodo Sanso Kk | Hydrogen separator by metal hydride |
| JPS60190537A (en) * | 1984-03-08 | 1985-09-28 | Agency Of Ind Science & Technol | Method for extracting nickel, cobalt and copper from manganese nodule |
| US9284627B2 (en) * | 2012-10-23 | 2016-03-15 | Deepgreen Engineering, Pte. Ltd. | Process for recovering metal values from oxides of manganese-containing materials |
-
1975
- 1975-03-24 CA CA222,914A patent/CA1060219A/en not_active Expired
-
1976
- 1976-03-24 JP JP51032406A patent/JPS5912732B2/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114207160A (en) * | 2019-08-09 | 2022-03-18 | 尤米科尔公司 | Method for recovering metals from oxidized ores |
| CN114207160B (en) * | 2019-08-09 | 2023-10-31 | 尤米科尔公司 | Method for recovering metals from oxidized ores |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS51139519A (en) | 1976-12-01 |
| JPS5912732B2 (en) | 1984-03-26 |
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