JPS63285164A - Refractory of slaking-resistant cao material - Google Patents

Abstract

PURPOSE:To obtain a slaking-resistant CaO refractory having bonded parts characterized by CaB6 containing no free CaO. CONSTITUTION:A calcareous refractory having bonded parts characteristized by CaB6 containing no free CaO, formed on CaO-containing Clinker having controlled particle size. In calcareous Clinker as a refractory, an indeterminate- form refractory such as blown material adjusted to 5-1mm coarse particles and 1-0.1mm middle particles is generally adjusted to <=1mm. To prevent slaking resistance, preferably regular-shape refractory is adjusted to 5-1mm coarse particles and 1-0.3mm middle particles and a refractory such as blown materials is adjusted to 1-0.3mm particle size. The adjustment is carried out because there is time limitation of use of an actual furnace wherein the refractory is slaked and collapsed for a week at 20 deg.C and at >=95% RH when the particle size is >=0.3mm. At least >=50wt.% CaO Clinker adjusted to 0.3-5mm particle size in a refractory raw material is preferably used from this point of view.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to calcareous refractories.

[Prior Art] Various refractories are currently being used for the lining of steelmaking equipment to improve their durability. In recent years, in the steel manufacturing field, there has been an active movement to produce highly clean steel, and the application of CaO refractories for clean steel is expanding due to CaO's ability to adsorb nonmetallic inclusions in molten steel.

Although quicklime has excellent properties as a refractory, such as a high melting point of 2572°C, good spall resistance, and low vapor pressure under reduced pressure and stability, its digestibility is extremely poor, so its practical use as a refractory has been delayed. ing.

As a technique to prevent digestion (hydration), for example, CaO 9
Clinker surface is treated in a CO8 atmosphere at around 50℃.
There are refractories that use aggregates with a CO3 protective layer formed, or that are hot-pressed at the temperature at which CaO and CaCl form a eutectic liquid phase, and pitch base, phenol resin, etc. are used as hydrogen binders. Also Tie,, FcJ
There is also a digestible clinker made by burning a low melting point substance such as s with quicklime to form a glassy protective layer.

[Problems to be Solved by the Invention] However, these conventional refractories and extinguishing prevention methods cause sagging, which is a cause of damage to steelmaking container refractories.
It is insufficient to protect against the erosion of kuware, ware, and kezure.

For example, a clinker whose surface is converted to CaC0 to form a protective layer has poor digestion resistance for fine powder of 0.3 mm or less and hydrates and disintegrates in a short period of time. Also, since CaCl□ has high hygroscopicity, it has poor workability and hot pressing is not common in terms of cost. Furthermore, when the clinker, which forms a glassy protective layer, becomes fine powder (0.3 mm or less), it similarly has poor digestion resistance and hydrates and disintegrates. Furthermore, fire resistance and fire resistance using non-aqueous binders are improved, but the period until actual furnace use is limited, and pollution problems occur during use.
It is necessary to use it with careful consideration.

Furthermore, as a refractory for clean steel, it goes without saying that it is desirable to have as good an adsorption effect as possible on non-metallic inclusions in molten steel. Therefore, the object of the present invention is to produce a calcareous refractory that is stable until it is used in an actual furnace, does not undergo digestive disintegration, has a high durability of practical value, and also has a strong clean steel effect.

[Means for Solving the Problems 1] The present invention has been made to solve the above-mentioned problems.
The present invention provides a calcareous refractory whose joint portion is characterized by CaBe that does not contain O.

In the present invention, the CaO-containing clinker has a CaO-containing surface.
Fe2O2 with a C0* protective layer formed.

Can clinker matrix formed from glass such as TiO□, SiO□, etc., or CaO clinker surface coated with silicon or fluorine resin, dolomite clinker, or electrofused or synthetic CaO-containing talin of CaO・Z'02. It can also be used with force.

Coarse grains are generally 5 to 1 m as CaO quaclinker fireworks.
m, medium grain is adjusted to 1 to 0.1 mm, and for monolithic refractories such as sprayed materials, it is adjusted to 1 mm or less, but in order to prevent durable rake properties, for regular refractories, coarse grain is adjusted to 5 to 1 mm, medium grain is 1.
~0.3mm or 1~0.3mm for refractories such as sprayed materials
It is desirable to adjust the particle size accordingly.

For example, if it is less than 0.3 mm, it will be 195% at 20°C.
This is because under the above conditions, there are time constraints for actual use of the reactor, such as digestion and disintegration within one week. From this point of view, in the present invention, it is desirable to use at least 50% by weight (I%) of the CaO-based quaclinker refractory raw material whose particle size is adjusted to 0.3 to 5 mm. In the present invention, the bonding portion of such an aggregate portion is characterized by the presence of CaBs, but it is preferable that this CaBe has a composition that does not contain free CaO. For example, 8203 and 8203 are added to the CaO raw material. 25% of the mixed raw material containing C
A material obtained by melting and re-solidifying at a high temperature of 00° C. or higher and then pulverizing is preferably used. Generally CaBs is 9
A material containing 9% or more and substantially no free CaO is used.

In the present invention, CaBe that does not contain free Can is mainly blended to form the matrix part (bonding part) in the refractory, but it may also be blended into the coarse particles as a part of CaO-containing talin. It is undeniable that the cost will be higher. It is preferably used as a fine powder of 0.3 mm or less, and enables a refractory having the objectives and effects of the present invention, such as fire resistance and corrosion resistance, as well as an excellent clean steel effect. Here, the blended amount of Ca[16 as a fine powder of 0.3 mm or less is 117 which forms the matrix part.
At least 3% or more is required in the refractory raw material mentioned above, but this is because if it is not added at least 3%, it will not be possible to form the refractory and the composition will become porous. This is because the amount of fine powder increases and the maximum filling ratio as a refractory breaks down, making it porous.
The content is preferably 5 to 30%, particularly preferably 10 to 30%.

A binder can be added as necessary, but for shaped refractories, aqueous binders such as water glass and non-aqueous binders such as ethyl silicate, phenol resin, urethane resin, coumaron resin, paraffin, and pitch tar can be used. Non-aqueous binders such as clay and water glass binders and phenol resins can be used for monolithic refractories such as sprayed materials, and these materials can be prepared and used for pouring as is or for spraying with a spray machine. becomes.

The present invention thus particularly provides free CaO of 0.3 mm or less.
By blending free CaBs as a fine powder, it prevents digestion resistance during use, and when used for the lining of steelmaking furnaces, the matrix of this brick is composed of Can5 etc., and when it comes into contact with slag at high temperatures, Cafe Because of its high heat resistance and good corrosion resistance, 2CaO3iO,,3C has a high melting point.
aO3iO, etc. are generated, and therefore the penetration of slag components remains in the surface layer, showing an excellent effect on structural spalling properties, and the nonmetallic inclusion removal effect of CaO (adsorption of Al2O, etc. in steel) It is thought that the modification was caused by the Can and coarse-grained CaO-containing clinker inside.

[Example] Table 1 shows examples of blending quality of calcareous refractories.

Shaped refractories are made by adding a predetermined amount of CaBs (purity of 99% or more) of 0.3 mm or less to CaO-containing clinker (98% or more of Ca) whose particle size is adjusted to 5 to 0.3 mm, and using phenol resin as a binder. After kneading and shaping, it is fired at an appropriate temperature of 1500 to 1750°C.

For monolithic refractories such as sprayed materials, a kneaded clay obtained by adding clay and water glass to the formulations shown in Examples was applied using a spraying machine. As comparative examples, the results for calcareous 1i'L bricks, Maguro bricks, and alumina sprayed materials are shown.

The bending strength is the bending strength at room temperature and 1400℃ (g/
am”).The slaking test was carried out on bricks at 20°C.
The weight change was measured by placing it in a 195% thermostatic room, and the degree of digestion resistance was shown (good with an O mark). Corrosion resistance test was conducted by forming a cylindrical crucible in a high frequency induction furnace and using 5S-41, C/S =
2 synthetic slag (Ca040%, 5ins20%, Δ
IJa 18%, Mg018%, Fe2rs 4%, etc.)
Corrosion resistance is the maximum corrosion residue (in mml), and spalling resistance is the result of examining the presence or absence of cracks inside the sample after the corrosion test (no O-field).

As a result, C that does not contain free CaO of 0.3 mm or less
It was found that the calcareous refractory containing fine powder of aB6 had good digestion resistance and high corrosion resistance.

Furthermore, a crucible was formed using the refractory sample Example 1.4 shown in Table 1 and a calcareous brick as a comparative example, and this crucible was placed in a tanman, and the iron (5S) was placed inside the crucible.
-41) and nonmetallic inclusions containing 2% A11as and 2% AI were tested in an argon atmosphere at 1600°C for 1 hour, and the surface of the crucible was analyzed after the test.
In the refractory of the present invention, C
Aa (CaO8AI20RiyaCsA (3CaO1A
IJa) etc. were detected on and near the crucible surface. In addition, C and A were detected in a calcareous crucible. This indicates that the refractory of the present invention has an excellent clean steel effect compared to the CaO-only refractory.

[Effect of the invention 1 As described above, the present invention not only improves the extinguishing resistance, which is the biggest drawback of CaO-containing refractories, and has excellent corrosion resistance and spalling resistance against molten metal and slag, but also eliminates non-metallic inclusions in steel. It is a highly durable lime-containing refractory with further enhanced material removal effect, and is suitable for gas injection siding in AOD furnaces for stainless steel refining, converters for special steel refining, ladles, tundishes, D11 furnaces, R1+ furnaces, etc., and for steel manufacturing. It can be used in a wide range of applications as furnace materials and components for kilns, such as container lining materials, molten metal passing rings, filters, and nozzles, and has great industrial value.

Claims (3)

[Claims] (1) Digestion-resistant CaO refractory whose bonding portion is characterized by CaBe that does not contain free CaO (2) 3-35% by weight of CaBe with a diameter of 0.3 mm or less
The CaO-based refractory according to claim 1, which contains (3) The CaO refractory according to claim 1 or 2, which contains at least 50% by weight of CaO clinker whose particle size is adjusted to 0.3 to 5 mm.