JPS6042184B2 - Manufacturing method for dense chromium oxide refractories - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing a dense chromium oxide resistant material,
In particular, the present invention relates to a method for producing a chromium oxide refractory suitable as a lining material for a glass melting furnace.

In general, chromium oxide has excellent corrosion resistance against highly corrosive molten glass such as borosilicate glass, but in order to use this chromium oxide as a lining material for glass melting furnaces, its properties must be made into a dense body. I can't perform to my full potential.

However, since chromium oxide itself has poor sinterability and there is no good sintering aid, the resulting refractory has a high porosity and cannot be put to practical use as the above-mentioned lining material. In view of this, the inventors of the present invention have conducted extensive research to eliminate the above-mentioned drawbacks, and have found that chromium oxide contains one or two types selected from manganese oxide, iron oxide, nickel oxide, and alkaline earth metal oxides. By adding a predetermined amount of sintering aid and firing, sinterability is significantly improved, and a dense chromium oxide refractory with low porosity and good corrosion resistance can be obtained, as well as large-sized refractories. We have discovered a method that makes it possible to manufacture The present invention will be explained in detail below.

First, one or more sintering aids selected from manganese oxide powder, iron oxide powder, nickel oxide powder, and alkaline earth metal oxide powder such as calcium oxide and barium oxide are added and mixed to chromium oxide powder. and use it as raw material.

Next, this raw material was granulated as necessary, a binder such as polyvinyl alcohol, carbonyl methyl cellulose, or thermosetting resin was added and kneaded, and the mixture was molded using a known molding method such as mold press or rubber press. Thereafter, this molded body is fired to produce a dense chromium oxide resistant material. The sintering aid used in the present invention is composed of one or more selected from manganese oxide powder, iron oxide powder, nickel oxide powder, and alkaline earth metal oxide powder, but especially manganese oxide powder, oxidized When iron powder, nickel oxide powder, and alkaline earth metal oxide powder are used together, the sinterability is further improved.
The precision can be significantly improved.

The reason why the amount of the sintering aid added in the present invention is limited to the above range is that if the amount added is less than 1% by weight, the desired effect of improving density cannot be sufficiently achieved. If the amount exceeds 1%, the corrosion-prone nature of the sintering aid becomes apparent, and the corrosion resistance of the obtained chromium oxide refractory decreases.

The firing temperature in the present invention may normally be in the range of 1,500 to 1,750°C.

Next, examples of the present invention will be described.

Examples 1 to 9 and Comparative Examples First, chromium oxide and one or more sintering aids selected from barium oxide, manganese oxide, nickel oxide, and iron oxide were mixed at various blending ratios shown in the table below. The raw materials obtained by blending [Examples 1 to 9] and the raw material consisting of a single component of 10 parts of chromium oxide [Comparative Example] were wet-pulverized and mixed for 3 hours in a rubber-lined pot mill, and then polyvinyl alcohol was added to these materials. After adding and kneading 7 parts by weight of the 3.5% solution, 10 types of molded bodies in the order of 50φ×5OH were molded using a rubber press under pressure conditions of 1000 k91 cIt.

Subsequently, these molded bodies were fired at a temperature of 1,700° C. for one hour to obtain a chromium oxide refractory of one size. Therefore, the dimensional change rate, apparent porosity, and bulk specific gravity of the chromium oxide refractories of Examples 1 to 9 and Comparative Example were investigated. Also,
These chromium oxide refractories are 20×20×20TnI! L
The erosion rate (volume reduction rate) was investigated using the so-called crucible immersion method (crucible AD-S method) in which the sample pieces were immersed in a borosilicate glass solution at 1400° C. for 10 C@. These results are shown in the table below. As is clear from the above table, the chromium oxide refractories obtained by the method of the present invention (Examples 1 to 9) have lower porosity and are denser than the chromium oxide refractories made of chromium oxide alone (comparative example). It can be seen that it has excellent corrosion resistance against borosilicate glass solution.

As described in detail above, according to the present invention, it is possible to obtain a dense chromium oxide resistant material that has low porosity and excellent corrosion resistance against highly corrosive molten glass such as borosilicate glass. It has become possible to manufacture shaped refractories, and has remarkable effects such as being able to be effectively used as a lining material for glass melting furnaces.

Claims (1)

[Claims] 1 After molding a raw material in which 1 to 10% by weight of one or more sintering aids selected from manganese oxide, iron oxide, nickel oxide, and alkaline earth metal oxides are added to chromium oxide, this molding is performed. A method for producing a dense chromium oxide resistant material, which comprises firing the body.