CN116814959A - A method for preparing nickel-iron alloy using waste petrochemical catalyst - Google Patents

Abstract

This application provides a method for preparing a nickel-iron alloy using a waste petrochemical catalyst, which includes: fully mixing the powdered waste petrochemical catalyst with cyanide tailings, reducing agent and flux in proportion to obtain a mixed material, and granulating the mixed material to prepare Obtain mixture pellets; roast the mixture pellets at low temperature to achieve primary reduction of nickel and iron oxides, and obtain pre-sintered pellets; melt the pre-sintered pellets at high temperature to achieve deep reduction of nickel and iron oxides, and achieve The slag and gold are separated, and finally nickel-iron alloy and glassy slag are obtained. The method provided by this application can realize the harmless co-processing of waste petrochemical catalysts and cyanide tailings to prepare high-grade nickel-iron alloy, and at the same time vitrify the slag. It has strong raw material adaptability, many types of hazardous/solid waste treatment, and does not add additional By adding iron-containing materials, the process is short, environmentally friendly, and has broad application prospects.

Description

A method for preparing nickel-iron alloy using waste petrochemical catalyst

Technical field

This application belongs to the smelting technical field of pyrometallurgical recovery of valuable metals from hazardous/solid waste, and specifically relates to a method of preparing nickel-iron alloy using a waste petrochemical catalyst.

Background technique

During the long-term use of petrochemical catalysts, their structure and chemical components continue to change and gradually reduce their catalytic ability, which is called "catalyst poisoning", which in turn makes the activity of petrochemical catalysts greatly reduced or even invalidated. They must be replaced regularly to ensure that each catalyst is poisoned. The production status of the industry will produce a large amount of waste petrochemical catalysts. Currently, most waste petrochemical catalysts are disposed of in landfills. This disposal method not only wastes a large amount of limited land resources, but also absorbs a large amount of toxic and harmful substances and heavy metal components during use over a long period of time. During the landfill process, it seeps out and pollutes the soil and groundwater, causing serious ecological and environmental problems. Therefore, there is an urgent need for harmless disposal of waste petrochemical catalysts. In addition, waste petrochemical catalysts are rich in valuable metal nickel, which can be used as an important raw material for stainless steel, precision alloys, hydrogen storage alloys, chemical catalysts and high-temperature alloys. The grade of nickel resources rich in waste petrochemical catalysts is much higher than that in mineral resources. With the rapid growth in the number of waste petrochemical catalysts every year, the total amount of nickel resources in waste petrochemical catalysts is very objective. Therefore, recycling 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 of nickel resources will achieve significant economic and ecological value. and social value.

At present, the treatment processes for waste petrochemical catalysts at home and abroad are mainly wet processes: oxidation roasting-alkali leaching, alkaline roasting-water leaching, microwave alkali leaching-microwave acid leaching, and atmospheric acid and alkali leaching. These traditional wet processes have many obvious shortcomings: poor adaptability of raw materials, long process flow, large amounts of secondary pollutants such as wastewater and residue, and low metal leaching rate. However, the traditional fire treatment process has shortcomings such as large equipment investment, single type of hazardous/solid waste treatment, many types and amounts of external materials added, and secondary pollution of tailings.

Contents of the invention

In order to solve the technical problems existing in the above background technology, this application provides a collaborative smelting process for the two hazardous/solid wastes of waste petrochemical catalysts and cyanide tailings, and simultaneously recovers the valuable metal nickel and iron to prepare High-grade nickel-iron alloy, and a method to achieve vitrification of slag, ultimately achieving efficient recovery and harmless disposal of valuable metals nickel and iron from waste petrochemical catalysts and cyanide tailings, two typical cross-industry hazardous/solid wastes.

Specifically, this application provides a method for preparing nickel-iron alloy using waste petrochemical catalysts, including:

Fully mix the powdered waste petrochemical catalyst with cyanide tailings, reducing agent and flux in proportion to obtain a mixture material, and granulate the mixture material to prepare mixture pellets;

The mixture pellets are roasted at low temperature to achieve primary reduction of nickel and iron oxides to obtain pre-sintered pellets;

The pre-sintered pellets are melted at high temperature to achieve deep reduction of nickel and iron oxides and separation of slag and gold, and finally obtain nickel-iron alloy and glassy slag.

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

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

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

As a further explanation of this application, the method also includes: crushing the waste petrochemical catalyst and cyanide tailings into powder, and then drying and removing free water to obtain powdered waste petrochemical catalyst and cyanide tailings.

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

As a further explanation of this application, the low-temperature roasting is carried out in an electrically heated rotary kiln. The conditions are: the rotation speed of the rotary kiln is 6 r/min, the temperature is 950~1000°C, and the time is 60~90 min.

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.

As a further explanation of this application, during the high-temperature melting process, the deep reduction conditions are: the melting temperature is 1450~1500°C, and the molten state is maintained for 40~60 minutes.

As a further explanation of this application, the nickel content in the nickel-iron alloy is 30% to 45%, the iron content is 50% to 65%, the carbon content is 3% to 5%, and the impurity content is 1% to 2%.

Compared with the existing technology, this application has the following beneficial technical effects:

The method provided by this application can realize the harmless co-processing of waste petrochemical catalysts and cyanide tailings to prepare high-grade nickel-iron alloy, and at the same time vitrify the slag. It has strong raw material adaptability, many types of hazardous/solid waste treatment, and does not add additional By adding iron-containing materials, the process is short, environmentally friendly, and has broad application prospects.

Description of the drawings

Figure 1 is a flow chart of a method for preparing nickel-iron alloy using waste petrochemical catalysts according to an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

As shown in Figure 1, the embodiment of the present application provides a method for preparing nickel-iron alloy using waste petrochemical catalyst, including the following steps:

S101. Low-temperature pretreatment of hazardous/solid waste: crush the waste petrochemical catalyst and cyanide tailings into powder, and then dry and remove free water to obtain powdered waste petrochemical catalyst and cyanide tailings.

In some embodiments, the above-mentioned drying conditions are: holding at 105°C for 120 minutes. After drying and removing free water, the accuracy of subsequent component determination and batching of raw materials can be ensured.

S102. Preparation of pre-sintered pellets: fully mix the powdered waste petrochemical catalyst with cyanide tailings, reducing agent and flux in proportion to obtain a mixture material, and granulate the mixture material to prepare mixture pellets.

In some embodiments, the mass ratio of waste petrochemical catalyst and cyanide tailings is (75~90): (25~10), for example, it can be 75:25, 80:20, 85:15, 90:10, etc. ; Mix cyanide tailings (mainly composed of SiO ₂ , FeO _x ) and waste petrochemical catalyst (mainly composed of Al ₂ O ₃ ) according to the above proportion to form SiO ₂ -Al ₂ O ₃ based glass slag, so no additional SiO ₂ slag-forming agent, thus reducing the excessive addition of external slag-forming agent caused by the disposal of a single waste petrochemical catalyst, to achieve the preparation of high-grade nickel-iron alloy and the addition of less carbon reducing agent, thereby achieving the two hazardous/solid waste Low carbon co-processing.

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 waste petrochemical catalyst and cyanide tailings mixture, for example, it can be 5%, 6%, 7.5%, 8%, 10%, etc.

In some embodiments, the flux includes quartz sand, calcium oxide, borax, and the like. Among them, the added amount of quartz sand is 10%~15% of the total mass of the waste petrochemical catalyst and cyanide tailings mixture, for example, it can be 10%, 12.5%, 15%, etc.; the added amount of calcium oxide is 10% to 15% of the total mass of the waste petrochemical catalyst and cyanide tailings mixture. 35%~45% of the total mass of the mixture of waste petrochemical catalysts and cyanide tailings, for example, it can be 35%, 40%, 45%, etc.; the amount of borax added is 5%~8% of the total mass of the mixture of waste petrochemical catalysts and cyanide tailings , for example, it can be 5%, 6%, 7.5%, 8%, etc.

Among them, the addition of borax can optimize the composition of the slag so that the slag is in a low melting point area, thereby reducing the melting temperature. After many tests in this application, the addition amount of borax is set to 5% to 8%, which can ensure that the iron component is fully melted. , effectively lowering the melting temperature, thereby ultimately reducing the high-temperature melting temperature to 1450~1500°C.

Furthermore, during the granulation process, the above-mentioned calcium oxide can be used as a binder, thereby avoiding the addition of other binders.

In some embodiments, a disc granulator can be used to realize the above granulation process; the diameter of the obtained mixture pellets is 0.5~1 cm, for example, it can be 0.5 cm, 0.7 cm, 0.8 cm, 0.9 cm, 1 cm etc.

S103. Low-temperature pre-sintered reduction: Roast the mixture pellets at low temperature to achieve primary reduction of nickel and iron oxides to obtain pre-sintered pellets.

The above-mentioned low-temperature roasting process can effectively remove volatile impurities in hazardous/solid waste, and at the same time achieve the reduction of most nickel and iron oxides, thus reducing the time of high-temperature smelting reduction.

In some embodiments, low-temperature roasting is performed in an electrically heated rotary kiln. The conditions are: the rotation speed of the rotary kiln is 6 r/min, the temperature is 950~1000°C, for example, it can be 950°C, 970°C, 1000°C, etc., and the time is 60~90 min, for example, it can be 60min, 70min, 80min, 90min, etc. The metallization rates of nickel and iron in the pre-sintered pellets are 90~97% respectively, for example, they can be 90%, 92%, 95%, 97%, etc. and 75~80%, for example, they can be 75%, 77%, 80% and so on.

S104. High-temperature melting and deep reduction slag and gold separation: The pre-sintered pellets are melted at high temperature to achieve deep reduction of nickel and iron oxides and separation of slag and gold, and finally obtain nickel-iron alloy and glassy slag.

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 the alloy phase and the slag phase realize the separation of slag and gold under the combined action of gravity and density difference, thereby obtaining nickel-iron alloy and Glassy slag.

During the smelting process, slag vitrification can solidify and stabilize toxic components such as heavy metals in the two hazardous/solid wastes, prevent toxic components from leaching during the stacking process and thereby pollute the environment, and realize the recycling, reduction and reduction of hazardous/solid wastes. The final smelting slag is rendered harmless.

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°C, for example, it can be 1450°C, 1460°C, 1470°C, 1480°C, 1490°C, 1500°C Etc.; the molten state is kept warm for 40~60 minutes, such as 40 min, 45 min, 50 min, 55 min, 60 min, etc.

Generally speaking, the higher the temperature, the higher the frequency of collisions between metals in the melt, the greater the combination rate, and the higher the degree of alloying. Therefore, traditional high-temperature melting generally uses a temperature higher than 1600°C, and this application is based on the composition of slag. Through blending and optimization, the physical and chemical properties of the slag are optimized at temperatures below 1500°C, thereby enabling low-temperature reduction smelting to prepare high-grade nickel-iron alloys.

In some embodiments, the glassy slag in S104 is divided into two parts to obtain: 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 in the slag, as well as the composition and content of the slag; 2) High-temperature melting After completion, the crucible containing the glassy slag phase and the nickel-iron alloy phase is cooled to room temperature with the furnace to obtain the result.

The nickel content in the nickel-iron alloy is 30~45%, for example, it can be 30%, 31.41%, 35%, 35.11%, 40%, 44.56%, 45%, etc.; the iron content is 50%~65%, for example, it can be 50 %, 52.06%, 55%, 60%, 61.36%, 64.11%, 65%, etc.; the carbon content is 3%~5%, for example, it can be 3%, 4%, 5%, etc.; the impurity content is 1% ~2%, for example, it can be 1%, 1.5%, 2%, etc.

This application processes two hazardous solid wastes (waste petrochemical catalysts and cyanide tailings) at the same time, which not only increases the types of hazardous/solid waste treatment, but also avoids the addition of external metals, and achieves the harmlessness of the two hazardous/solid wastes. , resource utilization and reduction co-processing. Two-stage reduction alloying (low-temperature reduction roasting-high-temperature smelting reduction) greatly reduces the holding time in the high-temperature melting stage, and effectively reduces the high-temperature smelting reduction temperature (1450~1500°C) through environmentally friendly slag making, achieving a more stable process than traditional high-temperature melting. The low-temperature separation of molten slag and gold effectively reduces process energy consumption.

The present application will be further described in detail below with reference to specific examples. The raw materials used in the following examples are preliminary deoiled waste petrochemical catalysts provided by a domestic petrochemical company in Hebei and cyanide tailings provided by a domestic aluminum electrolysis company in Shandong. Among them, the main components (mass fraction) of the waste petrochemical catalyst are: Al ₂ O ₃ 67.36%, SiO ₂ 6.68%, CaO2.14%, TFe 1.89%, Ni 6.64%, Na 4.58%; the main components of the cyanide tailings (Mass fraction): Al ₂ O ₃ 5.63%, SiO ₂ 25.47%, CaO 2.30%, TFe 37.41%, K ₂ O 1.42%.

Example 1

(1) Crush the waste petrochemical catalyst and cyanide tailings into powder, and then keep them at 105°C for 120 minutes to remove free water and ensure the accuracy of subsequent composition determination and batching of raw materials;

(2) Take 150 g of the finely ground and pretreated waste petrochemical catalyst and 50 g of cyanide tailings in step (1) (mass ratio of waste petrochemical catalyst to cyanide tailings = 75:25), add reducing agent metallurgy After uniformly mixing 20 g of coke, 20 g of quartz sand, 70 g of calcium oxide, and 12 g of borax, use a disc granulator to prepare the mixed materials into pellets with a diameter of 0.5~1 cm;

(3) Place the pellets obtained in step (2) in an electrically heated rotary kiln for low-temperature roasting and reduction. The roasting conditions are: rotary kiln speed 6 r/min, temperature 1000°C, time 90 min, and then pre-sintered Pellets;

(4) Quickly move the pre-sintered pellets obtained in step (3) to a medium frequency induction furnace for high-temperature melting depth reduction and separation. The conditions for high-temperature melting depth reduction and separation are: the melting temperature is 1500°C and the holding time is 60 minutes.

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

(6) Weigh the slag phase and nickel-iron alloy phase respectively, and then analyze the chemical composition to calculate the nickel-iron recovery rate.

After testing and calculation, it can be found that through the above process, this method can achieve a nickel recovery rate of 98.34% and an iron recovery rate of 92.14%. The nickel mass fraction in the nickel-iron alloy is 31.41% and the iron mass fraction is 64.11%.

Example 2

(1) Crush the waste petrochemical catalyst and cyanide tailings into powder, and then keep them at 105°C for 120 minutes to remove free water and ensure the accuracy of subsequent composition determination and batching of raw materials;

(2) Take 160 g of the finely ground and pretreated waste petrochemical catalyst and 40 g of cyanide tailings in step (1) (mass ratio of waste petrochemical catalyst to cyanide tailings = 80:20), add reducing agent metallurgy After uniformly mixing 15 g of coke, 25 g of quartz sand, 70 g of calcium oxide, and 12 g of borax, use a disc granulator to prepare the mixed materials into pellets with a diameter of 0.5~1 cm;

(3) Place the pellets obtained in step (2) in an electrically heated rotary kiln for low-temperature roasting and reduction. The roasting conditions are: rotary kiln speed 6 r/min, temperature 1000°C, time 90 min, and then pre-sintered Pellets;

(4) Quickly move the pre-sintered pellets obtained in step (3) to a medium frequency induction furnace for high-temperature melting depth reduction and separation. The conditions for high-temperature melting depth reduction and separation are: the melting temperature is 1500°C and the holding time is 60 minutes.

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

(6) Weigh the slag phase and nickel-iron alloy phase respectively, and then analyze the chemical composition to calculate the nickel-iron recovery rate.

After testing and calculation, it can be found that through the above process, this method can achieve a nickel recovery rate of 97.65% and an iron recovery rate of 91.14%. The nickel mass fraction in the nickel-iron alloy is 35.11% and the iron mass fraction is 61.36%.

Example 3

(1) Crush the waste petrochemical catalyst and cyanide tailings into powder, and then keep them at 105°C for 120 minutes to remove free water and ensure the accuracy of subsequent composition determination and batching of raw materials;

(2) Take 180 g of the finely ground and pretreated waste petrochemical catalyst and 20 g of cyanide tailings in step (1) (mass ratio of waste petrochemical catalyst to cyanide tailings = 90:10), add reducing agent metallurgy After uniformly mixing 10 g of coke, 30 g of quartz sand, 80 g of calcium oxide, and 15 g of borax, use a disc granulator to prepare the mixed materials into pellets with a diameter of 0.5~1 cm;

(3) Place the pellets obtained in step (2) in an electrically heated rotary kiln for low-temperature roasting and reduction. The roasting conditions are: rotary kiln speed 6 r/min, temperature 1000°C, time 90 min, and then pre-sintered Pellets;

(4) Quickly move the pre-sintered pellets obtained in step (3) to a medium frequency induction furnace for high-temperature melting depth reduction and separation. The conditions for high-temperature melting depth reduction and separation are: the melting temperature is 1500°C and the holding time is 60 minutes.

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

(6) Weigh the slag phase and nickel-iron alloy phase respectively, and then analyze the chemical composition to calculate the nickel-iron recovery rate.

After testing and calculation, it can be found that through the above process, this method can achieve a nickel recovery rate of 95.16% and an iron recovery rate of 89.73%. The nickel mass fraction in the nickel-iron alloy is 44.56% and the iron mass fraction is 52.06%.

Comparative example 1

(1) Crush the waste petrochemical catalyst and cyanide tailings into powder, and then keep them at 105°C for 120 minutes to remove free water and ensure the accuracy of subsequent composition determination and batching of raw materials;

(2) Take 150 g of the finely ground and pretreated waste petrochemical catalyst in step (1), add 20 g of reducing agent metallurgical coke, 30 g of analytically pure Fe ₂ O ₃ reagent, 18 g of alumina, and 100 g of quartz sand. , 80 g of calcium oxide and 15 g of borax are evenly mixed, and the mixed materials are prepared into pellets with a diameter of 0.5~1 cm using a disc granulator;

(3) Place the pellets obtained in step (2) in an electrically heated rotary kiln for low-temperature roasting and reduction. The roasting conditions are: rotary kiln speed 6 r/min, temperature 1000°C, time 90 min, and then pre-sintered Pellets;

(4) Quickly move the pre-sintered pellets obtained in step (3) to a medium frequency induction furnace for high-temperature melting depth reduction and separation. The conditions for high-temperature melting depth reduction and separation are: the melting temperature is 1500°C and the holding time is 60 minutes.

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

(6) Weigh the slag phase and nickel-iron alloy phase respectively, and then analyze the chemical composition to calculate the nickel-iron recovery rate.

After testing and calculation, it can be found that through the above traditional fire process, 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%.

According to Examples 1 to 3, it can be seen that the method of harmlessly co-processing waste petrochemical catalysts and cyanide tailings to prepare high-grade nickel-iron alloy, and simultaneously vitrifying to prepare glass slag is technically feasible, and the nickel-iron recovery rate is uniform. The nickel grade in the nickel-iron alloy can be adjusted according to the different ratios of waste petrochemical catalysts and cyanide tailings. Through the comparison between Example 1 and Comparative Example 1, it is found that for the waste petrochemical catalyst in the experiment, although cyanide tailings and analytical pure Fe ₂ O ₃ are added as iron-containing material collectors, the nickel in the waste petrochemical catalyst can be recovered . However, cyanide tailings can not only provide metallic iron but also provide part of the slag-forming agent, and can increase the types of hazardous/solid waste treatment. It can also recover the iron in cyanide tailings and use appropriate slag preparation in the collaborative smelting process. Ratio, the slag can be vitrified to obtain environmentally friendly and harmless glassy slag. This glass slag can stably solidify toxic components such as heavy metals in waste petrochemical catalysts and cyanide tailings, and is environmentally friendly. Therefore, the method proposed in this application The method of preparing high-grade nickel-iron alloy through harmless co-processing of waste petrochemical catalysts and cyanide tailings has broad application prospects.

It should be noted that in this document, terms such as "comprises", "comprises" or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article or device that includes a series of elements not only includes those elements , but also includes other elements not expressly listed or inherent in such process, method, article or equipment.

Although the embodiments of the present application have been shown and described, those of ordinary skill in the art will understand that various changes, modifications, and substitutions can be made to these embodiments without departing from the principles and spirit of the present application. and variations, the scope of the application is defined by the appended claims and their equivalents.

Claims (10)

1. A method for preparing nickel-iron alloy using waste petrochemical catalyst, which is characterized in that it includes: Fully mix the powdered waste petrochemical catalyst with cyanide tailings, reducing agent and flux in proportion to obtain a mixture material, and granulate the mixture material to prepare mixture pellets; The mixture pellets are roasted at low temperature to achieve primary reduction of nickel and iron oxides to obtain pre-sintered pellets; The pre-sintered pellets are melted at high temperature to achieve deep reduction of nickel and iron oxides and separation of slag and gold, and finally obtain nickel-iron alloy and glassy slag. 2. The method according to claim 1, characterized in that the mass ratio of the waste petrochemical catalyst and the cyanide tailings is (75~90): (25~10). 3. The method of claim 1, wherein the reducing agent is metallurgical coke, and the metallurgical coke addition amount is 5% of the total mass of the waste petrochemical catalyst and the cyanide tailings mixture. ~10%. 4. The method of claim 1, wherein the flux includes quartz sand, calcium oxide and borax; the quartz sand addition amount is the total of the waste petrochemical catalyst and the cyanide tailings mixture. 10%~15% of the mass; the calcium oxide addition amount is 35%~45% of the total mass of the waste petrochemical catalyst and the cyanide tailings mixture; the borax addition amount is the waste petrochemical catalyst and the cyanide tailings mixture 5% to 8% of the total mass of the cyanide tailings mixture. 5. The method according to claim 1, characterized in that the method further comprises: crushing the waste petrochemical catalyst and cyanide tailings into powder, and then drying and removing free water to obtain powdery waste petrochemical catalyst and cyanide tailings. Scum. 6. The method of claim 1, wherein the diameter of the mixture pellets is 0.5~1 cm. 7. The method of claim 1, wherein the low-temperature roasting is carried out in an electrically heated rotary kiln under the following conditions: rotary kiln speed 6 r/min, temperature 950~1000°C, and time 60~90 min. 8. The method of claim 1, wherein the metallization rates of nickel and iron in the pre-sintered pellets are 90~97% and 75~80% respectively. 9. The method of claim 1, wherein during the high-temperature melting process, the deep reduction conditions are: the melting temperature is 1450~1500°C, and the molten state is kept warm for 40~60 minutes. 10. The method of claim 1, wherein the nickel content in the nickel-iron alloy is 30% to 45%, the iron content is 50% to 65%, the carbon content is 3% to 5%, and the impurity content is 1%. ~2%.