JPS6049155B2 - Irregular spinel refractory furnace material for pouring and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an amorphous spinel refractory furnace material for pouring that has erosion resistance, thermal shock resistance, and excellent handling properties, and a method for manufacturing the same.

Conventionally, the optimal particle size composition as a refractory furnace material for pouring using spinel (magnesia/alumina) materials, the influence of pouring due to the fineness of natural alumina/silica raw materials, or the mineralogical reaction with spinel materials. ,
Physical and organizational relationships, etc., were not clear.

For the purpose of manufacturing monolithic spinel refractory materials for pouring, conventional alumina cement for monolithic refractories has high strength at room temperature, but it tends to generate dust when used and kneaded, and crystal water escapes when heated. However, there is a disadvantage that the strength decreases and the structure deteriorates. Current slinker materials generate dust when being projected,
After use, the remaining lining material will be removed and re-installed, resulting in leftover material. Commercially available aluminum phosphate (Al2O3・3P2
O, , 6H2O) is room temperature curable or room temperature reactive. Therefore, when this is used as a binder for refractory furnace materials for pouring, it is necessary to carry out pouring work immediately after kneading. Therefore, such materials aged at room temperature do not lose their mobility or plasticity, have poor workability and are difficult to pour, and have the disadvantages of forming a non-uniform structure. Furthermore, the aluminum phosphate is partially dehydrated by drying (at 100-120'C), and the dehydration temperature is 400-500C. Therefore, refractory/furnace materials for reverse use using aluminum phosphate that are dried below this temperature range absorb moisture at room temperature, form hydrates, and tend to reduce bond strength. It has been found that aluminum phosphate is difficult to use as a binder, particularly because it tends to react during kneading. In consideration of the above points, the present invention provides a castable spinel refractory furnace material having corrosion resistance, corrosion resistance, and thermal shock resistance, and a method for manufacturing the same. It consists of a single natural alumina/silica raw material or a natural alumina/silica raw material and SiC (silicon carbide), and the silicic acid content is within 1% by weight, and the P2O5/Na
2O=3.50-1.81 and PH3. An amorphous spinel refractory furnace material for pouring made by kneading a liquid aluminum/sodium phosphate binder of O~5.0 with water, a magnesia/alumina clinker, and a single natural alumina/silica raw material. Alternatively, a material made of natural alumina/silica raw materials and SiC and having a silicic acid content of 1% by weight or less is kneaded with water, and the kneaded product thus obtained is mixed with at least P2O, P2O, /Na2
O=3.50-1.81 and PH3. The present invention is characterized in that it is a method for producing an amorphous spinel refractory furnace material for pouring, which involves kneading a liquid aluminum/sodium phosphate binder having a particle diameter of 0 to 5.0.

This invention will be explained in detail below.

As a spinel clinker, for example, JP-A-52-2
Sintered spinel clinkers described in JP-A-4223 and JP-A-53-90308 are known.

Using a sintered spinel (theoretical M = 2135° C.) clinker, it was subjected to particle size adjustment, kneading, pressure molding, and drying to produce unfired spinel bricks and fired spinel bricks.

The results of comparative experiments of spinel bricks, such as their corrosion resistance against molten steel slag, their thermal shock resistance against molten steel, and their corrosion and erosion against slag and molten steel when laminated in a small ladle, are as follows:
It was 7 to 8 times more resistant to erosion than conventional low stone bricks, about 20 to 30 times more resistant to high alumina bricks, and moreover resistant to thermal shock. Spinel bricks made by adding natural alumina and silica raw materials to spinel materials have the effect of densifying the structure, and the penetration of molten slag into the structure is small.

However, erosion increases with increasing silicic acid content. Furthermore, the reaction surface with slag and molten steel becomes smooth and vitrified! do. The melting loss is caused by a chemical reaction between the molten slag H and the silicic acid.
Mineralogically, spinel mineral (MgO, Al2O3)
and silicic acid react to produce a cordierite mineral [2(Mg-Al.O4).5Sj02] with the highest spong resistance, and this mineral melts depending on the temperature of the molten steel. Spinel clinker is inert and is a homogeneous solid with a dense structure.

Therefore, even if the particle size composition is appropriate, it is difficult to pour it alone. However, by combining ultrafine particles of raw materials with appropriate plasticity and adjusting the particle size, pouring became possible. In addition, an amorphous spinel material with a densified structure for pouring could be obtained. An example of the particle size structure is spinel clinker coarse particles of 3360 to 1000μ.
50 parts by weight, 30 to 50 parts by weight of medium particles of 1000 to 100p, 5 to 1 part by weight of fine particles of 100μ or less, and 5 to 50 parts of ultrafine particles of 44μ or less of high alumina material, which is a natural alumina/silica-based raw material. 15 parts by weight, 44μ of plastic fireclay
1 to 5 parts by weight of the following ultrafine particles, and if necessary, viscosity S
1 to 8 parts by weight of iC ultrafine particles of 44 μm or less (10 parts by weight in total). On the other hand, commercially available aluminum phosphate (A
l2O3.3P2O. ．． If 6l (20, pH 1.4) is used, it will react during kneading and pouring will be difficult.

Furthermore, as a binder, phosphoric acid/sodium weight ratio P2O
,/Na2O=4.00-10.07, PH2.5-2
．． The aluminum/sodium phosphate binder in the range 0) tends to react during kneading. Furthermore, even after drying and dehydration, it absorbs moisture and is easily rehydrated. However, the phosphoric acid/sodium weight ratio=3.
The aluminum/sodium phosphate binder in the range of 50 to 1.81 (PH3.O to 5.0) retards the reaction of the kneaded material over time, especially when the phosphoric acid/sodium weight ratio is
Sodium aluminum phosphate binders in the range of 3.00 to 1.90 (PH 3.5 to 4.5) have a slow reaction time and are suitable for casting amorphous spinel materials. I found it. This range (P2O./Na2O
An amorphous spinel material (kneaded material) kneaded using an aluminum/sodium phosphate binder with a pH of 3.50 to 1.81 and a pH of 3.0 to 5.0 is dried (100 to
130'C) After dehydration, no rehydrate is produced if left at room temperature. Furthermore, there is no structural embrittlement or deterioration. However, the kneaded material itself reacts during long-term storage, and its tissue strength decreases over time. The aluminum/sodium phosphate binder is used in the liquid state produced by the neutralization reaction. Powdered aluminum/sodium phosphate binders obtained by drying liquid aluminum/sodium phosphate binders not only have poor solubility in water but also have low bond strength. Liquid aluminum/sodium phosphate binder (to P2/Na2O=3.50-1.81,
A dilute solution consisting of 8 weight parts of PH3.0 to 5.0) and 6 weight parts of purified water was kneaded into an amorphous spinel material for pouring having the above particle size structure, stored at room temperature, and after elapsed time. Figures 1A, A, and C show the changes in the dry physical properties of the product that was cast and vibration-molded during re-kneading (5 to 6% of purified water was applied).

(In the figure, Δ is P2O5/Na2O=3.50, PH3.
0 and O is P2O. /Na2O=2.09,PH4
．． 0, ● is P2O5/Na2O=1.80, PH
5.0) As a result, the tissue strength decreases due to the reaction between the binder and the material during long-term storage, but the extent of this decrease is small. Of these, P2O5/Na2O marked O
With a liquid aluminum/sodium phosphate binder having a pH of 2.09 and a pH of 4.0, the reactivity with the material was slow and the deterioration of tissue physical properties was particularly small. Furthermore, this binder (P2O5/Na2O = 2.09, PH4.0) was kneaded, and the material (after 7 days) was kneaded again and cast vibration molded, and after a drying process, it was heated at various temperatures. The relationship between the physical properties is shown in Figure 2 A, C] and C. The results show that the strength increases as the heating temperature increases, and the tissue porosity increases slightly in the intermediate temperature range, but decreases at high temperatures. Therefore, the amorphous spinel refractory furnace material for pouring according to the present invention is bonded by drying and dehydration, increases the structural strength by heating, and has corrosion resistance and
Has thermal shock resistance.

In the present invention, adding ultrafine particles of natural alumina-silica-based raw materials such as sillimanite and kyanite improves fluidity or mobility during pouring, and adding plastic fireclay or clay SlC improves filling. Good properties and fluidity.

These natural alumina and silica-based raw materials dissociate through thermal decomposition, and the silicic acid reacts with spinel minerals (Mg, Al2O4) to create spall-resistant cordierite [2 (Mg.
l. O4). 5S102] Add ultra-fine particles to generate minerals uniformly. As a result, tissue properties are improved. Furthermore, as the amount of natural alumina/silica-based raw materials increases, specifically, as the amount of silicic acid increases, densification occurs at high temperatures, tissue porosity decreases, and shrinkage increases.

However, tissue penetration of molten slag decreases but erosion increases. As mentioned above, it is difficult to use aluminum phosphate (PHl.4) as a binder because it is reactive and hardenable at room temperature.

Furthermore, after drying and dehydration, the tissue strength is likely to decrease due to moisture absorption when the tissue is returned to room temperature. A water-soluble aluminum/sodium phosphate binder (P2O5/Na2O=3.50-1) is a binder that has the characteristics of a delayed reaction when stored at room temperature, a hardening bond when dried and dehydrated, and no re-moisture reaction at room temperature. .81,PH
3.0 to 5.0), and in particular the reaction retardant composition is P2O
5/Na2O=3.00-1.90 (PH3.5-4.
5). This binder is uniformly dispersed when mixed with purified water, but as it is stored at room temperature, it reacts slightly and the binding effect decreases. Therefore, it is desirable to use the kneaded material kneaded with this binder for a short period of time. In reality, the timing between kneading and use is important. For long-term storage, knead with purified water without kneading the binder.
It is desirable to re-knead with the binder before use. By doing so, it can be stored for a long period of time. Note that the kneaded material made of the binder can be used as a ramming material (stamp), and hardens when rammed with an air rammer or bipro lammer and dried and dehydrated. An amorphous spinel refractory material using a water-soluble aluminum/sodium phosphate binder does not absorb moisture at room temperature after drying (100 to 130°C) and dehydration.

Furthermore, heating increases the tissue strength. Furthermore, the dry dehydrated area is amorphous and remains in the tissue as sodium phosphate in the intermediate temperature range. In particular, the melt reaction of sodium phosphate densifies the structure and improves properties. On the other hand, the reason why natural alumina/silica-based raw materials are added in the form of ultrafine particles is that, as mentioned above, spinel minerals) (Mg, Al2O4) and silicic acid (
In addition to reacting with SiO2 to produce cordierite mineral, phosphoric acid and alumina react to produce high melting point aluminum phosphate.

Further, the purpose of adding SiC is to improve spall resistance. However, in a high temperature oxidizing atmosphere, SiC decomposes to produce silicic acid. In amorphous spinel refractory materials,
Spinel materials obtained by secondary addition of natural alumina-silica raw materials experience increased heat shrinkage and corrosion as the amount of silicic acid increases. Therefore, the silicic acid content is 1%
Appropriately within When unfired spinel refractory furnace material with a water-soluble aluminum/sodium phosphate binder is used as a ladle lining for iron making or steelmaking, the binder is aluminum phosphate or sodium phosphate at the operating temperature. It remains in the refractory structure as a.

The refractory material itself is slightly eroded and has a low phosphoric acid content. Further, it is considered that the phosphoric acid compound remains in the slag and remains inside, and has almost no effect on the steel. Silica in the slag also reacts with spinel minerals to produce cordierite minerals. As a result, the refractory furnace material according to the present invention is considered to be a refractory furnace material that has a steel cleaning effect because of the effect of reducing silica inclusions and the small melting loss. Next, embodiments of the present invention will be described.

Example 1 Super*8 fine particles of natural alumina-silica-based raw materials such as sillimanite, kyanite, and plastic fireclay were added to a sintered spinel clinker, and
A liquid binder (P2O, /Na2O=2.09,
PH4.0): 80 parts by weight, purified water: 2 parts by weight. Add 5 to 6% of the dilute solution and knead. After storing at room temperature for 7 days, add 4 to 5% of purified water, knead again, and pour. After vibration molding, it was dried (110°C) and dehydrated.

Characteristics of the thus obtained amorphous spinel refractory furnace material,
Table 1 shows the chemical composition and physical property values when heated at each temperature. Table 1 shows that the castable monolithic spinel refractory furnace material made with a liquid aluminum/sodium phosphate binder has slightly inferior physical properties compared to the unfired spinel brick made with the same binder, but compared to the current slinger mass brick. It is clear that the physical properties are good. Table 2 shows examples of the quality of Sringamas bricks.

Example 2 Sintered spinel clinker with natural alumina-silica raw materials sillimanite (sillimanite), kyanite (kyanite), plastic fireclay, and viscous Si
Ultrafine particles of C were added and mixed, and to this mixture was added a binder (P.O=,
/Na. O = 2.09, PH 4.0): 80 parts by weight, purified water: 2 parts by weight, add 5 to 6% of the dilute solution and knead, and after storing at room temperature for 7 days, add 5 to 6% of purified water. After re-kneading, casting and vibration molding, the mixture was dried (110°C) and dehydrated. Table 3 shows the characteristics, chemical composition, and physical property values of the thus obtained amorphous spinel refractory furnace material when heated at various temperatures. Table 3 shows that the castable amorphous spinel refractory furnace material made with a liquid aluminum/sodium phosphate binder has slightly inferior physical properties compared to the unfired spinel brick made with the same type of binder, but compared to the current slinger mass brick. It is clear that the physical properties are good. As explained above, in the present invention, it is possible to obtain an amorphous spinel refractory furnace material for pouring, which has erosion resistance and thermal shock resistance and is excellent in handleability.

[Brief explanation of the drawing]

FIGS. 1A to 1C and FIGS. 2A to 2C are diagrams showing the characteristics of an amorphous spinel refractory furnace material for pouring using a specific liquid aluminum/sodium phosphate binder, respectively.

Claims (1)

[Claims] 1. A material consisting of a magnesia/alumina clinker, a single natural alumina/silica raw material or a natural alumina/silica raw material, and SiC, the silicic acid content of which is within 10% by weight, and P_2O_5 /Na_2O=3.
50 to 1.81 and a pH of 3.0 to 5.0, a liquid aluminum/sodium phosphate binder and water are kneaded. 2. A material consisting of magnesia/alumina clinker, a single natural alumina/silica raw material or a natural alumina/silica raw material and SiC, the silicic acid content of which is within 10% by weight, is kneaded with water, and thus At least P_2O_5/Na is added to the obtained kneaded product at the time of use.
_2O=3.50-1.81 and PH3.0-5.0
A method for producing an amorphous spinel refractory furnace material for pouring, which comprises kneading a liquid aluminum/sodium phosphate binder.