Method for treating seabed cobalt-manganese polymetallic oxidized ore through combination of wet process and pyrogenic process

Abstract

The invention provides a wet process-pyrogenic process combined treatment method for submarine cobalt-manganese polymetallic oxidized ore, and relates to the technical field of nonferrous metallurgy. The method comprises the following steps that S1, the seabed cobalt-manganese polymetallic oxidized ore is subjected to pressure acid leaching, leaching ore pulp is obtained, the pressure of pressure acid leaching ranges from 0.2 Mpa to 4 Mpa, and the temperature ranges from 120 DEG C to 250 DEG C; s2, carrying out solid-liquid separation on the leaching ore pulp obtained in the step S1 to obtain a leaching solution containing cobalt, nickel and copper and manganese-containing acid leaching residues; and S3, the manganese-containing acid leaching slag plasma obtained in the S2 is subjected to reduction smelting to obtain manganese-silicon alloy and slag, the manganese-silicon alloy is obtained through separation, the plasma is plasma containing hydrogen groups or amino groups, and the reduction smelting temperature ranges from 1400 DEG C to 1700 DEG C. According to the method, cobalt, nickel and copper can be selectively extracted through pressure acid leaching, the manganese-silicon alloy is obtained by reducing the acid leaching residues through hydrogen plasma, a carbonaceous reducing agent does not need to be used, and the problem of carbon emission caused by the adoption of the carbon reducing agent in manganese-silicon production is solved.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metallurgical technology, and in particular to a method for hydrometallurgical-pyrometallurgical combined processing of seabed cobalt-manganese polymetallic oxide ores. Background Technology

[0002] Submarine polymetallic oxide ores refer to complex polymetallic oxide ores rich in various valuable elements such as cobalt, nickel, copper, manganese, and iron, distributed on the ocean floor. These ores include polymetallic nodules (commonly known as manganese nodules) and cobalt-rich iron-manganese crusts. These ores are characterized by polymetallic association and low grade. Besides nickel, cobalt, and copper, they also contain large amounts of iron and manganese, with the total content of nickel, cobalt, and copper being approximately 1%–3%, and manganese content approximately 15%–30%. No similar ores have been discovered or used for production on land to date. Due to the complex mineral distribution characteristics, physical beneficiation cannot separate and enrich nickel, cobalt, and copper; direct smelting, including hydrometallurgy and pyrometallurgy, is required.

[0003] Hydrometallurgy involves direct reduction leaching or leaching after pre-reduction roasting of the ore. Ammonia or inorganic acids are commonly used as leaching agents. Especially when using inorganic acids for reduction leaching, nickel, cobalt, copper, and manganese are indiscriminately leached into the solution. This not only complicates subsequent solution purification and metal separation, but also limits the production of manganese to electrolytic manganese or manganese salts and other chemical manganese products. Both electrolytic and chemical manganese products have limited market demand, making them unsuitable as the mainstream manganese product (manganese-silicon or manganese-iron alloy) for large-scale development of polymetallic nodules and cobalt-rich crusts on the seabed. Furthermore, the acid leaching stage requires the addition of carbonaceous reducing agents, which is detrimental to carbon emission control.

[0004] The prior art CN111647742A discloses a method for the stepwise extraction of nickel, cobalt, and manganese from nickel-cobalt-manganese polymetallic oxide ores using a wet process. The method involves two stages of leaching to extract nickel, cobalt, copper, and manganese from the polymetallic oxide ores. In the first stage, pressurized sulfuric acid leaching and solid-liquid separation are carried out under high temperature conditions using carbonaceous materials as a reducing agent, prioritizing the extraction of nickel, cobalt, and copper. In the second stage, manganese is extracted by water leaching of the high-temperature acid leaching residue. Although this method can achieve the stepwise extraction of nickel, cobalt, copper, and manganese, the manganese is produced in the form of manganese sulfate solution. The final manganese product is still electrolytic manganese or manganese chemical products, which is not suitable for the production of bulk manganese products such as ferromanganese or manganese-silicon alloys. Summary of the Invention

[0005] This invention addresses the shortcomings of existing methods for recovering and extracting nickel-cobalt-manganese polymetallic oxide ores, which require the addition of carbonaceous reducing agents during the acid leaching stage, hindering carbon emission control, and are unable to extract and recover bulk manganese products such as manganese silicon or manganese ferroalloys. It provides a hydrometallurgical-pyrometallurgical combined process for treating seabed cobalt-manganese polymetallic oxide ores. This method selectively extracts cobalt, nickel, and copper through specific pressurized acid leaching, while simultaneously combining hydrogen plasma reduction to obtain manganese silicon alloys. The smelting process produces no carbon dioxide emissions.

[0006] This invention protects a method for the combined hydrometallurgical and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ores, comprising the following steps: S1. The seabed cobalt-manganese polymetallic oxide ore is subjected to pressure acid leaching to obtain a leaching slurry. The pressure of the pressure acid leaching is 0.4~4MPa and the temperature is 150~250℃. S2. The leaching pulp of S1 is separated into solid and liquid components to obtain a leaching solution containing cobalt, nickel, and copper and an acid leaching residue containing manganese; S3. The manganese-containing acid leaching residue from S2 is subjected to plasma reduction smelting to obtain manganese-silicon alloy and slag. The plasma is a hydrogen-based or amino-based plasma, and the reduction smelting temperature is 1400~1700℃.

[0007] According to the method for combined wet-fired treatment of seabed cobalt-manganese polymetallic oxide ore provided by the present invention, preferably, the pressure of the pressurized acid leaching in S1 is 1~2.8MPa and the temperature is 180~230℃.

[0008] According to the present invention, a method for combined wet-pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore is preferably wherein the manganese-containing acid leaching residue in step S3 is first subjected to reduction roasting to obtain reduction roasting material before plasma reduction melting, and then subjected to plasma reduction melting. The reduction roasting temperature is 400~1000℃, and the reduction roasting atmosphere is a reducing atmosphere containing hydrogen or ammonia.

[0009] According to the present invention, a method for combined wet-pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore is preferably wherein the reducing roasted material is subjected to magnetic separation or electric furnace melting separation to remove impurities before plasma reduction smelting. Preferably, the electric furnace melting separation to remove impurities involves melting the reducing roasted material at 1300~1500℃ and then separating the slag and metal to obtain a cobalt-nickel-copper multi-element alloy and a manganese-rich slag.

[0010] According to the method for combined hydrometallurgical and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore provided by the present invention, preferably, in step S3, the ternary basicity of the manganese-containing acid leaching residue is adjusted to 0.5~1, more preferably 0.6~0.8.

[0011] According to the method for hydrometallurgical-pyrometallurgical combined treatment of seabed cobalt-manganese polymetallic oxide ore provided by the present invention, preferably, the working gas for plasma reduction smelting in S3 is a mixed gas containing reducing gas and inert gas; preferably, the reducing gas is one or a combination of two of hydrogen and ammonia.

[0012] According to the method for combined wet-pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore provided by the present invention, preferably, the volume concentration of reducing gas in the working gas is 20-80%, more preferably 40-80%.

[0013] According to the method for combined wet and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore provided by the present invention, preferably, the acid used in the pressure acid leaching is selected from at least one of sulfuric acid and nitric acid, preferably sulfuric acid, and the mass ratio of seabed cobalt-manganese polymetallic oxide ore, sulfuric acid, and water is 1:(0.3~0.7):(2~5). According to the present invention, a method for combined wet and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore is provided, wherein the fineness of the seabed cobalt-manganese polymetallic oxide ore is less than or equal to 100 mesh, preferably 100-200 mesh.

[0014] According to the present invention, a method for combined wet-pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore is provided, wherein the seabed cobalt-manganese polymetallic oxide ore is a polymetallic nodule and / or a cobalt-rich crust.

[0015] Beneficial effects: This invention provides a combined hydrometallurgical and pyrometallurgical process for treating seabed cobalt-manganese polymetallic oxide ores. Through pressurized acid leaching, cobalt, nickel, and copper can be selectively extracted, yielding a leachate containing cobalt, nickel, and copper, and an acid leaching residue rich in manganese. The acid leaching residue is then reduced using hydrogen plasma to obtain a manganese-silicon alloy. Furthermore, this method eliminates the need for carbonaceous reducing agents, avoiding the carbon emissions associated with the use of carbonaceous reducing agents in manganese-silicon production. Attached Figure Description

[0016] Figure 1 This is a flowchart of the wet-pyrometallurgical combined treatment method for seabed cobalt-manganese polymetallic oxide ore in Example 1. Detailed Implementation

[0017] The following examples are for illustrative purposes only and are not intended to limit the scope of the invention. Where specific techniques or conditions are not specified in the examples, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased from legitimate channels.

[0018] In a specific embodiment, the present invention provides a method for combined hydrometallurgical and pyrometallurgical processing of seabed cobalt-manganese polymetallic oxide ore, comprising the following steps: S1. The seabed cobalt-manganese polymetallic oxide ore is subjected to pressure acid leaching to obtain a leaching slurry. The pressure of the pressure acid leaching is 0.4~4MPa and the temperature is 150~250℃. S2. The leaching pulp of S1 is separated into solid and liquid components to obtain a leaching solution containing cobalt, nickel, and copper and an acid leaching residue containing manganese; S3. The manganese-containing acid leaching residue from S2 is subjected to plasma reduction smelting to obtain manganese-silicon alloy and slag. The plasma is a hydrogen-based or amino-based plasma, and the reduction smelting temperature is 1400~1700℃.

[0019] It should be noted that: Existing technologies involve pressure acid leaching in the presence of carbonaceous reducing agents. This reduces manganese in the ore from tetravalent to divalent, resulting in manganese sulfate. Since manganese sulfate has low solubility at high temperatures, it exists as manganese sulfate crystals in the slag. Even after cooling or washing, the manganese sulfate still enters the solution. In contrast, the S1 method of this invention involves pressure acid leaching without adding any reducing agents, using only sulfuric acid (or nitric acid) and water. This leaching occurs under an oxidizing environment, preventing manganese reduction. The manganese remains in the slag as tetravalent manganese oxides. Furthermore, during pressure acid leaching, nickel, cobalt, copper, and even some aluminum and magnesium are leached out, reducing the amount of slag. The manganese grade in the slag is higher than in the original ore, making it suitable for producing manganese-silicon alloys.

[0020] In step S1 of this invention, the controlled leaching conditions can effectively increase the leaching reaction rate and improve the leaching rate of nickel, cobalt, and copper. This invention can also effectively reduce the leaching of manganese by controlling the leaching conditions.

[0021] In S3, plasma containing hydrogen or amino groups can reduce manganese from tetravalent to 0-valent metallic manganese, i.e., manganese-silicon alloy, which can also reduce carbon emissions. The reduction smelting temperature of this invention is higher than the conventional temperature. Increasing the temperature not only reduces the melt viscosity, which is beneficial for the separation of manganese-silicon alloy and slag and improves the recovery rate of manganese-silicon alloy, but also facilitates silicon reduction, resulting in manganese-silicon alloy with high silicon content. Products with high silicon content have higher value, and hydrogen plasma reduction can easily achieve high-temperature smelting.

[0022] The present invention provides a method for hydrometallurgical-pyrometallurgical combined treatment of seabed cobalt-manganese polymetallic oxide ores. The seabed polymetallic oxide ores are first subjected to pressure acid leaching, which can selectively extract cobalt, nickel, and copper, to obtain a leachate containing cobalt, nickel, and copper and an acid leaching residue rich in manganese. The acid leaching residue is reduced by hydrogen plasma to obtain manganese-silicon alloy, and the leachate is used to produce cobalt, nickel, and copper products by conventional methods.

[0023] In S1 of this invention, pressure acid leaching is used to extract cobalt, nickel, and copper. The leaching process only requires acid and water as leaching agents, without the need to add other reducing agents, including carbon, thus reducing leaching costs and eliminating carbon dioxide emissions. In S3, the production of manganese-silicon alloy from manganese-rich acid leaching residue utilizes hydrogen-based or amino-based plasma, avoiding the carbon emission problems caused by the use of carbon reducing agents in manganese-silicon production.

[0024] In some specific embodiments, the pressure of the pressurized acid leaching mentioned in S1 of the present invention can be, for example, a point value or any range of values ​​such as 0.4 MPa, 0.8 MPa, 1 MPa, 1.2 MPa, 1.5 MPa, 1.8 MPa, 2.0 MPa, 2.5 MPa, 2.8 MPa, 3 MPa, 3.5 MPa, 4 MPa, etc., and the temperature can be, for example, a point value or any range of values ​​such as 150℃, 180℃, 200℃, 220℃, 250℃, etc.

[0025] In some specific embodiments, the pressure of the pressurized acid leaching mentioned in S1 of the present invention is 1~2.8MPa and the temperature is 180~230℃.

[0026] In some specific embodiments, the reduction melting temperature mentioned in S3 of the present invention can be, for example, a point value such as 1400°C, 1500°C, 1600°C, 1700°C, or any range of values.

[0027] In some specific embodiments, in order to further improve the purity of the manganese-containing acid leaching residue obtained by pressure acid leaching, the manganese-containing acid leaching residue in step S3 of the present invention is first subjected to reduction roasting before plasma reduction melting. The reduction roasting temperature is 400~1000℃, and the reduction roasting atmosphere is a reducing atmosphere containing hydrogen or ammonia.

[0028] The reduced roasted material is then subjected to plasma reduction melting. Compared with the pre-reduction treatment step of plasma reduction melting in step S3, the reduction roasting treatment has a lower processing temperature. On the one hand, the pre-reduction treatment can reduce the processing difficulty of plasma reduction melting and reduce reaction energy consumption, and on the other hand, it also helps to improve the purity of the final manganese silicon alloy.

[0029] In some exemplary embodiments, the specific steps of the S3 plasma reduction melting mentioned in this invention include the following: S31. Reduce the manganese-containing acid leaching residue of S2 in a hydrogen atmosphere to obtain a reduced roasted material. The reduction roasting temperature is 400~1000℃. S32. The reduced roasted material obtained in step S2 is transferred into a plasma melting furnace. The working gas is ionized into hydrogen- or amino-containing plasma by a plasma generator. Then, the plasma is used for reduction melting to obtain manganese-silicon alloy and slag.

[0030] In some specific embodiments, the present invention can also perform magnetic separation or electric furnace melting separation on the reduction roasted material before plasma reduction melting, recover and remove the iron in the reduction roasted material, reduce the iron content entering the manganese silicon alloy, increase the manganese grade entering the furnace for plasma reduction melting, reduce the energy consumption of plasma melting, and obtain a high-grade manganese silicon alloy.

[0031] In some exemplary embodiments, the specific steps of the S3 plasma reduction melting mentioned in this invention include the following: S31. The manganese-containing acid leaching residue of S2 is loaded into a reduction roasting furnace and hydrogen is introduced for reduction to obtain a reduction roasting material. The reduction roasting temperature is 400~1000℃. S32-a. The reduced roasted material obtained in step S2 is separated by magnetic separation or electric furnace melting separation to remove impurities, resulting in manganese-rich slag. S32-b: The manganese-rich slag obtained in step S32-a is transferred into a plasma melting furnace. The working gas is ionized into hydrogen- or amino-containing plasma by a plasma generator. Then, the plasma is used for reduction melting to obtain manganese-silicon alloy and slag.

[0032] In some exemplary embodiments, magnetic separation may be used to remove iron from the reducing roasted feed.

[0033] In other exemplary embodiments, for example, an electric furnace melting and separation method can be used to remove impurities. This method involves melting the reduced roasted material at 1300-1500°C and then separating the slag from the alloy to obtain a cobalt-nickel-copper multi-element alloy and a manganese-rich slag. This temperature is conducive to the complete melting and separation of the slag and the alloy.

[0034] Furthermore, before producing manganese-silicon alloy by hydrogen plasma reduction smelting, the method also reduces manganese-containing acid leaching slag with hydrogen at a lower temperature, then separates it by magnetic separation or electric furnace melting to remove the iron, and then uses hydrogen plasma reduction smelting to produce manganese-silicon alloy, thereby realizing the stepwise extraction of cobalt, nickel, copper, iron and manganese from this type of polymetallic oxide ore.

[0035] In some specific embodiments, the plasma reduction smelting mentioned in this invention preferably controls the ternary basicity of the manganese-containing acid leaching residue to be 0.5~1, for example, it can be a point value of 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 or any range of values, preferably 0.6~0.8.

[0036] Appropriately increasing the basicity of the ternary alloy can reduce the viscosity and melting point of the slag, which is beneficial to improving the slag-metal separation efficiency and manganese recovery rate. However, if the basicity is too high, it will affect the reduction of silicon into the manganese-silicon alloy. The optimal basicity of the ternary alloy is 0.6~0.8.

[0037] In conjunction with the above embodiments, in step S32 or S32-b, one or more of calcium oxide, magnesium oxide, quartz, and dolomite can be added during plasma reduction smelting to adjust the ternary basicity of the slag to 0.5-1.

[0038] Wherein, alkalinity is the ratio of the mass percentage of basic oxides to acidic oxides, and the ternary alkalinity is R3 = (CaO% + MgO%) / SiO2.

[0039] In some specific embodiments, the working gas for plasma reduction melting mentioned in S3 of the present invention is a mixture of reducing gas and inert gas; preferably, the reducing gas is one or a combination of two of hydrogen and ammonia.

[0040] Plasma reduction smelting uses a mixed gas containing both reducing and inert gases as the working gas for plasma reduction. The working gas is ionized by a plasma generator into plasma containing hydrogen or amino groups. Then, the plasma is used to reduce and smelt manganese-containing acid leaching residue to obtain manganese-silicon alloy and slag.

[0041] The inert gas mentioned in this invention can be selected from any one or more of argon, nitrogen, etc.

[0042] Furthermore, in order to improve hydrogen utilization and obtain stable plasma, in some specific embodiments, the volume concentration of reducing gas in the working gas mentioned in this invention is 20-80%, for example, it can be a point value of 20%, 30%, 40%, 50%, 60%, 70%, 80% or any range of values, preferably 40-80%.

[0043] In some specific embodiments, the acid used for pressurized acid leaching mentioned in this invention is selected from at least one of sulfuric acid and nitric acid.

[0044] For example, if sulfuric acid is used for pressurized acid leaching, the specific operation is as follows: The cobalt-manganese polymetallic oxide ore from the seabed, along with sulfuric acid and water, is added to a pressure reactor and leached with stirring at 150-250°C. The mass ratio of the polymetallic oxide ore, sulfuric acid, and water is 1:(0.3-0.7):(2-5).

[0045] The amount of sulfuric acid used can be, for example, 30%, 40%, 50%, 60%, 70% of the mass of the seabed cobalt-manganese polymetallic oxide ore, or any range thereof, and the amount of water used can be, for example, 2 times, 3 times, 4 times, 5 times of the ore mass, or any range thereof.

[0046] In a specific embodiment, in order to increase the leaching rate, the seabed cobalt-manganese polymetallic oxide ore mentioned in the method of wet-fired combined treatment of seabed cobalt-manganese polymetallic oxide ore of the present invention is seabed cobalt-manganese polymetallic oxide ore with a grinding fineness of less than or equal to 100 mesh.

[0047] In a specific implementation, the cobalt-manganese polymetallic oxide ore from the seabed can be crushed and ground to a particle size finer than 100 mesh.

[0048] For example, it can be further refined to 100~200 mesh, preferably 100 wt% below 100 mesh and 65~75 wt% below 200 mesh.

[0049] The wet-pyrometallurgical combined treatment method for seabed cobalt-manganese polymetallic oxide ore provided by this invention is widely applicable to the metal recovery and extraction of seabed cobalt-manganese polymetallic oxide ore, including polymetallic nodules and / or cobalt-rich crusts.

[0050] The elemental mass content of seabed cobalt-manganese polymetallic oxide ore can be, for example: Co 0.2~0.5%, Ni 0.41~1.25%, Cu 0.22~1.2%, Mn 19.5~28%, Fe 6.5~16.5%.

[0051] Example 1 A method for combined hydrometallurgical and pyrometallurgical processing of seabed cobalt-manganese polymetallic oxide ores, such as... Figure 1 It includes the following steps: S1. Deep-sea polymetallic nodules (containing 0.2% Co, 1.25% Ni, 1.2% Cu, 28% Mn, and 6.5% Fe by mass) are crushed and finely ground (100 wt% below 100 mesh and 65 wt% below 200 mesh). The nodules are then added to a pressure reactor along with sulfuric acid and water to form a slurry. The mass ratio of nodules, sulfuric acid, and water is 1:0.45:4. The slurry is heated to 200°C and subjected to pressurized sulfuric acid leaching for 2 hours at a pressure of 1.5 MPa. S2. After leaching, the solution was filtered to obtain a leaching solution containing nickel, cobalt, and copper, and an acid leaching residue containing manganese. The leaching rates of nickel, cobalt, copper, and manganese were 98.5%, 98.2%, 97.8%, and 6.5%, respectively. S3. After drying the manganese-containing acid-leached slag obtained in S2, it is transferred into a plasma melting furnace. Hydrogen and argon are fed into the plasma lance at a ratio of 4:1. Under the action of high-frequency voltage and electric arc, they are ionized into plasma to form a high-temperature plasma flame. The manganese-rich slag is subjected to hydrogen plasma reduction melting at 1600℃. After melting, the slag and metal are separated to obtain a manganese-silicon alloy containing 65% manganese, 17% silicon, and less than 0.05% carbon. The total amount of manganese and silicon in the manganese-silicon alloy is 82%.

[0052] Example 2 A method for combined hydrometallurgical and pyrometallurgical processing of seabed cobalt-manganese polymetallic oxide ores includes the following steps: S1. Deep-sea polymetallic nodules (containing 0.50% Co, 0.41% Ni, 0.22% Cu, 19.5% Mn and 16.5% Fe by mass) are crushed and finely ground (100 wt% below 100 mesh and 65 wt% below 200 mesh). Then, they are added to a pressure reactor along with sulfuric acid and water. The mass ratio of nodules, sulfuric acid and water is 1:0.4:4. The slurry is heated to 150°C and subjected to pressurized sulfuric acid leaching for 2 hours at a leaching pressure of 0.48 MPa. S2. After leaching, the solution was filtered to obtain a leaching solution containing nickel, cobalt, and copper, and an acid leaching residue containing manganese. The leaching rates of nickel, cobalt, copper, and manganese were 98.7%, 98.5%, 97.5%, and 8.5%, respectively. S3-1: After drying the manganese-containing acid leaching residue, place it in a fluidized bed furnace at 1000℃ and continuously reduce it with hydrogen for 4 hours; S32-a: After cooling the reduced material, weak magnetic separation is performed. The magnetic field strength of the weak magnetic separation is 1500 Oersted, resulting in iron concentrate containing 70% iron and manganese slag containing 33.5% manganese. S32-b: The manganese slag containing 33.5% manganese obtained from S32-a is dried and transferred to a plasma melting furnace. Quartz sand is added to adjust the ternary basicity of the slag to 0.6. Hydrogen and argon are fed into the plasma torch in a 4:1 ratio. Under the action of high-frequency voltage and electric arc, they are ionized into plasma to form a high-temperature plasma flame. The manganese-rich slag is subjected to hydrogen plasma reduction melting at 1600℃. After melting, the slag and metal are separated to obtain a manganese-silicon alloy containing 65% manganese and 20% silicon. The total amount of manganese and silicon in the manganese-silicon alloy is 85%.

[0053] Example 3 A method for combined hydrometallurgical and pyrometallurgical processing of seabed cobalt-manganese polymetallic oxide ores includes the following steps: S1. Deep-sea polymetallic nodules (containing 0.20% Co, 1.0% Ni, 0.91% Cu, 23.5% Mn and 7.2% Fe by mass) are crushed and finely ground (100 wt% of nodules are below 100 mesh and 75 wt% of nodules are below 200 mesh). Then, they are added to a pressure reactor along with sulfuric acid and water. The mass ratio of nodules, sulfuric acid and water is 1:0.4:4. The slurry is heated to 250°C and subjected to pressurized sulfuric acid leaching for 2 hours at a leaching pressure of 4 MPa. S2. After leaching, the solution was filtered to obtain a leaching solution containing nickel, cobalt, and copper, and an acid leaching residue containing manganese. The leaching rates of nickel, cobalt, copper, and manganese were 99.0%, 98.5%, 98.5%, and 7%, respectively. S3. After drying the acid leaching residue obtained in S2, it is loaded into a plasma melting furnace, and quartz sand is added to adjust the ternary basicity of the slag to 0.8. Then, hydrogen and argon are fed into the plasma torch in a ratio of 4:1. Under the action of high-frequency voltage and electric arc, they are ionized into plasma to form a high-temperature plasma flame. The manganese-rich slag is subjected to hydrogen plasma reduction melting at 1600℃. After melting, the slag and metal are separated to obtain a manganese-silicon alloy containing 65% manganese and 18% silicon. The total content of manganese and silicon in the manganese-silicon alloy is 83%.

[0054] Example 4 A method for combined hydrometallurgical and pyrometallurgical processing of seabed cobalt-manganese polymetallic oxide ores includes the following steps: S1. Deep-sea polymetallic nodules (containing 0.2% Co, 1.25% Ni, 1.2% Cu, 28% Mn, and 6.5% Fe by mass) are crushed and finely ground (100 wt% of the material is below 100 mesh and 65 wt% is below 200 mesh). Then, they are added to a pressure reactor along with sulfuric acid and water. The mass ratio of nodules, sulfuric acid, and water is 1:0.45:4 to prepare a slurry with a slurry mass concentration of 20% and an initial sulfuric acid concentration of 110 g / L. The slurry is heated to 200°C and subjected to pressurized sulfuric acid leaching for 2 hours at a leaching pressure of 1.5 MPa. S2. After leaching, the solution was filtered to obtain a leaching solution containing nickel, cobalt, and copper, and an acid leaching residue containing manganese. The leaching rates of nickel, cobalt, copper, and manganese were 98.5%, 98.1%, 98.2%, and 6.8%, respectively. S3-1: After drying the manganese-containing acid leaching residue, place it in a fluidized bed furnace at 1000℃ and continuously reduce it with hydrogen for 4 hours; S32-a: The reduced material is transferred into an electric furnace, heated to 1450℃ for melting, and then the slag and alloy are separated to obtain an iron alloy containing 96.5% iron and a manganese-rich slag containing 43.5% manganese. S32-b: The obtained manganese-rich slag is loaded into a plasma melting furnace, and quartz sand is added to adjust the ternary basicity of the slag to 0.8. Then, hydrogen and argon are fed into the plasma torch in a ratio of 4:1. Under the action of high-frequency voltage and electric arc, they are ionized into plasma to form a high-temperature plasma flame. The manganese-rich slag is subjected to hydrogen plasma reduction melting at 1600℃. After melting, the slag and metal are separated to obtain a manganese-silicon alloy containing 64% manganese and 27% silicon. The total content of manganese and silicon in the manganese-silicon alloy is 91%.

[0055] Example 5 A method for combined hydrometallurgical and pyrometallurgical processing of seabed cobalt-manganese polymetallic oxide ores includes the following steps: S1. Deep-sea polymetallic nodules (containing 0.20% Co, 1.25% Ni, 1.20% Cu, 28.0% Mn and 6.5% Fe by mass) are crushed and finely ground (100 wt% below 100 mesh and 65 wt% below 200 mesh). Then, they are added to a pressure reactor along with sulfuric acid and water. The mass ratio of nodules, sulfuric acid and water is 1:0.5:3. The slurry is heated to 180°C and subjected to pressurized sulfuric acid leaching for 2 hours at a leaching pressure of 1.0 MPa. S2. After leaching, the solution was filtered to obtain a leaching solution containing nickel, cobalt, and copper, and an acid leaching residue containing manganese. The leaching rates of nickel, cobalt, copper, and manganese were 98.3%, 97.5%, 97.5%, and 7.5%, respectively. S3-1: After drying the manganese-containing acid leaching residue, place it in a fluidized bed furnace at 1000℃ and continuously reduce it with hydrogen for 4 hours; S3-2: The obtained manganese-rich slag is loaded into a plasma melting furnace. Hydrogen and argon are fed into the plasma lance at a ratio of 4:1. Under the action of high-frequency voltage and electric arc, the slag is ionized into plasma, forming a high-temperature plasma flame. The manganese-rich slag is subjected to hydrogen plasma reduction melting at 1600℃. After melting, the slag and metal are separated to obtain a manganese-silicon alloy containing 65% manganese and 17% silicon. The total content of manganese and silicon in the manganese-silicon alloy is 82%.

[0056] Example 6 A method for combined wet and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ores includes steps that are basically the same as those in Example 1, except that the pressure of the pressurized acid leaching in S1 is 1.0 MPa and the temperature is 230°C.

[0057] After leaching, the solution was filtered to obtain a leaching solution containing nickel, cobalt, and copper, and an acid leaching residue containing manganese. The leaching rates of nickel, cobalt, copper, and manganese were 98.8%, 98.2%, 98.3%, and 7%, respectively. Step S3 yields a manganese-silicon alloy containing 65% manganese and 18% silicon, with a total manganese and silicon content of 83%.

[0058] Example 7 A method for combined wet-pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore includes steps that are basically the same as those in Example 1, except that the volume concentration of reducing gas in the working gas in S3 is 20%.

[0059] Step S3 yields a manganese-silicon alloy containing 64% manganese and 16% silicon, with a total manganese and silicon content of 80%.

[0060] Example 8 A method for combined wet and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore includes steps that are basically the same as those in Example 1, except that the volume concentration of reducing gas in the working gas in S3 is 50%.

[0061] Step S3 yields a manganese-silicon alloy containing 65% manganese and 17% silicon, with a total manganese and silicon content of 82%.

[0062] Comparative Example 1 A method for combined wet and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ores includes steps that are basically the same as those in Example 1, except that the acid leaching pressure in S1 is 0.3 MPa and the temperature is 130°C.

[0063] After leaching, the solution was filtered to obtain a leaching solution containing nickel, cobalt, and copper, and an acid leaching residue containing manganese. The leaching rates of nickel, cobalt, copper, and manganese were 74.5%, 45.2%, 71.5%, and 5%, respectively. Step S3 yields a manganese-silicon alloy containing 60% manganese and 14% silicon, with a total manganese and silicon content of 74%.

[0064] Comparative Example 2 A conventional method for processing cobalt-manganese polymetallic oxide ore from the seabed includes the following steps: (1) Deep-sea polymetallic nodules (containing 0.20% Co, 1.25% Ni, 1.20% Cu, 28.0% Mn and 6.5% Fe by mass) are crushed and finely ground (100 wt% below 100 mesh and 65 wt% below 200 mesh), mixed with coke powder to form pellets, with the amount of coke powder being 15% of the mass of the nodules, and then the pellets are reduced at 1000℃ for 1 hour; (2) The pellets obtained from reduction are transferred to an electric furnace and heated to 1450℃ for melting. The slag and alloy are then separated to obtain a nickel-cobalt-copper multi-element alloy containing 10.4% nickel, 1.6% cobalt, 10.04% copper, and 53.4% ​​iron, as well as a manganese-rich slag containing 43.4% manganese. (3) Add quartz sand to the manganese-rich slag obtained by melting and separation to adjust the ternary basicity to 0.8, and add coke at 20% of the mass of the manganese-rich slag. Then, smelt at 1550℃. After smelting, slag and metal are separated to obtain a manganese-silicon alloy containing 65% manganese and 18% silicon.

[0065] Although existing technologies can also prepare manganese-silicon alloys, they still require the addition of coke powder or coke for reduction in steps (1) and (3), which is not conducive to controlling carbon emissions.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for combined hydrometallurgical and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore, characterized in that, Includes the following steps: S1. The seabed cobalt-manganese polymetallic oxide ore is subjected to pressure acid leaching to obtain a leaching slurry. The pressure of the pressure acid leaching is 0.4~4MPa and the temperature is 150~250℃. S2. The leaching pulp of S1 is separated into solid and liquid components to obtain a leaching solution containing cobalt, nickel, and copper and an acid leaching residue containing manganese; S3. The manganese-containing acid leaching residue from S2 is subjected to plasma reduction smelting to obtain manganese-silicon alloy and slag. The plasma is a hydrogen-based or amino-based plasma, and the reduction smelting temperature is 1400~1700℃.

2. The method for combined hydrometallurgical and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore according to claim 1, characterized in that, The pressure for the acid leaching described in S1 is 1~2.8MPa and the temperature is 180~230℃.

3. The method for combined hydrometallurgical and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore according to claim 1, characterized in that, The manganese-containing acid leaching residue described in S3 is first reduced and roasted to obtain a reduced roasted material before plasma reduction melting, and then subjected to plasma reduction melting. The reduction roasting temperature is 400~1000℃, and the reduction roasting atmosphere is a reducing atmosphere containing hydrogen or ammonia.

4. The method for combined hydrometallurgical and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore according to claim 3, characterized in that, The reduced roasted material is subjected to magnetic separation or electric furnace melting separation to remove impurities before plasma reduction smelting. Preferably, the electric furnace melting separation to remove impurities involves melting the reduced roasted material at 1300~1500℃ and then separating the slag and metal to obtain a cobalt-nickel-copper multi-element alloy and manganese-rich slag.

5. The method for combined hydrometallurgical and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore according to any one of claims 1 to 4, characterized in that, In step S3, the ternary basicity of the manganese-containing acid leaching residue is adjusted to 0.5~1, preferably 0.6~0.

8.

6. The method for combined hydrometallurgical and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore according to any one of claims 1 to 5, characterized in that, The working gas for plasma reduction melting described in S3 is a mixture of reducing gas and inert gas; preferably, the reducing gas is one or a combination of hydrogen and ammonia.

7. The method for combined hydrometallurgical and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore according to claim 6, characterized in that, The volume concentration of reducing gas in the working gas is 20-80%, preferably 40-80%.

8. The method for combined hydrometallurgical and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore according to any one of claims 1 to 7, characterized in that, The acid used in the pressurized acid leaching is selected from at least one of sulfuric acid and nitric acid, preferably sulfuric acid. The mass ratio of the seabed cobalt-manganese polymetallic oxide ore, sulfuric acid, and water is 1:(0.3~0.7):(2~5).

9. The method for combined hydrometallurgical and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore according to any one of claims 1 to 8, characterized in that, The fineness of the seabed cobalt-manganese polymetallic oxide ore is less than or equal to 100 mesh, preferably 100-200 mesh.

10. The method for combined hydrometallurgical and pyrometallurgical treatment of seabed cobalt-manganese polymetallic oxide ore according to any one of claims 1 to 9, characterized in that, Submarine cobalt-manganese polymetallic oxide deposits are polymetallic nodules and / or cobalt-rich crusts.

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