KR101778230B1 - Main runner castables for blast furnace using wasted sludge of solar-silicon - Google Patents

Abstract

The present invention relates to a main runner inflow material for a blast furnace, comprising: 5-10 wt% of solar silicon sludge; 40-70 wt% of alumina; 10-40 wt% of silicon carbide; 3-10 wt% of carbon; 10-15 wt% of calcined alumina; and the remaining consisting of a binder and other inevitable impurities. The solar silicon sludge comprises a solar sludge containing 3-10 wt% of metal silicon (Si). The main runner inflow material for a blast furnace is able to prevent oxidation of carbon using solar silicon sludge containing metal silicon. In addition, the silicon sludge discarded in a cutting process to make silicon wafers is recycled; thereby reducing the cost required for disposal or discardment, and at the same time, enhancing utilization of the resources.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a blast furnace for a blast furnace using solar silicon sludge,

The present invention relates to a blast furnace inflow material, and more particularly, to a blast furnace inflow material for preventing oxidation of carbon using solar silicon sludge containing metal silicon.

A large amount of silicon sludge is generated during the process of cutting a silicon ingot by a wire saw during the manufacturing process of a silicon wafer for a semiconductor or a solar cell. Silicon sludge is used as a cutting material (silicon carbide (SiC) having an average particle diameter of 20 占 퐉) used for cutting and cutting particles (silicon particles, which are abraded as abrasive particles in the cutting process) Metal particles, etc.) are dispersed in the cutting oil used to remove heat generated during the cutting process. These waste silicon sludges are classified as industrial wastes, but they can not be simply incinerated because they contain cuttings and cutting oil, and serious soil contamination is a concern when they are simply landfilled. It is known that waste sludge remaining as a final residue is about 21,000 tons / year in 2010 when the recyclable components are separated and recovered from the generated sludge, With the rapid growth of the industry, the generation of waste sludge will also increase significantly.

Such sludge needs to be recycled to reduce the cost of disposal or disposal, while at the same time increasing the availability of resources.

1. Korean Published Patent No. 1985-0003898 2. Japanese Patent No. 2922998

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned needs, and it is an object of the present invention to provide an inlet for a blast furnace using a silicon sludge which is discarded in a cutting process for making a silicon wafer.

Further, the present invention has an effect of preventing oxidation of carbon using solar silicon sludge containing metal silicon, and it is an object of the present invention to provide an inlet material for blast furnace through a minimum of pretreatment.

In order to achieve the above object, according to the present invention, there is provided a method of manufacturing a solar cell, comprising the steps of: preparing a photovoltaic silicon sludge comprising 5 to 10% by weight of photovoltaic silicon sludge, 40 to 70% by weight of alumina, 10 to 40% , Carbon 3 to 10 wt.%, The balance binder and other unavoidable impurities.

In some embodiments of the present invention, the solar silicon sludge may comprise 3 to 10 weight percent metal silicon (Metal Si).

In some embodiments of the present invention, the photovoltaic silicon sludge may have a particle size of less than 20 microns particle size and at least 80 weight percent silicon carbide (SiC).

In some embodiments of the present invention, it may further comprise 5-15 wt% calcined alumina.

The blast furnace inflow material according to the present invention has the effect of preventing oxidation of carbon by using solar silicon sludge containing metal silicon.

In addition, the silicon sludge that is discarded in the cutting process for making silicon wafers is recycled, thereby reducing the cost required for disposal or disposal, and at the same time, enhancing the utilization of resources.

The effects of the present invention described above are exemplarily described, and the scope of the present invention is not limited by these effects.

1 is a graph showing physical properties according to temperature according to an embodiment of the present invention.
2 is a photograph showing the results of the erosion test according to an embodiment of the present invention.
3 is a photograph showing a microstructure after erosion test according to an embodiment of the present invention.
FIG. 4 is a photograph showing an oxidation test result according to an embodiment of the present invention.
5 is a photograph showing a result of a spalling test according to an embodiment of the present invention.
6 is a photograph showing the results of the erosion test according to an embodiment of the present invention.
7 is a photograph showing a pilot test result according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. The scope of technical thought is not limited to the following examples. Rather, these embodiments are provided so that this disclosure will be more thorough and complete, and will fully convey the scope of the invention to those skilled in the art. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items. The same reference numerals denote the same elements at all times. Further, the various elements and regions in the drawings are schematically drawn. Accordingly, the technical spirit of the present invention is not limited by the relative size or spacing depicted in the accompanying drawings.

The present invention relates to an inflow material used in a blast furnace in a steelworks, which recycles waste silicon sludge generated during a silicon wafer manufacturing process, thereby reducing the cost of disposing or disposing of waste silicon sludge, have. It is also possible to prevent the oxidation of carbon by using it as an inflow material without performing the separation process of the metal silicon contained in the solar silicon sludge.

The blast furnace inflow material using the photovoltaic silicon sludge according to the present invention comprises 2 to 10% by weight of the photovoltaic silicon sludge, 40 to 70% by weight of alumina, 10 to 40% by weight of silicon carbide, 3 to 10% And other unavoidable impurities.

The photovoltaic silicon sludge may comprise 2 to 10 wt%. The silicon sludge discarded in the cutting process has an average particle size of 20 μm. And more than 80% by weight of silicon carbide (SiC). The photovoltaic silicon sludge is used as a substitute for SiC applied to the blast furnace inflow material, and the used silicon sludge can be used again as a refractory material. If the content of the above-described photovoltaic silicon sludge is less than 2% by weight, the efficiency of the silicon sludge targeted by the present invention may be reduced. Also, when the content exceeds 10% by weight, the physical properties may be inferior due to excessive grain size bias.

The photovoltaic silicon sludge may include 3 to 10 wt% of metal Si. The above-described photovoltaic silicon sludge contains 3 to 10% by weight of metal Si. However, in the case of the conventional solar cell, the sludge is applied to the refractory by separating it, but in the case of the inflow material, metal silicon (Si) Can be used for the purpose of preventing oxidation of the catalyst. In the case of metallic silicon contained in solar photovoltaic sludge, the particle size is as fine as 1 μm and the particle size distribution is narrow, so that the efficacy is excellent and no deterioration occurs. Such fine metallic silicon can not be added to refractories as a single material because of the risk of explosion when handling and because of the high cost. Therefore, it is possible not only economically to treat waste sludge which is generated in large quantity when adding solar silicon sludge, but also to make ultra-high temperature refractory material through minimal pretreatment. Therefore, it is superior in properties to existing refractories and can be manufactured at low cost.

The silicon carbide may include 10 to 40 wt%. The SiC content of the ultra-high temperature refractory material currently in use in the blast furnace is 10 to 40 wt%. The content of silicon carbide contained in the solar cell sludge is limited to 10 to 30% by weight for application to ultrahigh-temperature refractory materials. If it exceeds 30% by weight, there is a problem of high cost in terms of unit cost.

The alumina may include 40 to 70 wt%. The alumina has high mechanical strength, high resistance to various slags, and high specific gravity. By increasing the content of alumina, it is possible to improve the heat resistance temperature and abrasion resistance. As refractory aggregate, it can be molded into a certain form by kneading with additives and water, and can be manufactured as a refractory material through a drying and firing process. If it is less than 40% by weight, corrosion resistance is deteriorated. If it is added in an amount exceeding 70% by weight, the addition amount of silicon carbide may be limited, and corrosion resistance may be caused.

The carbon may comprise 3 to 10% by weight. The blast furnace inflow material may have the advantage of high rigidity due to the properties of carbon including carbon, such as high thermal conductivity and resistance to wetting by molten slag. The carbon material is not particularly limited. Materials having a high fixed carbon content are desirable for maintaining a high temperature structure, i.e., ensuring corrosion resistance. Commonly used carbon materials include carbon black. If the amount of carbon is less than 1% by weight, it is easily wetted by molten slag and the properties of the carbon material are not fully exerted. When the carbon content exceeds 10% by weight, there is a problem of high cost in terms of unit cost.

The blast furnace inflow material may further contain calcined alumina in an amount of 5 to 15% by weight. The calcined alumina is ultrafine powder calcined alumina having a particle size of 0.3 to 0.6 탆. When the ultrafine powder calcined alumina is used, the flowability of the inflow material is increased and the plasticizing strength of the inflow material is increased by acting as a binder. When the addition amount of calcined alumina exceeds 15% by weight, the workability is lowered.

The blast furnace inflow material may further include a binder. As the binder, alumina cement, clay, or the like can be used to contribute to moldability, manifestation of handling strength, and strength development of the final refractory material.

It is very important that the refractory temperature of the refractory equipment used in the equipment of the refining process is maintained at 1550 DEG C or higher because the temperature of the molten iron is in the range of 1500 to 1530 DEG C in the refining process. The blast furnace inflow material according to the present invention exhibits sufficient thermal durability even at a super-high temperature, i.e., a temperature of 1550 占 폚 or higher.

In addition, it can prevent oxidation of carbon by using solar silicon sludge containing metal silicon, and it is possible to make refractory for ultrahigh temperature through minimum pretreatment. Therefore, it is superior in properties to existing refractories and can be manufactured at low cost.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, details of the present invention will be described with reference to examples and experimental examples.

Experimental Example  1. Photovoltaic Silicon Sludge  Content change

1-1. Manufacture of blast furnace iron ingot material

1 is a graph showing physical properties according to temperature according to an embodiment of the present invention. After the blending of the solar cell sludge content controlled solar silicon sludge content as shown in the following Table 1, the blast furnace was kneaded, then dried at 110 ° C for 24 hours, dried, maintained at 800 ° C for 3hrs, maintained at 1100 ° C for 3hrs A high temperature physical property was measured and is shown in Fig. The total content of added silicon carbide (SiC) and solar silicon sludge was added in a range similar to that of the previously added silicon carbide (SiC).

The measured properties are Permanent Linear Change (%), Modulus of Rupture (MPa), Cold Crushing Strength (MPa), Bulk Density (g / cm3) and Porosity (%).

existing A B C Alumina 61 61 61 61 C 3 3 3 3 SiC 30 25 20 15 Silicon sludge - 5 10 15 Binder Remainder Total 100 100 100 100

Table 2 below shows an example of the silicon sludge composition discarded in the cutting process as the composition of the added solar silicon sludge. And has an average particle diameter of 20 mu m, and contains 80 wt% or more of silicon carbide (SiC) and 3 to 10 wt% of metal silicon (Metal Si). The composition range of the composition of the silicon sludge is not limited to this, and the composition range of SiC and the like may vary.

The above-described photovoltaic silicon sludge contains 3 to 10% by weight of metal Si. However, in the case of the conventional solar cell, the sludge is applied to the refractory by separating it, but in the case of the inflow material, metal silicon (Si) Can be used for the purpose of preventing oxidation of the catalyst.

Thus, it is possible not only to economically treat the waste silicon sludge which is generated in large quantity, but also to make an ultra-high temperature refractory material through the minimum pretreatment. Therefore, it is superior in properties to existing refractories and can be manufactured at low cost.

In FIG. 1, the permanent linear change is considered to have been fired in the vicinity of 1000 ° C as a percentage of the initial length of the refractory after heating the refractory and then cooling it to room temperature, which is considered to be expanded in the property evaluation at 1100 ° C .

Bulk density tends to increase and porosity tends to decrease with the increase in the amount of the above-described photovoltaic silicon sludge, as measured at high temperature (800 ° C, 1100 ° C). It can be confirmed that the void decreases and the bulk density increases.

Modulus of Rupture tends to increase and decrease when the solar cell sludge is added. It is judged that this is due to grain size bias due to the addition of a very fine amount of the above-described solar silicon sludge.

The cold crushing strength was increased with the addition of the photovoltaic silicon sludge, whereas the addition of 15 wt% of the photovoltaic silicon sludge showed similar strength to the case of adding 5 wt% of the sludge. Thus, it can be confirmed that the anti-oxidation effect is exhibited by the metal silicon (Si) added to the silicon sludge.

When the added amount of the photovoltaic silicon sludge exceeds 10% by weight, the modulus of rupture and the cold crushing strength are judged to be due to excessive grain size bias.

1-2. Erosion evaluation

FIG. 2 is a photograph showing an erosion test result according to an embodiment of the present invention, and FIG. 3 is a photograph showing a micro structure after an erosion test according to an embodiment of the present invention. In the erosion test method, the specimens were tested by applying 500 g slag 7 times to the rotation corrosion tester for 7 hrs at 1,550 ° C.

It was confirmed that corrosion resistance was increased due to a low erosion rate in proportion to the addition amount of the photovoltaic silicon sludge. However, it was confirmed that a slight amount of crack occurred in the C compounded specimen added with 15 wt% The samples were found to have the best corrosion resistance.

Experimental Example  2. calcination  Alumina addition

2-1. Manufacture and casting of blast furnaces

Casting admixtures were prepared by kneading a casting admixture having a composition of calcined alumina as shown in Table 3 below. The casting evaluation results are shown in Table 5. The total amount of added silicon carbide (SiC) and photovoltaic silicon sludge is in the range similar to that of the existing silicon carbide (SiC) Lt; / RTI > The flow ability was maintained by controlling the particle size of alumina and changing the additives. The calcined alumina can be used to increase the fluidity of the inlet material and to improve the drying strength of the inlet material by acting as a binder.

existing D E F Alumina 50 50 50 50 Calcined Alumina 10 10 10 10 C 3 3 3 3 SiC
30 25
20 15
Si sludge - 5 10 15 Binder Remainder Sum 100 100 100 100

Water
Required (%) Flow ability
(mm) Material Required
For Estimating (g / ml) Remarks existing 7.0 130 2.63 - D 7.5 130 2.62 Viscosity increase E 7.8 130 2.57 Viscosity increase F 8.5 135 2.54 Particle size deflection

As shown in Table 4, in the case of D and E blending, the viscosity increased. In the case of the F compound containing 15 wt% of the photovoltaic silicon sludge, aggregation occurred due to the increase in the viscosity, and particle size deflection was caused by the increase in the amount of the fine particles. Also, the mixing time is increased.

division Dry (110 ° C)
Oxidation firing (1200 ℃) Reduction firing (1500 ℃) Db Po
(%) CCS
(MPa) MOR
(MPa) PLC
(%) Db Po
(%) CCS
(MPa) MOR
(MPa) PLC
(%) Db Po
(%) CCS
(MPa) MOR
(MPa) PLC
(%) existing 2.63 20.1 21 4.9 -0.03 2.50 25.8 51 7.9 0.06 2.59 23.7 28 7.0 0.09 D 2.63 18.5 23 4.9 0.00 2.55 23.4 58 9.1 0.06 2.62 22.3 35 7.5 0.09 E 2.61 18.9 22 4.5 -0.01 2.51 24.9 72 13.2 0.15 2.55 24.2 55 9.6 0.11 F 2.58 19.4 18 2.4 0.00 2.28 29.6 22 2.6 0.23 2.32 28.5 24 2.2 0.10

In Table 5, Db represents Bulk Density (g / cm3), Po represents Porosity (%), C.C.S represents Cold Crushing Strength (MPa), MOR represents Modulus of Rupture (MPa), and P.L.C represents Permanent Linear Change (%).

The modulus of rupture and the cold crushing strength are increased in proportion to the addition amount of the photovoltaic silicon sludge, 15 wt% In the case of the F compound added, it is judged that the physical properties are inferior due to excessive grain size bias. It was confirmed that the D and E added with 5 to 10 wt% of the above-described photovoltaic silicon sludge were superior in physical properties to the conventional ones.

2-3. Oxidation & Spalling Experiment

FIG. 4 is a photograph showing an oxidation test result according to an embodiment of the present invention, and FIG. 5 is a photograph showing a result of a spalling test according to an embodiment of the present invention. Oxidation experiments were carried out at 1200 ℃ for 3hrs. Spalling experiments were carried out at 1450 ℃ for 1 hour and 1 hour by air cooling for 15 times.

It was confirmed that the oxidation resistance was equivalent regardless of the addition amount of the photovoltaic silicon sludge. Hair-cracks occurred after 12 doses in all specimens except F compound, and 15 cracks were observed. F is a phenomenon similar to that of the silicon sludge, and it is considered that the part phenomenon occurs from the addition of the photovoltaic silicon sludge by 15 wt% or more.

2-4. Erosion experiment

6 is a photograph showing the results of the erosion test according to an embodiment of the present invention. In the erosion test method, the specimens were tested by introducing 500 g slag 12 times into a rotation corrosion tester for 12 hrs at 1550 ℃. Corrosion resistance was increased up to 10 wt% in proportion to the amount of the above-described photovoltaic silicon sludge added The F compounded specimens with 15 wt% addition were broken during cutting and the slag penetration was observed in the specimen F which was not dense.

2-5. Pilot experiment

7 is a photograph showing a pilot test result according to an embodiment of the present invention. A pilot experiment was conducted using an E sample containing 10% by weight of the above-described photovoltaic silicon sludge for the blast furnace inlet material using the above-described photovoltaic silicon sludge. The application is Hyundai-Steel 1BF Slag Runner and the application period was about 74 days. Table 6 shows the thickness of the damping material after the pilot test. As a result of the pilot experiment, it was confirmed that the average residual was improved by about 10%.

Residual zone (mm) ①-side ②-side ③-bottom existing 275 310 510 E 305 330 550

Also, in contrast to the high temperature properties of the B sample and the E sample having the added amount of the above-described photovoltaic silicon sludge of 10 wt% and the high temperature of 1100 DEG C to 1200 DEG C, the modulus of rupture of the E sample to which calcined alumina was added was 72 As a result, it was confirmed that the compressive strength (cold crushing strength) of 13.2 MPa was higher than that of B sample (9 MPa). This is because the inclusion of calcined alumina enhances the fluidity of the inflow material and acts as a binder to increase the dry strength of the inflow material.

As described above in the above experimental results, the silicon sludge discarded in the cutting step of making a silicon wafer is recycled, and the silicon sludge is removed by adding 2 to 10% by weight of solar cell sludge, 40 to 70% by weight of alumina, By weight, and 3 to 10% by weight of carbon, which can reduce the cost required for disposing or disposing of the silicon sludge, and at the same time, improve the utilization of resources. In addition, it can prevent oxidation of carbon by using solar silicon sludge containing metal silicon, and it is possible to make refractory for ultrahigh temperature through minimum pretreatment. Therefore, it is superior in properties to existing refractories and can be manufactured at low cost.

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. And will be apparent to those skilled in the art.

Claims (4)

Wherein the sludge comprises 5 to 10 wt% of a solar silicon sludge, 40 to 70 wt% of alumina, 10 to 40 wt% of silicon carbide, 3 to 10 wt% of carbon, 10 to 15 wt% of calcined alumina,
Wherein the solar cell sludge comprises 3 to 10% by weight of metal silicon (Si).
delete The method according to claim 1,
Wherein the solar silicon sludge has a particle size of 20 탆 or less and a silicon carbide (SiC) content of 80 wt% or more.
delete

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