KR101436523B1 - Method for manufacturing refractory material using waste fire brick - Google Patents

Abstract

An aspect of the present invention is to provide a new refractory brick recovery technology that can prevent cost loss, energy consumption, and environmental pollution compared to the conventional refractory brick recovery technology.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for manufacturing a refractory material using a refractory brick,

FIELD OF THE INVENTION The present invention relates to a method for producing refractory materials using waste refractory bricks.

Various methods of reducing the manufacturing cost by recycling the refractory after use have been attempted in order to reduce the manufacturing cost due to the rise in the price of the refractory raw material and to produce the eco-friendly product.

Particularly, the raw materials used for the fluoric MgO-C brick are 97% or more of high purity MgO, Cl and graphite, and after use, they are disused or partly separated and recycled as refractory raw materials.

MgO-C (mag carbon) bricks used for converter, electric furnace, and ladle are limited in their recycling due to the expansion phenomenon due to hydration and high carbon content after use. In order to eliminate the volume expansion due to hydration, the bricks are recycled as refractory materials after hydrothermal treatment. However, as the content of the bricks is increased, the quality of the products is decreased and the application amount is limited.

MgO-C bricks are a typical refractory used in refining steel processes, and the largest amount of refractory materials is produced and collected. In order to recycle the MgO-C bricks after use, some materials can be applied as raw materials of MgO-C bricks after removing raw materials to be differentiated through hydrothermal treatment in advance and then pulverized. However, the chemical characteristics and the variation of particle size distribution are increased, The quality of the refractory material deteriorates sharply.

As a conventional refining technology capable of recovering waste MgO-C bricks and recycling them as refractory bricks, Al (OH) _{3 is introduced} into the waste MgO-C bricks through the hydration reaction of Al4C3 material, And then removing it by heat treatment at a high temperature.

In order to remove Al4C3, which is a cause of volume expansion, the above technique removes the damaged layer adhering to the working surface of the waste MgO-C brick, ages it in water at 100 ° C for 7 to 8 hours and ages the brick at 200 ° C And a step of putting it into a hot-air drying furnace to dry it at a moisture content of less than 1%.

The refractory raw material obtained through this process can control the volume expansion well but MgO and C are mixed, and when used in refractory bricks, the structure is deteriorated and can not be used in large quantities.

In recent years, Patent Document 1 proposes a technology capable of recycling as a raw material by forming spinel which is a more stable material as a refractory material through a decarburization process in which carbon is oxidized and removed by increasing the heat treatment temperature.

Through the decarburization process is closed-MgO-C within Al4C3 and carbon has been removed is generated Al ₂ O ₃ reacts with a refractory MgO MgO. By forming stable spinel of Al ₂ O ₃ , it can be used as a new type of refractory raw material. However, since it is necessary to perform calcination at a high temperature of 1100 DEG C or more for decarburization, it takes a lot of energy and is not economical.

Therefore, applying recycled MgO-C raw material that is water-treated to the existing fluoric MgO-C bricks is advantageous in cost reduction but there is a limit in the application amount due to the deterioration of the product quality.

Korean Patent Publication No. 10-2011-0124661

An aspect of the present invention is to provide a new refractory brick recovery technology that can prevent cost loss, energy consumption, and environmental pollution compared to the conventional refractory brick recovery technology.

A method of manufacturing a refractory material using waste refractory bricks, which is an aspect of the present invention, comprises the steps of crushing spent waste mica carbon used as refractory bricks, preparing a slurry by mixing the pulverized waste carbon and water, Separating the slurry of the assembly from the slurry using a clone, and drying the slurry of the separated assembly until the moisture content is less than 1 wt%.

In addition, the solution of the above-mentioned problems does not list all the features of the present invention. The various features of the present invention and the advantages and effects thereof will be more fully understood by reference to the following specific embodiments.

According to the present invention, it is possible to simply sort out the MgO clinker in the waste magic carbon using the wet cyclone. Since the separated clinker can be recycled as a refractory brick without any additional process, it contributes to the improvement of the environment, and energy cost can be minimized as compared with the conventional method which requires a hydrothermal treatment and decarburization process.

The inventors of the present invention conducted studies to solve problems such as cracking and molten steel penetration and poor appearance quality when the refractory after being used as refractory bricks is used as interior bricks such as converters, electric furnaces and ladles again As a result, it has been found that MgO clinker having a large particle size and carbon having a small particle size are separated when the used magnesium carbide refractory brick is crushed, and it is found that MgO clinker can be selected only by a simple process in case of particle separation. It is now.

Hereinafter, a method of manufacturing a refractory material using waste refractory bricks, which is one aspect of the present invention, will be described in detail.

A method of manufacturing a refractory material using waste refractory bricks, which is an aspect of the present invention, comprises the steps of crushing spent waste mica carbon used as refractory bricks, preparing a slurry by mixing the pulverized waste carbon and water, Separating the slurry of the assembly from the slurry using a clone, and drying the slurry of the separated assembly until the moisture content is less than 1 wt%.

That is, in order to easily separate the MgO clinker from carbon, the present invention includes a process of pulverizing the waste refractory material and then separating the pulverized material using a wet cyclone. The wet cyclone is advantageous for particle size classification of the pulverized waste refractory material and is easily removed by allowing Al ₄ C _{3, which} is abundantly contained in the mag- netic waste refractory material, to react with water to form a material such as Al (OH) ₃ The effect can be obtained.

In addition, the use of a wet cyclone is advantageous in securing a large amount of recyclable raw materials of the waste carbon-containing masonry bricks because the material that reacts with moisture in the atmosphere to be differentiated is removed.

Therefore, in the present invention, in order to recycle the waste refractory, a step of crushing the waste refractory is preceded.

It is preferable that the pulverization is such that the waste magnesium carbide refractory has an average particle size of 4 mm or less. By crushing the particles having a particle size of not more than 4 mm as described above, it is possible to prevent further undifferentiation of the aggregate upon reuse and to maintain a stable particle size. In addition, since the particle size of MgO contained in the refractory as aggregate is usually 5 mm or less, when the aggregate is crushed with the above-mentioned particle size, the aggregates can be prevented from bonding to each other as much as possible and the purity of the aggregate can be increased .

Thereafter, in order to separate the pulverized waste carbonaceous refractory material into a wet cyclone, a process of preparing slurry by adding water to the pulverized waste carbonaceous refractory material is required.

At this time, the content of the solid content in the slurry is preferably 1 to 40% by weight. That is, although it is preferable that the solid content of the slurry is not high for smooth particle separation, if it is too low, the process efficiency is decreased, so that the content of the solid content is defined as 1% by weight or more. In addition, when the solid content is high, the particle size separation is not easy, so the upper limit of the content is limited to 40 wt%. More preferably, the solid content is 5 to 30% by weight.

It is then preferable to separate MgO in the slurry using a wet cyclone. That is, the cyclone is a device for separating the granules and the granules using the difference in centrifugal force, and it is possible to easily separate the MgO component mainly contained in the granules of the granules. At this time, in the present invention, a portion including an average particle size of 0.3 to 4 mm is assembled, and a portion including an average particle size of 0.3 mm or less is defined as a fine particle.

It is preferable to control the MgO component included in the assembly in a direction that maximizes the MgO content. More preferably, the pressure of the slurry introduced into the wet cyclone is controlled.

The pressure of the slurry to be introduced into the wet cyclone is preferably 0.2 to 3 MPa. When the pressure of the slurry is less than 0.2 MPa, the amount of the recovered granules is small and the separation efficiency is lowered. On the other hand, if it exceeds 3 MPa, the separation of the fine particles and the granules is not carried out, and the discharged granules can not be obtained.

When the wet granulation is carried out using a wet cyclone as proposed by the present invention, the granulated granules can be efficiently separated at a purity of about 50 to 95% by weight based on the total granulated granules.

Thereafter, a step of drying may be followed to recycle the MgO component, which is abundant in the particles of the separated granules, as a raw material of the refractory.

At this time, any known method may be used as a method of filtration and drying, so that the present invention is not particularly limited.

However, in order to be used as a raw material for recycling, it is preferable that the moisture content of the granulation is dried to less than 1% by weight.

For this, it is preferable to dry at a temperature of 200 ° C or higher. When the drying temperature is 200 ° C or higher, Al (OH) ₃ formed in the slurry process is decomposed to remove H ₂ O, thereby having sufficient physical properties to be utilized as a refractory raw material.

Hereinafter, the present invention will be described more specifically by way of examples. It should be noted, however, that the following examples are intended to illustrate the invention in more detail and not to limit the scope of the invention. The scope of the present invention is determined by the matters set forth in the claims and the matters reasonably inferred therefrom.

(Example)

The waste magnesium carbonaceous refractory having the composition shown in Table 1 was prepared, ground to a particle size of 4 mm or less, and then water was supplied to prepare a slurry having solid contents of 10, 15 and 30 wt%. The prepared slurry was separated into granules and granules by using a wet cyclone. The composition of each separated particle was analyzed and shown in Table 2, and the particle size distribution is shown in Table 3.

The granulated slurry of the separated slurry was filtered and dried to obtain a refractory raw material. The slurry was maintained at 200 ° C for 24 hours for sufficient drying.

Name of sample Eagles
(lg-loss) SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO moisture Before separation 20.0 1.1 5.9 0.8 0.8 70.8 0.6

ingredient Assembly part Differential part Before separation 10% 15% 30% 10% 15% 30% This gross
(lg-loss) 6.6 10.0 11.0 29.1 26.7 34.7 20.0 SiO ₂ 0.8 0.9 0.9 1.3 1.2 1.6 1.1 Al ₂ O ₃ 2.8 3.2 3.6 9.0 7.2 9.4 5.9 Fe ₂ O ₃ 0.7 0.9 0.8 0.6 0.7 0.8 0.8 CaO 0.3 0.8 1.1 0.6 0.8 1.1 0.8 MgO 88.7 84.1 82.5 58.9 62.8 51.8 70.8 moisture 0.1 0.1 0.1 0.4 0.5 0.6 0.6

division Assembly part Fine particle Before separation 10% 15% 30% 10% 15% 30% Granularity
(Mm) 2.80 or higher 7 9.1 10.8 - 7.3 6.9 25.1 2.80 to 1.0 39.1 48.6 46.8 12 24.3 19.2 37.1 1.0 to 0.3 38.9 33 30.4 18.4 27.3 25.5 20.2 0.3 to 0.075 14.2 8.4 10.4 38.1 26.5 31.3 10.2 0.075 or less 0.8 1.1 1.6 31.5 14.6 17.1 7.4 yield(%) 80% 85% 90% 20% 15% 10% -

In order to compare with the effect of the method according to the present invention, the results of the case of pulverizing the waste mica carbon refractory having the same composition as the composition shown in Table 1, 4 and 5, respectively.

Name of sample Eagles
(lg-loss) SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO moisture Assembly part 9.8 0.8 3.4 0.7 0.9 84.2 0.3 Fine particle 22.3 1.1 7.6 0.8 0.6 67.3 0.3

division Before separation Assembly part Fine particle Particle size (mm) 2.8 or higher 25.1 20.8 - 1.0 to 2.8 37.1 68.8 0.1 0.3 to 1.0 20.2 10.4 48.1 0.075 to 0.3 10.2 - 38.2 0.075 or less 7.4 - 13.6 yield(%) - 60% 40%

In the case of performing the particle size separation using the wet cyclone as proposed by the present invention, since Al (OH) ₃ formed in the slurry process is decomposed to sufficiently remove H ₂ O, the yield of the granulation Can be confirmed by comparing Tables 2 and 3 with Tables 4 and 5 above.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

Claims (5)

Crushing spent waste mag carbon as a refractory brick;
Mixing the pulverized waste carbon with water to prepare a slurry;
Separating the slurry of the assembly from the slurry using a wet cyclone; And
Drying the slurry of the separated assembly until the moisture content is less than 1% by weight,
Wherein the step of separating the slurry of the assembly comprises separating the slurry into a granulate having an average particle size of 0.3 to 4 mm and a fine slurry having an average particle size of 0.3 mm or less.
The method according to claim 1,
And the particle size of the pulverized waste carbon is 4 mm or less.
The method according to claim 1,
The solid content of the slurry is 1 to 40 wt%.
delete The method according to claim 1,
Wherein the drying is performed at a temperature of 200 캜 or higher.