KR102596866B1 - Method for manufacturing oxide iron and reduced iron composite fuel - Google Patents

Abstract

Provided is an iron oxide reduced iron composite fuel and a manufacturing method thereof. The method for producing reduced iron oxide composite fuel includes i) a first step of collecting iron oxide generated during nickel ore smelting, ii) a second step of partially reducing iron oxide with hydrogen to provide reduced iron oxide composite fuel, and iii) reducing iron oxide. It includes a third step of processing the composite fuel into a preset size or shape.

Description

Method for manufacturing iron oxide reduced iron composite fuel {METHOD FOR MANUFACTURING OXIDE IRON AND REDUCED IRON COMPOSITE FUEL}

The present invention relates to iron oxide reduced iron composite fuel and a method for producing the same. More specifically, it relates to a fuel that can be used instead of charcoal using a composite of reduced iron and iron oxide and a method of manufacturing the same.

Charcoal is mainly used as a barbecue raw material. Recently, charcoal that can be burned has been developed and is widely used for dining in restaurants and camping. However, charcoal causes problems such as difficulty breathing for users and environmental pollution due to smoke generated during or after ignition. In addition, the ash remaining after use is classified as garbage and disposal costs are incurred.

Therefore, the development of alternative fuels that can overcome these shortcomings of charcoal is urgently needed. One of the alternative fuel candidates is iron powder. Iron powder is widely used as a material for pocket stoves by taking advantage of the phenomenon of heat generation during oxidation. However, iron powder has a small calorific value and is difficult to control, making it difficult to use as fuel.

Japanese Patent Publication No. 2008-215292

Provides iron oxide-reduced iron composite fuel that can replace charcoal. Additionally, a method for producing a reduced iron oxide composite fuel is provided.

The method for producing reduced iron oxide composite fuel according to an embodiment of the present invention includes i) a first step of collecting iron oxide generated during nickel ore smelting, ii) a step of partially reducing iron oxide with hydrogen to provide reduced iron oxide composite fuel. Step 2, and iii) a third step of processing the iron oxide reduced iron composite fuel into a preset size or shape.

A method for producing a reduced iron oxide composite fuel according to an embodiment of the present invention includes iv) a fourth step of burning the reduced iron oxide composite fuel to provide another iron oxide, and v) a fourth step of repeating the second step with another iron oxide. Five more steps may be included. In the second step, the reduction rate of the iron oxide reduced iron composite fuel may be 50% to 90%.

In the second step, the iron oxide reduced iron composite fuel is provided as a powder with a reduction rate of 50% to 75%, and in the third step, the iron oxide reduced iron composite fuel is processed and provided in the form of pellets with a particle size of 5 mm to 15 mm. In the second step, the reduction rate of the reduced iron oxide composite fuel is 75% to 90%, and the reduced iron oxide composite fuel can be processed into bulk material with a particle size of 20 mm to 50 mm.

The iron oxide reduced iron composite fuel according to an embodiment of the present invention can be produced by the above-described method.

Iron oxide-reduced iron composite fuel can be used as a substitute for charcoal. Reduced iron composite has fine pores due to a mixture of reduced iron and iron oxide, so it is easy to ignite and control fire power by adjusting the amount of air. And since almost no smoke is generated, there are no environmental pollution problems. Furthermore, it is expected to be very useful in reducing waste because the iron oxide reduced iron composite fuel can be collected and reduced after use and the reduced iron can be reused. In addition, the reduction rate can be arbitrarily adjusted, and iron oxide-reduced iron composite fuel can be manufactured in desired sizes from powder to bulk material.

1 is a schematic flowchart of a method for manufacturing a reduced iron oxide composite fuel according to an embodiment of the present invention.
Figure 2 is a photograph of charcoal of the prior art and reduced iron oxide composite fuel according to an experimental example of the present invention.
Figure 3 is a photograph of a temperature increase experiment of charcoal of the prior art and iron oxide reduced iron composite fuel according to an experimental example of the present invention.
Figure 4 is a photograph of a combustion experiment of charcoal of the prior art and iron oxide reduced iron composite fuel according to an experimental example of the present invention.
Figure 5 is a combustion experiment photograph of iron oxide reduced iron composite fuel according to particle size according to an experimental example of the present invention.

The terminology used herein is only intended to refer to specific embodiments and is not intended to limit the invention. As used herein, singular forms include plural forms unless phrases clearly indicate the contrary. As used in the specification, the meaning of "comprising" is to specify a specific characteristic, area, integer, step, operation, element and/or component, and to specify another specific property, area, integer, step, operation, element, component and/or group. It does not exclude the existence or addition of .

Although not defined differently, all terms including technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted as having meanings consistent with related technical literature and currently disclosed content, and are not interpreted in ideal or very formal meanings unless defined.

Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein.

Figure 1 schematically shows a method of manufacturing a reduced iron oxide composite fuel according to an embodiment of the present invention. The method for producing reduced iron oxide composite fuel in FIG. 1 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the manufacturing method of iron oxide reduced iron composite fuel can be modified differently.

As shown in FIG. 1, the method for producing reduced iron oxide composite fuel includes the steps of collecting iron oxide generated during nickel ore smelting (S10), reducing iron oxide with hydrogen to provide reduced iron (S20), and reducing iron oxide. Processing into a set size or preset shape (S30), mixing reduced iron and iron oxide to produce reduced iron oxide composite fuel (S40), burning the reduced iron oxide composite fuel to provide another iron oxide (S50), And it includes another step of reducing iron oxide and returning it to reduced iron (S60). In addition, the method for producing iron oxide reduced iron composite fuel may further include other steps, if necessary. In addition, steps (S50) and (S60) can be omitted in the method of manufacturing the iron oxide reduced iron composite fuel of FIG. 1.

First, the step of collecting iron oxide generated during nickel ore smelting (S10) collects porous iron oxide generated during the nickel ore smelting process. Since iron oxide is generated as a by-product during nickel ore smelting, it is desirable to obtain raw materials for iron oxide reduced iron composite fuel. In contrast, in the iron ore iron making process, iron ore contains about 5 to 20 wt% of iron (Fe). However, since the iron component is completely reduced to molten iron in a blast furnace, it is difficult to obtain the above-mentioned iron oxide without a special process. Therefore, it is desirable to use iron oxide as a by-product during nickel ore smelting. More specifically, the smelting process of nickel ore includes the steps of i) leaching nickel ions from nickel reduction ore, ii) removing leaching residues from the leach liquid obtained in the leaching step, and iii) adding reduced iron to the leach liquid from which the leaching residues have been removed. Precipitating nickel ions into ferronickel, iv) separating the leachate into ferronickel precipitate and precipitated filtrate, v) concentrating the precipitated filtrate to crystallize the iron compound, and vi) roasting the iron compound to obtain iron oxide. Includes steps. Iron oxide occurs as a by-product. Iron oxide is produced through an acid leaching process and a preliminary reduction process. Unlike regular iron oxide, the iron oxide produced here has many fine pores and has a large surface area. Unlike in the past, in this process, metal components including iron are dissolved in acid through acid leaching in the smelting process and then precipitated again as crystals, producing iron oxide. Therefore, through this process, iron oxide has a high fraction of pores and its surface area is very large. As a result, When reducing iron oxide using hydrogen in the subsequent process, the reduction rate of iron oxide can be increased because the surface area of iron oxide is large and the contact area with hydrogen is large. Since this iron oxide collection process can be easily understood by those skilled in the art, detailed description thereof will be omitted.

Next, in step S20, iron oxide is reduced with hydrogen to provide reduced iron oxide composite fuel. The reduction rate of iron oxide can be controlled according to the reduction conditions by hydrogen. Reduction conditions include reduction temperature, reduction time, or iron oxide input amount. The reduction rate and size of iron oxide can be controlled by controlling the hydrogen exposure time. For example, reduced iron can be produced with the reduction rate controlled to 50%, 75%, and 90%, respectively. That is, the reduction rate may be 50% to 90%. If the reduction rate is too small, it is unsuitable for use as fuel. Additionally, if the reduction rate is too large, the cost required for the reduction process increases. Therefore, the reduction rate is adjusted to the above-mentioned range.

The reduction rate varies depending on reduction conditions such as reduction furnace, reduction temperature, hydrogen input amount, amount of iron oxide input, or reduction atmosphere maintenance time. When the reduction rate of completely reduced iron is 100%, reduced iron with various reduction rates such as 90%, 75%, and 50% can be produced depending on the reduction conditions. The shape of reduced iron changes depending on the degree of reduction. The higher the reduction rate, the harder the reduced iron becomes, and the lower the reduction rate, the closer it is to powder. Therefore, reduced iron can be manufactured in the form of powder, granule, or lump depending on the reduction rate.

When dry reducing iron oxide using hydrogen gas, etc., the reduction rate can be controlled by controlling reduction conditions such as reduction temperature, holding time, input amount, and thickness. For example, when the reduction rate of the reduced iron oxide composite fuel is 50% to 75%, the reduced iron oxide composite fuel has almost a powder shape. This type of iron oxide-reduced iron composite fuel is easily ignited even in contact with a little air, that is, oxygen in the atmosphere. On the other hand, when the reduction rate of the reduced iron oxide composite fuel is 75% to 90%, the reduced iron and iron oxide tend to agglomerate slightly, but are easily broken. In addition, when the reduction rate of the reduced iron oxide composite fuel is 90% to 99%, fusion occurs between the reduced iron and it is hardly broken, but it can be manufactured in a partially pulverized form by applying impact during transportation through conveyor belt bending in the reduction process. Since the detailed process of step S20 can be easily understood by those skilled in the art to which the present invention pertains, detailed description thereof is omitted.

Next, in step S30, the iron oxide reduced iron composite fuel is processed into a preset size or shape. That is, in step S30, the iron oxide reduced iron composite fuel can be processed into a specific size or shape. For example, iron oxide reduced iron composite fuel prepared as a powder can be compacted and manufactured into pellets or bulk materials. Conversely, iron oxide reduced iron composite fuel manufactured as bulk material can be ground to produce powder or pellets. The size of this iron oxide reduced iron composite fuel can be modified depending on the usage environment of the iron oxide reduced iron composite fuel. For example, powder form is desirable for rapid ignition of iron oxide reduced iron composite fuel. Additionally, in order to ensure combustion sustainability of iron oxide-reduced iron composite fuel, pellet or bulk material form is preferable. And in order to meet the two conditions mentioned above, that is, to ensure rapid ignition and combustion sustainability, all of the above types of reduced iron oxide composite fuels can be used.

In step S30, for example, the iron oxide reduced iron composite fuel may be provided in powder form. Powdered iron oxide reduced iron composite fuel can be molded into pellets with a particle size of 5mm to 15mm. If the particle size of the pellets is too small, it is difficult to secure the desired combustion duration. Additionally, if the particle size of the pellet is too large, ignition may take a long time. Therefore, the pellets are controlled to the above-mentioned particle size range.

Meanwhile, the reduction rate of the reduced iron oxide composite fuel is 75% to 90%, and the reduced iron oxide composite fuel can be processed into bulk material with a particle size of 20 mm to 50 mm. In other words, powder and pellets can be compressed to produce bulk materials. If the particle size of the bulk material is too small, the combustion duration is too short. Additionally, if the particle size of the bulk material is too large, it may be difficult to use in a furnace, etc. and it may be difficult to ignite it. Therefore, the particle size of the bulk material is adjusted to the above-mentioned range.

In step S40, the iron oxide reduced iron composite fuel is burned to provide iron oxide. That is, the iron oxide reduced iron composite fuel is stacked and ignited in the furnace and used as fuel, and as the iron oxide reduced iron composite fuel is burned, the reduced iron contained in the iron oxide reduced iron composite fuel is transformed into iron oxide. And iron oxide-reduced iron composite fuel releases a large amount of heat as it burns.

Finally, in step 50, the iron oxide obtained in step 40 is returned to step S20 and step S20 is repeated. In other words, iron oxide can be reduced to hydrogen and recycled as reduced iron composite fuel. As a result, there is no need to discard it as ashes after use like conventional charcoal, thereby preventing environmental pollution.

Hereinafter, the present invention will be described in more detail through experimental examples. These experimental examples are only for illustrating the present invention, and the present invention is not limited thereto.

Experiment example

A reduced iron oxide composite fuel was manufactured using the manufacturing method of the reduced iron oxide composite fuel of FIG. 1. The average reduction rate of the iron oxide reduced iron composite fuel was 50% to 90%. Since the details of the manufacturing method of the iron oxide reduced iron composite fuel can be easily understood by those skilled in the art to which the present invention pertains, detailed description thereof will be omitted.

Figure 2 is a photograph of charcoal of the prior art and reduced iron oxide composite fuel according to an experimental example of the present invention. The left side of Figure 2 shows charcoal contained in a furnace, and the right side of Figure 2 shows reduced iron oxide composite fuel contained in a furnace. Charcoal was used as charcoal.

Ignition and combustion experiments

The ignition time of the charcoal of the prior art and the reduced iron oxide composite fuel according to the experimental example of the present invention were compared. In addition, the combustion states of charcoal and reduced iron oxide composite fuel according to the experimental example of the present invention were compared.

Figure 3 is a photograph of a combustion experiment of charcoal of the prior art and iron oxide reduced iron composite fuel according to an experimental example of the present invention. The left side of Figure 3 shows a furnace containing charcoal, and the right side of Figure 3 shows a furnace containing reduced iron oxide composite fuel.

Charcoal was used as charcoal. After heating the surface of the charcoal and reduced iron oxide composite fuel using a pickaxe, ignition occurred after a certain period of time. As a result of the experiment, the ignition time of the iron oxide-reduced iron composite fuel was similar to that of charcoal. In other words, the time required for ignition was slightly faster for iron oxide reduced iron composite fuel or almost similar to charcoal. On the other hand, as shown in Figure 3, a lot of smoke was generated from charcoal before and after ignition. On the other hand, almost no smoke was generated before or after ignition in the iron oxide reduced iron composite fuel. As a result, it was not only convenient to use, but also caused almost no environmental pollution. In contrast, charcoal generated a large amount of smoke when burned and was disposed of as ash after use, which was harmful to the environment.

temperature increase experiment

Charcoal, which is charcoal, and iron oxide-reduced iron composite fuel were heated and raised respectively. And the temperature increase of both fuels was compared.

Figure 4 is a photograph of a temperature increase experiment of charcoal of the prior art and iron oxide reduced iron composite fuel according to an experimental example of the present invention. Charcoal was used in the left furnace of Figure 4, and reduced iron oxide composite fuel was used in the right furnace of Figure 4. A wire mesh was placed on top of each furnace, a beaker containing water was placed, and a thermocouple was inserted to measure the temperature.

In this experiment, the time required for water to be heated to 100°C after ignition was 14 minutes for charcoal and 13 minutes for reduced iron oxide composite fuel. Therefore, the charcoal of the prior art reached 100° C. about 1 minute faster than the iron oxide-reduced composite fuel, but the iron oxide-reduced iron composite fuel was much better in terms of sustainability. In other words, while charcoal produced a high calorific value after ignition and then quickly decreased, the calorific value of iron oxide reduced iron composite fuel gradually increased and remained uniform.

Combustion experiment according to particle size

The iron oxide reduced iron composite fuel was compressed into preset sizes to produce small pellets, medium pellets, and bulk materials, respectively. The average particle diameter of the small pellets was 5 mm to 10 mm and the average weight was 6 g. The average particle diameter of the medium-sized pellets was 10 mm to 20 mm and the average weight was 14 g. And the average particle diameter of the bulk material was 20mm to 30mm and its average weight was 38g. The small pellets, medium pellets, and bulk materials were each heated and ignited with a torch.

Figure 5 is a combustion experiment photograph of iron oxide reduced iron composite fuel according to particle size according to an experimental example of the present invention. Figure 5(a) shows combustion pictures of small pellets, Figure 5(b) shows combustion pictures of medium-sized pellets, and Figure 5(c) shows pictures of ignition of bulk materials.

Ignition of the powder or very small pellets shown in (a) of Figure 5 was easy. However, there was a problem with dust splashing. The small pellets ignited relatively quickly compared to the charcoal of the prior art, and no smoke was generated when ignited. Once ignited, the small pellet burned on its own and continued to generate heat if there were no external factors such as air blocking.

The ignition time of the medium-sized pellets in Figure 5(b) was longer than that of the small pellets. However, there was no problem with dust splashing, and once ignited, the combustion time was maintained relatively long. In addition, the bulk material shown in (c) of Figure 5 took a long time to ignite, but once ignited, the flame spread quietly and did not go out easily and continued to burn for a long time. Considering this, it is necessary to appropriately adjust the size of the iron oxide reduced iron composite fuel according to the surrounding environment, such as the purpose of the iron oxide reduced iron composite fuel and the amount of air supplied.

Although the present invention has been described according to the foregoing description, those skilled in the art will easily understand that various modifications and variations are possible without departing from the concept and scope of the claims described below.

Claims (6)

The first step is to collect iron oxide generated during nickel ore smelting,
A second step of partially reducing the iron oxide with hydrogen to provide a reduced iron oxide composite fuel, and
A third step of processing the iron oxide reduced iron composite fuel into a preset size or shape.
Including,
The first step is,
leaching nickel ions from nickel reduction light,
Removing the leaching residue in the leach solution obtained in the leaching step,
Adding reduced iron to the leach liquid from which the leach residue has been removed to precipitate nickel ions into ferronickel;
Separating the leachate into ferronickel precipitate and precipitated filtrate,
Concentrating the precipitated filtrate to crystallize the iron compound, and
Obtaining the iron oxide by roasting the iron compound
Including,
In the second step, the iron oxide reduced iron composite fuel is provided as a powder with a reduction rate of 50% to 75%,
In the third step, the iron oxide reduced iron composite fuel is processed and provided in the form of pellets with a particle size of 5 mm to 15 mm. The first step is to collect iron oxide generated during nickel ore smelting,
A second step of partially reducing the iron oxide with hydrogen to provide a reduced iron oxide composite fuel, and
A third step of processing the iron oxide reduced iron composite fuel into a preset size or shape.
Including,
The first step is,
leaching nickel ions from nickel reduction light,
Removing the leaching residue in the leach solution obtained in the leaching step,
Adding reduced iron to the leach liquid from which the leach residue has been removed to precipitate nickel ions into ferronickel;
Separating the leachate into ferronickel precipitate and precipitated filtrate,
Concentrating the precipitated filtrate to crystallize the iron compound, and
Obtaining the iron oxide by roasting the iron compound
Including,
In the second step, the reduction rate of the iron oxide reduced iron composite fuel is 75% to 90%,
In the third step, a method of producing a reduced iron oxide composite fuel by processing the reduced iron oxide composite fuel into bulk material with a particle size of 20 mm to 50 mm. In paragraph 1 or 2:
a fourth step of combusting the iron oxide reduced iron composite fuel to provide another iron oxide; and
A fifth step of repeating the second step with another iron oxide.
A method for producing a reduced iron oxide composite fuel further comprising: delete delete delete

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