Method for manufacturing nickel matte

Abstract

A method for manufacturing a nickel matte, according to an embodiment of the present invention, comprises the steps of: mixing sodium sulfate and a nickel oxide ore raw material containing nickel (Ni) and iron (Fe), thereby forming a mixture; compressing the mixture to form pellets; drying and then curing the pellets to form cured pellets; and melting the cured pellets to form a nickel matte, wherein the recovery rate of Ni in the nickel oxide ore raw material is 97% or more, and the removal rate of Fe is 45% or more.

Description

Method for manufacturing nickel mat

[0001] The present invention relates to a method for manufacturing a low-quality nickel mat using nickel oxide dust.

[0002] This application claims priority to Korean Patent Application No. 10-2024-0191958, filed on December 19, 2024, the entire contents of which are incorporated herein by reference.

[0003] Conventional dry processes utilizing nickel oxide ore generally consist of a process in which calcination and pre-reduction are performed at a temperature of approximately 900°C using a rotary kiln, followed by the separation of slag and molten FeNi (ferronickel) in an electric furnace to produce molten iron. In this process, the pre-reduction step is carried out by manufacturing nickel oxide ore in pellet form and feeding it in; however, some of the fed pellets break down, generating a large amount of nickel oxide dust. This generated dust requires a re-feeding process, which acts as a major cause of reduced productivity in the overall process.

[0004] Therefore, ensuring pellet stability and increasing the efficiency of pre-reduction have emerged as critical challenges, and to this end, the development of binder mixing technology is required. Currently, molasses, water glass, and bentonite are mainly used as binders, but there is a growing demand for the development of technologies utilizing by-products with similar compositions.

[0005] Meanwhile, due to the recent growth of the secondary battery industry, large amounts of sodium sulfate (Na2SO4) are being generated in wet purification processes. However, most of these byproducts require additional process technology to produce high-purity products or are disposed of or landfilled. Accordingly, there is an urgent need to develop technology that can effectively utilize sodium sulfate as a raw material for sulfidation roasting and pre-reduction.

[0006] One objective of the present invention is to solve the aforementioned problems by providing a new process and material that improve the efficiency of the nickel oxide dry process and effectively utilize the byproduct, sodium sulfate.

[0007] Another objective of the present invention is to provide a method for manufacturing a nickel mat with excellent Ni recovery rate and Fe removal rate by utilizing nickel oxide dust.

[0008] A method for manufacturing a nickel mat from nickel oxide ore according to one embodiment of the present invention comprises the steps of: mixing a nickel oxide ore raw material containing nickel (Ni) and iron (Fe) with sodium sulfate to form a mixture; pressing the mixture to form a pellet; drying the pellet and then curing it to form a formed pellet; and melting the cured pellet to form a nickel mat; wherein the Ni recovery rate of the nickel mat may be 97% or higher and the Fe removal rate may be 45% or higher.

[0009] In the step of forming a mixture by mixing the nickel oxide raw material and sodium sulfate, the sodium sulfate content may be greater than 3.0 and less than 10.0 wt% based on the total weight of the nickel oxide raw material and sodium sulfate.

[0010] The step of melting the above-mentioned cured pellets to form a nickel mat may be performed while maintaining a temperature of 1500°C or higher.

[0011] The step of melting the above-mentioned cured pellets to form a nickel mat may be performed while maintaining a reducing gas atmosphere.

[0012] In the step of forming pellets by drying and then curing the above pellets, the compressive strength of the cured pellets is 50 kgf / cm² 2 That is the limit, and simultaneously 70 kgf / cm² 2 It may be less than

[0013] The step of forming the pellets by drying and then curing the above pellets may be performed at room temperature for more than 100 hours.

[0014] In the step of forming a mixture by mixing the nickel oxide raw material and sodium sulfate, the content of nickel oxide in the nickel oxide raw material may be 1.5 to 4.0 wt%.

[0015] In the step of forming a mixture by mixing the nickel oxide raw material and sodium sulfate, the iron oxide content in the nickel oxide raw material may be 15 to 30 wt%.

[0016] In the step of forming a mixture by mixing the nickel oxide raw material and sodium sulfate, the carbon content in the nickel oxide raw material may be 2.0 to 4.0 wt%.

[0017] In the step of forming a mixture by mixing the nickel oxide raw material and sodium sulfate, the content of sodium sulfate (Na2SO4) in the sodium sulfate may be 90 to 100%.

[0018] In the step of forming a mixture by mixing the nickel oxide raw material and sodium sulfate, the sodium sulfate may be liquid sodium sulfate.

[0019] In the step of forming a mixture by mixing the nickel oxide raw material and sodium sulfate, the average particle size of the nickel oxide raw material may be 0.1 to 150.0 μm.

[0020] The step of forming pellets by compressing the above mixture may be performed by applying pressure of 100 bar or more to the mixture for 2 seconds or more.

[0021] The step of melting the above-mentioned cured pellets to form a nickel mat may be performed for 20 hours or more.

[0022] In the step of forming a pellet by drying and then curing the above pellet, the pellet may be dried while maintaining a temperature of 100°C or higher.

[0023] In the step of forming a pellet by drying and then curing the above pellet, the pellet may be dried for 10 hours or more.

[0024] A nickel oxide dust treatment method according to one embodiment of the present invention has the advantage of increasing the compressive strength of the final pellets and improving the pre-reduction ratio by adding sodium sulfate in a predetermined content range.

[0025] A nickel oxide light dust treatment method according to one embodiment of the present invention has the advantage of increasing nickel production by improving the treatment efficiency of nickel oxide light dust.

[0026] A nickel oxide dust treatment method according to one embodiment of the present invention can achieve the effect of reducing the cost of treating sodium sulfate by effectively utilizing sodium sulfate.

[0027] A nickel oxide dust treatment method according to one embodiment of the present invention has the advantage of increasing the economic efficiency of the nickel smelting process while mitigating environmental problems.

[0028]

[0029] Figure 1 schematically illustrates the nickel oxide light dust treatment process flow of the present invention.

[0030] FIG. 2 shows the measurement results of the compressive strength of cured pellets and the final obtained molded product prepared according to Comparative Examples 3 to 5 of the present invention.

[0031] In this specification, terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the invention.

[0032] The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and / or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and / or components.

[0033] When it is stated that one part is "above" or "on" another part, it may be directly above or on the other part, or other parts may be involved in between. In contrast, when it is stated that one part is "directly above" another part, no other parts are interposed in between.

[0034] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined.

[0035] Also, unless otherwise specified, % means weight %, and 1 ppm is 0.0001 weight %.

[0036] In this specification, the term “combination(s) of these” described in the Markush-type expression means one or more mixtures or combinations selected from the group consisting of the components described in the Markush-type expression, and means including any one or more selected from the group consisting of said components.

[0037] Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0038]

[0039] A method for manufacturing a nickel mat according to one embodiment of the present invention may include the steps of: mixing a nickel oxide raw material containing nickel (Ni) and iron (Fe) with sodium sulfate to form a mixture; compressing the mixture to form a pellet; drying the pellet and then curing it to form a formed pellet; and melting the cured pellet to form a nickel mat.

[0040]

[0041] First, a step is performed to form a mixture by mixing the prepared nickel oxide raw material containing nickel (Ni) and iron (Fe) with sodium sulfate.

[0042] The content of nickel oxide in the nickel oxide raw material containing nickel (Ni) and iron (Fe) may be 1.5 to 4.0 wt%, and specifically 1.5 to 3.0 wt%.

[0043] The carbon content in the nickel oxide raw material may be 2.0 to 4.0 wt%, and specifically 2.0 to 3.0 wt%.

[0044] The content of iron oxide in the above nickel oxide raw material may be 15 to 30 wt%, and specifically 15 to 25 wt%.

[0045] The average particle size of the nickel oxide raw material may be 0.1 to 150.0 μm.

[0046]

[0047] In the present invention, when the average particle size of the nickel oxide raw material is within the above range, there is an advantage in that the physical stability of the pellets described later is improved, and the compressive strength and durability of the pellets are increased through the formation of a homogeneous mixture. In addition, uniform heat transfer in the subsequent heat treatment step can prevent quality degradation during the sintering and reduction processes, and there is an advantage in that the phenomenon of disintegration is reduced and productivity is improved. If the average particle size of the nickel oxide raw material is below the above range, problems may arise such as excessive aggregation and intensified disintegration during pellet manufacturing. If the average particle size of the nickel oxide raw material exceeds the above range, there is a problem in that the uniformity of the mixture mixed with sodium sulfate is reduced, the efficiency of the subsequent heat treatment is reduced, and the quality of the manufactured nickel mat is degraded.

[0048] In the present invention, the sodium sulfate is a liquid sodium sulfate, and the content of sodium sulfate (Na2SO4) in the liquid sodium sulfate may be 90% to 100%.

[0049] In the present invention, if the sodium sulfate (Na2SO4) content in the sodium sulfate satisfies the above range, it is desirable to be able to manufacture high-quality nickel matte.

[0050] If the sodium sulfate (Na2SO4) content in the above sodium sulfate is below the above range, the manufactured pellets may easily break or pulverize, leading to a decrease in pellet strength and reduction efficiency, and a decrease in the quality of the nickel mat.

[0051] If the sodium sulfate (Na2SO4) content in the above sodium sulfate exceeds the above range, a problem may occur where the amount of slag generated increases.

[0052]

[0053] In the present invention, the sodium sulfate content can be mixed in a range of more than 3.0 wt% to less than 10.0 wt% based on the total weight of the nickel oxide raw material and sodium sulfate, and specifically, in a range of 4.5 to 9.0 wt%.

[0054] In the present invention, by controlling the sodium sulfate content to the above range, there is an advantage in that both the nickel (Ni) recovery rate and the iron (Fe) removal rate of the nickel mat produced can be improved.

[0055]

[0056] In the present invention, the nickel oxide ore raw material and solid sodium sulfate can be manually mixed in a barn bowl.

[0057] By mixing the nickel oxide raw material with the above average particle size and the sodium sulfate for the above stirring speed and / or time, the nickel oxide raw material and the sodium sulfate are uniformly distributed, which has the advantage of enabling the production of a high-quality nickel mat.

[0058]

[0059] In the present invention, the step of forming pellets by compressing the mixture of the nickel oxide ore raw material and sodium sulfate can be performed by applying pressure of 100 bar or more for 2 seconds or more. Specifically, it can be applied at a pressure of 100 to 200 bar and 140 to 160 bar for 2 to 10 seconds and 4 to 6 seconds.

[0060] When pressurized within the above pressure range and time, there is an advantage in forming pellets with excellent compressive strength. If the pressure and / or time is below the above range, the mixture may not condense sufficiently, which may result in a problem where the density of the pellets is low and strength is reduced; if the pressure and / or time exceed the above range, it may induce internal stress in the pellets, leading to a problem where quality deteriorates.

[0061]

[0062] In the present invention, the step of drying the pellets can be performed while maintaining a temperature of 100°C or higher, specifically 100 to 150°C.

[0063] In the present invention, the step of drying the pellets can be performed for 10 hours or more, specifically for 10 to 30 hours or 15 to 25 hours.

[0064] In the present invention, when drying under the above temperature and time range conditions, there is an advantage of being able to efficiently remove moisture from the pellets while ensuring the structural stability of the pellets.

[0065] If the temperature and / or time range is below the above range, moisture removal from the pellets is insufficient, which may cause cracking or collapse of the pellets during the subsequent heat treatment process due to residual moisture. Furthermore, if the temperature and / or time range is exceeded, the surface of the pellets dries rapidly, causing a thermal imbalance with the interior and leading to excessive hardening of the pellets, which may result in reduced reactivity during the subsequent process.

[0066] The step of forming a pellet by curing the above-mentioned dried pellet can be performed at room temperature for 100 hours or more, specifically for 100 to 200 hours, or 150 to 180 hours.

[0067] Meanwhile, the step of curing the dried pellets can be performed in an air atmosphere. Specifically, it can be performed in an air atmosphere with a humidity of 40 to 70%RH.

[0068] In the present invention, when cured under the above conditions, a nickel mat with excellent compressive strength can be manufactured in the subsequent heat treatment process.

[0069] In the present invention, the compressive strength (Cs1) of the cured pellet is 50 kgf / cm² 2 It may be greater than, specifically 50 kgf / cm² 2 1 to 70 kgf / cm² 2 It may be less than

[0070] As described above in the present invention, by mixing the sulfate within the above range and drying, and then curing the pellets, the strength of the pellets satisfies the above range, thereby providing the advantage of being able to manufacture nickel mats with the desired compressive strength and quality through a subsequent heat treatment process.

[0071]

[0072] The step of melting the cured pellets to form a nickel mat can be performed while maintaining a temperature of 1500°C or higher, specifically while maintaining a temperature in the range of 1500 to 1800°C or 1500 to 1700°C.

[0073] The step of melting the cured pellets to form a nickel mat can be performed for 20 hours or more, specifically for 20 to 30 hours.

[0074] When heat treatment is performed within the above range of temperature and / or time, there is an advantage in being able to manufacture nickel mats with the desired compressive strength and quality.

[0075] The step of melting the above-mentioned cured pellets to form a nickel mat can be performed in a reducing gas atmosphere, specifically while flowing carbon monoxide (CO) gas. A gas atmosphere was maintained to simulate a carbon-containing electric furnace, and an increase in the Ni recovery rate was induced in the reducing atmosphere.

[0076]

[0077] Meanwhile, in the step of melting the above-mentioned cured pellets to form a nickel mat, the following reaction may occur.

[0078] 3Ni + 2S = Ni3S2(1)

[0079] Fe + 1 / 2O2= FeO (2)

[0080] 6Fe + 3Ni + 2Na2SO4= 2Na2O + 6FeO + Ni3S2(matte) (3)

[0081]

[0082] The embodiments of the present invention will be described in more detail below through examples. However, the following examples are merely preferred embodiments of the present invention, and the present invention is not limited by the following examples.

[0083]

[0084] (Comparative Example 1) (Liquid Glauber's salt 2.5 wt%)

[0085] (Formation of mixture)

[0086] Nickel oxide dust and liquid sodium sulfate were placed into a barbed wire bowl and uniformly mixed by a mixing milling method to prepare a mixture.

[0087] The compositions of the nickel oxide dust and liquid sodium sulfate mentioned above are shown in Table 1 and Table 2 below, respectively.

[0088]

[0089] Sample Name Composition (wt%) FeO Fe2O3 NiOCoOM gOS iO2 Al2O3 Cr2O3 MnOCS Other Nickel Oxide Dust 2.2 2.5 2.7 9 0.10 3 19.3 3 4.4 2.1 10.8 4 0.4 3 2.9 7 0.0 9 12.27

[0090] In Table 2, Na, Si, Ca, and Ni are all ICP analysis values, and C and S are CS analysis values.

[0091] NaSiCaNiCS Liquid (mg / L) 52,0000.41.40.8--

[0092] At this time, the mixing ratio of the liquid sodium sulfate dispersion was set to 2.5 wt% based on the total weight of the nickel oxide dust and liquid sodium sulfate, and the amount of raw material mixture is shown in Table 3. The results of the chemical composition analysis of the mixture of the nickel oxide dust and liquid sodium sulfate are shown in Table 4 below. The chemical composition analysis is the result of XRF analysis.

[0093]

[0094] (Pellet manufacturing)

[0095] The above-mentioned mixture was loaded into a pellet press and pressurized at a pressure of 150 bar for 5 seconds to produce pellets.

[0096]

[0097] (Drying and curing)

[0098] After placing the above pellets into a Dry Oven, they were dried for 20 hours while maintaining a temperature of 120°C in an air atmosphere.

[0099] The above dried pellets were prepared by curing them for 7 days in an air atmosphere of 50~60%RH at room temperature.

[0100]

[0101] (Melting treatment)

[0102] After feeding the above-mentioned cured pellets into a vertical tubular furnace, a nickel mat was manufactured by heat treating them for 24 hours while maintaining a temperature of 1600°C in a carbon monoxide (CO) gas atmosphere.

[0103]

[0104] (Example 1) (Sodium glutamate 5wt%)

[0105] A nickel mat was prepared in the same manner as Comparative Example 1, except that in the step of forming the mixture, the mixing ratio of the sodium sulfate dispersion was set to 5.0 wt% based on the total weight of the nickel oxide dust and the liquid sodium sulfate.

[0106] The amount of raw materials mixed is shown in Table 3, and the results of the chemical composition analysis of the mixture are shown in Table 4 below.

[0107]

[0108] (Example 2) (Sodium glutamate 7.5 wt%)

[0109] A nickel mat was prepared in the same manner as Comparative Example 1, except that in the step of forming the mixture, the mixing ratio of the sodium sulfate dispersion was set to 7.5 wt% based on the total weight of the nickel oxide dust and the liquid sodium sulfate.

[0110] The amount of raw materials mixed is shown in Table 3, and the results of the chemical composition analysis of the mixture are shown in Table 4 below.

[0111]

[0112] (Comparative Example 2) (Solid Glauber's salt 10wt%)

[0113] A nickel mat was prepared in the same manner as Comparative Example 1, except that in the step of forming the mixture, the mixing ratio of the sodium sulfate dispersion was set to 10.0 wt% based on the total weight of the nickel oxide dust and the liquid sodium sulfate.

[0114] The amount of raw materials mixed is shown in Table 3, and the results of the chemical composition analysis of the mixture are shown in Table 4 below.

[0115]

[0116] Classification Dust input amount (g) Sodium glutamate input amount (g) Sodium glutamate content (wt%) based on total weight of dust and sodium glutamate Reference Example 1100g--Comparative Example 197.52.52.5 Example 19555 Example 292.57.57.5 Comparative Example 2901010

[0117] Composition Analysis Results (wt%) Na2OMgOAl2O3SiO2CaOCr2O3MnOFe2O3Co2O3NiO Other Reference Example 1 1.0229.942.8741.770.640.850.3619.610.102.090.75 Comparative Example 10.1032.712.3039.610.570.920.3720.540.092.200.59 Example 11.7729.642.9640.500.720.940.3520.050.101.980.99 Comparative Example 20.5630.062.7840.730.730.950.3520.410.112.211.11

[0118] (Reference Example 1) (No mixing of horseradish)

[0119] A nickel mat was prepared in the same manner as in Example 1, except that only nickel oxide dust was used without mixing in sodium sulfate.

[0120]

[0121] (Evaluation Example 1)

[0122] The composition of the nickel matte and nickel matte slag according to Examples 1 to 2, Comparative Examples 1 to 2 and Reference Example 1 was measured by inductively coupled plasma mass spectrometry (ICP-OES).

[0123] Table 5 below shows the results of the nickel matte slag composition analysis, and Table 6 shows the results of the nickel matte composition analysis.

[0124] Here, Fe, Ni, Co, Mg, Si, Al, Cr, and Mn are all values ​​converted based on ICP analysis results, C and S are CS analysis results, and O is the oxygen analysis result.

[0125]

[0126] Sodium Glauberis Mixing Ratio Nickel Mat Slag Composition (wt%) Na2O2O3Al2O3SiO2CaOCr2O3MnOFeONiOsum Reference Example 1 0.0% 0.26 49.45 4.31 44.40 1.00 0.11 0.07 0.65 0.01 0.26 Comparative Example 1 2.5% 0.28 41.15 3.13 45.97 0.83 1.20 0.567.01 0.17 0.28 Example 1 5.0% 0.47 36.38 3.18 48.51 0.85 1.12 0.53 9.37 0.06 0.47 Comparative Example 2 10.0% 0.63 39.74 3.044 5.87 0.82 1.15 0.55 8.69 0.15 0.63

[0127] Sodium Glutamate Mixing Ratio Nickel Mat Composition (wt%) FeNiCoMnCrAlPCaSiMgNaCS Reference Example 1 0.0% 63.7 15.3 80.2 10.5 02.3 40.6 20.0 60.0 319.2 00.7 40.0 57.1 50.0 2 Comparative Example 1 2.5% 84.7 813.5 50.4 9<0.0 100.2 40.0 10.0 4<0.0 100.1 80.120.010.060.53 Example 1 5.0%90.85 4.220.220.040.490.110.070.041.521.44 -0.190.82 Comparative Example 2 10.0%82.80 14.670.53<0.0100.210.020.05<0.0100.220.210.010.051.23

[0128] Referring to Tables 5 and 6 above, the composition of the matte and slag after mixing with sodium sulfate and melting and reducing was confirmed.

[0129] Table 7 below shows the slag production amount, Ni recovery rate, and Fe recovery rate.

[0130] The Ni recovery rate and Fe recovery rate were calculated using the following formula.

[0131] Ni Recovery Rate (%) = (Weight of Ni contained in manufactured nickel matte) / (Weight of Ni contained in initial raw nickel oxide dust) × 100 (%)

[0132] Fe Recovery Rate (%) = (Weight of Fe contained in manufactured nickel matte) / (Weight of Fe contained in initial raw material nickel oxide dust) × 100 (%)

[0133] Slag Amount Ni Recovery Rate (%) Fe Recovery Rate (%) Reference Example 1 88.86 99.52 96.89 Comparative Example 1 92.95 93.16 66.18 Example 1 84.95 97.75 54.25 Comparative Example 2 93.70 93.61 57.47

[0134] Referring to Table 7 above, it can be seen that in Examples 1 and 2, the Ni recovery rate is 97% or higher and the Fe recovery rate is less than 55%. On the other hand, in Comparative Examples 1 and 2, the Ni recovery rate is less than 97% and the Fe recovery rate is 55% or higher.

[0135]

[0136] (Comparative Example 3) (Liquid Glauber's salt 2.5 wt%)

[0137] A molded product was manufactured in the same manner as Comparative Example 1, except that the above-mentioned cured pellets were fed into a vertical tubular furnace and heat-treated for 3 hours while maintaining a temperature of 1100°C in a carbon monoxide (CO) gas atmosphere.

[0138]

[0139] (Comparative Example 4) (Liquid Glauber's salt 5 wt%)

[0140] A molded product was manufactured in the same manner as in Example 1, except that the above-mentioned cured pellets were fed into a vertical tubular furnace and heat-treated for 3 hours while maintaining a temperature of 1100°C in a carbon monoxide (CO) gas atmosphere.

[0141]

[0142] (Comparative Example 5) (Liquid Glauber's salt 7.5 wt%)

[0143] A molded product was manufactured in the same manner as Comparative Example 2, except that the above-mentioned cured pellets were fed into a vertical tubular furnace and heat-treated for 3 hours while maintaining a temperature of 1100°C in a carbon monoxide (CO) gas atmosphere.

[0144] (Comparative Example 6) (Liquid Glauber's salt 10 wt%)

[0145] A molded product was manufactured in the same manner as Comparative Example 2, except that the above-mentioned cured pellets were fed into a vertical tubular furnace and heat-treated for 3 hours while maintaining a temperature of 1100°C in a carbon monoxide (CO) gas atmosphere.

[0146]

[0147] (Evaluation Example 3: Compressive Strength Analysis)

[0148] The compressive strength of the cured pellets and the final molded product prepared according to Comparative Examples 3 to 5 above was measured and is shown in Table 8 and Figure 2 below.

[0149] Compressive strength (Cs1) of cured pellets (kgf / cm²) 2 )Compressive strength of heat-treated molded product (Cs2) (kgf / cm²) 2 Comparative Example 332.256.9 Comparative Example 451.468.2 Comparative Example 563.075.5 Comparative Example 678.744.3

[0150] Referring to Table 8 and FIG. 2 above, the compressive strength of the cured pellets prepared according to Comparative Examples 4 and 5 of the present invention is 50 kgf / cm² 2 That is the limit, and simultaneously 70 kgf / cm² 2 Included in the range less than, the compressive strength of the heat-treated molded articles is 68.2 kgf / cm² each. 2 , 75.5 kgf / cm² 2 It was found that...

[0151] On the other hand, the compressive strength of the cured pellets prepared according to Comparative Examples 3 and 6 of the present invention was 32.3 kgf / cm², respectively. 2 , 78.7 kgf / cm² 2 and the compressive strength of the heat-treated molded body is 56.9 kgf / cm², respectively. 2 , 44.3 kgf / cm² 2 It was found that it is not suitable for commercial processes.

[0152]

[0153] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto and can be implemented with various modifications within the scope of the claims, the detailed description of the invention, and the attached drawings, and it is obvious that such modifications also fall within the scope of the present invention.

[0154] Therefore, the substantive scope of the present invention shall be defined by the appended claims and their equivalents.

Claims

1. A step of forming a mixture by mixing a nickel oxide raw material containing nickel (Ni) and iron (Fe) with sodium sulfate; A step of forming pellets by compressing the above mixture; A step of drying the above pellets and then curing them to form cured pellets; and The method includes the step of melting the above-mentioned cured pellets to form a nickel mat; The above nickel mat has a Ni recovery rate of 97% or higher and an Fe removal rate of 45% or higher, Method for manufacturing nickel mat.

2. In Paragraph 1, In the step of forming a mixture by mixing the above nickel oxide ore raw material and sodium sulfate, Based on the total weight of the nickel oxide raw material and the sodium sulfate, the sodium sulfate content is greater than 3.0 and less than 10.0 wt%, Method for manufacturing nickel mat.

3. In Paragraph 1, The step of melting the above-mentioned cured pellets to form a nickel mat is: Performed while maintaining a temperature of 1500℃ or higher, Method for manufacturing nickel mat.

4. In Paragraph 1, The step of melting the above-mentioned cured pellets to form a nickel mat is: Performed while maintaining a reducing gas atmosphere, Method for manufacturing nickel mat.

5. In Paragraph 1, In the step of forming pellets by drying and then curing the above pellets, The compressive strength of the above-mentioned cured pellets is 50 kgf / cm² 2 70 kgf / cm² or higher 2 That which is less than, Method for manufacturing nickel mat.

6. In Paragraph 1, The step of forming a pellet by drying and then curing the above pellet is: Performing at room temperature for more than 100 hours, Method for manufacturing nickel mat.

7. In Paragraph 1, In the step of forming a mixture by mixing the above nickel oxide ore raw material and sodium sulfate, The nickel oxide content in the above nickel oxide raw material is 1.5 to 4.0 wt%, Method for manufacturing nickel mat.

8. In Paragraph 1, In the step of forming a mixture by mixing the above nickel oxide ore raw material and sodium sulfate, The iron oxide content in the nickel oxide raw material is 15 to 30 wt%, Method for manufacturing nickel mat.

9. In Paragraph 1, In the step of forming a mixture by mixing the above nickel oxide ore raw material and sodium sulfate, The carbon content in the nickel oxide raw material is 2.0 to 4.0 wt%, Method for manufacturing nickel mat.

10. In Paragraph 1, In the step of forming a mixture by mixing the above nickel oxide ore raw material and sodium sulfate, The sodium sulfate (Na2SO4) content in the above sodium sulfate is 90 to 100%. Method for manufacturing nickel mat.

11. In Paragraph 1, In the step of forming a mixture by mixing the above nickel oxide ore raw material and sodium sulfate, The above-mentioned fleabane is a liquid fleabane. Method for manufacturing nickel mat.

12. In Paragraph 1, In the step of forming a mixture by mixing the above nickel oxide ore raw material and sodium sulfate, The average particle size of the nickel oxide raw material is 0.1 to 150.0 μm. Method for manufacturing nickel mat.

13. In Paragraph 1, The step of forming pellets by compressing the above mixture is, Performing the above mixture while pressurizing it to a pressure of 100 bar or more for 2 seconds or more, Method for manufacturing nickel mat.

14. In Paragraph 1, The step of melting the above-mentioned cured pellets to form a nickel mat is performed for 20 hours or more. Method for manufacturing nickel mat.

15. In Paragraph 1, In the step of forming pellets by drying and then curing the above pellets, Drying the above pellets while maintaining a temperature of 100℃ or higher, Method for manufacturing nickel mat.

16. In Paragraph 15, In the step of forming pellets by drying and then curing the above pellets, Drying the above pellets for more than 10 hours, Method for manufacturing nickel mat.

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