Low-carbon ferro-nickel alloy and preparation method thereof

Abstract

The invention is suitable for the technical field of alloy materials, and provides a low-carbon ferro-nickel alloy and a preparation method thereof.The low-carbon ferro-nickel alloy is obtained through a silicothermic reduction reaction of the following raw materials including, by mass, 20-25% of nickel slag, 25-30% of laterite-nickel ore, 30-35% of silicon iron and 12-15% of lime. The low-carbon ferro-nickel alloy has good mechanical properties, the tensile strength reaches 880 MPa, the yield strength reaches 660 MPa, the ductility is larger than 15%, meanwhile, the material further has good corrosion resistance, and therefore the low-carbon ferro-nickel alloy is widely applied to the petroleum industry, the chemical industry, the aerospace industry and the mechanical manufacturing industry. Besides, the silicothermic reduction process is controlled, iron and nickel in the laterite-nickel ore and the nickel slag are selectively reduced, a material directly applied to terminal products is formed, CaO can improve the alkalinity of the slag, the slag and the alloy are better separated, and low-carbon production of the corrosion-resistant alloy material is achieved.

Description

Technical Field

[0001] The present application belongs to the technical field of alloy materials, and in particular relates to a low-carbon nickel-iron alloy and a preparation method thereof. Background Art

[0002] Nickel slag is an industrial waste generated during the nickel smelting process. Its FeO mass fraction is as high as 50%, and it also contains valuable metal oxides such as NiO. At present, the treatment of nickel slag is mainly stockpiling. The existing nickel slag stockpile in my country is close to 50 million tons. The idle stockpiling of a large amount of nickel slag not only wastes the valuable metal resources contained in the slag, but also causes a series of serious social problems such as environmental pollution and land occupation.

[0003] With the increasing depletion of high-quality resources such as nickel sulfide ore, laterite nickel ore has become the main source of nickel resources. Laterite nickel ore contains an average of 1% to 3% nickel and cannot be enriched through mineral processing, resulting in high energy consumption, high cost and low economic benefits in smelting laterite nickel ore. my country's mineral resources are scarce, the mining depth, difficulty and cost of mines are increasing, and there are fewer and fewer rich ores available for mining. The rational use of nickel resources is of great significance to promoting the sustainable development of my country's chemical industry, new energy industry and aerospace manufacturing industry. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a low-carbon nickel-iron alloy and a preparation method thereof, aiming to solve the problems of high energy consumption, high cost and low economic benefit in smelting laterite nickel ore in the prior art.

[0005] The embodiment of the present application is implemented as follows: a low-carbon nickel-iron alloy, wherein the low-carbon nickel-iron alloy is obtained by silicon thermal reduction reaction of the following raw materials in mass percentage:

[0006] Nickel slag 20-25%, laterite nickel ore 25-30%, ferrosilicon 30-35% and lime 12-15%.

[0007] Another object of the embodiment of the present application is a method for preparing the above-mentioned low-carbon nickel-iron alloy, comprising:

[0008] Weigh each raw material according to the formula of the above-mentioned low-carbon nickel-iron alloy;

[0009] The laterite nickel ore, lime and nickel slag are crushed and then uniformly mixed to obtain a mixture;

[0010] After heating the ferrosilicon to a liquid state, the mixture is added thereto for heat preservation reaction to obtain a low-carbon nickel-iron alloy.

[0011] The low-carbon nickel-iron alloy provided in the embodiment of the present application has good mechanical properties, tensile strength reaches 880MPa, yield strength reaches 660MPa, elongation is greater than 15%, and the material also has good corrosion resistance, so it is widely used in petroleum, chemical, aerospace, and machinery manufacturing industries. On the one hand, the present application uses laterite nickel ore and nickel slag as the main raw materials, Si as a reducing agent, and a large amount of chemical heat is released by the silicon thermal reduction reaction, which has lower cost, more stable chemical properties, and easy storage conditions. The whole reaction process can be effectively controlled, saving energy, suitable for industrial production, and has a significant promoting effect on environmental protection and promoting the preparation of key materials for new energy. On the other hand, the present application controls the silicon thermal reduction process, selectively reduces the iron and nickel in laterite nickel ore and nickel slag, and forms a material that is directly applied to terminal products. CaO can improve the slag basicity, so that the slag and alloy are better separated, and the low-carbon production of corrosion-resistant alloy materials is realized. On the other hand, since no carbonaceous reducing agent is used in the reduction process, the carbon content in the finished alloy is reduced, and the chromium in the nickel slag is reduced by silicon thermal reduction, which effectively improves the corrosion resistance of the nickel-iron alloy. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical solution and advantages of the present application more clear, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

[0013] The embodiment of the present application provides a low-carbon nickel-iron alloy, which is obtained by silicon thermal reduction reaction of the following raw materials in mass percentage: 20-25% nickel slag, 25-30% laterite nickel ore, 30-35% ferrosilicon and 12-15% lime. It is worth noting that the mass ratio of nickel slag, laterite nickel ore, ferrosilicon and lime directly affects the mechanical properties and metal recovery rate of the obtained low-carbon nickel-iron alloy, and the ratio of each component needs to be strictly controlled.

[0014] Preferably, the low carbon nickel-iron alloy is obtained by silicon thermal reduction reaction of the following raw materials in percentage by mass: 25% nickel slag, 30% laterite nickel ore, 30% ferrosilicon and 15% lime.

[0015] Preferably, the ferrosilicon used in the specific embodiments of the present application can be purchased from a conventional ferroalloy plant, and its silicon content is 25-40%. It should be noted that if the silicon content is too high, too much SiO2 will be produced during the smelting process, making slag difficult and not conducive to smelting; if the silicon content is too low, the metal elements in the nickel slag and laterite nickel ore cannot be completely reduced, and the nickel and iron recovery rates are low.

[0016] It is worth noting that the nickel slag used in the specific embodiment of the present application is the waste generated in the nickel smelting process, and its main components are: FeO 45-50%, SiO2 25-30%, MgO 15-18%, NiO 3-5% and CaO 2-3%; the main components of the laterite nickel ore used are SiO2 40-45%, FeO 20-25%, MgO 15-20%, NiO 5-8%, Cr2O3 3-5% and Al2O3 3-5%. The electromagnetic induction furnace uses induction heat to heat the ferrosilicon to liquid state, and the silicon in the ferrosilicon reacts with FeO, NiO and Cr2O3 in the laterite nickel ore and nickel slag:

[0017] 2FeO+Si=Fe+SiO2

[0018] 2NiO+Si=Ni+SiO2

[0019] 2C r2 O3+3Si=4Cr+3SiO2

[0020] The heat released by the reaction causes the liquid iron and nickel to solidify into nickel-iron alloy during the cooling process. The reaction product SiO2 component combines with CaO in the raw material to form 2 CaO•SiO2, which promotes the reaction process. However, A12O3 and MgO cannot be reduced and enter the slag.

[0021] It is worth noting that during the raw material smelting process of this application, the oxide is reduced by the reducing agent Si at high temperature:

[0022] [Fe, Si] +2MeO→[FeMe]+ 2 CaO·SiO2

[0023] After pouring out some of the slag, the above reaction will be more thorough and more alloy will be generated.

[0024] The present application also provides a method for preparing the above-mentioned low-carbon nickel-iron alloy, comprising:

[0025] Weigh each raw material according to the formula of the above-mentioned low-carbon nickel-iron alloy;

[0026] The laterite nickel ore, lime and nickel slag are crushed and then uniformly mixed to obtain a mixture;

[0027] After heating the ferrosilicon to a liquid state, the mixture is added thereto for heat preservation reaction to obtain a low-carbon nickel-iron alloy.

[0028] Optionally, the step of uniformly mixing the laterite nickel ore, lime and nickel slag after crushing to obtain a mixture comprises:

[0029] crushing the nickel slag into particles less than 10 mm to obtain nickel slag particles;

[0030] The laterite nickel ore, lime and nickel slag particles were respectively ball-milled by a planetary ball mill, passed through a 100-mesh sieve, and put into a three-dimensional mixer for mixing for 10 hours to obtain a mixture.

[0031] Optionally, the step of heating the ferrosilicon to a liquid state and then adding the mixture to carry out a heat preservation reaction to obtain a low-carbon nickel-iron alloy comprises:

[0032] Add ferrosilicon to the bottom of the crucible of the electromagnetic induction furnace, use induction heat to heat the ferrosilicon to liquid state, add the mixed material into the crucible, keep warm for 30 minutes, pour out the upper slag liquid in the crucible, pour the refined molten metal into the cast iron ingot mold, and demold after cooling to obtain low-carbon nickel-iron alloy.

[0033] Optionally, the heating temperature is 1500°C.

[0034] The low carbon nickel-iron alloy and its preparation method are described in detail with specific examples as follows. The experimental methods used in the following examples are conventional methods unless otherwise specified; the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0035] Embodiment 1: The method for preparing nickel-iron alloy from nickel slag and laterite nickel ore of the present embodiment, the specific steps are as follows:

[0036] (1) Take 25% nickel slag, 28% laterite nickel ore, 35% ferrosilicon and 12% lime in percentage by weight for later use;

[0037] (2) Coarsely crushing the nickel slag into particles less than 10 mm;

[0038] (3) Grinding the coarsely crushed nickel slag particles, laterite nickel ore and lime powder separately by a planetary ball mill and then passing through a 100-mesh sieve;

[0039] (4) Put the sieved raw materials into a three-dimensional mixer and mix them for 10 hours to obtain a mixture for later use;

[0040] (5) First, add the ferrosilicon sheet to the bottom of the crucible of the electromagnetic induction furnace, power on the induction furnace and heat it to 1500°C, add the mixed material into the crucible, and then keep it warm for 30 minutes. After pouring out the upper slag liquid in the crucible (slag and gold separation), pour the refined metal liquid into the cast iron ingot mold, cool it down and demold it to obtain the nickel-iron alloy;

[0041] Embodiment 2: The method for preparing nickel-iron alloy from nickel slag and laterite nickel ore of the present embodiment specifically comprises the following steps:

[0042] (1) Take 22% nickel slag, 30% laterite nickel ore, 33% ferrosilicon and 15% lime in percentage by weight and set aside;

[0043] (2) Coarsely crushing the nickel slag into particles less than 10 mm;

[0044] (3) Grinding the coarsely crushed nickel slag particles, laterite nickel ore and lime powder separately by a planetary ball mill and then passing through a 100-mesh sieve;

[0045] (4) Put the sieved raw materials into a three-dimensional mixer and mix them for 10 hours to obtain a mixture for later use;

[0046] (5) First, add the ferrosilicon sheet to the bottom of the crucible of the electromagnetic induction furnace, power on the induction furnace and heat it to 1500°C, add the mixed material into the crucible, and then keep it warm for 30 minutes. After pouring out the upper slag liquid in the crucible (slag and gold separation), pour the refined molten metal into the cast iron ingot mold, cool it down and demold it to obtain the nickel-iron alloy.

[0047] Embodiment 3: The method for preparing nickel-iron alloy from nickel slag and laterite nickel ore of the present embodiment specifically comprises the following steps:

[0048] (1) Take 25% nickel slag, 30% laterite nickel ore, 30% ferrosilicon and 15% lime respectively according to weight percentage and set aside;

[0049] (2) Coarsely crushing the nickel slag into particles less than 10 mm;

[0050] (3) Grinding the coarsely crushed nickel slag particles, laterite nickel ore and lime powder separately by a planetary ball mill and then passing through a 100-mesh sieve;

[0051] (4) Put the sieved raw materials into a three-dimensional mixer and mix them for 10 hours to obtain a mixture for later use;

[0052] (5) First, add the ferrosilicon sheet to the bottom of the crucible of the electromagnetic induction furnace, power on the induction furnace and heat it to 1500°C, add the mixed material into the crucible, and then keep it warm for 30 minutes. After pouring out the upper slag liquid in the crucible (slag and gold separation), pour the refined molten metal into the cast iron ingot mold, cool it down and demold it to obtain the nickel-iron alloy.

[0053] Embodiment 4: The method for preparing nickel-iron alloy from nickel slag and laterite nickel ore of the present embodiment specifically comprises the following steps:

[0054] (1) Take 20% nickel slag, 30% laterite nickel ore, 35% ferrosilicon and 15% lime in percentage by weight and set aside;

[0055] (2) Coarsely crushing the nickel slag into particles less than 10 mm;

[0056] (3) Grinding the coarsely crushed nickel slag particles, laterite nickel ore and lime powder separately by a planetary ball mill and then passing through a 100-mesh sieve;

[0057] (4) Put the sieved raw materials into a three-dimensional mixer and mix them for 10 hours to obtain a mixture for later use;

[0058] (5) First, add the ferrosilicon sheet to the bottom of the crucible of the electromagnetic induction furnace, power on the induction furnace and heat it to 1500°C, add the mixed material into the crucible, and then keep it warm for 30 minutes. After pouring out the upper slag liquid in the crucible (slag and gold separation), pour the refined molten metal into the cast iron ingot mold, cool it down and demold it to obtain the nickel-iron alloy.

[0059] Embodiment 5: The method for preparing nickel-iron alloy from nickel slag and laterite nickel ore of the present embodiment specifically comprises the following steps:

[0060] (1) Take 24% nickel slag, 28% laterite nickel ore, 34% ferrosilicon and 14% lime in percentage by weight for later use;

[0061] (2) Coarsely crushing the nickel slag into particles less than 10 mm;

[0062] (3) Grinding the coarsely crushed nickel slag particles, laterite nickel ore and lime powder separately by a planetary ball mill and then passing through a 100-mesh sieve;

[0063] (4) Put the sieved raw materials into a three-dimensional mixer and mix them for 10 hours to obtain a mixture for later use;

[0064] (5) First, add the ferrosilicon sheet to the bottom of the crucible of the electromagnetic induction furnace, power on the induction furnace and heat it to 1500°C, add the mixed material into the crucible, and then keep it warm for 30 minutes. After pouring out the upper slag liquid in the crucible (slag and gold separation), pour the refined molten metal into the cast iron ingot mold, cool it down and demold it to obtain the nickel-iron alloy.

[0065] Comparative Example 1: The method for preparing nickel-iron alloy from nickel slag and laterite nickel ore of this embodiment specifically comprises the following steps:

[0066] (1) Take 25% nickel slag, 30% laterite nickel ore, 35% ferrosilicon and 10% lime in percentage by weight and set aside;

[0067] (2) Coarsely crushing the nickel slag into particles less than 10 mm;

[0068] (3) Grinding the coarsely crushed nickel slag particles, laterite nickel ore and lime powder separately by a planetary ball mill and then passing through a 100-mesh sieve;

[0069] (4) Put the sieved raw materials into a three-dimensional mixer and mix them for 10 hours to obtain a mixture for later use;

[0070] (5) First, add the ferrosilicon sheet to the bottom of the crucible of the electromagnetic induction furnace, power on the induction furnace and heat it to 1500°C, add the mixed material into the crucible, and then keep it warm for 30 minutes. After pouring out the upper slag liquid in the crucible (slag and gold separation), pour the refined molten metal into the cast iron ingot mold, cool it down and demold it to obtain the nickel-iron alloy.

[0071] Comparative Example 2: The method for preparing nickel-iron alloy from nickel slag and laterite nickel ore of this embodiment specifically comprises the following steps:

[0072] (1) Take 28% nickel slag, 32% laterite nickel ore, 25% ferrosilicon and 15% lime in percentage by weight for later use;

[0073] (2) Coarsely crushing the nickel slag into particles less than 10 mm;

[0074] (3) Grinding the coarsely crushed nickel slag particles, laterite nickel ore and lime powder separately by a planetary ball mill and then passing through a 100-mesh sieve;

[0075] (4) Put the sieved raw materials into a three-dimensional mixer and mix them for 10 hours to obtain a mixture for later use;

[0076] (5) First, add the ferrosilicon sheet to the bottom of the crucible of the electromagnetic induction furnace, power on the induction furnace and heat it to 1500°C, add the mixed material into the crucible, and then keep it warm for 30 minutes. After pouring out the upper slag liquid in the crucible (slag and gold separation), pour the refined molten metal into the cast iron ingot mold, cool it down and demold it to obtain the nickel-iron alloy.

[0077] Comparative Example 3: The method for preparing nickel-iron alloy from nickel slag and laterite nickel ore of this embodiment specifically comprises the following steps:

[0078] (1) Take 22% nickel slag, 28% laterite nickel ore, 30% ferrosilicon and 20% lime in percentage by weight for later use;

[0079] (2) Coarsely crushing the nickel slag into particles less than 10 mm;

[0080] (3) Grinding the coarsely crushed nickel slag particles, laterite nickel ore and lime powder separately by a planetary ball mill and then passing through a 100-mesh sieve;

[0081] (4) Put the sieved raw materials into a three-dimensional mixer and mix them for 10 hours to obtain a mixture for later use;

[0082] (5) First, add the ferrosilicon sheet to the bottom of the crucible of the electromagnetic induction furnace, power on the induction furnace and heat it to 1500°C, add the mixed material into the crucible, and then keep it warm for 30 minutes. After pouring out the upper slag liquid in the crucible (slag and gold separation), pour the refined molten metal into the cast iron ingot mold, cool it down and demold it to obtain the nickel-iron alloy.

[0083] Comparative Example 4: The method for preparing nickel-iron alloy from nickel slag and laterite nickel ore of this embodiment specifically comprises the following steps:

[0084] (1) Take 20% nickel slag, 25% laterite nickel ore, 40% ferrosilicon and 15% lime respectively according to weight percentage and set aside;

[0085] (2) Coarsely crushing the nickel slag into particles less than 10 mm;

[0086] (3) Grinding the coarsely crushed nickel slag particles, laterite nickel ore and lime powder separately by a planetary ball mill and then passing through a 100-mesh sieve;

[0087] (4) Put the sieved raw materials into a three-dimensional mixer and mix them for 10 hours to obtain a mixture for later use;

[0088] (5) First, add the ferrosilicon sheet to the bottom of the crucible of the electromagnetic induction furnace, power on the induction furnace and heat it to 1500°C, add the mixed material into the crucible, and then keep it warm for 30 minutes. After pouring out the upper slag liquid in the crucible (slag and gold separation), pour the refined molten metal into the cast iron ingot mold, cool it down and demold it to obtain the nickel-iron alloy.

[0089] Comparative Example 5: The method for preparing nickel-iron alloy from nickel slag and laterite nickel ore of this embodiment specifically comprises the following steps:

[0090] (1) Take 21% nickel slag, 26% laterite nickel ore, 36% ferrosilicon and 17% lime in percentage by weight for later use;

[0091] (2) Coarsely crushing the nickel slag into particles less than 10 mm;

[0092] (3) Grinding the coarsely crushed nickel slag particles, laterite nickel ore and lime powder separately by a planetary ball mill and then passing through a 100-mesh sieve;

[0093] (4) Put the sieved raw materials into a three-dimensional mixer and mix them for 10 hours to obtain a mixture for later use;

[0094] (5) First, add the ferrosilicon sheet to the bottom of the crucible of the electromagnetic induction furnace, power on the induction furnace and heat it to 1500°C, add the mixed material into the crucible, and then keep it warm for 30 minutes. After pouring out the upper slag liquid in the crucible (slag and gold separation), pour the refined molten metal into the cast iron ingot mold, cool it down and demold it to obtain the nickel-iron alloy.

[0095] According to GB / T228.1-2021 "Tensile test of metallic materials Part 1: Room temperature test method", the mechanical properties of the nickel-iron alloys prepared in the above Examples 1-5 and Comparative Examples 1-5 were tested. The metal recovery rate was calculated based on the metal content in the raw materials and the metal content in the finished products. The test results are shown in Table 1 below.

[0096] Table 1 Metal recovery rate and performance of the products

[0097]

[0098] In summary, it can be seen from Table 1 that the quantitative ferrosilicon in the embodiment of the present application can reduce the iron, nickel and chromium elements in the nickel slag and laterite nickel ore, and the lime and silicon dioxide are separated from the metal into slag, so that the obtained product has good mechanical properties. However, due to the insufficient amount of lime in Comparative Example 1, the slag-making capacity is limited, resulting in a significant decrease in the metal recovery rate of the product and a decrease in mechanical properties. Similarly, the insufficient amount of silicon in Comparative Example 2 makes it impossible to reduce the metal oxides in the raw materials, and the metal recovery rate of the product is significantly reduced. Due to the excessive amount of lime and the thin slag in Comparative Example 3, the metal recovery rate of the product is significantly reduced and the mechanical properties are reduced. Due to the excessive amount of ferrosilicon and the high viscosity of the slag in Comparative Example 4, the metal recovery rate of the product is significantly reduced and the mechanical properties are reduced. Due to the excessive amount of ferrosilicon and lime in Comparative Example 5, the slag is too large, and the slag gold is not easy to separate, resulting in many inclusions in the product and a low metal recovery rate, and the mechanical properties are reduced.

[0099] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

[0100] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A low carbon nickel-iron alloy, characterized in that: The low carbon nickel-iron alloy is obtained by silicon thermal reduction reaction of the following raw materials in mass percentage: Nickel slag 20-25%, laterite nickel ore 25-30%, ferrosilicon 30-35% and lime 12-15%.

2. The low carbon nickel-iron alloy according to claim 1, characterized in that The low carbon nickel-iron alloy is obtained by silicon thermal reduction reaction of the following raw materials in mass percentage: Nickel slag 25%, laterite nickel ore 30%, ferrosilicon 30% and lime 15%.

3. The low carbon nickel-iron alloy according to claim 1, characterized in that: The silicon content in the ferrosilicon is 25-40%.

4. The low carbon nickel-iron alloy according to claim 1, characterized in that: The nickel slag comprises the following components in percentage by mass: FeO 45-50%, SiO2 25-30%, MgO 15-18%, NiO 3-5% and CaO 2-3%.

5. The low carbon nickel-iron alloy according to claim 1, characterized in that: The laterite nickel ore comprises the following components in percentage by mass: SiO2 40~45%, FeO 20~25%, MgO 15~20%, NiO 5~8%, Cr2O3 3~5% and Al2O3 3~5%.

6. A method for preparing the low carbon nickel-iron alloy according to claim 1, characterized in that: include: Weigh the raw materials according to the formula of the low-carbon nickel-iron alloy according to claim 1; The laterite nickel ore, lime and nickel slag are crushed and then uniformly mixed to obtain a mixture; After heating the ferrosilicon to a liquid state, the mixture is added thereto for heat preservation reaction to obtain a low-carbon nickel-iron alloy.

7. The method for preparing a low carbon nickel-iron alloy according to claim 6, characterized in that: The step of crushing the laterite nickel ore, lime and nickel slag and then uniformly mixing them to obtain a mixture comprises: crushing the nickel slag into particles less than 10 mm to obtain nickel slag particles; The laterite nickel ore, lime and nickel slag particles were respectively ball-milled by a planetary ball mill, passed through a 100-mesh sieve, and put into a three-dimensional mixer for mixing for 10 hours to obtain a mixture.

8. The method for preparing a low carbon nickel-iron alloy according to claim 6, characterized in that: The step of heating the ferrosilicon to a liquid state, adding the mixture to carry out a heat preservation reaction, and obtaining a low-carbon nickel-iron alloy comprises: Add ferrosilicon to the bottom of the crucible of the electromagnetic induction furnace, use induction heat to heat the ferrosilicon to liquid state, add the mixed material into the crucible, keep warm for 30 minutes, pour out the upper slag liquid in the crucible, pour the refined molten metal into the cast iron ingot mold, and demold after cooling to obtain low-carbon nickel-iron alloy.

9. The method for preparing a low carbon nickel-iron alloy according to claim 8, characterized in that: The heating temperature is 1500°C.

10. The method for preparing a low carbon nickel-iron alloy according to claim 8, characterized in that: The low-carbon nickel-iron alloy has a tensile strength of 880 MPa, a yield strength of 660 MPa, and an elongation of more than 15%.

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