A method for producing a nickel-iron alloy using spent petrochemical catalysts

Abstract

The application provides a method for preparing a nickel-iron alloy by using waste petrochemical catalysts, comprising: mixing a powdered waste petrochemical catalyst with a cyanidation tailings, a reducing agent and a fluxing agent in a proper proportion to obtain a mixture, and granulating the mixture to obtain a mixture pellet; low-temperature roasting the mixture pellet to achieve primary reduction of nickel and iron oxides, and obtaining a pre-sintered pellet; high-temperature melting the pre-sintered pellet to achieve deep reduction of nickel and iron oxides and realize slag-gold separation, and finally obtain a nickel-iron alloy and a glassy molten slag. The method provided by the application can realize harmless and collaborative disposal of waste petrochemical catalysts and cyanidation tailings to prepare high-grade nickel-iron alloy, and simultaneously realize slag glassification. The method has strong adaptability to raw materials, can treat various types of hazardous and solid wastes, does not need to add additional iron-containing materials, has a short process, is friendly to the environment, and has a broad application prospect.

Description

A method for preparing nickel-iron alloy using waste petrochemical catalysts Technical Field

[0001] This application belongs to the field of pyrometallurgical smelting technology for recovering valuable metals from hazardous / solid waste, specifically relating to a method for preparing nickel-iron alloys using waste petrochemical catalysts. Background Technology

[0002] During long-term use, petrochemical catalysts undergo continuous changes in their structure and chemical composition, gradually reducing their catalytic capacity—a phenomenon known as "catalyst poisoning." This leads to a significant decrease in catalyst activity or even complete failure, necessitating periodic replacement to maintain production stability across various industries. This process generates a large amount of waste petrochemical catalysts. Currently, most waste petrochemical catalysts are disposed of through landfill. This method not only wastes vast amounts of limited land resources but also, due to the adsorption of toxic and harmful substances during use, as well as the leaching of heavy metals during long-term landfilling, pollutes soil and groundwater, causing serious ecological and environmental problems. Therefore, the need for harmless disposal of waste petrochemical catalysts is urgent. Furthermore, waste petrochemical catalysts are rich in valuable nickel, which can serve as an important raw material for stainless steel, precision alloys, hydrogen storage alloys, chemical catalysts, and high-temperature alloys. The nickel grade in waste petrochemical catalysts is far higher than that in mineral resources, and with the rapid annual increase in the amount of waste petrochemical catalysts, the total amount of nickel resources in waste petrochemical catalysts is substantial. Therefore, recovering nickel from waste petrochemical catalysts can not only alleviate the imbalance between supply and demand of nickel resources in my country, but also reduce the environmental problems caused by waste petrochemical catalysts. The recycling and utilization of nickel resources will yield significant economic, ecological and social value.

[0003] Currently, the main treatment processes for waste petrochemical catalysts both domestically and internationally are wet processes: oxidative roasting-alkali leaching, alkaline roasting-water leaching, microwave alkaline leaching-microwave acid leaching, and atmospheric pressure acid and alkaline leaching. These traditional wet processes have many significant drawbacks, such as poor raw material adaptability, long process flow, generation of large amounts of secondary pollutants like wastewater and waste residue, and low metal leaching rates. Traditional pyrometallurgical treatment processes, on the other hand, suffer from high equipment investment, limited range of hazardous / solid waste treatment, a large variety and quantity of added materials, and secondary pollution from tailings. Summary of the Invention

[0004] To address the technical problems mentioned above, this application provides a co-smelting process for treating two types of hazardous / solid waste: waste petrochemical catalysts and cyanide tailings. This process simultaneously recovers valuable nickel and iron from these wastes to prepare high-grade nickel-iron alloys and achieves slag vitrification. Ultimately, this method enables the efficient recovery and harmless treatment of valuable nickel and iron from two typical cross-industry hazardous / solid wastes: waste petrochemical catalysts and cyanide tailings.

[0005] Specifically, this application provides a method for preparing nickel-iron alloy using waste petrochemical catalysts, comprising:

[0006] Powdered waste petrochemical catalyst is thoroughly mixed with cyanide tailings, reducing agent and flux in a certain proportion to obtain a mixture, and the mixture is granulated to prepare mixture pellets;

[0007] The mixture pellets are subjected to low-temperature calcination to achieve primary reduction of nickel and iron oxides, resulting in pre-sintered pellets.

[0008] The pre-sintered pellets are melted at high temperature to achieve deep reduction of nickel and iron oxides and slag-gold separation, ultimately yielding nickel-iron alloy and glassy slag.

[0009] As a further explanation of this application, the mass ratio of the waste petrochemical catalyst to the cyanide tailings is (75~90):(25~10).

[0010] As a further explanation of this application, the reducing agent is metallurgical coke, and the amount of metallurgical coke added is 5% to 10% of the total mass of the mixture of the waste petrochemical catalyst and the cyanide tailings.

[0011] As a further explanation of this application, the flux includes quartz sand, calcium oxide, and borax; the amount of quartz sand added is 10% to 15% of the total mass of the mixture of the waste petrochemical catalyst and the cyanide tailings; the amount of calcium oxide added is 35% to 45% of the total mass of the mixture of the waste petrochemical catalyst and the cyanide tailings; and the amount of borax added is 5% to 8% of the total mass of the mixture of the waste petrochemical catalyst and the cyanide tailings.

[0012] As a further explanation of this application, the method further includes: crushing and pulverizing the waste petrochemical catalyst and cyanide tailings, and then drying to remove free water to obtain powdered waste petrochemical catalyst and cyanide tailings.

[0013] As a further explanation of this application, the diameter of the mixture pellets is 0.5~1 cm.

[0014] As a further explanation of this application, the low-temperature calcination is carried out in an electrically heated rotary kiln under the following conditions: rotary kiln speed 6 r / min, temperature 950~1000℃, and time 60~90 min.

[0015] As a further explanation of this application, the metallization rates of nickel and iron in the pre-sintered pellets are 90-97% and 75-80%, respectively.

[0016] As a further explanation of this application, the deep reduction conditions during the high-temperature melting process are: melting temperature of 1450~1500℃, and holding in the molten state for 40~60 min.

[0017] As a further explanation of this application, the nickel-iron alloy contains 30-45% nickel, 50-65% iron, 3-5% carbon, and 1-2% impurities.

[0018] Compared with the prior art, this application has the following beneficial technical effects:

[0019] The method provided in this application enables the harmless co-processing of waste petrochemical catalysts and cyanide tailings to prepare high-grade nickel-iron alloys, while simultaneously vitrifying the slag. This method has strong raw material adaptability, can handle a wide variety of hazardous / solid wastes, does not require the addition of extra iron-containing materials, has a short process, and is environmentally friendly, thus having broad application prospects. Attached Figure Description

[0020] Figure 1 is a flowchart of the method for preparing nickel-iron alloy using waste petrochemical catalysts provided in an embodiment of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] As shown in Figure 1, this application provides a method for preparing nickel-iron alloy using waste petrochemical catalysts, comprising the following steps:

[0023] S101. Low-temperature pretreatment of hazardous / solid waste: The waste petrochemical catalyst and cyanide tailings are crushed and powdered, and then dried to remove free water, to obtain powdered waste petrochemical catalyst and cyanide tailings.

[0024] In some embodiments, the above drying conditions are: holding at 105°C for 120 min. After drying to remove free water, the accuracy of subsequent component determination and batching of raw materials can be guaranteed.

[0025] S102, Preparation of pre-sintered pellets: Powdered waste petrochemical catalyst is fully mixed with cyanide tailings, reducing agent and flux in proportion to obtain a mixture, and the mixture is granulated to prepare mixed pellets.

[0026] In some embodiments, the mass ratio of waste petrochemical catalyst to cyanide tailings is (75~90):(25~10), for example, it can be 75:25, 80:20, 85:15, 90:10, etc.; the cyanide tailings (mainly composed of SiO2 and FeO) x When SiO2 and Al2O3-based glass slag are mixed in the above proportions, no additional SiO2 slag-forming agent is required. This reduces the excessive addition of slag-forming agent caused by the disposal of a single waste petrochemical catalyst, thereby enabling the preparation of high-grade nickel-iron alloys and the addition of less carbon reducing agent, thus achieving low-carbon co-processing of two hazardous / solid wastes.

[0027] In some embodiments, the reducing agent can be metallurgical coke, and the amount of metallurgical coke added is 5% to 10% of the total mass of the mixture of waste petrochemical catalyst and cyanide tailings, for example, 5%, 6%, 7.5%, 8%, 10%, etc.

[0028] In some embodiments, the flux includes quartz sand, calcium oxide, and borax, etc. The amount of quartz sand added is 10% to 15% of the total mass of the mixture of waste petrochemical catalyst and cyanide tailings, for example, 10%, 12.5%, 15%, etc.; the amount of calcium oxide added is 35% to 45% of the total mass of the mixture of waste petrochemical catalyst and cyanide tailings, for example, 35%, 40%, 45%, etc.; and the amount of borax added is 5% to 8% of the total mass of the mixture of waste petrochemical catalyst and cyanide tailings, for example, 5%, 6%, 7.5%, 8%, etc.

[0029] The addition of borax can optimize the slag composition and keep the slag in the low melting point region, thereby reducing the smelting temperature. After multiple experiments, this application sets the amount of borax added to 5%~8%, which can effectively reduce the smelting temperature while ensuring that the iron is fully melted, thereby ultimately reducing the high temperature melting temperature to 1450~1500℃.

[0030] Furthermore, during the granulation process, the aforementioned calcium oxide can be used as a binder, thereby avoiding the need for the addition of other binders.

[0031] In some embodiments, the above granulation process can be achieved using a disc granulator; the diameter of the resulting mixture pellets is 0.5 to 1 cm, for example, 0.5 cm, 0.7 cm, 0.8 cm, 0.9 cm, 1 cm, etc.

[0032] S103, Low-temperature pre-sintering reduction: The mixed pellets are calcined at low temperature to achieve primary reduction of nickel and iron oxides, resulting in pre-sintered pellets.

[0033] The aforementioned low-temperature roasting process can effectively remove volatile impurities from hazardous / solid waste, while simultaneously reducing most of the nickel and iron oxides, thereby reducing the time required for high-temperature melting and reduction.

[0034] In some embodiments, low-temperature calcination is carried out in an electrically heated rotary kiln under the following conditions: kiln speed 6 r / min, temperature 950~1000℃ (e.g., 950℃, 970℃, 1000℃, etc.), and time 60~90 min (e.g., 60 min, 70 min, 80 min, 90 min, etc.). The metallization rates of nickel and iron in the pre-sintered pellets are 90~97% (e.g., 90%, 92%, 95%, 97%, etc.) and 75~80% (e.g., 75%, 77%, 80%, etc.), respectively.

[0035] S104. High-temperature melting and deep reduction slag-metal separation: The pre-sintered pellets are melted at high temperature to achieve deep reduction of nickel and iron oxides and slag-metal separation, ultimately obtaining nickel-iron alloy and glassy slag.

[0036] The above-mentioned high-temperature melting process can achieve deep reduction of nickel and iron oxides. At the same time, the slag is vitrified during the melting process. Then, under the combined action of gravity and density difference, the alloy phase and the slag phase achieve slag-metal separation, thereby obtaining nickel-iron alloy and glassy slag.

[0037] Vitrification of slag during the smelting process can solidify and stabilize toxic components such as heavy metals in two types of hazardous / solid waste, preventing toxic components from leaching out during stockpiling and polluting the environment, thus achieving resource recovery, volume reduction, and harmless treatment of smelting slag.

[0038] In some embodiments, the above-mentioned high-temperature melting process is carried out in a medium-frequency induction furnace, and the deep reduction conditions are: the melting temperature is 1450~1500℃, for example, 1450℃, 1460℃, 1470℃, 1480℃, 1490℃, 1500℃, etc.; the molten state is held for 40~60 min, for example, 40 min, 45 min, 50 min, 55 min, 60 min, etc.

[0039] Generally speaking, the higher the temperature, the higher the frequency of collisions between metals in the melt, the greater the bonding rate, and the higher the degree of alloying. Therefore, traditional high-temperature melting generally uses temperatures above 1600℃. However, this application, based on the adjustment and optimization of slag composition, has achieved optimization of slag physicochemical properties at temperatures below 1500℃, thereby realizing the preparation of high-grade nickel-iron alloys by low-temperature reduction smelting.

[0040] In some embodiments, the glassy slag in S104 is obtained in two parts: 1) the upper part of the slag is poured out in the later stage of high-temperature melting to detect the nickel and iron content and the composition and content of the slag; 2) after the high-temperature melting is completed, the crucible containing the glassy slag phase and the nickel-iron alloy phase is cooled to room temperature with the furnace.

[0041] Nickel-iron alloys contain 30-45% nickel (e.g., 30%, 31.41%, 35%, 35.11%, 40%, 44.56%, 45%), 50-65% iron (e.g., 50%, 52.06%, 55%, 60%, 61.36%, 64.11%, 65%), 3-5% carbon (e.g., 3%, 4%, 5%), and 1-2% impurities (e.g., 1%, 1.5%, 2%).

[0042] This application simultaneously treats two types of hazardous solid waste (waste petrochemical catalyst and cyanide tailings), increasing the variety of hazardous / solid wastes treated while avoiding the introduction of external metals, achieving the synergistic disposal of the two types of hazardous / solid wastes in a harmless, resource-efficient, and volume-reduced manner. The two-stage reduction alloying (low-temperature reduction roasting - high-temperature melting reduction) significantly reduces the holding time in the high-temperature melting stage, and effectively lowers the high-temperature melting reduction temperature (1450~1500°C) through environmentally friendly slag formation, achieving gold separation from the molten slag at a lower temperature than traditional high-temperature melting, effectively reducing process energy consumption.

[0043] The present application will be further described in detail below with reference to specific embodiments. The raw materials used in the following embodiments are waste petrochemical catalyst that has undergone preliminary deoiling provided by a petrochemical enterprise in Hebei Province, China, and cyanide tailings provided by an aluminum electrolysis enterprise in Shandong Province, China. The main components (mass fraction) of the waste petrochemical catalyst are: Al2O3 67.36%, SiO2 6.68%, CaO 2.14%, TFe 1.89%, Ni 6.64%, Na 4.58%; the main components (mass fraction) of the cyanide tailings are: Al2O3 5.63%, SiO2 25.47%, CaO 2.30%, TFe 37.41%, K2O 1.42%.

[0044] Example 1

[0045] (1) The waste petrochemical catalyst and cyanide tailings are crushed and powdered, and then kept at 105℃ for 120 min to remove free water and ensure the accuracy of subsequent component determination and batching of raw materials.

[0046] (2) Take 150 g of finely ground and pretreated waste petrochemical catalyst and 50 g of cyanide tailings (mass ratio of waste petrochemical catalyst to cyanide tailings = 75:25), add 20 g of reducing agent metallurgical coke, 20 g of quartz sand, 70 g of calcium oxide and 12 g of borax, mix evenly, and use a disc granulator to prepare the mixture into pellets with a diameter of 0.5~1 cm.

[0047] (3) The pellets obtained in step (2) are placed in an electrically heated rotary kiln for low-temperature calcination and reduction. The calcination conditions are: rotary kiln speed 6 r / min, temperature 1000℃, time 90 min, and thus pre-sintered pellets are obtained.

[0048] (4) The pre-sintered pellets obtained in step (3) are quickly transferred to a medium-frequency induction furnace for high-temperature melting and deep reduction separation. The conditions for high-temperature melting and deep reduction separation are: melting temperature of 1500℃ and holding time of 60 min.

[0049] (5) At the end of the high-temperature melting, the upper layer of melt is poured out, and the rest is cooled together with the nickel-iron alloy phase in the furnace. After cooling, the nickel-iron alloy and glassy tailings are obtained by mechanical separation.

[0050] (6) Weigh the slag phase and the nickel-iron alloy phase separately, then analyze their chemical composition and calculate the nickel-iron recovery rate.

[0051] Calculations and tests show that the above process can achieve a nickel recovery rate of 98.34%, an iron recovery rate of 92.14%, and a nickel mass fraction of 31.41% and an iron mass fraction of 64.11% in the nickel-iron alloy.

[0052] Example 2

[0053] (1) The waste petrochemical catalyst and cyanide tailings are crushed and powdered, and then kept at 105℃ for 120 min to remove free water and ensure the accuracy of subsequent component determination and batching of raw materials.

[0054] (2) Take 160 g of finely ground and pretreated waste petrochemical catalyst and 40 g of cyanide tailings (mass ratio of waste petrochemical catalyst to cyanide tailings = 80:20), add 15 g of reducing agent metallurgical coke, 25 g of quartz sand, 70 g of calcium oxide and 12 g of borax, mix evenly, and use a disc granulator to prepare the mixture into pellets with a diameter of 0.5~1 cm.

[0055] (3) The pellets obtained in step (2) are placed in an electrically heated rotary kiln for low-temperature calcination and reduction. The calcination conditions are: rotary kiln speed 6 r / min, temperature 1000℃, time 90 min, and thus pre-sintered pellets are obtained.

[0056] (4) The pre-sintered pellets obtained in step (3) are quickly transferred to a medium-frequency induction furnace for high-temperature melting and deep reduction separation. The conditions for high-temperature melting and deep reduction separation are: melting temperature of 1500℃ and holding time of 60 min.

[0057] (5) At the end of the high-temperature melting, the upper layer of melt is poured out, and the rest is cooled together with the nickel-iron alloy phase in the furnace. After cooling, the nickel-iron alloy and glassy tailings are obtained by mechanical separation.

[0058] (6) Weigh the slag phase and the nickel-iron alloy phase separately, and then analyze their chemical composition to calculate the nickel-iron recovery rate.

[0059] Calculations and tests show that the above process can achieve a nickel recovery rate of 97.65%, an iron recovery rate of 91.14%, and a nickel mass fraction of 35.11% and an iron mass fraction of 61.36% in the nickel-iron alloy.

[0060] Example 3

[0061] (1) The waste petrochemical catalyst and cyanide tailings are crushed and powdered, and then kept at 105℃ for 120 min to remove free water and ensure the accuracy of subsequent component determination and batching of raw materials.

[0062] (2) Take 180 g of finely ground and pretreated waste petrochemical catalyst and 20 g of cyanide tailings (mass ratio of waste petrochemical catalyst to cyanide tailings = 90:10), add 10 g of reducing agent metallurgical coke, 30 g of quartz sand, 80 g of calcium oxide and 15 g of borax, mix evenly, and use a disc granulator to prepare the mixture into pellets with a diameter of 0.5~1 cm.

[0063] (3) The pellets obtained in step (2) are placed in an electrically heated rotary kiln for low-temperature calcination and reduction. The calcination conditions are: rotary kiln speed 6 r / min, temperature 1000℃, time 90 min, and thus pre-sintered pellets are obtained.

[0064] (4) The pre-sintered pellets obtained in step (3) are quickly transferred to a medium-frequency induction furnace for high-temperature melting and deep reduction separation. The conditions for high-temperature melting and deep reduction separation are: melting temperature of 1500℃ and holding time of 60 min.

[0065] (5) At the end of the high-temperature melting, the upper layer of melt is poured out, and the rest is cooled together with the nickel-iron alloy phase in the furnace. After cooling, the nickel-iron alloy and glassy tailings are obtained by mechanical separation.

[0066] (6) Weigh the slag phase and the nickel-iron alloy phase separately, then analyze their chemical composition and calculate the nickel-iron recovery rate.

[0067] Calculations and tests show that the above process can achieve a nickel recovery rate of 95.16%, an iron recovery rate of 89.73%, and a nickel mass fraction of 44.56% and an iron mass fraction of 52.06% in the nickel-iron alloy.

[0068] Comparative Example 1

[0069] (1) The waste petrochemical catalyst and cyanide tailings are crushed and powdered, and then kept at 105℃ for 120 min to remove free water and ensure the accuracy of subsequent component determination and batching of raw materials.

[0070] (2) Take 150 g of the finely ground and pretreated waste petrochemical catalyst from step (1), add 20 g of reducing agent metallurgical coke, 30 g of analytical grade Fe2O3 reagent, 18 g of alumina, 100 g of quartz sand, 80 g of calcium oxide and 15 g of borax, mix them evenly, and use a disc granulator to prepare the mixture into pellets with a diameter of 0.5~1 cm.

[0071] (3) The pellets obtained in step (2) are placed in an electrically heated rotary kiln for low-temperature calcination and reduction. The calcination conditions are: rotary kiln speed 6 r / min, temperature 1000℃, time 90 min, and thus pre-sintered pellets are obtained.

[0072] (4) The pre-sintered pellets obtained in step (3) are quickly transferred to a medium-frequency induction furnace for high-temperature melting and deep reduction separation. The conditions for high-temperature melting and deep reduction separation are: melting temperature of 1500℃ and holding time of 60 min.

[0073] (5) At the end of the high-temperature melting, the upper layer of melt is poured out, and the rest is cooled together with the nickel-iron alloy phase in the furnace. After cooling, the nickel-iron alloy and glassy tailings are obtained by mechanical separation.

[0074] (6) Weigh the slag phase and the nickel-iron alloy phase separately, then analyze their chemical composition and calculate the nickel-iron recovery rate.

[0075] Calculations and tests show that, using the traditional pyrometallurgical process described above, this method can achieve a nickel recovery rate of 97.42%, a nickel mass fraction of 27.56%, and an iron mass fraction of 67.55% in the nickel-iron alloy.

[0076] As can be seen from Examples 1-3, the method of harmlessly co-processing waste petrochemical catalysts and cyanide tailings to prepare high-grade nickel-iron alloys, while simultaneously preparing glass slag through vitrification, is technologically feasible, and the nickel-iron recovery rates are all high. The nickel grade in the nickel-iron alloys can be adjusted according to different ratios of waste petrochemical catalysts and cyanide tailings. A comparison between Example 1 and Comparative Example 1 reveals that, for the waste petrochemical catalysts used in the experiments, even with the addition of cyanide tailings and analytical grade Fe2O3 as iron-containing material collectors, nickel in the waste petrochemical catalysts can still be recovered. However, cyanide tailings can not only provide metallic iron but also some slag-forming agents, while increasing the types of hazardous / solid waste that can be treated. Furthermore, iron can be recovered from the cyanide tailings. In the co-smelting process, by using a suitable slag ratio, the slag can be vitrified to obtain environmentally friendly and harmless glassy slag. This glassy slag can stabilize and solidify toxic components such as heavy metals in waste petrochemical catalysts and cyanide tailings, which is environmentally friendly. Therefore, the method for preparing high-grade nickel-iron alloys through the harmless co-processing of waste petrochemical catalysts and cyanide tailings proposed in this application has broad application prospects.

[0077] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0078] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing nickel-iron alloy using waste petrochemical catalysts, characterized in that, include: A mixture of powdered waste petrochemical catalyst, cyanide tailings, reducing agent, and flux is prepared by fully mixing the mixture in a specific ratio. The mixture is then granulated to obtain pellets. The mass ratio of the waste petrochemical catalyst to the cyanide tailings is (75-90):(25-10). The reducing agent is metallurgical coke, and the amount of metallurgical coke added is 5%-10% of the total mass of the mixture of waste petrochemical catalyst and cyanide tailings. The flux includes quartz sand, calcium oxide, and borax. The amount of quartz sand added is 10%-15% of the total mass of the mixture of waste petrochemical catalyst and cyanide tailings. The amount of calcium oxide added is... The amount of borax added is 35%~45% of the total mass of the mixture of the catalyst and the cyanide tailings; the amount of borax added is 5%~8% of the total mass of the mixture of the waste petrochemical catalyst and the cyanide tailings; the mixture pellets are subjected to low-temperature roasting to achieve primary reduction of nickel and iron oxides, and to obtain pre-sintered pellets; the low-temperature roasting temperature is 1000℃; the pre-sintered pellets are subjected to high-temperature melting to achieve deep reduction of nickel and iron oxides and to achieve slag-metal separation, and finally to obtain nickel-iron alloy and glassy slag; the melting temperature during the high-temperature melting process is 1450~1500℃, and the nickel content in the nickel-iron alloy is 30%~45% and the iron content is 50%~65%.

2. The method as described in claim 1, characterized in that, The method further includes: crushing and pulverizing the waste petrochemical catalyst and cyanide tailings, and then drying to remove free water, to obtain powdered waste petrochemical catalyst and cyanide tailings.

3. The method as described in claim 1, characterized in that, The diameter of the mixture pellets is 0.5~1 cm.

4. The method as described in claim 1, characterized in that, The low-temperature calcination is carried out in an electrically heated rotary kiln under the following conditions: rotary kiln speed 6 r / min, time 60~90 min.

5. The method as described in claim 1, characterized in that, The metallization rates of nickel and iron in the pre-sintered pellets are 90-97% and 75-80%, respectively.

6. The method as described in claim 1, characterized in that, During the high-temperature melting process, the deep reduction conditions are: holding the molten state at a temperature of 40~60 min.

7. The method as described in claim 1, characterized in that, The nickel-iron alloy contains 3% to 5% carbon and 1% to 2% impurities.

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