Method for recovery of nickel from nickel matte in sulfide form

Abstract

One embodiment of the present invention discloses a method for recovery of nickel from a nickel matte in a sulfide form, comprising: an atmospheric pressure leaching process that leaches nickel matte in a sulfide form at atmospheric pressure; and a pressurized leaching process that leaches atmospheric pressure leaching residue of the nickel matte obtained in the atmospheric pressure leaching process at a pressure higher than the atmospheric pressure, wherein the acid concentration of a pressurized leaching solution of the nickel matte obtained in the pressurized leaching process is in a range of 10 g / L to 40 g / L.

Description

Method for recovering nickel from nickel matte in the form of sulfide

[0001] The present invention relates to a method for recovering nickel from nickel matte. More specifically, the present invention relates to a method for recovering nickel from nickel matte in the form of a sulfide, which can precipitate and remove iron (Fe) contained in the nickel matte.

[0002] To recover nickel from nickel matte, the matte is leached in an acid solution under atmospheric pressure. In the atmospheric leaching process, the reaction time must be prolonged (e.g., more than 16 hours) to increase the leaching efficiency of the nickel component. Consequently, production efficiency is low, and the cost of the input gas or steam increases, as well as the cost of the hydrogen peroxide (H2O2) used as an oxidizer, making it less economical. Furthermore, in the atmospheric leaching process, most of the iron (Fe) component, other than nickel, is leached together, necessitating an additional process for iron removal.

[0003] The present invention aims to provide a method for recovering nickel from nickel matte in the form of sulfide, which shortens the leaching time, thereby improving production efficiency, and removes iron through precipitation during the leaching process, thereby eliminating the need for an additional process for iron removal.

[0004] One embodiment of the present invention discloses a method for recovering nickel from a nickel mat in a sulfide form, comprising: an atmospheric pressure leaching process for leaching a nickel mat in a sulfide form at atmospheric pressure; and a pressure leaching process for leaching an atmospheric pressure leaching residue of the nickel mat obtained in the atmospheric pressure leaching process at a pressure higher than the atmospheric pressure; wherein the acid concentration of the post-pressure leaching solution of the nickel mat obtained in the pressure leaching process is in a range of 10 g / L to 40 g / L.

[0005] In one embodiment, the pressurized leaching liquid can be introduced into the atmospheric leaching process.

[0006] In one embodiment, the atmospheric pressure leaching process is performed at a pH range of 2.5 to 5.0, and iron components can be precipitated in the atmospheric pressure leaching process.

[0007] In one embodiment, the acid concentration of the pressure leaching liquid of the nickel mat obtained in the pressure leaching process may be in the range of 10 g / L to 30 g / L.

[0008] In one embodiment, nickel matte in the form of sulfide may be additionally added in the pressurized leaching process.

[0009] In one embodiment, oxygen gas and sulfuric acid solution may be introduced in the pressurized leaching process.

[0010] In one embodiment, the concentration of the sulfuric acid solution introduced in the pressurized leaching process may be in the range of 110 g / L to 140 g / L.

[0011] In one embodiment, the concentration of the sulfuric acid solution introduced in the pressurized leaching process may be in the range of 110 g / L to 130 g / L.

[0012] In one embodiment, the iron component may be precipitated in the form of hematite in the pressurized leaching process.

[0013] In one embodiment, the method further includes a repulping process of stirring the pressure leaching residue of the nickel mat obtained in the pressure leaching process with water; and a purification process of purifying the atmospheric leaching liquid of the nickel mat obtained in the atmospheric leaching process to recover a nickel component; wherein the repulping liquid of the nickel mat formed in the repulping process can be input into the pressure leaching process.

[0014] According to the present invention, the leaching time can be shortened through a pressurized leaching process in which nickel matte is leached at a pressure higher than atmospheric pressure, thereby increasing production efficiency.

[0015] In addition, according to the present invention, acid is generated in the leaching process, thereby reducing the cost of introducing an acid solution for leaching.

[0016] In addition, according to the present invention, the leaching efficiency of nickel is increased by controlling the acid concentration of the post-pressure leaching liquid of the nickel mat obtained in the pressure leaching process.

[0017] In addition, according to the present invention, since the iron component, which is an impurity, can be removed by precipitation simultaneously with the nickel leaching, an additional process for removing the iron component is omitted.

[0018] Figure 1 is a flow chart showing a method for recovering nickel from a nickel matte in the form of sulfide according to one embodiment of the present invention.

[0019] The embodiments of the present invention are provided for the purpose of illustrating the technical concept of the present invention. The scope of the rights of the present invention is not limited to the embodiments presented below or the specific descriptions of these embodiments.

[0020] Figure 1 is a flow chart showing a method for recovering nickel from a nickel matte in the form of sulfide according to one embodiment of the present invention.

[0021] Referring to FIG. 1, a method for recovering nickel from nickel matte in the form of sulfide may include a pressure leaching process (S100), a pressure leaching process (S200), a repulping process (S300), and a purification process (S400).

[0022] Nickel matte is an intermediate product produced by refining oxide and sulfide ores. Nickel matte may contain at least nickel, cobalt, copper, and iron. In one embodiment, nickel matte may contain at least 70% nickel. The nickel content in nickel matte may be higher than that of other elements. Nickel may be included in nickel matte in the form of sulfides. For example, nickel may be included in nickel matte in the form of Ni3S2.

[0023] Nickel matte may be in a pulverized state. In one embodiment, a method for recovering nickel from nickel matte in the form of a sulfide may include a raw material pulverization process prior to the atmospheric leaching process (S100). In the raw material pulverization process, the nickel matte raw material may be pulverized.

[0024] Atmospheric pressure leaching process (S100)

[0025] In the atmospheric pressure leaching process (S100), nickel matte is leached at atmospheric pressure. Oxygen gas (O2 gas) may be added to the atmospheric pressure leaching process (S100). In the atmospheric pressure leaching process (S100), nickel matte may be leached with the atmospheric pressure leaching solution of the nickel matte. The remainder of the nickel matte, excluding the atmospheric pressure leaching solution, is the atmospheric pressure leaching residue of the nickel matte.

[0026] The atmospheric pressure may be atmospheric pressure. For example, the atmospheric pressure may be 0.1 MPa or 1.0 bar. Nickel matte may be introduced into the atmospheric pressure leaching process (S100). In addition, as described below, the post-pressure leaching solution of the nickel matte obtained in the pressurized leaching process (S200) may be introduced into the atmospheric pressure leaching process (S100).

[0027] The atmospheric pressure leaching process (S100) can be carried out at a temperature range of 80°C to 95°C. The atmospheric pressure leaching process (S100) can preferably be carried out at a temperature range of 85°C to 95°C. For example, the atmospheric pressure leaching process (S100) can be carried out at 90°C. If the atmospheric pressure leaching process (S100) is carried out at a temperature lower than 80°C, the leaching efficiency may decrease, thereby reducing the nickel recovery rate. If the atmospheric pressure leaching process (S100) is carried out at a temperature higher than 95°C, water evaporates, requiring the input of industrial water due to the reduced amount of liquid, which may increase the process cost.

[0028] The atmospheric leaching process (S100) can be carried out for a period of 1 to 4 hours. For example, the atmospheric leaching process (S100) can be carried out for 3 hours. If the atmospheric leaching process (S100) is carried out for less than 1 hour, the precipitation efficiency of the iron component may be reduced. If the atmospheric leaching process (S100) is carried out for more than 4 hours, the process cost and the unit price of the operation process may increase.

[0029] The atmospheric pressure leaching process (S100) can be performed at a pH range of 2.5 to 5.0. By introducing the nickel mat into the pressurized leaching solution of the nickel mat and leaching it in the atmospheric pressure leaching process (S100), the acid remaining in the pressurized leaching solution of the nickel mat can be neutralized.

[0030] In the atmospheric pressure leaching process (S100), the iron component may be precipitated. In the atmospheric pressure leaching process (S100), the iron component may be precipitated in the form of goethite (FeO(OH)). In one embodiment, the atmospheric pressure leaching process (S100) may be performed at a pH range of 2.5 to 5.0 so that the iron component may be precipitated. Since the nickel matte is added to the pressurized leaching liquid of the nickel matte in the atmospheric pressure leaching process (S100), the acid remaining in the pressurized leaching liquid may be neutralized. Therefore, the iron component may be precipitated in the atmospheric pressure leaching process (S100). When the pH is greater than 5.0 in the atmospheric pressure leaching process (S100), precipitation of nickel and cobalt components may occur. Preferably, the atmospheric pressure leaching process (S100) may be performed at a pH range of 2.5 to 4.0.

[0031] Pressure leaching process (S200)

[0032] In the pressure leaching process (S200), the atmospheric leaching residue of the nickel matte obtained in the atmospheric leaching process (S100) can be leached. In the pressure leaching process (S200), nickel matte in the form of sulfide can be additionally introduced. In the pressure leaching process (S200), the atmospheric leaching residue of the nickel matte can be introduced together with the nickel matte. Therefore, in the pressure leaching process (S200), the atmospheric leaching residue of the nickel matte and the nickel matte can be leached. In the pressure leaching process (S200), the nickel matte or the atmospheric leaching residue of the nickel matte can be leached as the pressure leaching liquid of the nickel matte. Among the nickel matte or the atmospheric leaching residue of the nickel matte, the remainder excluding the pressure leaching liquid can be the pressure leaching residue of the nickel matte.

[0033] The pressure leaching process (S200) may be performed at a pressure higher than atmospheric pressure. In one embodiment, the pressure leaching process (S200) may be performed at a pressure ranging from 0.8 MPa to 1 MPa. For example, the pressure leaching process (S200) may be performed at a pressure of 0.9 MPa. If the pressure leaching process (S200) is performed at a pressure less than 0.8 MPa, the amount of oxygen gas input may be reduced, thereby reducing the iron precipitation rate. If the pressure leaching process (S200) is performed at a pressure exceeding 1 MPa, there may be a risk of operation due to the increased pressure, and the unit cost of the process may increase.

[0034] The pressure leaching process (S200) may be performed in a pressurized device. The pressurized device may be, for example, an autoclave. The pressurized device may include a stirrer.

[0035] The pressure leaching process (S200) can be carried out at a temperature range of 150°C or higher. If the pressure leaching process (S200) is carried out at a temperature lower than 150°C, the leaching rate of nickel components may be reduced, and thus the recovery rate of nickel components may be reduced.

[0036] The pressure leaching process (S200) may be performed for a period of time ranging from 5 to 10 hours. For example, the pressure leaching process (S200) may be performed for 7 hours. If the pressure leaching process (S200) is performed for less than 5 hours, the recovery rate of nickel components may decrease. If the pressure leaching process (S200) is performed for more than 10 hours, the process cost may increase, making it unsuitable for operation.

[0037] In the pressure leaching process (S200), the solid density of the nickel matte may be 130 g / L to 180 g / L. For example, the solid density of the nickel matte may be 150 g / L. The solid density of the nickel matte in the pressure leaching process (S200) is the sum of the mass of the atmospheric leaching residue of the nickel matte and the mass of the newly introduced nickel matte with respect to the volume of the liquid in the pressurized device where the pressure leaching process (S200) is performed. If the solid density of the nickel matte is less than 130 g / L, the liquid amount increases during raw material processing, so the facility size and liquid amount may increase. If the solid density of the nickel matte exceeds 200 g / L, the agitator of the pressurized device may not operate smoothly.

[0038] In the pressure leaching process (S200), oxygen gas (O2 gas) and an acid solution may be introduced. In one embodiment, oxygen gas and a sulfuric acid solution may be introduced in the pressure leaching process (S200). The oxygen gas may be used as an oxidizing agent. Acid may be generated in the pressure leaching process (S200). The acid generated in the pressure leaching process (S200) may be used in the pressure leaching process (S200), and the post-pressure leaching liquid may be introduced in the atmospheric leaching process (S100), thereby reducing the cost of acid introduction. The reaction formula for leaching nickel into the raw material may be represented by [Reaction Formula 1] to [Reaction Formula 4] below.

[0039] [Reaction Formula 1]

[0040] Ni3S2+ H2SO4+0.5O2→ NiSO4+ 2NiS + H2O

[0041] [Reaction Formula 2]

[0042] 4NiS + H2SO4+ 0.5O2→ NiSO4+ Ni3S4+ H2O

[0043] [Reaction Formula 3]

[0044] NiS + 2O2→ NiSO4

[0045] [Reaction Formula 4]

[0046] Ni3S4+ H2O + 7.5O2→ 3NiSO4+ H2SO4

[0047] Nickel components can be leached from nickel matte or the atmospheric leaching residue of nickel matte by [Reaction Scheme 1]. At this time, approximately 50% to 60% of the nickel components in the nickel matte or the atmospheric leaching residue of nickel matte can be leached.

[0048] NiS produced by [Reaction Scheme 1] is a stable substance at atmospheric pressure. Therefore, if NiS reacts with a sulfuric acid solution at atmospheric pressure, nickel components may not be leached. In an embodiment of the present invention, nickel components may be leached by reacting NiS with oxygen gas and a sulfuric acid solution at high pressure according to [Reaction Schemes 2] to [Reaction Schemes 4] through a pressure leaching process (S200). That is, since the nickel component of NiS is also leached, the leaching rate of the nickel component may be further increased.

[0049] In the pressure leaching process (S200), the iron component can be precipitated in the form of hematite (Fe2O3). Specifically, when oxygen gas is injected and pressure leaching is performed, the iron component is Fe 2+ It can be leached in the form of Fe by the oxygen gas injected. 3+ It is oxidized in the form of. The reaction formula can be expressed as [Reaction Formula 5] and [Reaction Formula 6] below.

[0050] [Reaction Formula 5]

[0051] FeS + H2SO4+0.5O2→ FeSO4+ H2O + S

[0052] [Reaction Formula 6]

[0053] 2Fe 2+ + 2H + +1 / 2O2→ 2Fe 3+ + H2O

[0054] And according to [Reaction Formula 7] below, Fe 3+ The iron component leached in the form can be precipitated in the form of hematite.

[0055] [Reaction Formula 7]

[0056] Fe2(SO4)3+ 4H2O → Fe2O3+ 3H2SO4+ H2O

[0057] In one embodiment, the concentration of the sulfuric acid solution introduced in the pressure leaching process (S200) may be 140 g / L or less. When the concentration of the sulfuric acid solution is 140 g / L or less, most of the nickel component may be leached. When the concentration of the sulfuric acid solution is higher than 140 g / L, the leaching efficiency of the nickel component may decrease. This may be because NiS does not react under strong acid conditions (e.g., when the concentration of the sulfuric acid solution is higher than 140 g / L). Therefore, the leaching efficiency of the nickel component may decrease. In addition, when the concentration of the sulfuric acid solution is higher than 140 g / L, the iron component may be leached without being precipitated.

[0058] In one embodiment, the concentration of the sulfuric acid solution introduced in the pressure leaching process (S200) may be 130 g / L or less. If the concentration of the sulfuric acid solution is lower than 130 g / L, most of the iron component may be precipitated.

[0059] In one embodiment, the concentration of the sulfuric acid solution introduced in the pressure leaching process (S200) may be 110 g / L or more. If the concentration of the sulfuric acid solution in the pressure leaching process (S200) is lower than 110 g / L, the leaching rate of the nickel component may be reduced, making it unsuitable.

[0060] In one embodiment, the concentration of the sulfuric acid solution introduced in the pressure leaching process (S200) may be in the range of 110 g / L to 140 g / L. Preferably, the concentration of the sulfuric acid solution introduced in the pressure leaching process (S200) may be in the range of 110 g / L to 130 g / L.

[0061] If the concentration of the acid solution being injected (e.g., the concentration of the sulfuric acid solution) is controlled, the acid concentration of the pressurized leaching solution can be controlled. In one embodiment, the acid concentration of the pressurized leaching solution of the nickel mat obtained in the pressurized leaching process (S200) can be 40 g / L or less. The acid concentration of the pressurized leaching solution can be the concentration of sulfuric acid contained in the pressurized leaching solution. When the acid concentration of the pressurized leaching solution is 40 g / L or less, most of the nickel component can be leached. For example, more than 99% of the nickel component can be leached from the nickel mat. When the acid concentration of the pressurized leaching solution is higher than 40 g / L, the leaching rate of the nickel component can be reduced.

[0062] In one embodiment, the acid concentration of the pressure leaching liquid of the nickel mat obtained in the pressure leaching process (S200) may be 30 g / L or less. When the acid concentration of the pressure leaching liquid is 30 g / L or less, the precipitation rate of the iron component may be significantly increased. For example, more than 85% of the iron component may be precipitated in the nickel mat.

[0063] In one embodiment, the acid concentration of the pressure leaching liquid of the nickel mat obtained in the pressure leaching process (S200) may be 10 g / L or more. If the acid concentration of the pressure leaching liquid is lower than 10 g / L, the nickel leaching efficiency may be reduced.

[0064] In one embodiment, the acid concentration of the pressure leaching liquid of the nickel mat obtained in the pressure leaching process (S200) may be in the range of 10 g / L to 40 g / L. Preferably, the acid concentration of the pressure leaching liquid of the nickel mat obtained in the pressure leaching process (S200) may be in the range of 10 g / L to 30 g / L.

[0065] The pressurized leaching liquid of the nickel mat can be introduced into the atmospheric leaching process (S100). By introducing the nickel mat into the pressurized leaching liquid of the nickel mat and leaching it in the atmospheric leaching process (S100), the acid remaining in the pressurized leaching liquid of the nickel mat can be neutralized.

[0066] Repulping process (S300)

[0067] In the repulping process (S300), the pressure leaching residue of the nickel mat obtained in the pressure leaching process (S200) may be stirred with water. The repulping process (S300) may be a process for recovering water-soluble nickel components remaining in the pressure leaching residue. If the repulping process (S300) is not performed, a loss in the recovery of nickel components may occur.

[0068] The repulping process (S300) may be performed at 60°C. In one embodiment, the water introduced into the repulping process (S300) may be at 60°C.

[0069] The repulping process (S300) can be performed for a time ranging from 1 hour to 2 hours. For example, the repulping process (S300) can be performed for 1 hour. If the repulping process (S300) is performed for less than 1 hour, it may be difficult to completely dissolve the nickel component. If the repulping process (S300) is performed for more than 2 hours, the process cost may increase.

[0070] In the repulping process (S300), the solid-to-liquid ratio may be in the range of 130 g / L to 180 g / L. For example, the solid-to-liquid ratio in the repulping process (S300) may be 150 g / L. If the solid-to-liquid ratio in the repulping process (S300) is higher than 200 g / L, the liquid may not be stirred smoothly in the repulping process (S300).

[0071] In the repulping process (S300), a repulping liquid of the nickel mat can be formed. The repulping liquid of the nickel mat can contain nickel components. The repulping liquid of the nickel mat can be input into the pressure leaching process (S200). Therefore, in order to recover nickel components from the nickel mat, the atmospheric pressure leaching process (S100), the pressure leaching process (S200), and the repulping process (S300) can be performed in a cycle, and the recovery of nickel components can be continuously performed.

[0072] The remaining residue from the pressure leaching of nickel matte, excluding the post-pulping liquid of nickel matte after the repulping process (S300), may be the final residue of nickel matte. In one embodiment, the final residue of nickel matte may include hematite.

[0073] Refining process (S400)

[0074] The atmospheric leaching liquid of the nickel matte can be purified in a purification process (S400). In the purification process (S400), the atmospheric leaching liquid of the nickel matte can be purified to recover the nickel component.

[0075] The method for recovering nickel from a nickel matte in the form of a sulfide according to an embodiment of the present invention can shorten the process time by including a pressure leaching process (S200) for pressurizing and leaching the nickel matte. Therefore, the production efficiency can be increased. In addition, since acid is generated in the pressure leaching process (S200), the cost of acid input can be reduced. In addition, by controlling the concentration of the input acid solution, when the acid concentration of the pressure leaching solution is 40 g / L or less, the nickel leaching efficiency can be increased, and the iron component, which is an impurity, can be precipitated simultaneously with the leaching of the nickel component. In particular, when the acid concentration of the pressure leaching solution is 30 g / L or less by controlling the concentration of the input acid solution, the iron component, which is an impurity, can be precipitated by 85% or more. Therefore, an additional process for removing the iron component can be omitted.

[0076] Example

[0077] The raw material used was nickel matte containing 73.4% nickel (Ni), 0.49% cobalt (Co), 0.18% copper (Cu), and 3.61% iron (Fe). The content ratio is in mass%. The components of the nickel matte raw material are shown in Table 1 below.

[0078] Nickel (Ni), Cobalt (Co), Copper (Cu), Iron (Fe) Content (%) 73.40.490.183.61

[0079] The leaching process used the nickel recovery method from the nickel mat in the form of sulfide according to the embodiment of the present invention described above. The solid density of the input raw material was set to 150 g / L. The atmospheric leaching process (S100) was carried out at a temperature of 90°C and a pH of 3.5 for 3 hours. The pressurized leaching process (S200) was carried out at a temperature of 150°C and a pressure of 0.9 MPa for 7 hours. The repulping process (S300) was carried out at a temperature of 60°C for 1 hour. The solid-to-liquid ratio in the repulping process (S300) was 150 g / L.

[0080] Examples 1 to 4

[0081] In Examples 1 to 4, the final leaching rate of nickel components and the precipitation rate of iron components from the nickel recovery method from the nickel mat in the form of sulfide according to the examples of the present invention were compared by controlling the concentration conditions of the sulfuric acid solution in the pressurized leaching liquid. In Example 1, the initial sulfuric acid solution concentration was set to 110 g / L, and the sulfuric acid concentration in the pressurized leaching liquid was adjusted to 10 g / L. In Example 2, the initial sulfuric acid solution concentration was set to 120 g / L, and the sulfuric acid concentration in the pressurized leaching liquid was adjusted to 20 g / L. In Example 3, the initial sulfuric acid solution concentration was set to 130 g / L, and the sulfuric acid concentration in the pressurized leaching liquid was adjusted to 30 g / L. In Example 4, the initial sulfuric acid solution concentration was set to 140 g / L, and the sulfuric acid concentration in the pressurized leaching liquid was adjusted to 40 g / L.

[0082] Comparative Examples 1 to 3

[0083] In Comparative Examples 1 to 3, the final leaching rate of nickel components and the precipitation rate of iron components were compared by controlling the conditions of the sulfuric acid concentration in the pressurized leaching liquid. In Comparative Example 1, the initial sulfuric acid solution concentration was set to 180 g / L, and the sulfuric acid concentration in the pressurized leaching liquid was adjusted to 80 g / L. In Comparative Example 2, the initial sulfuric acid solution concentration was set to 190 g / L, and the sulfuric acid concentration in the pressurized leaching liquid was adjusted to 90 g / L. In Comparative Example 3, the initial sulfuric acid solution concentration was set to 200 g / L, and the sulfuric acid concentration in the pressurized leaching liquid was adjusted to 100 g / L. Other experimental conditions are the same as those of the examples.

[0084] Initial sulfuric acid concentration (g / L) Sulfuric acid concentration in the pressurized leaching solution (g / L) Leaching rate of nickel component (%) Precipitation rate of iron component (%) Example 1 11 10 10 99.89 3.4 Example 2 1 2 0 2 99.99 0.4 Example 3 1 3 0 3 99.98 9.3 Example 4 1 4 0 4 0 99.93 0.1 Comparative example 1 1 8 0 8 0 6 1.44 20 Comparative example 2 1 9 0 9 0 6 0.82 18 Comparative example 3 2 0 0 10 0 6 1.22 11

[0085] According to Table 2, when the concentration of the initial sulfuric acid solution was adjusted so that the sulfuric acid concentration in the pressurized leaching liquid was 10 g / L to 40 g / L, the nickel leaching rate was over 99%. In addition, when the concentration of the initial sulfuric acid solution was adjusted so that the sulfuric acid concentration in the pressurized leaching liquid was 10 g / L to 30 g / L, more than about 85% of the iron components were precipitated. On the other hand, when the initial sulfuric acid concentration was adjusted high so that the sulfuric acid concentration in the pressurized leaching liquid was 80 g / L or more, the leaching rate of the nickel components decreased to about 60%, and most of the iron components were not precipitated.

[0086] While the technical concept of the present invention has been described above with reference to certain embodiments and examples illustrated in the accompanying drawings, it should be understood that various substitutions, modifications, and variations may be made without departing from the technical concept and scope of the invention, which would be understood by those skilled in the art. Furthermore, such substitutions, modifications, and variations should be considered to fall within the scope of the appended claims.

Claims

1. A pressure leaching process for leaching nickel matte in the form of sulfide at pressure; and A pressure leaching process for leaching the atmospheric pressure leaching residue of the nickel matte obtained in the atmospheric pressure leaching process at a pressure higher than the atmospheric pressure; A method for recovering nickel from a nickel matte in the form of sulfide, wherein the acid concentration of the post-pressure leaching solution of the nickel matte obtained in the above-mentioned pressure leaching process is in the range of 10 g / L to 40 g / L.

2. In paragraph 1, A method for recovering nickel from nickel matte in the form of sulfide, wherein the pressurized leachate is fed into the atmospheric leach process.

3. In paragraph 1, The above atmospheric pressure leaching process is performed at a pH range of 2.5 to 5.0, A method for recovering nickel from nickel matte in the form of sulfide, wherein iron components are precipitated in the above atmospheric leaching process.

4. In paragraph 1, A method for recovering nickel from a nickel matte in the form of sulfide, wherein the acid concentration of the pressure leaching solution obtained from the above pressure leaching process is in the range of 10 g / L to 30 g / L.

5. In paragraph 1, A method for recovering nickel from nickel matte in sulfide form, wherein nickel matte in sulfide form is additionally added in the above-mentioned pressurized leaching process.

6. In paragraph 1, A method for recovering nickel from nickel matte in the form of sulfide, wherein oxygen gas and sulfuric acid solution are injected in the above-mentioned pressurized leaching process.

7. In paragraph 6, A method for recovering nickel from nickel matte in the form of sulfide, wherein the concentration of the sulfuric acid solution injected in the above-mentioned pressure leaching process is in the range of 110 g / L to 140 g / L.

8. In paragraph 7, A method for recovering nickel from nickel matte in the form of sulfide, wherein the concentration of the sulfuric acid solution injected in the above-mentioned pressure leaching process is in the range of 110 g / L to 130 g / L.

9. In paragraph 1, A method for recovering nickel from nickel matte in the form of sulfide, wherein iron components are precipitated in the form of hematite in the above-mentioned pressurized leaching process.

10. In paragraph 1, A repulping process of stirring the pressure leaching residue of the nickel matte obtained in the pressure leaching process with water; and It further includes a purification process for purifying the post-atmospheric leaching liquid of the nickel matte obtained in the above atmospheric leaching process to recover the nickel component; A method for recovering nickel from a nickel matte in the form of a sulfide, wherein the post-pulping liquid of the nickel matte formed in the above repulping process is input into the above pressure leaching process.

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