JPH0873226A - Unburned spinel refractory for generator of glass kiln - Google Patents

Abstract

PURPOSE: To produce an unburned refractory for a generator of glass kiln having excellent strength in a temp. range from room temp. to 1200 deg.C. CONSTITUTION: This refractory contains spinel, alumina, and magnesia as main starting materials and has a chemical composition of 10-80wt.% Al2 O3 , 15-85wt.% MgO, 1-5wt.% CaO, 1-5wt.% SiO2 and 0-10wt.% balance inevitable impurities, and by heating CaO and SiO2 at the inside of the generator, calcium silicate having high m.p. is formed and this silicate is allowed to function as a binding agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spinel non-fired refractory material such as a checker brick used in a glass kiln heat storage chamber.

[0002]

2. Description of the Related Art Conventionally, as a spinel-like unfired refractory, a refractory raw material containing a magnesia clinker, a spinel clinker, and an alumina clinker is used, and a condensed alkali phosphate is used as a binder (Japanese Patent Publication No. 61-286).
22), using sodium silicate (Japanese Patent Publication No. 5)
No. 0-7611) and those using tricalcium phosphate and sodium hexametaphosphate (Japanese Patent Publication No. 54-3).
No. 5208) is known.

[0003]

However, all of the conventional non-fired spinel refractory materials have a drawback that their strength is lowered in the temperature range above the middle stage of the glass kiln heat storage chamber (about 1000 ° C. or higher). Therefore, the present invention is to
An object of the present invention is to provide a spinel-like unfired refractory for a glass kiln heat storage chamber, which exhibits excellent strength in a temperature range up to 00 ° C.

[0004]

In order to solve the above problems, the spinel-like unfired refractory for a glass kiln heat storage chamber of the present invention is mainly composed of spinel, alumina and magnesia, and has a chemical composition of Al ₂ O ₃ 10 ˜80 wt%, MgO 15 to 85 wt%, CaO 1 to 5 wt%, SiO ₂ 1 to 5 wt%, and the balance unavoidable components 0 to 10 wt%. The chemical composition is preferably Al ₂ O ₃ 45-75 wt%, MgO 2
0-50% by weight, CaO 1.5-3% by weight, SiO ₂ 1.5-
3% by weight and the balance unavoidable components are 0 to 3% by weight.

[0005]

[Function] In the spinel-like unfired refractory for a glass kiln heat storage chamber of the present invention, CaO (calcia) and SiO ₂ (silica) are used.
But by being heated in the heat storage chamber, CaO · SiO _2, 2
Generate CaO · SiO _2, 3 CaO · refractory calcium silicate of SiO ₂ or the like, which functions as a binder.

Al ₂ O ₃ (alumina) is less than 10% by weight,
When MgO (magnesia) exceeds 85% by weight, thermal expansion becomes large and volume stability and heat-resistant spalling property deteriorate. If Al ₂ O ₃ exceeds 80% by weight and MgO is less than 15% by weight, the corrosion resistance against alkali is lowered.
On the other hand, when both CaO and SiO ₂ are less than 1% by weight, the amount of calcium silicate produced is small and the strength as a refractory is insufficient. Further, when CaO exceeds 5% by weight, it reacts with Al ₂ O ₃ in the raw material to form low-melting-point calcium aluminate, resulting in strength reduction, and when SiO ₂ exceeds 5% by weight, it is against alkali. Corrosion resistance decreases.

The spinel-like unfired refractory for a glass kiln storage chamber according to the present invention is a refractory raw material mainly containing spinel, alumina and magnesia, CaO source such as calcium carbonate and pulp waste liquid, silica powder, clay and the like. The SiO ₂ source is mixed at a predetermined ratio, kneaded, molded, and then dried and cured at a temperature of room temperature to 150 ° C. to be manufactured.

[0008]

EXAMPLES Examples of the present invention will be described below together with comparative examples. Examples 1-9 Spinel 1, spinel 2, having the chemical composition shown in Table 1,
Alumina and magnesia were used as main raw materials, and alumina, magnesia, calcium carbonate, silica, EPK (clay), and pulp waste liquid were mixed in the proportions shown in Table 2 and kneaded and molded by a known method. After 15
Each sample was obtained by drying at a temperature of 0 ° C. for 24 hours to obtain a spinel-like unfired refractory material. For these samples, the apparent porosity,
Bulk specific gravity, coefficient of thermal expansion, and bending strength (RT ~ 1200
° C). In addition, the erosion test by the crucible method (12
The corrosion resistance to alkali was tested by carrying out 00 ° C. × 24 Hr, erosion agent: Na ₂ CO ₃ ). Furthermore, each sample (114 × 230 × 65 m) fired at a temperature of 1200 ° C. for 10 hours
m) was alternately exposed to room temperature and a temperature of 1200 ° C. for 20 times to test the heat-resistant spalling property. Table 2 also shows the chemical composition of each refractory, the measurement results of the physical properties, and the test results.

[0009]

[Table 1]

[0010]

[Table 2]

Comparative Examples 1 to 8 Spinel 2, which has the chemical composition shown in Table 1, alumina and magnesia as main raw materials, and calcium carbonate, silica, pulp waste liquid, sodium tetrapolyphosphate and sodium hexametaphosphate are shown in Table 3 below. After mixing in a ratio, kneading and molding by a known method, the sample was dried at a temperature of 150 ° C. for 24 hours to obtain each sample of a spinel-like unfired refractory. For these samples, the apparent porosity, bulk specific gravity, coefficient of thermal expansion, and bending strength (RT to 1200 ° C.) were measured in the same manner as in Examples 1 to 9. Further, an erosion test (1200 ° C. × 24 Hr, erosion agent: Na ₂ CO ₃ ) by the crucible method was carried out in the same manner as in Examples 1 to 9 to test the corrosion resistance to alkali. Further, each sample (114 × 230 × 65 mm) fired at a temperature of 1200 ° C. for 10 hours in the same manner as in Examples 1 to 9 was used at room temperature and 120 ° C.
The test for heat-resistant spalling property was conducted by alternately exposing to a temperature of 0 ° C. 20 times. Table 3 shows the chemical composition of each refractory, the measurement results of the physical properties, and the test results.

[0012]

[Table 3]

From Tables 1 to 3, spinel, alumina and magnesia are used as main raw materials, and the chemical compositions are 10 to 80% by weight of Al ₂ O ₃ , 15 to 85% by weight of MgO, 1 to 5% by weight of CaO and SiO ₂ 1.
~ 5 wt% and the remaining unavoidable components 0-10 wt% spinel non-fired refractory, especially chemical composition Al ₂ O ₃ 45-75 wt%, MgO 20-50 wt%, CaO 1.5-3 wt% ,
SiO ₂ 1.5-3% by weight and the balance unavoidable components 0-3% by weight
It can be seen that the spinel-type unfired refractory material of No. 1 not only has excellent corrosion resistance to alkali, volume stability and heat-resistant spalling resistance, but also exhibits excellent strength in the temperature range from room temperature to 1200 ° C.

[0014]

As described above, according to the spinel type non-fired refractory for a glass kiln storage chamber of the present invention, CaO and SiO ₂
Is heated in the heat storage chamber, CaO ・ SiO ₂ , 2Ca
Compared with conventional spinel non-fired refractories, it produces high-melting calcium silicates such as O ₂ · SiO ₂ and 3CaO · SiO _{2 that} function as a binder.
It can exhibit remarkably excellent strength in a temperature range up to ℃.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C04B 35/101

Claims (2)

[Claims] 1. Spinel, alumina, and magnesia as main raw materials, with chemical composition of Al ₂ O _{3 of} 10 to 80 wt%, MgO 15
~ 85% by weight, CaO 1-5% by weight, SiO ₂ 1-5% by weight and the balance unavoidable components 0-10% by weight, a spinel-like unfired refractory for a glass kiln thermal storage chamber. 2. The chemical composition is preferably Al ₂ O ₃ 45.
~ 75 wt%, MgO 20-50 wt%, CaO 1.5-3
% By weight, 1.5 to 3% by weight of SiO ₂ and the balance unavoidable components 0
It is 3 weight% or less, The spinel non-firing refractory material for glass kiln thermal storage chambers of Claim 1 characterized by the above-mentioned.