Method for manufacturing nickel matte

Abstract

An aspect of the present invention is to provide a method for manufacturing a nickel matte, capable of easily controlling the temperature and enhancing efficiency compared with an existing process by using sodium sulfate (Na2SO4) instead of sulfur, as a sulfurization raw material, during the manufacture of the nickel matte.

Description

Nickel mat manufacturing method

[0001] The present invention relates to a method for manufacturing nickel mat.

[0002] Typically, the nickel matte manufacturing process involves a sulfidation process and a de-ironization process. The sulfidation process typically utilizes sulfur (S), which sulfides the nickel within ferronickel into nickel sulfide (Ni3S2), concentrating the nickel in the matte layer. Meanwhile, the de-ironization process oxidizes the iron within ferronickel (FeNi) to iron (II) oxide and removes the slag layer containing iron (II) oxide.

[0003]

[0004] However, the existing nickel matte manufacturing process using sulfur has several process-related problems, such as requiring multiple stages of de-ironization and requiring temperature control throughout the process due to the physical properties of liquid sulfur.

[0005] One aspect of the present invention is to provide a method for manufacturing nickel matte capable of selectively oxidizing iron in the initial raw materials, such as molten alloy and ferronickel (FeNi), and sulfiding and concentrating nickel.

[0006]

[0007] The objectives of the present invention are not limited to the above-described scope. Those skilled in the art will have no difficulty understanding the additional objectives of the present invention from the overall content of this specification.

[0008] One aspect of the present invention provides a method for manufacturing a nickel matte, comprising the steps of: preparing a molten alloy containing nickel; and adding ferronickel (FeNi) and sodium sulfate (Na2SO4) to the molten alloy to concentrate nickel and sulfur.

[0009]

[0010] The above alloy melt may contain 50.0 wt% or more of nickel.

[0011]

[0012] The above ferronickel may be added in an amount of 15.0 wt% or more and 35.0 wt% or less based on the total weight of the molten alloy, and the above sodium sulfate may be added in an amount of 5.0 wt% or more and 15.0 wt% or less based on the total weight of the molten alloy.

[0013]

[0014] The above alloy melt may be derived from a ferronickel process.

[0015]

[0016] The nickel content of the manufactured nickel mat may be 55.0 wt% or more based on the total weight of the nickel mat, and the sulfur content may be 10.0 wt% or more based on the total weight of the nickel mat.

[0017]

[0018] Meanwhile, the method for manufacturing a nickel mat of the present invention may additionally include a step of introducing oxygen (O2) into the alloy molten metal.

[0019]

[0020] The oxygen may be injected using at least one of a lance and a tuyere.

[0021]

[0022] In addition, the nickel mat manufacturing method of the present invention can introduce a slag forming agent together with the oxygen.

[0023]

[0024] The above slag forming agent may include silica (SiO2).

[0025]

[0026] The step of preparing the above alloy molten metal can be performed at a temperature range of 0°C to 300°C higher than the melting point of the above alloy molten metal, and the step of concentrating the nickel and sulfur can be performed at a temperature range of 0°C to 300°C higher than the melting point of the above alloy molten metal.

[0027]

[0028] Another aspect of the present invention provides a nickel mat comprising nickel in an amount of 55.0 wt% or more, sulfur in an amount of 10.0 wt% or more, and sodium, based on the total weight of the nickel mat.

[0029]

[0030] The above sodium may be included in an amount of 0.10 wt% or less based on the total weight of the nickel mat.

[0031]

[0032] The above nickel mat may have an A value of 50.0 or more derived by the following [Relationship 1].

[0033] [Relationship 1] A =

[0034] (In the above [Relationship 1], [Ni], [S], and [Na] represent the weight percentages of nickel, sulfur, and sodium contained in the nickel mat, respectively, with respect to the total weight of the nickel mat.)

[0035] The present invention can provide a de-ironization reaction with easy temperature control compared to existing processes by using sodium sulfate (Na2SO4) instead of sulfur (S) as a sulfide raw material in the production of nickel matte.

[0036] In this way, when sodium sulfate is used instead of sulfur, the de-ironization time can be shortened, thereby increasing process efficiency.

[0037] In addition, in this case, sodium sulfate, which is discarded as a by-product, can be used as sulfur fuel, which saves disposal costs, making it economically advantageous.

[0038] Figure 1 shows the thermodynamic calculation results of component changes during nickel sulfidation.

[0039] Figure 2 is a schematic diagram showing a simplified nickel mat manufacturing process using conventional sulfur (S) and a nickel mat manufacturing process using sodium sulfate (Na2SO4).

[0040] Figure 3 is a schematic diagram showing a simplified de-ironization process using conventional sulfur and a de-ironization process using sodium sulfate.

[0041] Figure 4 is a graph showing changes in the composition of nickel mat over time for each of the invention examples and comparative examples.

[0042] Figure 5 is a graph showing the nickel recovery rate and sulfur sulfidation efficiency according to the de-ironization reaction of each of the invention examples and comparative examples.

[0043] Hereinafter, preferred embodiments of the present invention will be described. However, the embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

[0044]

[0045] In this specification, the term "including" is used to indicate that other components may be included rather than excluding other components unless specifically stated to the contrary.

[0046]

[0047] Additionally, unless otherwise specifically provided in the specification of the present invention, the % unit means weight%.

[0048]

[0049] As mentioned above, the nickel matte manufacturing process generally involves a sulfurization process using sulfur (S) and a de-ironization process. In this case, the reaction formula within the sulfurization process using sulfur (S) is as shown in [Reaction Formula 1] below, and the reaction formula within the de-ironization process is as shown in [Reaction Formula 2] below.

[0050]

[0051] [Reaction Formula 1]

[0052]

[0053]

[0054] [Reaction Formula 2]

[0055]

[0056] However, since the nickel matte manufacturing process using sulfur goes through several stages of de-ironization, there are problems with very low flexibility in operation control, such as heat and material balance imbalance and damage to refractory materials during long-term tempering operations.

[0057]

[0058] In addition, since liquid sulfur requires temperature control between 130°C and 150°C, considering its melting point and high-temperature viscosity, problems such as reduced fluidity within the process may also arise.

[0059]

[0060] In order to solve the problems of these existing processes, the inventors of the present invention devised a nickel mat manufacturing process using sodium sulfate (Na2SO4) instead of the existing sulfur (S) through thermodynamic calculations and repeated experiments.

[0061]

[0062] Figure 1 shows the results of thermodynamic calculations of component changes during nickel sulfidation. At this time, Figure 1-(A) shows the case where liquid sulfur (S) is used, and Figure 1-(B) shows the case where sodium sulfate (Na2SO4) is used. According to this, when liquid sulfur is used, the nickel after sulfidation is only 10 wt%, but when sodium sulfate is used, the nickel after sulfidation is 70 wt%, which shows that a relatively high content of nickel can be concentrated in the nickel matte when sodium sulfate is used. Based on these thermodynamic calculation results, the inventors of the present invention invented the nickel matte manufacturing process described below.

[0063]

[0064] That is, a nickel mat manufacturing process according to one embodiment of the present invention may include a step of preparing a molten alloy containing nickel; and a step of adding ferronickel (FeNi) and sodium sulfate (Na2SO4) to the molten alloy to concentrate nickel and sulfur.

[0065]

[0066] According to one embodiment of the present invention, the alloy melt can be obtained by melting an iron and nickel alloy. As an example, such an alloy melt can be derived from a ferronickel process. The ferronickel process refers to a process for producing a ferronickel alloy through dry refining from nickel oxide ore. The alloy derived from the ferronickel process can be a melt as an intermediate product or a melt as a final product during the ferronickel process, or a mixture of the two. However, the present invention is not limited thereto.

[0067]

[0068] According to one embodiment of the present invention, the alloy melt may contain nickel in an amount of 50.0 wt% or more. If the nickel content of the alloy melt is less than 50.0 wt%, the de-ironization reaction time may increase, thereby reducing the efficiency of the nickel matte manufacturing process. According to another embodiment, the nickel content of the alloy melt may be 70.0 wt% or more.

[0069]

[0070] The above ferronickel may be added in an amount of 15.0 wt% or more and 35.0 wt% or less based on the total weight of the molten alloy, and the above sodium sulfate may be added in an amount of 5.0 wt% or more and 15.0 wt% or less based on the total weight of the molten alloy.

[0071]

[0072] Meanwhile, the step of preparing the alloy molten metal may be performed at a temperature range of 0°C to 300°C higher than the melting point of the alloy molten metal. This is to melt the alloy molten metal by applying heat, thereby improving the fluidity of the alloy molten metal. In another embodiment, the step of preparing the alloy molten metal may be performed at a temperature range of 100°C to 200°C higher than the melting point of the alloy molten metal.

[0073]

[0074] A nickel mat manufacturing process according to one embodiment of the present invention may include a step of preparing a molten alloy and then adding ferronickel (FeNi) and sodium sulfate (Na2SO4) to the molten alloy to concentrate nickel and sulfur.

[0075]

[0076] At this time, ferronickel can function as a raw material for nickel. Through the above step, the nickel component in the alloy molten metal and the ferronickel can undergo a sulfurization reaction with sodium sulfate and be concentrated in the nickel matte layer in the form of nickel (II) sulfide (Ni3S2), and the iron component in the alloy molten metal and the ferronickel can be oxidized to iron (II) oxide (FeO). The reaction formula for this sulfurization / de-ironization complex reaction is as follows [Reaction Formula 3].

[0077]

[0078] [Reaction Formula 3]

[0079]

[0080] That is, as described above, the existing nickel matte manufacturing process using sulfur only causes a sulfidation reaction when sulfur is added, whereas in the nickel matte manufacturing process of the present invention using sodium sulfate, an iron oxidation reaction can occur simultaneously during the nickel sulfidation reaction. Accordingly, the nickel matte manufacturing process of the present invention can reduce the burden of the subsequent de-ironization reaction, thereby increasing process efficiency.

[0081]

[0082] The nickel matte manufacturing process using the existing sulfur and the nickel matte manufacturing process using sodium sulfate described above are schematically illustrated in Fig. 2-(A) and Fig. 2-(B), respectively.

[0083]

[0084] In addition, FIG. 3-(A) and FIG. 3-(B) are schematic diagrams illustrating a simplified de-ironization process using conventional sulfur and a de-ironization process using sodium sulfate, respectively. As shown in these drawings, the nickel matte manufacturing process using sodium sulfate of the present invention can reduce the de-ironization time by providing a simplified de-ironization process compared to the conventional process using sulfur.

[0085]

[0086] In addition, this sulfidation / de-ironization complex reaction has the advantage of easy temperature control as it is an endothermic reaction (ΔH= 6,119.8 MJ / ton-Ni), unlike the existing process using sulfur which is an exothermic reaction (ΔH=-6,358.1 MJ / ton-Ni) and requires the use of a refrigerant.

[0087]

[0088] Meanwhile, the nickel content of the nickel matte after the step of concentrating nickel and sulfur described above may be 55.0 wt% or more based on the total weight of the nickel matte, and the sulfur content may be 10.0 wt% or more based on the total weight of the nickel matte. In another embodiment, the nickel content of the nickel matte may be 70.0 wt% or more, and the sulfur content may be 20.0 wt% or more.

[0089]

[0090] Additionally, the step of concentrating nickel and sulfur may be performed at a temperature range of 0°C to 300°C higher than the melting point of the molten alloy. This is to improve the reaction efficiency of the sulfidation reaction and the de-ironization reaction by applying heat. In another embodiment, the step of concentrating nickel and sulfur may be performed at a temperature range of 100°C to 200°C higher than the melting point of the molten alloy.

[0091]

[0092] Meanwhile, according to a nickel mat manufacturing process according to another embodiment of the present invention, after adding sodium sulfate as described above, oxygen (O2) can be additionally added to the alloy molten metal.

[0093]

[0094] By additionally adding oxygen in this manner, the present invention can induce a de-ironization reaction that occurs sequentially after the sulfidation / de-ironization complex reaction. The reaction formula at this time is as shown in [Reaction Formula 2] below.

[0095]

[0096] [Reaction Formula 2]

[0097]

[0098]

[0099] At this time, the oxygen can be injected using at least one of a lance and a tuyere.

[0100]

[0101] Additionally, a slag forming agent may be added together with the oxygen, which may serve to lower the melting point and viscosity of the slag. The slag forming agent may be, but is not limited to, silica (SiO2).

[0102]

[0103] As described above, the nickel matte manufacturing process of the present invention, unlike conventional sulfur-based processes, utilizes sodium sulfate to induce a sulfidation / de-ironization complex reaction. Thus, the present invention provides a nickel matte manufacturing process with high process efficiency and easy temperature control.

[0104]

[0105] In addition, the present invention is economically advantageous in that it can reduce disposal costs by consuming sodium sulfate, which is discarded as a by-product, as a sulfide raw material in the nickel matte manufacturing process.

[0106]

[0107] Below, the nickel mat of the present invention is described in detail.

[0108]

[0109] As described above, a nickel mat according to one embodiment of the present invention may include nickel in an amount of 55.0 wt% or more and sulfur in an amount of 10.0 wt% or more based on the total weight of the nickel mat.

[0110]

[0111] In addition, since the present invention uses sodium sulfate instead of sulfur as a sulfur raw material, the nickel mat according to one embodiment of the present invention may additionally include sodium.

[0112]

[0113] Since the sodium of the present invention is included as an unavoidable impurity during the manufacturing process, the nickel mat according to one embodiment of the present invention may include sodium in an amount of 0.10 wt% or less based on the total weight. If the weight % of sodium exceeds 0.10 wt%, a problem may arise in removing impurities during the purification process. In another embodiment, the weight % of sodium may be 0.75 wt% or less, and in another embodiment, it may be 0.50 wt% or less. On the other hand, since the nickel mat of the present invention can provide a nickel mat of higher purity as it contains less sodium, the present invention does not specifically limit the lower limit of the weight % of sodium. However, considering that nickel is inevitably included during the manufacturing process of the nickel mat of the present invention, the lower limit of sodium of the nickel mat of the present invention may be 0.01%.

[0114]

[0115] In addition, according to one embodiment of the present invention, the nickel mat may have an A value of 50.0 or more derived by the following [Relational Expression 1].

[0116]

[0117] [Relationship 1] A =

[0118] (In the above [Relationship 1], [Ni], [S], and [Na] represent the weight percentages of nickel, sulfur, and sodium contained in the nickel mat, respectively, with respect to the total weight of the nickel mat.)

[0119]

[0120] The present invention can provide a nickel mat that contains a high concentration of nickel and sulfur while containing a small amount of sodium, an impurity, by setting the A value to 50.0 or higher. In another embodiment, the A value may be 100.0 or higher, and in another embodiment, it may be 250.0 or higher.

[0121] (1) Invention example - Nickel mat manufacturing process using sodium sulfate

[0122] First, pig iron, nickel, and solid sulfur were melted in an induction furnace to prepare a molten alloy. After preparing the molten alloy, the temperature of the molten alloy was maintained at 1250°C to 1350°C. At this time, the composition of the molten alloy is as shown in M0 of Table 1 below. Thereafter, while stirring the molten alloy, ferronickel (FeNi) (Fe = 78–82% and Ni = 18–22%) and sodium sulfate (Na2SO4) powder were continuously added. The composition of the molten alloy in which ferronickel was added and a sulfidation / de-ironization complex reaction was performed is as shown in M1 of Table 1 below. At this time, the weight ratio of the added ferronickel (FeNi), sodium sulfate (Na2SO4) powder, and molten alloy was 0.2875:0.1075:1. The composition in Table 1 is the weight% based on the total weight of the nickel matte. Thereafter, air (21% O2-78% N2) and silica (SiO2) were introduced at a flow rate of 5 L / min for 3 hours to induce a de-ironization reaction. At this time, air was introduced through a lance. Thereafter, the compositions of the nickel matte measured every hour are as shown in M2, M3, and M4 in Table 1, respectively. In addition, the weight% of each component of the final slag based on the total weight of the slag is shown in Table 2 below. Fig. 4-(A) is a graph of Table 1, showing the change in the composition of the nickel matte according to the combined sulfidation / de-ironization reaction and the de-ironization reaction of the invention example.

[0123]

[0124] Nickel mat composition (wt%)FeNiCoNaSM030.751.81.870.0613.8M1 (0h)31.456.21.910.0810.7M2 (1h)22.759.91.940.1218.9M3 (2h)11.167.61.760.0821.4M4 (3h)6.9370.81.50.0521.4

[0125]

[0126] FeOFe2O3SiO2MgONa2ONiOCoOSslag composition (weight%)37.6017.9023.534.033.442.740.990.36

[0127]

[0128] (2) Comparative example - sulfur-injected nickel mat manufacturing process

[0129] First, pig iron, nickel, and solid sulfur were melted in an induction furnace to prepare a molten alloy. After preparing the molten alloy, the temperature of the molten alloy was maintained at 1200°C to 1300°C, and the composition of the molten alloy is as shown in M0 of Table 3 below. Thereafter, while stirring the molten alloy, ferronickel (FeNi) (Fe = 78-82% and Ni = 18-22%) and solid sulfur (S) powder were continuously added. The composition of the molten alloy to which ferronickel was added and the sulfurization reaction was performed is as shown in M1 of Table 3 below. At this time, the weight ratio of the added ferronickel (FeNi), solid sulfur (S) powder, and molten alloy was 0.2875: 0.2875: 1. The contents in Table 3 are the weight% of each component based on the total weight of the nickel matte. Thereafter, air (21% O2-78% N2) and silica (SiO2) were introduced at a flow rate of 5 L / min for 4 hours to induce the de-ironization reaction. At this time, the air was introduced through a lance. Thereafter, the compositions of the nickel mats measured every hour are as shown in Table 3, M2, M3, M4, and M5, respectively. The weight% of each component of the final slag based on the total weight of the slag is shown in Table 4 below. Fig. 4-(B) is a graph of Table 3, showing the change in the mat composition according to the sulfidation reaction and de-ironization reaction of the comparative example.

[0130]

[0131] Nickel mat composition (wt%)FeNiCoSM029.8251.311.915.40M1 (0h)38.7644.591.613.90M2 (1h)32.8250.191.813.80M3 (1.5h)28.9154.191.914.60M4 (3h)16.3666.122.114.70M5 (4h)3.7475.371.319.40

[0132]

[0133] FeOFe2O3SiO2MgONa2ONiOCoOS slag composition (weight%) 36.512.521.643.00-15.433.031.78

[0134]

[0135] (3) Experimental results

[0136] In the case of the invention example, nickel was sulfided and concentrated in the nickel matte in the form of Ni3S2 through a complex sulfidation / de-ironization reaction due to the addition of sodium sulfate and a de-ironization reaction due to the addition of oxygen, and iron was oxidized and separated in the form of slag.

[0137]

[0138] In addition, in the case of the comparative example, nickel was sulfurized and concentrated in the nickel matte in the form of Ni3S2 through the sulfurization reaction due to the injection of solid sulfur and the de-ironization reaction due to the injection of oxygen, and iron was oxidized and separated in the form of slag.

[0139]

[0140] The invention example using sodium sulfate reduced the burden of the subsequent de-ironization reaction through the above-described sulfidation / de-ironization complex reaction, thereby simplifying the de-ironization reaction process. As a result, the invention example was able to produce a nickel mat having the desired nickel content in a relatively shorter time compared to the comparative example.

[0141]

[0142] In addition, Fig. 5-(A) and Fig. 5-(B) are graphs showing the nickel recovery rate and sulfur sulfidation efficiency according to the de-ironization reaction of the invention example and the comparative example, respectively. The x-axis here represents the weight % of iron (Fe) in the nickel mat. The nickel recovery rate and sulfur sulfidation efficiency were derived by the following equation.

[0143]

[0144]

[0145]

[0146]

[0147]

[0148] As can be seen from the graph, in the case of the invention example in which sodium sulfate was added, the nickel recovery rate and sulfur sulfidation efficiency did not decrease significantly, reaching 95% and 93%, respectively, depending on the de-ironization reaction. On the other hand, in the comparative example in which solid sulfur was added, as the de-ironization reaction time increased, the nickel and sulfur contents in the form of slag increased, as can be seen in Table 4, and as a result, the nickel recovery rate and sulfur sulfidation efficiency decreased to 91% and 76%, respectively.

[0149]

[0150] As a result of the above experiment, it was confirmed that the present invention can provide a nickel mat manufacturing process with high process efficiency by reducing the de-ironization time by using sodium sulfate (Na2SO4) instead of the existing sulfur (S).

Claims

1. A step of preparing a molten alloy containing nickel; and Ferronickel (FeNi) and sodium sulfate (Na) were added to the above alloy melt. 2 SO 4 ) to concentrate nickel and sulfur.

2. In paragraph 1, A method for manufacturing a nickel matte, wherein the above alloy melt contains nickel of 50.0 wt% or more.

3. In paragraph 1, A method for manufacturing a nickel matte, wherein the above ferronickel is added in an amount of 15.0 wt% or more and 35.0 wt% or less based on the total weight of the alloy molten metal.

4. In paragraph 1, A method for manufacturing a nickel matte, wherein the sodium sulfate is added in an amount of 5.0 wt% to 15.0 wt% based on the total weight of the molten alloy.

5. In paragraph 1, The above alloy melt is a method for producing nickel matte derived from a ferronickel process.

6. In paragraph 1, A method for manufacturing a nickel mat, wherein the nickel content of the manufactured nickel mat is 55.0 wt% or more with respect to the total weight of the nickel mat, and the sulfur content is 10.0 wt% or more with respect to the total weight of the nickel mat.

7. In paragraph 1, Oxygen (O) is added to the above alloy melt 2 ) additionally comprising a step of introducing a nickel matte.

8. In paragraph 7, A method for manufacturing a nickel matte, wherein the oxygen is injected using at least one of a lance and a tuyere.

9. In paragraph 7, A method for manufacturing nickel matte by adding a slag forming agent together with the above oxygen.

10. In paragraph 9, The above slag forming agent is silica (SiO 2 ) A method for manufacturing a nickel matte comprising:

11. In paragraph 1, A method for manufacturing a nickel matte, wherein the step of preparing the alloy molten metal is performed at a temperature range of 0°C to 300°C higher than the melting point of the alloy molten metal, and the step of concentrating nickel and sulfur is performed at a temperature range of 0°C to 300°C higher than the melting point of the alloy molten metal.

12. Contains nickel of 55.0 wt% or more and sulfur of 10.0 wt% or more based on the total weight of the nickel mat; Nickel matte with additional sodium content.

13. In paragraph 12, Nickel mat wherein the above sodium is contained in an amount of 0.10 wt% or less based on the total weight of the nickel mat.

14. In paragraph 12, Nickel mat having an A value of 50.0 or more derived by the following [Relational Formula 1]. [Relationship 1] A = (In the above [Relational Expression 1], [Ni], [S], and [Na] represent the weight % of nickel, sulfur, and sodium contained in the nickel mat, respectively, with respect to the total weight of the nickel mat.)

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