KR100797317B1 - The manufacturing method of body for matallic dust - Google Patents

Abstract

The present invention relates to a method for producing a molded article of iron-based dust, 2-10% hydrochloric acid solution based on the weight of the iron-based dust and iron-based dust with iron as the main component of the total content of iron more than 30% by weight 8-12 After mixing and molding the weight%, there is provided a method for producing a molded article of iron-based dust, characterized in that curing for at least 12 hours under a temperature of 60-100 ° C. and a relative humidity of 70-100%.

According to the present invention, a molded body of iron dusts in a form suitable for recovering iron from iron dusts can be produced.

Iron-based dust, hydrochloric acid solution, molded body, metal iron, iron oxide

Description

Manufacturing method of molded article of iron-based dust {THE MANUFACTURING METHOD OF BODY FOR MATALLIC DUST}

The present invention relates to a method for producing a molded article of iron-based dust, and more particularly, iron-based dust having an appropriate strength that can be recycled in an electric furnace by curing the iron-based dust containing iron as a main component under appropriate conditions using an appropriate binder. It relates to a method for producing a molded article.

Iron-based dust is currently iron-based in the shipbuilding industry when metal oxides or non-metallic abrasives are blown and peeled off to remove rust on the surface of the steel sheet formed by oxidation of the steel sheet during shipment manufacture or repair. A large amount occurs in the form of fine powder of oxide. As the abrasive used in such a process, metal balls are used in the case of metals, and in the case of nonmetals, Cu slag generated as a by-product during copper smelting process is generally used. Metal ball, which is metal based, can be used repeatedly because of its high hardness, but has the disadvantage of being expensive. Non-metal Cu slag has relatively low hardness and is destroyed during polishing, so it is used only for one-time use. It is very inexpensive.                         

As a main component of Cu slag used as a nonmetallic abrasive, as shown in Table 1 below, it is composed of iron-based elements such as FeO ₃ , FeO, and M-Fe, and CaO and SiO ₂ , which are slag forming agents, and Al ₂ O ₃ and MnO, etc. It is contained as a minor ingredient and contains few ingredients such as heavy metals that have a harmful effect on the human body.

As the main component of the iron dust generated by the use of metallic abrasives and non-metallic abrasives, as shown in Table 1, about 97% of FeO ₃ , FeO, M-Fe, etc., contains iron as a main component and heavy metals that have a harmful effect on the human body. It can be seen that it is an environmentally friendly material containing almost no such ingredients.

Iron-based dust produced by the steelmaking process is typically iron-based dust generated in the process of peeling the iron oxide generated on the surface after rolling the slab in the hot rolling process. As shown in Table 1, the iron-based dust is also composed of about 99% or more of iron, such as Fe ₂ O ₃ and FeO, and contains almost no heavy metals such as heavy metals that have harmful effects on the human body. .

Iron-based dust generated by the above process when constructing new ships or repairing old ships is not recycled at all but is released into the atmosphere and causes air pollution. The particles become very fine and are not buried as secondary resources, but are being buried.

On the other hand, iron-based dusts by-produced in steel mills are used for the purpose of increasing the production of iron oxide by inputting them to the acid recovery process in the state of raw materials which are some fine powders, or some are sintered raw materials, and some are landfilled.

Component of Iron Dust (Unit: wt%) Fe ₂ O ₃ FeO M-Fe CaO Al ₂ O ₃ MnO P ₂ O ₅ Na ₂ O SiO ₂ CuO Cu slag 30.45 25.41 2.03 16.62 2.32 1.85 0.41 0.13 11.27 0.60 Dust (ship) 38.07 41.69 17.28 0.17 0.096 0.95 0.013 0.011 0.80 0.059 Dust (hot rolled steel mill) 79.21 20.42 Tr. Tr. Tr. 0.29 0.03 0.073 Tr. -

As shown in Table 2, the particle size of iron-based dust generated in the process of polishing the steel surface of the ship contains a large particle size of 2.36mm or more, but most of the particle size distribution is less than 1㎛. Dust produced during the grinding process and dust produced in the hot-rolling mill are mostly composed of very fine particle size distribution of less than 600㎛.

Particle Size of Iron Dust (Unit:%) 2.36mm or more 2.36- 1.18mm 1.18- 600 µm 600- 300㎛ 300- 212㎛ 212- 150㎛ 150- 106㎛ 106㎛ or less Cu slag 7.2 13.2 23.8 24.2 8.6 5.6 4.6 12.6 Dust (ship) - - 6.5 22.5 24.5 10.5 10.6 25.4 Dust (Hot Mill) - - 10.2 29.6 21.3 8.4 5.5 25.0

The proposed method for recycling general iron-based dusts having such a fine particle size is mixed with carbonaceous material in dust to reduce and recover non-ferrous metals such as iron and zinc contained in steel dust. (Japanese Patent JP8-43393), a method of adding a part of the iron-making dust generated in the steelmaking process as a sintered raw material (Korean Patent Laid-Open Patent No. 1999-043750), and the fine powder of iron ore and dust as a binder and water And cement or hydraulic blast furnace slag is added as a binder to produce a pellet.

As mentioned above, methods for treating iron-based dusts which have been proposed to date include mainly reduction treatment by mixing with a reducing agent or partial addition of dust to its original state, and water, cement or Hence, crushing slag may be used.

However, the recycling of iron-based dust is still complicated and inefficient, and thus, a method for easily and simply recycling the iron-based dust in an electric furnace is required.

In addition, when iron-based dust is dissolved in an electric furnace to recover and recycle iron, when the iron-based dust itself is put into an electric furnace, dust is scattered at the time of the input, and dust is scattered when dissolved in the electric furnace.

Accordingly, an object of the present invention is to provide a method of forming iron-based dusts containing iron as a main component into a shaped body in a mass having a suitable strength for recycling.

It is another object of the present invention to provide a method for molding an iron component contained in iron-based dust into a molded body having an applicable strength for recovering from an electric furnace.

According to one aspect of the invention,

After mixing and molding iron-based dust containing iron having a total content of iron of 30% by weight or more and 8-12% by weight of 2-10% hydrochloric acid solution based on the weight of the iron-based dust, 60-100 ° C Provided is a method for producing a molded article of iron-based dust, characterized by curing at least 12 hours under conditions of temperature and relative humidity of 70-100%.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

If iron dust is to be dissolved in an electric furnace to recover and recycle iron, the iron dust should be made into a molded body having an appropriate strength and applied to the electric furnace. When iron-based dust is added to the electric furnace by itself, dust is scattered in addition to the dust, and when dissolved in the electric furnace, dust is scattered, and thus, productivity improvement cannot be expected.

The present invention is to form a molded body having a strength suitable for application to an electric furnace by mixing the iron-based dust with a hydrochloric acid solution as a binder and curing under appropriate temperature and humidity.

First, iron-based dusts and hydrochloric acid solution are mixed to form a desired shape. It can be shaped into any (lump) shape.

The iron dusts used in the present invention include any dust containing iron components such as iron oxides and metal irons, for example, Cu slag used as an abrasive, and iron dusts having a total content of iron of 30% by weight or more. do.

The higher the iron content in the dust, the more advantageous for the production of molded articles. When the total iron content in the dust is less than 30% by weight, the reaction with the hydrochloric acid as a binder is weak, resulting in insufficient production of iron hydroxide, which serves as a bond between the fine particles. It is difficult to produce shaped bodies having strength. Here, the appropriate strength of the molded body means a strength of 30 or more that does not collapse the dust is not collapsed when the injection into the electric furnace.

A hydrochloric acid solution at a concentration of 2-10% is used as a binder to react with iron to form a shaped body having an appropriate strength. If the concentration of hydrochloric acid is less than 2%, the binding between fine particles is weak, and if it exceeds 10%, the reaction of hydrochloric acid with iron oxide or metal iron in the dust proceeds rapidly, causing the molded body to crack and rather to reduce the strength.

The hydrochloric acid solution having a concentration of 2-10% is mixed with the iron-based dust at 8-12% by weight based on the weight of the iron-based dust. When the hydrochloric acid solution is less than 8% by weight, the contact between the iron-based dust and the hydrochloric acid solution is insufficient, so that molding is difficult, and when the hydrochloric acid solution is more than 12%, the solid dust is caused by the excess hydrochloric acid solution. Since it becomes a slurry state, it cannot also be manufactured in a molded object.

By mixing the iron-based dust with an appropriate concentration of hydrochloric acid solution, a FeCl ₂ solution is formed on the particle interface by the reaction of metal iron or iron oxide with hydrochloric acid, and then curing during a predetermined curing process, that is, a temperature, humidity and a holding time. As a result, FeCl ₂ is produced. On the other hand, the particles are precipitated to iron hydroxide gradually by the oxidation reaction of FeCl ₂ , and the particles and particles are firmly connected to each other by the precipitation reaction to produce a molded article having an appropriate strength.

After mixing and molding the iron-based dust and hydrochloric acid as described above, the molded product is cured under appropriate temperature and relative humidity conditions to prepare a molded body of the iron-based dust.

Curing conditions suitable for the present invention are curing at least 12 hours, preferably 12-24 hours, at a temperature of 60-100 ° C. and a relative humidity of 70-100% . Through repeated experiments, the present inventors produced a molded article of iron-based dust having a strength of 30 or more by sufficiently reacting the hydrochloric acid solution with iron oxide or metal iron under such temperature, humidity and curing conditions to form iron hydroxide in the solid particle interface. I found it possible.

Hereinafter, the present invention will be described in detail through examples.

Example 1

(Invention Example 1-9)

Hydrochloric acid solutions of 2%, 4%, 8% and 10% in hydrochloric acid solutions containing 120% of iron dust dust and Cu slag, which are by-products produced by polishing of the steel surface during the construction of the vessel shown in Table 1, were used as the weight of solid dust. 8 g of 96% by weight was added and mixed uniformly.

In addition, the hydrochloric acid solution of 2% concentration was added to 96 g of 8% by weight based on the weight of the solid dust to 120 g of hot rolled dust generated in the iron mill hot rolling process and mixed uniformly. Each of the mixed mixtures were prepared according to the mortar compressive strength test method of KSF2514, respectively. After the molded product was cured at a temperature of 60 ° C. and a relative humidity of 95% for 24 hours, the molded product was taken out to measure compressive strength, and the results are shown in Table 3 below.

(Comparative Example 1-6)                     

Except for the use of hydrochloric acid solution having a concentration of 1% and 12% for the fine dust and Cu slag generated during ship construction, the same method as in the invention was carried out and the results are shown in Table 3 below. In addition, except that Portland cement was added in an amount of 8% by weight and 20% by weight and 20% by weight of Cu slag based on the weight of fine dust, and the results were shown in Table 3 below. Shown in

Condition Molded physical properties Dust type Binder Hydrochloric acid concentration (%) Hydrochloric acid use / solid dust (% by weight) Curing temperature (℃) Curing Humidity (%) Curing time (hr) Compressive strength (Kg / ㎠)  Foot honor One Dust Hydrochloric acid 2 8 60 95 24 43 2 Dust Hydrochloric acid 4 8 60 95 24 51 3 Dust Hydrochloric acid 8 8 60 95 24 50 4 Dust Hydrochloric acid 10 8 60 95 24 52 5 Cu slag Hydrochloric acid 2 8 60 95 24 30 6 Cu slag Hydrochloric acid 4 8 60 95 24 32 7 Cu slag Hydrochloric acid 8 8 60 95 24 35 8 Cu slag Hydrochloric acid 10 8 60 95 24 39 9 Hot rolled dust Hydrochloric acid 2 8 60 95 24 38   Comparative Example One Dust Hydrochloric acid One 8 60 95 24 Shattered by contact 2 Dust Hydrochloric acid 12 8 60 95 24 12 3 Cu slag Hydrochloric acid One 8 60 95 24 Shattered by contact 4 Cu slag Hydrochloric acid 12 8 60 95 24 5 5 Dust cement - 8 wt% cement 60 95 24 Shattered by contact 6 Dust cement - 20 wt% cement 60 95 24 Shattered by contact 7 Cu slag cement - 20 wt% cement 60 95 24 Shattered by contact

Dust: Iron-based dust produced by grinding steel surface during ship construction

As can be seen in Table 3, the compressive strength of the molded product prepared by adjusting the concentration of the hydrochloric acid solution to the range of 2-10% as the binder of the present invention increases the concentration of the hydrochloric acid solution within the above range. Showed a tendency to increase and it was possible to produce molded articles having good compressive strength values.

In Comparative Example 1-4, when the amount of hydrochloric acid used is 2% or less, the dissolution reaction of iron is insufficient, so that the interfacial reaction between the particles and particles is insufficient, and an excess exothermic acid solution is added to the exothermic reaction by the rapid iron component reaction. By inducing cracks, the cracks were exhibited by a slight contact.

In addition, in the case of Comparative Example 5-7 using the most commonly used cement as a general binder, the particles of iron-based dusts are very fine, so that even if the cement, which is a binder, is added up to 20% by weight of the solid dust, it is brittle by contact. Status was shown. Therefore, it is determined that a large amount of cement should be used when producing a molded article having a predetermined strength using cement as a binder. However, the use of a large amount of cement as a binder is not only economically disadvantageous, but also increases the slag which is a by-product generated when iron is recovered from an electric furnace, which is not suitable for the process.

Example 2

(Invention Example 10-12)

The total iron content is added by adding an appropriate amount of slag fines from the blast furnace blast furnace blast furnace, which is composed mainly of CaO and SiO ₂ , which contains almost no iron, to the fine dust of iron-based dust produced by grinding of the steel surface during the construction of the ship shown in Table 1. 10% hydrochloric acid solution was added to 120g of dust adjusted to 50%, 70% and 90% by weight, and 8% by weight of 96g, based on the weight of solid dust, was mixed uniformly and then the mortar of KSF2514 was compressed. According to the strength test method, each molded body was produced. After the production of the molded article, the cured under a condition of temperature 60 ℃, relative humidity 95% for 24 hours, the molded article was taken out to measure the compressive strength and the results are shown in Table 4 below.

(Comparative Example 8-9)

Except that the dust was adjusted to 10% by weight and 30% by weight of the total iron content in the fine dust was carried out in the same manner as in the invention example and the results are shown in Table 4 below.

Condition Molding properties Dust type Binder Hydrochloric acid concentration (%) Hydrochloric Acid Usage / Solid Dust (wt%) Total iron content (% by weight) Curing temperature (℃) Curing Humidity (%) Curing time (hr) Compressive strength (Kg / ㎠) Inventive Example 10 Dust Hydrochloric acid 10 8 50 60 95 24 44 11 Dust Hydrochloric acid 10 8 70 60 95 24 48 12 Dust Hydrochloric acid 10 8 90 60 95 24 50 Comparative example 8 Dust Hydrochloric acid 10 8 10 60 95 24 5 9 Dust Hydrochloric acid 10 8 29 60 95 24 12

Dust: Iron-based dust produced by grinding steel surface during ship construction

As can be seen from Table 4, when the total iron content in the raw material dust to be molded, as in Example 10-12 of the present invention contained more than 30% by weight, it can be produced as a molded article having a predetermined strength, Comparative Example If the total iron content is less than 30% by weight, such as 8-9, the formed article does not exhibit sufficient strength. This is because the iron content reacting with hydrochloric acid is insufficient, and the production of iron hydroxide, which acts as a binding agent at the fine particle interface, is insufficient. Therefore, in order to produce a molded article having a predetermined strength, it is preferable to use dust having an iron content of 30% by weight or more in the iron-based dust.

Example 3

(Invention Example 13-15)

Hydrochloric acid solution of 10% concentration is added to 8%, 10% by weight and 12% by weight of 120% of ground dust, which is a by-product of dust produced by polishing of steel surface during the process of ship construction shown in Table 1. After the addition and uniform mixing, the molded bodies were prepared according to the mortar compressive strength test method of KSF2514. After the molded article was cured for 24 hours under the condition of 60 ° C. and 95% relative humidity, the molded article was taken out to measure the compressive strength, and the results are shown in Table 5 below.

(Comparative Example 10-12)

A 10% hydrochloric acid solution was added in 6 wt%, 14 wt%, and 16 wt% based on the weight of solid dust, and the results were shown in Table 5 below. .

Condition Molding properties Dust type Binder Hydrochloric acid concentration (%) Hydrochloric acid consumption / solid dust (wt%) Curing temperature (℃) Curing Humidity (%) Curing time (hr) Compressive strength (Kg / ㎠) Inventive Example 13 Dust Hydrochloric acid 10 8 60 95 24 52 14 Dust Hydrochloric acid 10 10 60 95 24 53 15 Dust Hydrochloric acid 10 12 60 95 24 52 Comparative example 10 Dust Hydrochloric acid 10 6 60 95 24 Molding impossible 11 Dust Hydrochloric acid 10 14 60 95 24 Slurry 12 Dust Hydrochloric acid 10 16 60 95 24 Slurry

Dust: Iron-based dust produced by grinding steel surface during ship construction

As can be seen in Inventive Example 13-15 of Table 5, when the amount of hydrochloric acid used as a binder in the present invention is used in the range of 8-12% by weight based on the weight of the solid iron dusts, the compressive strength characteristics are A good molded body could be produced. However, as in the case of Comparative Example 10-12, if it is less or more than the above range condition, the molding is not possible due to the lack or excess of the solution to the solid dust, or the slurry is formed, so that the production as a molded product was not performed.

Example 4

(Invention Example 16-21)

10% by weight of hydrochloric acid solution based on the weight of the solid dust was added to 120 g of fine dust, which is an iron-based dust produced by grinding of the steel surface during the construction of the ship shown in Table 1, and mixed uniformly. According to the mortar compressive strength test method of the molded bodies were prepared. After the molded product was cured for 24 hours under the conditions of 70 ℃, 80 ℃ and 90 ℃ and 95% relative humidity and then the molded product was taken out to measure the compressive strength and the results are shown in Table 6. In addition, the relative humidity was set at 70% and the curing time was 12 hours and 18 hours, respectively.

(Comparative Example 13-17)

After the molding was prepared, the curing temperature was 20 ° C. and 40 ° C., the relative humidity was 50% and the curing time was 4 hours and 8 hours. Indicated.

Condition Molding Properties Dust type Binder Hydrochloric acid concentration (%) Hydrochloric acid use / dust (% by weight) Curing temperature (℃) Curing Humidity (%) Curing time (hr) Compressive strength (Kg / ㎠) Inventive Example 16 Dust Hydrochloric acid 10 10 70 95 24 53 17 Dust Hydrochloric acid 10 10 80 95 24 55 18 Dust Hydrochloric acid 10 10 90 95 24 56 19 Dust Hydrochloric acid 10 10 70 70 24 53 20 Dust Hydrochloric acid 10 10 70 95 12 49 21 Dust Hydrochloric acid 10 10 70 95 18 53 Comparative example 13 Dust Hydrochloric acid 10 10 20 95 24 8 14 Dust Hydrochloric acid 10 10 40 95 24 18 15 Dust Hydrochloric acid 10 10 70 50 24 23 16 Dust Hydrochloric acid 10 10 70 95 4 15 17 Dust Hydrochloric acid 10 10 70 95 8 29

Dust: Iron-based dust produced by grinding steel surface during ship construction

As can be seen from Inventive Example 16-21 of Table 6, the curing conditions, that is, curing temperature, curing humidity, curing time, etc., which play an important role in the strength development of the molded body, are determined by the reaction of solid dusts with hydrochloric acid. It can be seen that it is preferable to perform the FeCl ₂ solution generated at the interface for at least 12 hours under a temperature of 60-100 ° C. and a relative humidity of 70-100% as a process for promoting the precipitation of iron hydroxide.

By using a hydrochloric acid solution as a binder to produce a molded body of iron-based dust, it is possible to produce a molded body of iron-based dust suitable for recovering iron from the iron-based dust in an electric furnace or the like.

Claims (3)

After mixing and molding iron-based dust containing iron with a total content of iron of 30% by weight or more and 8-12% by weight of 2-10% hydrochloric acid solution based on the weight of the iron-based dust, A method for producing a molded article of iron-based dust, characterized by curing at least 12 hours under temperature and a relative humidity of 70-95%. The method of claim 1, wherein the iron contained in the iron-based dusts is iron oxide or metal iron. The method of claim 1, wherein the curing treatment is performed for 12-24 hours under the temperature and humidity conditions.