CA1180902A - Process for recovering metals - Google Patents
Process for recovering metalsInfo
- Publication number
- CA1180902A CA1180902A CA000391843A CA391843A CA1180902A CA 1180902 A CA1180902 A CA 1180902A CA 000391843 A CA000391843 A CA 000391843A CA 391843 A CA391843 A CA 391843A CA 1180902 A CA1180902 A CA 1180902A
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- CA
- Canada
- Prior art keywords
- weight
- metal
- nickel
- sulfide
- substance
- 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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Classifications
-
- 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
- C22B15/00—Obtaining copper
- C22B15/0002—Preliminary treatment
- C22B15/0004—Preliminary treatment without modification of the copper constituent
- C22B15/0006—Preliminary treatment without modification of the copper constituent by dry processes
-
- 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
- C22B15/00—Obtaining copper
- C22B15/0002—Preliminary treatment
- C22B15/001—Preliminary treatment with modification of the copper constituent
- C22B15/0021—Preliminary treatment with modification of the copper constituent by reducing in gaseous or solid state
-
- 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
- C22B23/02—Obtaining nickel or cobalt by dry processes
- C22B23/021—Obtaining nickel or cobalt by dry processes by reduction in solid state, e.g. by segregation processes
-
- 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
- C22B5/00—General methods of reducing to metals
- C22B5/02—Dry methods smelting of sulfides or formation of mattes
- C22B5/10—Dry methods smelting of sulfides or formation of mattes by solid carbonaceous reducing agents
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A carbonaceous reducing agent, at least one of calcium oxide and a substance capable of forming calcium oxide, and a sodium salt are admixed into a substance containing a sulfide of at least one of nickel, cobalt and copper. The resulting mixture is heated to at least 750°C directly by a non-reducing gas, such as the combustion product of heavy oil. A metal or metals are recovered in powder form by beneficial methods and acid washing from the roasted product.
A carbonaceous reducing agent, at least one of calcium oxide and a substance capable of forming calcium oxide, and a sodium salt are admixed into a substance containing a sulfide of at least one of nickel, cobalt and copper. The resulting mixture is heated to at least 750°C directly by a non-reducing gas, such as the combustion product of heavy oil. A metal or metals are recovered in powder form by beneficial methods and acid washing from the roasted product.
Description
(399~
PROCESS FOR RECOVERING METALS
BACXGROUND OF TH~ INVENTION
1. Field of the In~ention:
This invention relates to a process for recovering a metal from a substance containing it in sulfide form by direct desulfurization and reduction.
PROCESS FOR RECOVERING METALS
BACXGROUND OF TH~ INVENTION
1. Field of the In~ention:
This invention relates to a process for recovering a metal from a substance containing it in sulfide form by direct desulfurization and reduction.
2. Description of the Prior Art:
Metals occur in sulfide for~ in various substances.
There are, for example, known concentrates obtained by dressing sulfidé ores, mattes obtained by smelting concentrates, sulfides obtained by the reducing and sulfiding roasting of oxide ores, and sulfide precipitates obtained by the sulfiding and precipita-tion of metal ions in waste water.
There is known a process for obtaining a metal from a substance containing its sulfide by desulfurizing and reducing it with hydrogen. A process for reducing copper, nickel, cohalt and iron sulfides with hydrogen is reported in Trans. Met. Soc., AIME, 245 (1969), 1927. This process employs CaO in the reac-tion system to remove effectively the H2S formed in accordance with equation (1) to help the reaction proceed smoothly to the right-hand side of equation (1):
M S ~ H ' M ~ H S (1) The efficient reduction to the metal in accordance with this reaction, however, requires the formation of a strongly reducing atmosphere by introducing a large quantity of hydrogen, as well as heating the substance. The use of a non-reducing gas, such as the combustion product of heavy oil, for heating the substance results in the necessity for a still larger quantity of hydrogen. This process is, therefore, uneconomical, and has ~b ~80~
not yet been put to practical application.
SUMMARY OF THE INVENTI ON
It is an object of this invention to provide a process which can economically recover a metal from a substance containing its sulfide by direct desulfurization and reduction.
The inventors of this invention have devoted themselves to a study of the reaction expressed by equation (2~ by employing an inexpensive carbonaceous reducing agent, such as coal or coke, instead of an expensive one such as hydrogen, and CaO for fixing sulfur:
MeS ~ CaO + 1/2C ~ Me + CaS + 1/2 CO2 (2) Although they have been able to reduce the metal sulfide satisfactorily if a neutral gas, such as nitrogen, is introduced, they have found it impossible to achieve a satisfactory rate of metal reduction if the sulfide-containing substance is heated directly by the combustion product of heavy oil, and considered it difficult to make any practical use of the reaction. As a result of ~heir further study, however, they have discovered that if a small quantity of a sodium salt is incorporated, it is possible to achieve a satisfactory rate of metal reduction even if the substance is heated directly by a non-reducing gas.
According to the invention there is provided a process for recovering a metal, which comprises: ad-mixing a carbonaceous reducing agent, at least one member selected from the group consisting of calcium oxide and a substance capable of ~orming calcium oxide, and at least one member selected ~rom the group consisting of sodium .j....
.~.
J~
~10~2 oxide and a sodium salt capable of producing sodium oxide, with a substance containing a sulfide of a metal selected from the group consisting of nickel, cobalt and copper;
and heating the resulting mixture to a temperature of at least 750C directly by a non-reducing gas, whereby a metal powder is formed.
- 2a -3V~
DET~ILED DESCRIPTION OF T~E INVE~NTION
The process oE this invention employs a sodium salt.
It is possible to use sodium oxide, or any other sodium salt capable of forming sodium oxide upon decomposition. It may, for example, in the form of a carbonate, sulfite, sulfate or halide. It is preferable to incorporate at least 0.5 part by weight of sodium oxide, or any other sodium salt in terms of sodium oxide, or more preferably at least one part by weight thereof, for 100 parts by weight of the substance containing a metal sulfide. It is, however, not necessary to increase its quantity greatly, since a nearly maximum rate of metal reduc-tion is obtained at that level.
The carbonaceous reducing agent employed by the pro-cess of this invention may, for example, be coal, coke or charcoal.
In some cases, it may also be possible to use a liquld carbo-naceous material, such as pitch or heavy oil~ It is suitable to employ at least 1.2 times as much of any such carbonaceous reducing agent as the quantity which can be obtained theoretical-ly by calculation according to equation (2).
The process of this invention also employs calcium oxide, or any other substance capable of forming calcium oxide upon thermal decomposition. Suitable examples of -the latter include limestone and slaked lime. It is also possible ~o use quick lime, or two or more of those substances in combination.
It is suitable to use 1.2 to 2.5 times as much of any such calcium oxide and/or substance forming calcium oxide as the quantity which can be obtained theoretically by cal~ulation according to equation (2). The use of any larger quantity is likely to lower the efficiency for the separation of the metal to be reduced.
~ 3 --The substance from which a metal is to be recovered is crushed into a powder having a particle size of 20 mesh or less, and preferably 48 mesh or less. The carbonaceous reducing agent, calcium oxide or any other substance forming calcium S oxide, and the sodium salt are also crushed appropriately, if they are a solid. It is possible to mix theml-~re efectivelv if they are mixed while they are being crushed. The resulting mixture may be heated directly, or after it has been formed into pellets or lumps. If it is formed into pellets or the like, it is advantageously possible to reduce dust.
Various types of kilns of furnaces, such as a rotary kiln, multi-hearth furnace or shaft kiln, can be used for heating the mixture. An annular vertical kiln is superior to any other kiln or furnace from the standpoint of thermal efficiency~ If this kiln is used for heating the mixture in pellets or lumps, it is possible to reduce the quantity of the non-reducing gas required for heating, and create a more reducing atmosphere in the kiln.
The non reducing gas used for heating the mixture is easv to obtain as the combustion product of a liquid fuel such as heavy oil, or a solid or gaseous fuel. It is preferable for the non-reducing gas to have an oxvgen content not exceed-ing 1% ~y volume. The presence of oxygen in any larger quantity is likely to activate oxidation and resulfurization of the reduced metal, and increase its sulfur and oxygen contents with a resultant waste of the carbonaceous reducing agent.
The following is a description of the reactions which are considered to take place during the direct desulfurization and reduction of a substance containing a metal sulfide accord ing to this invention. The carbonaceous reducing agent forms ~L18V~
a reducing gas of H2 and CO by its water gas reaction and Boudouard's reaction with H2O and CO2 in the combustion product at a prescribed temperature. This reducing gas reacts with the metal sulfide to effect its desulfurization and reduction, while forming a sulfide gas composed of H2S and COS, and maintains a reducing atmosphere in the kiln or Eurnace to pre-~ent resulfurization of the reduced metal. The sulfide gas reacts with calcium oxide, whereby sulfur is fixed by calcium.
The reactions by which the reducing gas is formed take place at a temperature of about 600C or above, and the resulfuriza-tion and reduction of nickel, cobalt and copper sulfides take place at about the same temperature~ Therefore, the heating of the reaction mixture at a temperature of at leas~ about 600C
enables the reaction from the left to right side of equation (2), whereby nickel, cobalt or copper can be reduced. In order to achieve a practically satisfactory reaction speed, however, it is necessary to employ a heating temperature of at least 750C. The optimum temperature for desulfurization and reduction depends on the metal to be reduced, while the optimum temperature for the formation of the reducing gas depends on the carbonaceous reducing agent employed. It is, thus, advisable to fin~ out an appropriate combination of the materials to be handled, and the temperature to be employed. For example, it is suitable to use bituminous coal and brown coal, which produce a large quantity of gas upon thermal decomposition, at a temperature of 750C to 900C, and coke at a temperature of 90QC to 1,200C.
The crabonaceous reducing agent is consumed with the progress of desulfurization and reduction. A decrease in 0 residual carbon leads to a reduction in the quantity of the reducing gas which is formed. A less reducing atmosphere in the kiln or furnace is likely to cause resulfurization of the reduced metal. This resulfurization takes place to a remarkable extent if the quantity of the residual carbon becomes less than 1.5% by weight~ It is, therefore, advisable to keep the residual carbon at least 1.5%, or preferzbly at least 2.0%, by weight.
The ~uantity of the residual carbon can be determined if the heated product is analyzed. A close watch for this value is advisable to ensure that the reaction product should not stay in the kiln or furnace for too long a time.
The process of this invention is applicable to any metal that can be reduced with a reducing gas. A metal having a relatively low boiling point, such as zinc, is entrained with the exhaust gas of the kiln or furnace, and can be recovered by condensation. A high~boiling metal stays in the product of desulfurization ànd reduction which contains CaS, CaO, residual carbon, ash, or the like. This product may be treated by a variety of methods for the recovery of the metai. For example, the metal can effectively be separated from the other substances by floation, or magnetic, gravitational or electrostatic con-centration. CaS and CaO can be removed by pickling with hydro-chloric, nitric, acetic or like acid. It is practically advisable to start with the recovery of the metal by dressing, and proceed with the pickling thereo~ for removing CaS and CaO.
The process of this invention can advantageously be combined with a process for producing matte from oxide ore by reducing and sulfiding rousting, so that sulfur may be effec-tively utilized. For example, an oxide ore containing nickel and cobalt oxide, such as laterite or garnierite, may be reduced and sulfurized by roasting, and the roasted ore may be reduced ~(3~
and melted to produce a nickel matte containing iron, or an iron free nickel matte if iron is removed. The process of this invention is applicable to any such nickel matte, so that the calcium sulfide and residual carbon separated from the product obtained by the direct desulfurization and reduction of the matte may be recycled for use as a sulfiding or reducing agent for the oxide ores.
As is obvious from the foregoing description, this invention provides a practical and ecnomical process which does not require any expensive hydrogen, and which can be carried out by employing an easily available source of heat, such as the combustion product of heavy oil.
The process of this invention, which is not selec-tively reducing, recovers substantially any metal from a metal 1~ sulfide-containing substance. It is, therefore, advisable to apply the process of this invention to a matte, or like con-centrate containing only the metal sought to be recovered. In order to recover nickel from a nickel matte, for example, it has been usual to employ direct electrolysis of the matte, gaseous or electric furnace reduction of a product obtained by oxidizing roasting of matte, or gaseous or electrolytic reduc-tion of a extracted product from wet-oxidization of matte.
If the process of this invention is applied to such a nickel matte, it is possible to recover nickel at a lower cost.
The invention will now be described with reference to examples thereof.
Nickel sulfide comprising 77.5% by weight of nickel and 20.5% by weight of sulfur was crushed into a powder having a particle size not greater than 100 mesh. This powder was -~ 8q~
mixed with two equivalents each of quick lime and coke, and different quantities of various sodium salts. The resulting mixture was heated at a temperature of 1,000C to 1,100C. The sodium salts were employed in the quantities of 0, 0.5, 1, 11.5, 2 and 3 parts by weight in terms of Na2O for 100 parts by weight of nickel sulfide to enable comparison of the rduc-tion rate of nickel. The quantity of the sodium salt, the type of the salt used, and the rate of nickel reduction for each of these test runs are shown in TABLE 1 below.
Sodium salt Quantity in Rate of terms of Na2O nickel Run (parts bY weiqht) Type reduction (~) 1 0 - 32 Compara-tive 2 0.5 Na2C3 91 Invention
Metals occur in sulfide for~ in various substances.
There are, for example, known concentrates obtained by dressing sulfidé ores, mattes obtained by smelting concentrates, sulfides obtained by the reducing and sulfiding roasting of oxide ores, and sulfide precipitates obtained by the sulfiding and precipita-tion of metal ions in waste water.
There is known a process for obtaining a metal from a substance containing its sulfide by desulfurizing and reducing it with hydrogen. A process for reducing copper, nickel, cohalt and iron sulfides with hydrogen is reported in Trans. Met. Soc., AIME, 245 (1969), 1927. This process employs CaO in the reac-tion system to remove effectively the H2S formed in accordance with equation (1) to help the reaction proceed smoothly to the right-hand side of equation (1):
M S ~ H ' M ~ H S (1) The efficient reduction to the metal in accordance with this reaction, however, requires the formation of a strongly reducing atmosphere by introducing a large quantity of hydrogen, as well as heating the substance. The use of a non-reducing gas, such as the combustion product of heavy oil, for heating the substance results in the necessity for a still larger quantity of hydrogen. This process is, therefore, uneconomical, and has ~b ~80~
not yet been put to practical application.
SUMMARY OF THE INVENTI ON
It is an object of this invention to provide a process which can economically recover a metal from a substance containing its sulfide by direct desulfurization and reduction.
The inventors of this invention have devoted themselves to a study of the reaction expressed by equation (2~ by employing an inexpensive carbonaceous reducing agent, such as coal or coke, instead of an expensive one such as hydrogen, and CaO for fixing sulfur:
MeS ~ CaO + 1/2C ~ Me + CaS + 1/2 CO2 (2) Although they have been able to reduce the metal sulfide satisfactorily if a neutral gas, such as nitrogen, is introduced, they have found it impossible to achieve a satisfactory rate of metal reduction if the sulfide-containing substance is heated directly by the combustion product of heavy oil, and considered it difficult to make any practical use of the reaction. As a result of ~heir further study, however, they have discovered that if a small quantity of a sodium salt is incorporated, it is possible to achieve a satisfactory rate of metal reduction even if the substance is heated directly by a non-reducing gas.
According to the invention there is provided a process for recovering a metal, which comprises: ad-mixing a carbonaceous reducing agent, at least one member selected from the group consisting of calcium oxide and a substance capable of ~orming calcium oxide, and at least one member selected ~rom the group consisting of sodium .j....
.~.
J~
~10~2 oxide and a sodium salt capable of producing sodium oxide, with a substance containing a sulfide of a metal selected from the group consisting of nickel, cobalt and copper;
and heating the resulting mixture to a temperature of at least 750C directly by a non-reducing gas, whereby a metal powder is formed.
- 2a -3V~
DET~ILED DESCRIPTION OF T~E INVE~NTION
The process oE this invention employs a sodium salt.
It is possible to use sodium oxide, or any other sodium salt capable of forming sodium oxide upon decomposition. It may, for example, in the form of a carbonate, sulfite, sulfate or halide. It is preferable to incorporate at least 0.5 part by weight of sodium oxide, or any other sodium salt in terms of sodium oxide, or more preferably at least one part by weight thereof, for 100 parts by weight of the substance containing a metal sulfide. It is, however, not necessary to increase its quantity greatly, since a nearly maximum rate of metal reduc-tion is obtained at that level.
The carbonaceous reducing agent employed by the pro-cess of this invention may, for example, be coal, coke or charcoal.
In some cases, it may also be possible to use a liquld carbo-naceous material, such as pitch or heavy oil~ It is suitable to employ at least 1.2 times as much of any such carbonaceous reducing agent as the quantity which can be obtained theoretical-ly by calculation according to equation (2).
The process of this invention also employs calcium oxide, or any other substance capable of forming calcium oxide upon thermal decomposition. Suitable examples of -the latter include limestone and slaked lime. It is also possible ~o use quick lime, or two or more of those substances in combination.
It is suitable to use 1.2 to 2.5 times as much of any such calcium oxide and/or substance forming calcium oxide as the quantity which can be obtained theoretically by cal~ulation according to equation (2). The use of any larger quantity is likely to lower the efficiency for the separation of the metal to be reduced.
~ 3 --The substance from which a metal is to be recovered is crushed into a powder having a particle size of 20 mesh or less, and preferably 48 mesh or less. The carbonaceous reducing agent, calcium oxide or any other substance forming calcium S oxide, and the sodium salt are also crushed appropriately, if they are a solid. It is possible to mix theml-~re efectivelv if they are mixed while they are being crushed. The resulting mixture may be heated directly, or after it has been formed into pellets or lumps. If it is formed into pellets or the like, it is advantageously possible to reduce dust.
Various types of kilns of furnaces, such as a rotary kiln, multi-hearth furnace or shaft kiln, can be used for heating the mixture. An annular vertical kiln is superior to any other kiln or furnace from the standpoint of thermal efficiency~ If this kiln is used for heating the mixture in pellets or lumps, it is possible to reduce the quantity of the non-reducing gas required for heating, and create a more reducing atmosphere in the kiln.
The non reducing gas used for heating the mixture is easv to obtain as the combustion product of a liquid fuel such as heavy oil, or a solid or gaseous fuel. It is preferable for the non-reducing gas to have an oxvgen content not exceed-ing 1% ~y volume. The presence of oxygen in any larger quantity is likely to activate oxidation and resulfurization of the reduced metal, and increase its sulfur and oxygen contents with a resultant waste of the carbonaceous reducing agent.
The following is a description of the reactions which are considered to take place during the direct desulfurization and reduction of a substance containing a metal sulfide accord ing to this invention. The carbonaceous reducing agent forms ~L18V~
a reducing gas of H2 and CO by its water gas reaction and Boudouard's reaction with H2O and CO2 in the combustion product at a prescribed temperature. This reducing gas reacts with the metal sulfide to effect its desulfurization and reduction, while forming a sulfide gas composed of H2S and COS, and maintains a reducing atmosphere in the kiln or Eurnace to pre-~ent resulfurization of the reduced metal. The sulfide gas reacts with calcium oxide, whereby sulfur is fixed by calcium.
The reactions by which the reducing gas is formed take place at a temperature of about 600C or above, and the resulfuriza-tion and reduction of nickel, cobalt and copper sulfides take place at about the same temperature~ Therefore, the heating of the reaction mixture at a temperature of at leas~ about 600C
enables the reaction from the left to right side of equation (2), whereby nickel, cobalt or copper can be reduced. In order to achieve a practically satisfactory reaction speed, however, it is necessary to employ a heating temperature of at least 750C. The optimum temperature for desulfurization and reduction depends on the metal to be reduced, while the optimum temperature for the formation of the reducing gas depends on the carbonaceous reducing agent employed. It is, thus, advisable to fin~ out an appropriate combination of the materials to be handled, and the temperature to be employed. For example, it is suitable to use bituminous coal and brown coal, which produce a large quantity of gas upon thermal decomposition, at a temperature of 750C to 900C, and coke at a temperature of 90QC to 1,200C.
The crabonaceous reducing agent is consumed with the progress of desulfurization and reduction. A decrease in 0 residual carbon leads to a reduction in the quantity of the reducing gas which is formed. A less reducing atmosphere in the kiln or furnace is likely to cause resulfurization of the reduced metal. This resulfurization takes place to a remarkable extent if the quantity of the residual carbon becomes less than 1.5% by weight~ It is, therefore, advisable to keep the residual carbon at least 1.5%, or preferzbly at least 2.0%, by weight.
The ~uantity of the residual carbon can be determined if the heated product is analyzed. A close watch for this value is advisable to ensure that the reaction product should not stay in the kiln or furnace for too long a time.
The process of this invention is applicable to any metal that can be reduced with a reducing gas. A metal having a relatively low boiling point, such as zinc, is entrained with the exhaust gas of the kiln or furnace, and can be recovered by condensation. A high~boiling metal stays in the product of desulfurization ànd reduction which contains CaS, CaO, residual carbon, ash, or the like. This product may be treated by a variety of methods for the recovery of the metai. For example, the metal can effectively be separated from the other substances by floation, or magnetic, gravitational or electrostatic con-centration. CaS and CaO can be removed by pickling with hydro-chloric, nitric, acetic or like acid. It is practically advisable to start with the recovery of the metal by dressing, and proceed with the pickling thereo~ for removing CaS and CaO.
The process of this invention can advantageously be combined with a process for producing matte from oxide ore by reducing and sulfiding rousting, so that sulfur may be effec-tively utilized. For example, an oxide ore containing nickel and cobalt oxide, such as laterite or garnierite, may be reduced and sulfurized by roasting, and the roasted ore may be reduced ~(3~
and melted to produce a nickel matte containing iron, or an iron free nickel matte if iron is removed. The process of this invention is applicable to any such nickel matte, so that the calcium sulfide and residual carbon separated from the product obtained by the direct desulfurization and reduction of the matte may be recycled for use as a sulfiding or reducing agent for the oxide ores.
As is obvious from the foregoing description, this invention provides a practical and ecnomical process which does not require any expensive hydrogen, and which can be carried out by employing an easily available source of heat, such as the combustion product of heavy oil.
The process of this invention, which is not selec-tively reducing, recovers substantially any metal from a metal 1~ sulfide-containing substance. It is, therefore, advisable to apply the process of this invention to a matte, or like con-centrate containing only the metal sought to be recovered. In order to recover nickel from a nickel matte, for example, it has been usual to employ direct electrolysis of the matte, gaseous or electric furnace reduction of a product obtained by oxidizing roasting of matte, or gaseous or electrolytic reduc-tion of a extracted product from wet-oxidization of matte.
If the process of this invention is applied to such a nickel matte, it is possible to recover nickel at a lower cost.
The invention will now be described with reference to examples thereof.
Nickel sulfide comprising 77.5% by weight of nickel and 20.5% by weight of sulfur was crushed into a powder having a particle size not greater than 100 mesh. This powder was -~ 8q~
mixed with two equivalents each of quick lime and coke, and different quantities of various sodium salts. The resulting mixture was heated at a temperature of 1,000C to 1,100C. The sodium salts were employed in the quantities of 0, 0.5, 1, 11.5, 2 and 3 parts by weight in terms of Na2O for 100 parts by weight of nickel sulfide to enable comparison of the rduc-tion rate of nickel. The quantity of the sodium salt, the type of the salt used, and the rate of nickel reduction for each of these test runs are shown in TABLE 1 below.
Sodium salt Quantity in Rate of terms of Na2O nickel Run (parts bY weiqht) Type reduction (~) 1 0 - 32 Compara-tive 2 0.5 Na2C3 91 Invention
3 1 Na~CO3 99 "
4 1.5 Na2S4 98 "
2 Na2CO3 99 "
6 2 NaCl 96 "
7 3 Na2CO3 99 "
As is obvious from TABLE 1, it is possible to achieve a metal reduction rate higher than 90% easily if at least 0.5 part by weight o a sodium salt in terms of Na2O is employed for 100 parts by weight of nickel sulfide.
A nickel matte obtained by smelting of garnierite, and containing 77.03 by weight of Ni, 0.6% by weight of Co, 0.4~ by weight of Fe and 21.0% by weight of S was crushed into a powder having a part:icle size not greater than 48 mesh, and composed of about 90% by weight of particles having a particle ~o~
size not greater than 100 mesh. Admixed thereinto were 15 parts by weight of coke having a particle size not greater than 65 mesh, and having a total carbon content of 95~ by weight, 64 parts by weight o~ quick lime and 2 parts by weight of sodium carbonate ~or 100 parts by weight of the matte powder. The resulting mixture was charged in a horizontal rotary kiln having an inside diameter of 50 cm and a length of ~ m, and heated directly by the combustion product of heavy oil containing 12%
bv volume of H2O~ 15% by volume of CO2 and 0.8% by volume of 2 The kiln had a maximum temperature of 950C, and the powder mixture stayed in the kiln for 60 minutes, including 30 minutes for which the powder mixture was heated at a temperature of at least 800C. The roasted product thus obtained had a residual carbon content of 2.8% by weight. After the roasted product had been cooled to ordinary room temperature, it was placed in water to form a slurry. The slurry was stirred for 30 minutes, while hydrochloric acid was added thereinto a maintain its pH value at 4, whereby CaS, CaO, etc. were completely eluated. The residu thus obtained was subjected to floatation, and the residual coke was separated therefrom, whereby there was obtained a nickel powder containing 97.9% by weight of Ni, 0.7% by weight of Co, 0.4~ by weight of Fe, 0.3B by weight of C and 0.2% by weight of S. Nickel per se showed a yield of 9~%. The nickel which is recovered as hereinabove described is suitable for use in the manufacture of various kinds of nickel-containing ferroalloys, such as stainless steel. The residual coke recovered by floata-tion can be reused in another cycle of roasting operation.
According to the process of this invention, it is possible to eliminate substantially any metal loss.
g -~8~
A nickel ma~te powder of the same nature as that which had been employed in EXAMPLE 2 was employed. Admixed thereinto were 15 parts by weight of bituminous coal having a particle size not greater than 65 mesh, and a total carbon content of 65% by weight, 66 parts by weight of slaked lime and 1.5 parts by weight of sodium carbonate for 100 parts by weight of the matte powder. The mixture was formed into lumps having a diameter of about 3 cm. The lumps were charged into an annular vertical kiln through the top thereof, while a mixed gas com-posed of the combustion product of heavy oil and the exhaust gas of the kiln, and having a temperature of 850C and an oxygen content of 0.1% by volume was injected into the kiln through the bottom thereof. The lumps stayed in the kiln for 45 minutes, including 20 minutes for which they were exposed to a temperature of at least 800C. The roasted product was cooled by a rotary cooler, and placed in water. The roasted lumps had an average residual carbon content of 1.9~ by weight. The water-cooled lumps were crushed by a wet ball mill into a powder having a particle size not greater than 100 mesh. The slurry thus obtained was subjected to wet magnetic concentration at 1,000 G, whereby there was obtained a nickel powder containing 94.8~
by weight of Ni, 1~3% by weight of Ca, 1.2~ by weight of S and 0.2% by weight of C. An aqueous slurry was formed from this nickel powder, and washed for 30 minutes ater hydrochloric acid had been added thereinto to adjust its pH value to 3.5.
The metal powder thus obtained contained 98~1% by weight of Ni, 0.7% by weight of Co, 0.4% by weight of Fe, 0.2% by weight o C and 0.1~ by weight oE S. Thus, nickel and cobalt showed a yield of 98.3% and 97.5~, respectively.
O~
EXAMPLE_4 A copper sulfide consisting mainly of Cu2S, and containing 79.2~ by weight of Cu and 20.5% by weight of S was crushed into a powder having a particle size not greater than 100 mesh. Admixed thereinto were 13 parts by weight of coke, 45 parts by weight of quick lime and 3 parts by weight of sodium sulfate each having a particle size not greater than 100 mesh. The resulting mixture was roasted under the same conditions as those employed in EXAMPLE 2. The roasted product had a residual carbon content of 1.7% by weight. After the roasted product had been cooled to ordinary room temperature, it was formed into an aqueous slurry. After CaS, CaO, ash, etc.
had been separated from the slurry by decantation, coke was separated from the slurry by floatation, whereby a copper powder was recovered. the copper powder contained 99.6% by weight of Cu and 0.1% by weight of S. Copper showed a yield of 99%.
2 Na2CO3 99 "
6 2 NaCl 96 "
7 3 Na2CO3 99 "
As is obvious from TABLE 1, it is possible to achieve a metal reduction rate higher than 90% easily if at least 0.5 part by weight o a sodium salt in terms of Na2O is employed for 100 parts by weight of nickel sulfide.
A nickel matte obtained by smelting of garnierite, and containing 77.03 by weight of Ni, 0.6% by weight of Co, 0.4~ by weight of Fe and 21.0% by weight of S was crushed into a powder having a part:icle size not greater than 48 mesh, and composed of about 90% by weight of particles having a particle ~o~
size not greater than 100 mesh. Admixed thereinto were 15 parts by weight of coke having a particle size not greater than 65 mesh, and having a total carbon content of 95~ by weight, 64 parts by weight o~ quick lime and 2 parts by weight of sodium carbonate ~or 100 parts by weight of the matte powder. The resulting mixture was charged in a horizontal rotary kiln having an inside diameter of 50 cm and a length of ~ m, and heated directly by the combustion product of heavy oil containing 12%
bv volume of H2O~ 15% by volume of CO2 and 0.8% by volume of 2 The kiln had a maximum temperature of 950C, and the powder mixture stayed in the kiln for 60 minutes, including 30 minutes for which the powder mixture was heated at a temperature of at least 800C. The roasted product thus obtained had a residual carbon content of 2.8% by weight. After the roasted product had been cooled to ordinary room temperature, it was placed in water to form a slurry. The slurry was stirred for 30 minutes, while hydrochloric acid was added thereinto a maintain its pH value at 4, whereby CaS, CaO, etc. were completely eluated. The residu thus obtained was subjected to floatation, and the residual coke was separated therefrom, whereby there was obtained a nickel powder containing 97.9% by weight of Ni, 0.7% by weight of Co, 0.4~ by weight of Fe, 0.3B by weight of C and 0.2% by weight of S. Nickel per se showed a yield of 9~%. The nickel which is recovered as hereinabove described is suitable for use in the manufacture of various kinds of nickel-containing ferroalloys, such as stainless steel. The residual coke recovered by floata-tion can be reused in another cycle of roasting operation.
According to the process of this invention, it is possible to eliminate substantially any metal loss.
g -~8~
A nickel ma~te powder of the same nature as that which had been employed in EXAMPLE 2 was employed. Admixed thereinto were 15 parts by weight of bituminous coal having a particle size not greater than 65 mesh, and a total carbon content of 65% by weight, 66 parts by weight of slaked lime and 1.5 parts by weight of sodium carbonate for 100 parts by weight of the matte powder. The mixture was formed into lumps having a diameter of about 3 cm. The lumps were charged into an annular vertical kiln through the top thereof, while a mixed gas com-posed of the combustion product of heavy oil and the exhaust gas of the kiln, and having a temperature of 850C and an oxygen content of 0.1% by volume was injected into the kiln through the bottom thereof. The lumps stayed in the kiln for 45 minutes, including 20 minutes for which they were exposed to a temperature of at least 800C. The roasted product was cooled by a rotary cooler, and placed in water. The roasted lumps had an average residual carbon content of 1.9~ by weight. The water-cooled lumps were crushed by a wet ball mill into a powder having a particle size not greater than 100 mesh. The slurry thus obtained was subjected to wet magnetic concentration at 1,000 G, whereby there was obtained a nickel powder containing 94.8~
by weight of Ni, 1~3% by weight of Ca, 1.2~ by weight of S and 0.2% by weight of C. An aqueous slurry was formed from this nickel powder, and washed for 30 minutes ater hydrochloric acid had been added thereinto to adjust its pH value to 3.5.
The metal powder thus obtained contained 98~1% by weight of Ni, 0.7% by weight of Co, 0.4% by weight of Fe, 0.2% by weight o C and 0.1~ by weight oE S. Thus, nickel and cobalt showed a yield of 98.3% and 97.5~, respectively.
O~
EXAMPLE_4 A copper sulfide consisting mainly of Cu2S, and containing 79.2~ by weight of Cu and 20.5% by weight of S was crushed into a powder having a particle size not greater than 100 mesh. Admixed thereinto were 13 parts by weight of coke, 45 parts by weight of quick lime and 3 parts by weight of sodium sulfate each having a particle size not greater than 100 mesh. The resulting mixture was roasted under the same conditions as those employed in EXAMPLE 2. The roasted product had a residual carbon content of 1.7% by weight. After the roasted product had been cooled to ordinary room temperature, it was formed into an aqueous slurry. After CaS, CaO, ash, etc.
had been separated from the slurry by decantation, coke was separated from the slurry by floatation, whereby a copper powder was recovered. the copper powder contained 99.6% by weight of Cu and 0.1% by weight of S. Copper showed a yield of 99%.
Claims (5)
1. A process for recovering a metal, which comprises:
admixing a carbonaceous reducing agent, at least one member selected from the group consisting of calcium oxide and a substance capable of forming calcium oxide, and at least one member selected from the group consisting of sodium oxide and a sodium salt capable of producing sodium oxide, with a substance containing a sulfide of a metal selected from the group consisting of nickel, cobalt and copper; and heating the resulting mixture to a temperature of at least 750°C directly by a non-reducing gas, whereby a metal powder is formed.
admixing a carbonaceous reducing agent, at least one member selected from the group consisting of calcium oxide and a substance capable of forming calcium oxide, and at least one member selected from the group consisting of sodium oxide and a sodium salt capable of producing sodium oxide, with a substance containing a sulfide of a metal selected from the group consisting of nickel, cobalt and copper; and heating the resulting mixture to a temperature of at least 750°C directly by a non-reducing gas, whereby a metal powder is formed.
2. A process as set forth in claim 1, wherein said sodium oxide or sodium salt is employed in a quantity of at least 0.5 parts by weight based on Na2O for 100 parts by weight of said sulfide containing substance.
3. A process as set forth in claim 1, further in-cluding forming said mixture into a shape selected from the group consisting of pellets and lumps before heating it.
4. A process as set forth in claim 2, further in-cluding forming said mixture into a shape selected from the group consisting of pellets and lumps before heating it.
5. A process as set forth in claim 3 or claim 4, wherein an annular vertical kiln is employed for heating said mixture.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17858280A JPS6040500B2 (en) | 1980-12-17 | 1980-12-17 | Metal recovery method |
| JP178582/55 | 1980-12-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1180902A true CA1180902A (en) | 1985-01-15 |
Family
ID=16050990
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000391843A Expired CA1180902A (en) | 1980-12-17 | 1981-12-09 | Process for recovering metals |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS6040500B2 (en) |
| CA (1) | CA1180902A (en) |
| FR (1) | FR2496125B1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2516545B1 (en) * | 1981-11-17 | 1987-06-19 | Sumitomo Metal Mining Co | PROCESS FOR THE TREATMENT OF OXIDATED ORES CONTAINING NICKEL AND COBALT |
| JPS63238225A (en) * | 1987-03-26 | 1988-10-04 | Sumitomo Metal Mining Co Ltd | Method for refining blister copper |
| JP4110404B2 (en) * | 2003-07-30 | 2008-07-02 | ヴァーレ・インコ・ジャパン株式会社 | Metallic nickel and its manufacturing method |
| JP4656327B2 (en) * | 2006-09-29 | 2011-03-23 | Ｔｄｋ株式会社 | Metal particle manufacturing method and metal particle manufacturing apparatus |
| CN109536732B (en) * | 2018-12-13 | 2021-03-19 | 江西赣锋循环科技有限公司 | Method for preparing ternary precursor material by recycling copper sulfide slag |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1263316B (en) * | 1965-04-07 | 1968-03-14 | Internat Nickel Company Of Can | Process for the production of nickel, nickel compounds and / or ferronickel from iron-containing, oxydic-silicate nickel ores |
| US3856505A (en) * | 1969-03-28 | 1974-12-24 | T Ogawa | Process for obtaining nickel concentrates from nickel oxide ores |
| US3754896A (en) * | 1970-08-11 | 1973-08-28 | Univ Minnesota | Process for recovering nickel from very low grade primary nickel ores |
| US3932170A (en) * | 1974-08-19 | 1976-01-13 | The United States Of America As Represented By The Secretary Of The Interior | Use of scavenger in recovery of metal values |
-
1980
- 1980-12-17 JP JP17858280A patent/JPS6040500B2/en not_active Expired
-
1981
- 1981-12-09 CA CA000391843A patent/CA1180902A/en not_active Expired
- 1981-12-16 FR FR8123489A patent/FR2496125B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57101624A (en) | 1982-06-24 |
| JPS6040500B2 (en) | 1985-09-11 |
| FR2496125B1 (en) | 1987-08-07 |
| FR2496125A1 (en) | 1982-06-18 |
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