JPS6283362A - Manufacture of low expansion high anticorrosion refractories - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a low expansion, highly corrosion resistant refractory suitable for lining a blast furnace.

(Conventional technology) Cordierite (2MgO・2A7IzCh・5Si0
Combining 2) with chamotte or alumina is carried out, for example, in the production of refractory linings for blast furnace shafts. This is because cordierite has a very small coefficient of thermal expansion, and adding it improves the spalling resistance of the refractory.

(Problems to be Solved by the Invention) However, when exposed to high temperatures of 1,400 ℃ or more, cornelite melts or changes into other substances, and the spalling resistance effect is not fully exhibited, and the corrosion resistance It had the disadvantage of being inferior to

The present invention provides a refractory raw material that maintains the low expansion properties of cordierite even under high temperatures and does not reduce corrosion resistance, and by blending this with chamotte and/or alumina in a specific ratio, the lining of a blast furnace can be lined. The purpose of the present invention is to provide a method for producing a low-expansion, high-corrosion-resistant refractory suitable for applications such as the following.

(Means for Solving the Problems) According to experiments conducted by the present inventors, MgO component and 5
It has been found that it is preferable to use a refractory raw material obtained by mixing iO=components in a specific ratio and sintering or melting the mixture. The main component of this refractory raw material is cordierite, and microcracks caused by the difference in thermal expansion between these two products and the transformation expansion of baddellite are thought to alleviate thermal shock and improve spalling resistance. . Furthermore, the improvement in corrosion resistance is thought to be due to the fact that baddellite, one of the main components, has excellent corrosion resistance against molten metal or molten slag.

The present invention combines chamotte and/or alumina with this refractory raw material. This is to provide alkali resistance to the lining of the blast furnace shaft.

The main structure of the present invention made from the above viewpoint is that the zircon raw material contains 50 to 90 wt% of the Zr0z-810z component,
A refractory raw material 15 to 60 wt % obtained by sintering or melting a mixture consisting of an alumina raw material with an AjlzO component of 7 to 35 wt % and a magnesia raw material with an MgO component of 3 to 15 wt %.
% and the balance is chamotte and/or alumina, and then firing the mixture.

In the present invention, a method for producing a refractory raw material, which is synthesized by combining a zircon raw material, an acetic raw material, and a magnesia raw material, will be described in detail.

The zircon material used here is obtained using zircon sand as a starting material. Zircon raw material is ZrOs・S
If the iO2 component is less than 5Qwt%, the formation of baddellite is small, resulting in insufficient fire resistance and corrosion resistance, and if it exceeds 9Qwt%, the formation of cordierite is small, resulting in poor spalling resistance.

Examples of aluminous raw materials that can be used include bauxite, sillimanite, kyanite, clay, and limestone shale. The ratio is 120. If the content is less than 7 wt%, cordierite is less produced and the spalling resistance is poor. If it exceeds 35 wt%, the amount of corundum, spinel, etc. produced will be large, and the amount of cordierite produced will be correspondingly small, resulting in poor spalling resistance.

Examples of the magnesia raw materials include seawater magnesia, natural magnesite, talc, dunnite, jamonite, and magnesia peridotite. If the MgO component is less than 3 wt%, the amount of cordierite produced decreases, resulting in poor spalling resistance. 15w
If it exceeds t%, more corundum, spinel, etc. will be produced and less cordierite will be produced, and in this case too, the corrosion resistance will be poor.

A more preferable ratio for each raw material is Zr0
2-S 1oz70-80Wj%, A 7+2031
0 to 25 wt%, MgO5 to 1Qwt%.

The raw materials are combined as described above, and then the particle size of each raw material is adjusted to about 100 meshes or less, preferably 200 meshes or less, as usual in the production of refractory raw materials. When obtaining a refractory raw material by firing, it is mixed with an organic or inorganic binder and, if necessary, water, and formed into briquettes, rods, or granules, and after drying, e.g.
Calcinate at a temperature range of oo to 1,450°C. On the other hand, in the case of a molten product, it is melted in a furnace at a temperature of 1,500 yen and the varnish is removed immediately.

By firing or melting, the refractory raw material produces cordierite and vaterite as main components through a chemical reaction represented by the following formula.

Z r 02 ・S iOx (zircon) + A
II 20a + M g 0→Z rot (vatterite) + 2Mg0.2AAzO3,58i0□ (cordierite) In addition, components other than the main components cordierite and baddellite are unreacted ZrO2・SiO2, AjbO3, M
In addition to gO, Mg O-8+ Oh, Mg O-A J2
03, SiO□・A71203, etc. may also be produced.

In the present invention, a mixture of 10 to 6 Qwt% of the above refractory raw materials and the remainder consisting of chamotte and/or alumina is molded and fired to produce the desired refractory. If the above refractory raw material is less than 15 wt%, the low expansion effect will be insufficient, and if it exceeds 6 Qwt%, the proportion of chamotte or alumina will be small, resulting in poor alkali resistance. More preferably, it is 20 to 55 wt%. During molding, an organic or inorganic binder is added in an amount of about 5 wt %, and the kneaded mixture is pressure molded. Firing is t, ao
It is preferably about 0 to 1,450'c.

(Implementation-Example) Examples of the present invention and comparative examples thereof are shown below.

Table 1 shows production examples of refractory raw materials. The blending ratio of each component and the mineral composition produced after firing are shown at the same time. This refractory raw material is made of ZrOz・SiO−, Al2
Blended in terms of O5, MgO, S i 02 components,
P, V, and A were added as binders to an external layer of about 1 wt% and an appropriate amount of water, molded, and dried.

It was fired for 5 hours.

Table 2 shows the proportions of some of the refractory raw materials shown in Table 1 in combination with chamotte and/or alumina. These are made by adding 1.5 wt% of sodium lignin sulfonate as a binder, molding them, and drying them to 1,400'
A refractory was produced by firing for 5 hours. The test results of the obtained refractories are shown in the same table. The measurement method is as follows.

Spalling resistance: A test piece cut out into a cube with sides of 40 square feet was heated and cooled with water to compare the size of cracks.

Fire resistance, measured according to JIS, R2204-76.

Corrosion resistance: 20Wφ x height 15o! A test piece cut out at 01 was immersed in 1.500'c of molten iron (pig iron: 80 wt%, blast furnace slag: 20 wt%) for 60 minutes, and the dimensions of the melt damage were determined. The purpose of combining blast furnace slag with molten iron as a solvent was to examine the effects of alkaline erosion.

(Effects) As is clear from the test results of Examples, the refractory obtained by the present invention has excellent spalling resistance and corrosion resistance even under high temperature conditions of, for example, 1,400°C or higher.

Therefore, the present invention is suitable as a method for manufacturing blast furnace lining refractories that have a long life cycle and are required to have alkali resistance.

Claims (1)

[Claims] Zircon raw material with ZrO_2 and SiO_2 components from 50 to
90wt%, alumina raw material with Al_2O component of 7 to 3
5wt%, magnesia raw material with MgO component 3~15w
Refractory raw material 1 obtained by sintering or melting a mixture consisting of t%
A method for producing a low-expansion, high-corrosion-resistant refractory, which comprises molding and firing a compound consisting of 5 to 60 wt% and the remainder chamotte and/or alumina.