Method for preparing ferronickel raw material

Abstract

A method for preparing a ferronickel raw material, according to one embodiment of the present invention, may comprise the steps of: mixing a nickel (Ni) oxide ore raw material and sodium sulfate so as to form a mixture; compressing the mixture so as to form pellets; drying the pellets, and then curing same so as to form pellets; and heat-treating the cured pellets so as to form a ferronickel raw material.

Description

Method for manufacturing ferronickel raw materials

[0001] The present invention relates to a nickel oxide ore treatment method, and more specifically, to a nickel oxide ore dust treatment method for producing a ferronickel raw material with excellent pressure strength using sodium sulfate.

[0002] This application claims priority to Korean Patent Application No. 10-2024-0191957, 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, a large amount of sodium sulfate byproduct (Na2SO₄) is being generated in wet refining processes. However, most of this byproduct requires additional process technology to produce high-purity products, or is disposed of or landfilled. Accordingly, there is an urgent need to develop technology that can effectively utilize sodium sulfate byproducts as raw materials 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 process for increasing the compressive strength of pellets and improving the pre-reduction ratio by introducing liquid or solid sodium sulfate during the process of manufacturing pellets using nickel oxide dust.

[0008] A method for manufacturing a ferronickel raw material using nickel (Ni) oxide ore according to an embodiment of the present invention comprises: a step of mixing a nickel (Ni) oxide ore raw material and sodium sulfate to form a mixture; a step of compressing the mixture to form pellets; a step of drying the pellets and then curing them to form pellets; and a step of heat-treating the cured pellets to form a ferronickel raw material, wherein the compressive strength of the ferronickel raw material is 70 kgf / cm² 2 The above is the case, and the strength ratio (Cs2 / Cs1) of the compressive strength (Cs2) of the ferronickel raw material to the compressive strength (Cs1) of the cured pellet may be 1.1 to 4.0.

[0009] The step of forming a pellet by drying and then curing the above pellet can be performed at room temperature for more than 100 hours.

[0010] In the step of forming a mixture by mixing the nickel oxide raw material and sodium sulfate, the sodium sulfate content may be in the range of 3.0 to 15.0 wt% based on the total weight of the nickel (Ni) oxide raw material and sodium sulfate.

[0011] In the step of forming a mixture by mixing the nickel (Ni) oxide raw material and sodium sulfate, the content of nickel oxide in the nickel (Ni) oxide raw material may be 1.5 wt% or more.

[0012] In the step of forming a mixture by mixing the nickel (Ni) oxide raw material and sodium sulfate, the content of iron oxide in the nickel (Ni) oxide raw material may be 15 wt% or more.

[0013] In the step of forming a mixture by mixing the nickel (Ni) oxide raw material and sodium sulfate, the carbon content in the nickel (Ni) oxide raw material may be 2.0 wt% or more.

[0014] In the step of forming a mixture by mixing the nickel (Ni) oxide raw material and sodium sulfate, the sodium sulfate may be solid sodium sulfate.

[0015] 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.

[0016] In the step of forming a mixture by mixing the nickel (Ni) oxide raw material and sodium sulfate, the sodium sulfate (Na2SO4) content in the sodium sulfate may be 90 to 100%.

[0017] The step of heat-treating the above-mentioned cured pellets to form a ferronickel raw material may be performed while maintaining the mixture at a temperature of 1000°C or higher.

[0018] The step of heat-treating the above-mentioned cured pellets to form ferronickel raw materials may be performed for more than 1 hour.

[0019] In the step of forming a pellet by drying and then curing the above pellet, the pellet can be dried while maintaining a temperature of 100°C or higher.

[0020] In the step of forming a pellet by drying and then curing the above pellet, the pellet may be dried for more than 10 hours.

[0021] 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.

[0022] 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.

[0023] 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 by-products.

[0024] 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.

[0025] Figure 1 schematically illustrates the nickel oxide light dust treatment process flow of the present invention.

[0026] FIGS. 2 and 3 show the shapes of cured pellets and heat-treated pellets according to embodiments and comparative examples of the present invention.

[0027] Figures 4 and 5 show the results of the compressive strength analysis of cured pellets and heat-treated pellets according to the embodiments and comparative examples of the present invention.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] Also, unless otherwise specified, % means weight %, and 1 ppm is 0.0001 weight %.

[0033] 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.

[0034] 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.

[0035]

[0036] A method for manufacturing a ferronickel raw material according to one embodiment of the present invention may include the steps of: mixing a nickel (Ni) oxide ore raw material and 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 heat-treating the cured pellet to form a ferronickel raw material.

[0037] First, a step is performed to form a mixture by mixing the prepared nickel (Ni) oxide raw material with sodium sulfate.

[0038] The content of nickel oxide in the above nickel oxide raw material may be 1.5 wt% or more, and specifically 1.5 to 4.0 wt%, or 1.5 to 3.0 wt%.

[0039] The carbon content in the nickel oxide raw material may be 2.0 wt% or more, and specifically, may be 2.0 to 4.0 wt% or 2.0 to 3.0 wt%.

[0040] The content of iron oxide in the above nickel oxide raw material may be 15 wt% or more, and specifically 15 to 30 wt%, or 15 to 25 wt%.

[0041] The above nickel oxide raw material may have an average particle size of 0.1 to 150 μm.

[0042] 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 pellet is improved, and the compressive strength and durability of the pellet 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 pellet may deteriorate.

[0043] In the present invention, the content of sodium sulfate (Na2SO4) in the sodium sulfate may be up to 90% to 100%.

[0044] In the present invention, it is desirable that the sodium sulfate (Na2SO4) content in the sodium sulfate satisfies the above range, as this enables the production of high-quality ferronickel raw materials.

[0045] If the sodium sulfate (Na2SO4) content in the above-mentioned sodium sulfate is below the above range, the manufactured pellets may easily break or pulverize, which may result in a decrease in pellet strength and reduction efficiency.

[0046] 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.

[0047]

[0048] In the present invention, the sodium sulfate content can be mixed in the range of 3.0 to 15.0 wt% based on the total weight of the nickel oxide ore raw material and sodium sulfate, and specifically, in the range of 4.5 to 10.5 wt%.

[0049] In the present invention, by controlling the sodium sulfate content to the above range, there is an advantage in that the compressive strength of the ferronickel raw material being manufactured can be excellently expressed.

[0050]

[0051] In the present invention, the nickel oxide ore raw material and solid sodium sulfate can be mixed while being introduced into a stirrer and stirred.

[0052] By mixing the nickel oxide raw material with the above average particle size and sodium sulfate for the above stirring speed and / or time, the nickel oxide raw material and sodium sulfate are uniformly distributed, which has the advantage of enabling the production of high-quality ferronickel raw materials.

[0053] In the present invention, the above-mentioned sodium sulfate may be one selected from liquid sodium sulfate, solid sodium sulfate, or a mixture thereof.

[0054] In the present invention, when the above-mentioned sodium sulfate is in a solid state, the average particle size of the solid sodium sulfate may be 0.1 to 150 μm.

[0055] In the present invention, if the average particle size of the nickel oxide ore raw material and the solid sodium sulfate satisfies the above range, there is an advantage in that layer separation of the mixture is prevented and a uniform distribution can be formed.

[0056]

[0057] 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 while applying pressure of 100 bar or more for 2 seconds or more. Specifically, pressure can be applied at 100 to 200 bar and 140 to 160 bar for 2 to 10 seconds and 4 to 6 seconds.

[0058] 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.

[0059]

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] In the present invention, when cured under the above conditions, a ferronickel raw material with excellent compressive strength can be produced in the subsequent heat treatment process.

[0067] In the present invention, the compressive strength (Cs1) of the cured pellet is 40 kgf / cm² 2 It may be greater than, specifically 40 kgf / cm² 2 1 to 70 kgf / cm² 2 It may be less than

[0068] As described above in the present invention, by mixing the sodium 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 ferronickel raw materials with the desired compressive strength quality through a subsequent heat treatment process.

[0069]

[0070] The step of heat-treating the above-mentioned cured pellets to form a ferronickel raw material can be performed while maintaining a temperature of 1000°C or higher, specifically, it can be performed while maintaining a temperature of 1000 to 1500°C or 1000 to 1200°C.

[0071] The step of heat-treating the above-mentioned cured pellets to form a ferronickel raw material can be performed for at least 1 hour, and specifically, for 1 to 5 hours or 2 to 5 hours.

[0072] When heat treatment is performed within the above range of heat treatment temperature and / or time, there is an advantage in being able to produce ferronickel raw materials with the desired compressive strength quality.

[0073] In the present invention, the compressive strength (Cs2) of the ferronickel raw material is 70 kgf / cm 2 It may be higher, specifically 90 kgf / cm² 2 Above, 90 to 130 kgf / cm²2 It could be.

[0074] In the present invention, the strength ratio (Cs2 / Cs1) of the compressive strength (Cs2) of the ferronickel raw material to the compressive strength (Cs1) of the cured pellet may be 1.5 to 4.0.

[0075] In the present invention, the ratio of the compressive strength (Cs2) of the ferronickel raw material to the compressive strength (Cs1) of the cured pellet satisfies the above range, thereby allowing the ferronickel raw material of the desired compressive strength quality to be produced by appropriately controlling the amount of sodium sulfate used in the entire production process of manufacturing ferronickel raw material using nickel-containing dust and sodium sulfate, and there is an advantage of improving overall production efficiency and economic benefits.

[0076] Meanwhile, in the step of heat-treating the above-mentioned cured pellets to form a ferronickel raw material, the following reaction may occur.

[0077] Na2SO4 + 4CO → Na2S + 4CO2

[0078] NiFe2O4+ CO → Ni + Fe2O3+ CO2

[0079] Na2SO4+ 2Fe2SiO4→ 4FeO + Na2Si2O5

[0080] Na2S + FeO + 2SiO2→ FeS + Na2Si2O5

[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) (Solid Glauber's salt 2.5 wt%)

[0085] (Formation of mixture)

[0086] Nickel oxide dust with an average particle size of about 100 µm and solid Na2SO4 byproduct with an average particle size of about 100 µm (Na2SO4 content in the byproduct was 95 wt% or more) were used, and the nickel oxide dust and solid Na2SO4 byproduct were uniformly mixed by manual mixing in a barn to prepare a mixture.

[0087] At this time, the mixing ratio of the solid sodium sulfate dispersion was set to 2.5 wt% based on the total weight of the nickel oxide dust and solid sodium sulfate by-product, and the amount of raw material mixed is shown in Table 3.

[0088] The compositions of the nickel oxide ore and solid sodium sulfate byproducts are shown in Table 1 and Table 2 below, respectively.

[0089] In Table 2, Na, Si, Ca, and Ni are all ICP analysis values, and C and S are CS analysis values.

[0090]

[0091] 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

[0092] NaSiCaNiCS Other Solid Phase (wt%) 32<0.01<0.01<0.01 0.03133.1> 34.854 Liquid Phase (mg / L) 52,000 0.41.40.8

[0093] 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 130g -- Comparative Example 129.25 (Solid) 0.75 2.5 Example 128.5 (Solid) 1.55 Example 227.75 (Solid) 2.25 7.5 Example 327 (Solid) 310 Comparative Example 229.25 (Liquid) 0.75 2.5 Comparative Example 328.5 (Liquid) 1.55 Comparative Example 427 (Liquid) 310

[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 40~60%RH at room temperature.

[0100]

[0101] (Heat treatment)

[0102] After the above-mentioned cured pellets were fed into a pellet box, they were heat-treated for 3 hours at a temperature of 1100°C in an air atmosphere to produce ferronickel raw materials.

[0103]

[0104] (Example 1) (Solid Glauber's salt 5wt%)

[0105] Ferronickel raw material 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 solid sodium sulfate by-product.

[0106]

[0107] (Example 2) (Solid Glauber's salt 7.5 wt%)

[0108] Ferronickel raw materials were 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 sodium sulfate byproduct.

[0109]

[0110] (Example 3) (Solid Glauber's salt 10 wt%)

[0111] Ferronickel raw material 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 sodium sulfate byproduct.

[0112]

[0113] (Reference Example 1) (No mixing of horseradish)

[0114] Ferronickel raw materials were prepared in the same manner as in Example 1, except that only nickel oxide dust was used without mixing in sodium sulfate byproducts.

[0115]

[0116] (Example 4) (Liquid Glauber's salt 7.5 wt%)

[0117] Ferronickel raw material was prepared in the same manner as Comparative Example 1, except that in the step of forming the mixture, liquid sodium sulfate shown in Table 2 was used instead of solid sodium sulfate by-product, and the mixing ratio of the liquid sodium sulfate dispersion was 7.5 wt% based on the total weight of the nickel oxide dust and the liquid sodium sulfate by-product.

[0118]

[0119] (Comparative Example 3) (Liquid Glauber's salt 2.5 wt%)

[0120] Ferronickel raw material was prepared in the same manner as in Example 4, except that in the step of forming the mixture, the mixing ratio of the sodium sulfate dispersion was set to 2.5 wt% based on the total weight of the nickel oxide dust and sodium sulfate byproduct.

[0121]

[0122] (Comparative Example 4) (Liquid Glauber's salt 5.0 wt%)

[0123] Ferronickel raw material was prepared in the same manner as in Example 4, 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 sodium sulfate byproduct.

[0124]

[0125] (Comparative Example 5) (Liquid Glauber's salt 10.0 wt%)

[0126] Ferronickel raw material was prepared in the same manner as in Example 4, 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 sodium sulfate byproduct.

[0127]

[0128] (Evaluation Example 1: Shape Observation)

[0129] The shapes of the cured pellets and heat-treated pellets prepared according to the above examples, comparative examples, and reference examples were observed and are shown in FIGS. 2 and FIGS. 3.

[0130] Referring to FIGS. 2 and FIGS. 3, it can be seen that the cured pellets prepared according to Examples 1 to 4, Comparative Examples 1 to 4 and Reference Example did not exhibit differentiation.

[0131] Referring to FIGS. 2 and FIGS. 3, it can be seen that the heat-treated pellets prepared according to Examples 1 to 4 did not exhibit a differentiation phenomenon, whereas the heat-treated pellets prepared according to the Reference Example and Comparative Example exhibited a differentiation phenomenon.

[0132]

[0133] (Evaluation Example 2: Chemical Composition Analysis)

[0134] Table 4 below shows the chemical composition analysis values ​​of the cured pellets and heat-treated pellets according to Examples 1 to 3, Reference Example 1, and Comparative Examples 1 to 4.

[0135] 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.

[0136] Cured pellet components (wt%) Heat-treated pellet components (wt%) M-FeFe2O3FeOOCS Other M-FeFe2O3FeONiCoNaSiCaMgAl Other Reference Example 1 < 0.22 2.65 2.52 4 2.13 50.09 4>28.94 < 0.2 < 0.32 8.65 2.44 0.09 0.07 18.8 10.29 12.86 1.26>35.03 Comparative Example 1 < 0.22 1.39 2.52 40.74 40.7 16>30.07 < 0.2 < 0.32 8.24 2.38 0.09 0.23 18.43 0.29 12.42 1.29>36.13 Example 1 < 0.222.062.39413.190.362>30.80< 0.2< 0.328.522.450.090.4718.710.2812.691.28>35.01 Example 2< 0.221.752.6235.23.660.441>36.13< 0.2< 0.326.962.310.092.9317.220.2811.831.22>36.66 Example 3< 0.219.722.3840.73.172.62>31.21< 0.2< 0.326.462.250.083.7917.230.2711.951.21>36.26Comparative Example 2< 0.221.902.0837.93.560.197>34.16< 0.2< 0.326.122.240.083.6417.100.2611.631.16Comparative Example 3< 0.222.082.3138.73.690.382>32.64< ​​0.2< 0.326.742.270.092.9017.200.2811.661.24Comparative Example 4< 0.222.052.4939.83.570.529>31.36< 0.2< 0.328.022.400.091.1218.020.3112.151.29

[0137] Referring to Table 4 above, it was confirmed that Fe2O3 was reduced to FeO in the heat-treated pellets.

[0138] Table 5 below shows the XRD analysis values ​​of the cured pellets and heat-treated pellets according to Examples 1 to 3, Reference Example 1, and Comparative Examples 1 to 4.

[0139]

[0140] Cured Pellet Heat-treated Pellet Compound Name Quartz(wt%) Lizardite(wt%) Talc(wt%) Norbergite(wt%) Forsterite(wt%) Brucite(wt%) Quartz(wt%) Cristobalite(wt%) Forsterite(wt%) Protoenstatite(wt%) Magnesioferrite(wt%) Chemical Formula SiO2Mg3(Si2O5)(OH)4Mg3(Si4O 10 )(OH)2Mg3(SiO4)(F,OH)2Mg2SiO4Mg(OH)2SiO2SiO2Mg2SiO4MgSiO3MgFe2O4 Reference Example 1 15.147.138---8.175.910.333.941.7 Comparative Example 1 10.923.817-48-8.347.45.339.339.7 Example 1 23.942.633---7.84.997.141. 838.2 Example 2 20.4 44.6 35---0.58 -32 26.6 40.9 Example 3 11.9 29.3 16.8 20-2 20.55 -49 9.4 41 Comparative Example 2 25.1 44.5 30---1.3 -46 25.1 44.5 Comparative Example 3 20.2 49.5 30.3---1 -31.3 20.2 49.5 Comparative Example 4 21.2 46.3 32.5---3.4 -7 21.2 46.3

[0141] Referring to Table 5 above, it was confirmed that mineral phase components were reduced in the heat-treated pellets.

[0142] (Evaluation Example 3: Compressive Strength Analysis)

[0143] The compressive strength of cured pellets and heat-treated pellets prepared according to the above examples, comparative examples, and reference examples was measured and is shown in Table 6 and Figures 4 and 5 below.

[0144] Compressive strength (Cs1) of cured pellets (kgf / cm²) 2 ) Heat-treated pellet compressive strength (Cs2) (kgf / cm²) 2Compressive strength ratio (Cs2 / Cs1) Reference Example 1 -- Comparative Example 1 30.4 20.9 0.69 Example 1 44.7 104.3 2.34 Example 2 68.6 125.5 1.83 Example 3 26.9 96.0 3.57 Comparative Example 2 32.2 56.9 1.77 Comparative Example 3 51.4 68.2 1.33 Comparative Example 4 78.7 44.3 0.56

[0145] Referring to Table 8, FIG. 4, and FIG. 6 above, the compressive strength of the heat-treated pellets, i.e., the ferronickel raw material, manufactured according to an embodiment of the present invention is 70 kgf / cm² 2 It can be confirmed that the strength ratio (Cs2 / Cs1) of the compressive strength (Cs2) of the ferronickel raw material to the compressive strength (Cs1) of the cured pellet is 1.8 to 4.0.

[0146] 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.

[0147] 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 nickel oxide raw material and sodium sulfate; A step of forming pellets by compressing the above mixture; A step of forming a pellet by drying the above pellet and then curing it; and The method includes the step of heat-treating the above-mentioned cured pellets to form a ferronickel raw material; The compressive strength of the above ferronickel raw material is 70 to 130.0 kgf / cm 2 That is all, The strength ratio (Cs2 / Cs1) of the compressive strength (Cs2) of the ferronickel raw material to the compressive strength (Cs1) of the cured pellet is in the range of 1.8 to 4.

0. Method for manufacturing ferronickel raw materials.

2. 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 ferronickel raw materials.

3. 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 (Ni) oxide raw material and the sodium sulfate, the sodium sulfate content is in the range of 3.0 to 15.0 wt%, Method for manufacturing ferronickel raw materials.

4. In Paragraph 1, In the step of forming a mixture by mixing the above nickel (Ni) oxide raw material and sodium sulfate, The nickel oxide content in the above nickel (Ni) oxide raw material is 1.5 wt% or more, Method for manufacturing ferronickel raw materials.

5. In Paragraph 1, In the step of forming a mixture by mixing the above nickel (Ni) oxide raw material and sodium sulfate, The iron oxide content in the above nickel (Ni) oxide raw material is 15 wt% or more, Method for manufacturing ferronickel raw materials.

6. In Paragraph 1, In the step of forming a mixture by mixing the above nickel (Ni) oxide raw material and sodium sulfate, The carbon content in the above nickel (Ni) oxide raw material is 2.0 wt% or more, Method for manufacturing ferronickel raw materials.

7. In Paragraph 1, In the step of forming a mixture by mixing the above nickel (Ni) oxide raw material and sodium sulfate, The above-mentioned fleabane is an elevated fleabane, Method for manufacturing ferronickel raw materials.

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

9. 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 ferronickel raw materials.

10. In Paragraph 1, The step of heat-treating the above-mentioned cured pellets to form a ferronickel raw material is: The above mixture is performed while maintaining a temperature of 1000℃ or higher, Method for manufacturing ferronickel raw materials.

11. In Paragraph 1, The step of heat-treating the above-mentioned cured pellets to form a ferronickel raw material is performed for at least one hour. Method for manufacturing ferronickel raw materials.

12. 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 ferronickel raw materials.

13. In Paragraph 12, 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 ferronickel raw materials.

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