KR20160082380A - Ferruginous by-product recycling method - Google Patents

Abstract

The method for recycling iron and iron by-product according to the present invention comprises the steps of: preparing a mixture by dissolving alkali in water or a by-product by-product of iron, carbon, zinc, chlorine and alkali in dust or sludge form; Supplying an air bubble to said mixture, and recovering carbon particles adhered to said air bubble; Applying magnetic force to the mixture from which carbon has been removed to recover iron powder; Separating a solution containing alkali ions in the mixture from which carbon and iron are removed, and recovering the solid containing zinc; And adsorbing and recovering alkali ions from the solution; .

Description

{FERRUGINOUS BY-PRODUCT RECYCLING METHOD}

The present invention relates to a method for recycling by-product by-products, and more particularly, to a method for recycling by-product by-products that can separate and recycle iron, carbon, zinc, and alkali from a by-product.

Among the byproducts generated in the steel industry, sludge and dust containing zinc and alkali are generally sintered secondary dust collecting dust, blast furnace sludge, blast furnace dust, sludge sludge and the like. Such sludge and dust are generally minute particles having a very small particle size, and contain zinc and alkali, which makes recycling extremely difficult. Listed below are some of the problems in recycling these iron and steel by-

First, when the byproducts of iron and iron are directly used as raw materials for sintering, the sintering productivity and the deterioration of reductive differentiation deteriorate,

Secondly, since it is volatilized at a relatively low temperature, it is collected in the sintered electrostatic precipitator, thereby lowering the dust collecting efficiency of the electrostatic precipitator,

Third, when metal zinc vapor is concentrated, there is a risk of fire in the oxidation process of zinc,

Fourth, when the sintered ores having high zinc and alkali contents are charged into the blast furnace, there is a problem that they cause damage due to the shape of the wall of the furnace wall and damage to the sphalerite.

Therefore, it is necessary to remove zinc and alkali components in order to be recycled as a raw material for sintering or blast furnace charging.

Conventionally, a method of removing zinc and alkali from a mixture or removing the impurities and then recycling them has been disclosed. A method of producing sintered ores by using a sintered iron oxide dust (Korean Patent No. 10-0309782 (Sep. 11, 2001) A method for separating low zinc dust from a sludge separation method (Korean Patent Registration No. 10-0400416 (Sep. 22, 2003)), a sulfur removing method in a secondary electrostatic dust dust generated in a sintering plant of a steel mill (Korean Patent Registration No. 10-0376501 (Japanese Unexamined Patent Application Publication No. 1997-241773 (1997.09.16)), a method of wet treatment of seasoned dust (Japanese Patent Laid-Open No. 1997-075891 (Mar. 25, 1997)), a method of recovering zinc from dust containing zinc (Korean Patent No. 10-0210649 (Apr. 27, 1999)), a method of recovering alkali metal from charcoal using catalytic vaporization (U.S. Patent No. 7897126 (Mar. have.

These inventions include a method of separating zinc by centrifugation using a wet cyclone or the like, a method of removing sulfur by stirring together with an aqueous alkaline solution, a method of roasting a zinc-containing dust in an oxidizing atmosphere and then extracting zinc using sulfuric acid A method in which zinc is volatilized and recovered, iron is used in a charcoal, and a method in which charcoal is used to recover alkaline metals.

The selection method using centrifugal separation using the specific gravity difference between the zinc particles and the iron particles is advantageous in that the process is simple and the operation cost is low. However, the zinc removal rate is significantly lower than the recovery method after volatilizing the zinc at high temperature Have. On the other hand, the method of recovering zinc by volatilization at a high temperature is a process of manufacturing a direct reduction iron by using a by-product of iron and iron as a raw material because the process installation cost and operation cost are high and the economical efficiency is low. Some of the by-products containing zinc and alkali are used in the rotary hearth funace.

Patents for some wet smelting processes are effective for the recovery of nickel and the like from the by-products of the plating and surface treatment processes, which have a very high zinc content, or by-products of the stainless steel process, but for the removal of zinc and alkali from common by- It is difficult to apply it because there are problems such as the use of acid and alkali solution and the treatment of spent acid.

Accordingly, the present invention provides a method for recovering zinc, alkali, carbon and iron from various dusts and sludges containing zinc and alkali through a relatively simple process.

Korean Patent No. 10-0309782 (Sep. 11, 2001) Korean Patent No. 10-0400416 (September 22, 2003) Korean Patent No. 10-0376501 (Mar. 2003) Japanese Patent Application Laid-Open No. 1997-075891 (Mar. 25, 1997) Japanese Patent Application Laid-Open No. 1997-241773 (September 16, 1997) Korean Patent No. 10-0210649 (Apr. 27, 1999) US Patent No. 7897126 (Mar. 1, 2011)

SUMMARY OF THE INVENTION The present invention has been made in order to solve such problems, and an object of the present invention is to provide a method for recycling iron and iron byproducts which can separate and recycle iron, carbon, alkali and zinc.

To achieve the above object, a method for recycling by-product iron by-products according to an embodiment of the present invention comprises the steps of: preparing a mixture by dissolving alkali by mixing water with iron ore, carbon, zinc, chlorine, step; Supplying an air bubble to said mixture, and recovering carbon particles adhered to said air bubble; Applying magnetic force to the mixture from which carbon has been removed to recover iron powder; Separating a solution containing alkali ions in the mixture from which carbon and iron are removed, and recovering the solid containing zinc; And adsorbing and recovering alkali ions from the solution; .

After the step of adsorbing and recovering the alkali ion, the alkali ion is separated from the solution and the remaining water is recycled to the mixture preparation step.

The step of recovering the carbon particles is characterized in that the air bubbles having a diameter of 1 cm or less are supplied to the bottom surface of the chamber on which the mixture is loaded and the carbon suspended in the water surface of the mixture is recovered as a scraper attached to the air bubbles do.

The step of recovering the iron powder is characterized by using a magnet having a magnetic force of 500 to 1000 Gauss.

The step of adsorbing and recovering the alkali ion includes a step of adsorbing the alkali ion dissolved in the solution to the cation exchange resin, and a step of desorbing the alkali ion adsorbed to the cation exchange resin.

The iron and steel by-product is characterized in that it is at least one of sintering dust collecting dust, steelmaking sludge, blast furnace dust, and blast furnace sludge.

The step of preparing the mixture may include a step of mixing water with the sintered dust collecting dust to dissolve alkali and chlorine, and the step of adsorbing and recovering the ions may include a step of adsorbing the alkali ion dissolved in the solution to the cation exchange resin, A process of adsorbing chlorine ions dissolved in a solution on an anion exchange resin, a process of desorbing alkali ions adsorbed on the cation exchange resin, and a process of desorbing chlorine ions adsorbed on the anion exchange resin.

The mixture preparation step is characterized in that the by-product by-product and water are mixed in a ratio of 1: 4 to 6 (wt%) and stirred for 30 to 60 minutes.

The method for recycling byproducts by-products according to the present invention has the following effects.

First, it is possible to prevent waste of resources and environmental pollution by separating and recycling waste iron and steel by-products.

Second, zinc and alkali can be separated at high efficiency from the by-product of iron and iron.

Third, the water used in the recycling process can be circulated to prevent the outflow of contaminants.

Fourth, because it has a simple process, it is easy to apply and has low operating cost.

1 is a flowchart illustrating a method for recycling by-product by-products according to an embodiment of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified, and that other specific features, regions, integers, steps, operations, elements, components, and / And the like.

Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Commonly used predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

Hereinafter, a method for recycling by-product by-products according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 1, the alkali is dissolved in water in the step of preparing a mixture by mixing water with a by-product byproduct of dust or sludge in the form of iron, carbon, zinc, chlorine and alkali. Substances that do not dissolve in the remaining water are solid, including iron, carbon, and zinc, mixed with water in the form of slurry. When this is done, the solids will sink to the bottom, so they must be agitated continuously to allow the solids to float.

Thereafter, air bubbles are supplied to the mixture, and the carbon easily adheres to the surface of these air bubbles. This is because the surface of the carbon is hydrophobic, so that the carbon particles float together with air bubbles on the surface while sticking to the surface of the air bubbles. When air bubbles are supplied with continuous agitation, the carbon particles gathered near the water surface are layered and separated from the iron particles and zinc particles beneath them. Various methods can be used to recover the carbon collected on the surface, but it can be efficiently recovered even with a simple scraper.

In the mixture in which carbon is removed, iron and zinc are mixed. Since magnetic iron is stronger than zinc, separation using magnetic force is effective. As will be described later in more detail, the separation using magnetic force enables a high efficiency separation by using a wet drum type magnetic separator.

The mixture in which carbon and iron are removed contains zinc and alkali ion dissolved in water. When the mixture is separated into solid and liquid, it is possible to separate water-insoluble zinc and water-soluble alkali. Separation of solids and liquids can be accomplished in a variety of ways, from simple screening to filter presses.

Finally, in order to recover the alkali ions from the solution in which the remaining alkali is dissolved, alkali ions are adsorbed by using an ion exchange apparatus. As the ion exchange apparatus, an ion exchange resin, an ion exchange membrane, or the like which will be described later can be used.

The solution remaining after the removal of the alkali ion is almost pure water. This water is recycled back to the mixture preparation stage to mix with the by-product. This recycling of water can reduce wastewater and also reduce the amount of water used.

The step of recovering the carbon particles preferably comprises supplying air bubbles having a diameter of 1 cm or less to the bottom surface of the chamber on which the mixture is loaded, and recovering the carbon suspended in the water surface of the mixture with a scraper attached to the air bubbles.

The smaller the size of the air bubbles is, the larger the surface area is. Therefore, it is preferable to use air bubbles having a diameter of several tens of micrometers. However, since air bubbles having a size substantially equal to or smaller than 1 cm in diameter can reach the water surface, the present invention is applicable. Air bubbles exceeding 1 cm in diameter are not likely to rise to the surface and are likely to burst on the way, so that the carbon particles may not float entirely to the surface of the water.

The step of recovering the iron powder preferably uses a magnet having a magnetic force of 500 to 1000 Gauss. Iron oxide such as Fe ₂ O ₃ , Fe ₃ O ₄ or the like is difficult to be drawn when it is less than 500 Gauss, and magnetic force can be limited to 500 to 1000 Gauss because it can attract iron as well as zinc when it exceeds 1000 Gauss .

In order to adsorb and recover the alkali ion in the solution, it is preferable that the step of adsorbing the alkali ion dissolved in the solution to the cation exchange resin and the step of desorbing the alkali ion adsorbed to the cation exchange resin are included.

Cation exchange resins have cations that easily fall off to a negatively charged fixed ion. When the cation exchange resin enters the solution, the cations in the solution are exchanged with the cation attached to the ion exchange resin and adsorbed on the cation exchange resin. Therefore, the alkali ions contained in the solution are adsorbed on the cation exchange resin and separated. The cation exchange resin is regenerated through the regeneration so that the alkali ion is eluted and again adsorbed the alkali ion. The regeneration method of the cation exchange resin is out of the scope of the present invention and thus will be omitted.

The by-product iron product is characterized by being at least one of sintered electric dust collecting dust, steel making sludge, blast furnace dust, and blast furnace sludge.

Examples of compositions of by-products of iron and iron are shown in Tables 1 to 3 below. The percentages of ingredients in the tables mean Wt%.

ingredient C CaO S SiO ₂ Al ₂ O ₃ T-Fe M-Fe Zn Na ₂ O MgO P Cl K ₂ O moisture % 10.7 5.65 0.76 4.94 1.6 42.7 0.45 1.13 0.19 0.69 0.05 0.85 0.75 3.58

division T-Fe (%) Zn (%) R ₂ O (%) K ₂ O (%) Na ₂ O (%) Sample 1 61.1 1.386 0.923 0.463 0.65 Sample 2 28.9 5.779 4.297 1.482 5.41

division C (%) T-Fe (%) Zn (%) moisture (%) Pb (mg / L) Gorodust 13.35 5.67 25.39 5.7 3 Blast furnace sludge 16.2 6.42 35.87 53.3 0.06

Table 1 shows the chemical composition of the sintered ED dust, Table 2 shows the chemical composition of the steel sludge, and Table 3 shows the chemical composition of the blast furnace and blast furnace sludge.

Sintered electrostatic dust dirt contains not only alkali but also chlorine, and it is an impurity which must also remove chlorine in the production of sintered ores. In addition to cation exchange resins, anion exchange resins are needed to remove chlorine. The cation exchange resin and the anion exchange resin may be simultaneously injected to adsorb the alkali ion and the chlorine ion. Alternatively, the solution may be sequentially passed through the cation exchange resin and the anion exchange resin to sequentially adsorb the alkali ion and the chlorine ion. The adsorbed alkali and chlorine ions can be desorbed and reused or neutralized during the regeneration of the ion exchange resin.

When the by-product and water are mixed to dissolve the alkali and chlorine, it is preferable to mix the ratio of by-product by-product to water by 1: 4 to 6 by weight and stir for 30 to 60 minutes.

As the amount of byproducts increases, the solid content of the mixture increases, which makes it difficult to agitate properly, and when the carbon is suspended, it may not float due to other solid components. On the other hand, if the amount of by-product by-products is reduced, it takes too much time to treat the same amount of by-product by-products.

Hereinafter, a practical embodiment of the present invention will be described.

200 g of a sample and 1 liter of water were put into a 2 liter beaker to prepare a slurry. The slurry was mixed with a stirrer for 30 minutes to 60 minutes to dissolve the alkaline component and chlorine having high solubility in water. Then, the mixture was stirred with a floating separator Air bubbles having a diameter of several tens of micrometers in diameter are blown into the lower part of the beaker, and carbon having a hydrophobic surface is adhered to air bubbles and floated to the surface layer of the solution. At this time, the suspended carbon is recovered as scrapers. After recovering the carbon, the remaining solution is put into a drum type wet magnetic separator having a magnetic force of 500 gauss to recover the iron powder, and then solid-liquid separation is performed by a filter press to remove the concentrated solid component of zinc. In the filter press, the dehydrated solution is injected into an ion exchanger composed of a cation exchange resin and an anion exchange resin to remove alkaline components and chlorine, and the recovered water is recycled as the water for the first sample mixing.

Table 4 shows the ratio of the amount of iron, zinc, alkali and carbon contained in the first sample to the amount of each component separated during the step. As shown in Table 4, it can be seen that the recovery rate is 75% or more of carbon, 90% or more of zinc and alkali, and 85% or more of iron powder.

division zinc Alkaline Carbon iron content Sintered electrostatic dust dust 95% 93% 78% 86% Steelmaking sludge 92% 97% - 93% Gorodust 90% 94% 83% 88% Blast furnace sludge 93% 96% 78% 87%

As shown in Fig. 1, each of the separated materials can be recycled for various purposes. For example, iron powder may be used as a raw material for sintered ores, carbon may be used as a heat source or reducing material for iron powder drying, zinc may be used as zinc powder for zinc smelting, and alkali may be used as neutralizing agent for acidic waste water.

In this way, if the by-product by-products that can not be used in the past can be recycled, environmental pollution and resource loss can be suppressed at the same time.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention .

Claims (8)

A step of preparing a mixture by mixing water with iron by-product containing iron, carbon, zinc, chlorine, and alkali to dissolve the alkali;
Supplying an air bubble to said mixture, and recovering carbon particles adhered to said air bubble;
Recovering iron by applying magnetic force to the mixture from which carbon has been removed;
Separating a solution containing alkali ions in the mixture from which carbon and iron are removed, and recovering the solid containing zinc; And
Adsorbing and recovering alkali ions from the solution; And recycling the by-product.
The method according to claim 1,
Characterized in that after the step of adsorbing and recovering the alkali ion, the alkaline ion is separated from the solution and the remaining water is recycled to the mixture preparation step.
The method according to claim 1,
The step of recovering the carbon particles is characterized in that the air bubbles having a diameter of 1 cm or less are supplied to the bottom surface of the chamber on which the mixture is loaded and the carbon suspended in the water surface of the mixture is recovered as a scraper attached to the air bubbles How to recycle by-product of iron.
The method according to claim 1,
Wherein the step of recovering the iron powder comprises applying a magnetic force to the mixture using a magnet having a magnetic force of 500 to 1000 Gauss.
The method according to claim 1,
The step of adsorbing and recovering the alkali ion includes a step of adsorbing the alkali ion dissolved in the solution to the cation exchange resin, and a step of desorbing the alkali ion adsorbed to the cation exchange resin.
The method of claim 5,
In the preparation of the mixture, water is mixed with the by-product of the iron so as to further dissolve the chlorine,
The step of adsorbing and recovering the ions further comprises the step of adsorbing the chloride ion dissolved in the solution to the anion exchange resin and the step of desorbing the chloride ion adsorbed on the anion exchange resin. How to recycle.
The method according to any one of claims 1 to 6,
The method for recycling by-product by-products according to claim 1, wherein the step of preparing the mixture uses the by-product by-product, which is at least one of sintered electric dust collecting dust, steel sludge, blast furnace dust and blast furnace sludge.
The method of claim 7,
Wherein the step of preparing the mixture comprises mixing the by-product by-product with water in a ratio of 1: 4 to 6 (wt%) and stirring for 30 to 60 minutes.

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