JPS6146428B2 - - Google Patents

Description

[Detailed description of the invention]

Conventional carbonaceous refractories have excellent characteristics such as corrosion resistance, abrasion resistance, alkali resistance, and high thermal conductivity. It has poor fluidity and requires high molding pressure and a large amount of solvent, and a large press is required to mold shaped refractories.
In the case of monolithic refractories such as gutter materials and ramming materials, high molding pressure must be used, making the work difficult. The present invention provides a method for producing refractories for smelting mainly composed of carbonaceous materials, without using aggregates such as alumina, magnesia, zircon, and silica stone, or using only a small amount of aggregates, as described above. The purpose is to solve this problem. Carbon black, pitch, and other carbonaceous materials are first granulated into microspheres, and then resin varnish is added and kneaded to improve the fluidity during molding. By obtaining a good refractory, it is possible to mold carbonaceous refractories with low molding pressure. In other words, carbon beads have a smooth surface, have a uniform particle size, and air is evenly mixed in, so they have excellent fluidity. Therefore, if they are used in place of carbon black, they will be easier to use during pressure molding. Since no bridges are formed, low-pressure molding is possible, and since the surface area can be reduced, large amounts of binders and solvents are not required, thus improving the high-temperature properties of the resulting refractory and reducing material costs. It can be done. The method of the present invention will be explained in further detail by the examples shown in Table 1. The carbon beads used in this example are commercially available under the trade name "Crecas Sphere", and are made into fine particles by adding a dispersant to a highly viscous pitch, dispersing them into fine particles, and instantaneously heating them with a flash dryer. It is made by granulating into spherical shapes and then heating and carbonizing them at high temperatures. The test method was to knead the various compounds listed in Table 1 at room temperature, and
65×114× by hydraulic press with molding pressure of Kg/ ^cm2
It was molded into a shape of 230 mm, heated at 100°C for 5 hours, and then baked at 300°C for 10 hours. The baked test piece was then coated with coke,
It was baked at 1200°C for 3 hours. For the corrosion resistance test, each test piece was cut into a bar shape of 25 x 25 x 200 mm.
The specimens were immersed in an erosive agent (blast furnace slag) at 1550°C for 3 hours, cooled after the reaction, and evaluated by comparing the dimensions of the damage.

[Table] The results of testing under the same conditions using graphite with the same particle size as the carbon beads used in this example are shown as a reference example, but the beads are usually molded at a higher molding pressure. As is clear from a comparison between Example 1 and the reference example, the carbonaceous refractories produced by the method of the present invention exhibit superior properties to those made of 100% graphite. This shows that it has good fluidity and a much lower porosity than graphite powder of the same particle size. Examples 2 and 3 show that when a small amount of graphite powder or aggregate is added to carbon beads, the porosity is further improved and dense particles can be obtained. The corrosion resistance in the high temperature range is extremely good, and the compressive strength after firing of Examples 2 and 3 is significantly improved compared to Example 1. In the method of the present invention, a small amount of graphite or This shows that mixing aggregate is extremely effective in improving high temperature properties. As described above, according to the method of the present invention, carbonaceous refractories, which have conventionally been difficult to be formed at low pressure, can be formed at low pressure by first granulating the carbonaceous material into microspheres, and the method has particularly good high-temperature properties. Examples and reference examples have the advantage of providing a method for manufacturing carbonaceous refractories suitable for forming monolithic refractories, and since the material is spherical and has a small surface area, large amounts of binders and solvents are not required. It is clear from the comparison that, since it is spherical, it not only has good fluidity during molding as described above, but also has good filling properties with the monolithic refractory. In addition, the small surface area improves oxidation resistance, and since the surface is carbonaceous and smooth, it does not wet easily with hot metal, further improving corrosion resistance and wear resistance, and also has good mold release properties after hot metal solidification. There are advantages.

Claims (1)

[Claims] 1 Carbonaceous or carbon-containing materials such as carbon black, pitch, and phenolic resin are granulated into microspheres, and if they contain uncarbonized substances, they are heated and carbonized, and the resulting carbon spherules are injected with phenolic resin. A method for producing a refractory for iron making, which comprises adding a binder made of resin, kneading the mixture, and press-molding the mixture.