Compositions: ceramic – Ceramic compositions – Refractory
Patent
1986-10-20
1988-12-06
Capella, Steven
Compositions: ceramic
Ceramic compositions
Refractory
501 94, 501122, 501133, 501146, C04B 3502
Patent
active
047896523
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a basic refractory such as unburned bricks, gunning materials, trowelling materials, and castable materials for steel-making containers such as electric furnaces, converters, ladles, and tundishes.
TECHNICAL BACKGROUND
Various types of chemical binders are used in basic unburned bricks and various types of basic castable refractories. Namely, well-known chemical binders such as organic binders such as tar, pitch, and phenol resins, and magnesium sulfate, alkali phosphates, alkali earth metal phosphates, alkali silicates, alkali borates, alumina cement, and the like are used. These chemical binders play a very important roll, increasing the binding power of the refractory, making the refractory easy to apply, and the like.
However, there are various problems with refractories employing the above-described chemical binders. Namely, when refractories employing organic chemical binders such as phenol resins, tar, pitch, and the like are used in an oxidizing atmosphere, combustion of carbon takes place, the texture deteriorates, and there is the drawback that adequate durability can not be obtained. Furthermore, with refractories using magnesium sulfate, various types of phosphates, and alkali borates, there is the fear of molten steel being contaminated by the phosphorus, sulfur, boron, and the like contained in the chemical binder. In addition, the hot strength of a basic refractory employing alumina cement or alkali silicate is low, the damage from wear by molten steel and the like is large, and the fire resistance is inadequate.
DISCLOSURE OF THE INVENTION
This invention was made in order to solve the above-described problems, and its object resides in the provision of a basic unburned brick or castable refractory which contains none or only an extremely small amount of components such as phosphorus, sulfur, and boron which exert a harmful influence on molten steel and which has a high hot strength.
The object of the present invention resides in the provision of a basic refractory composition characterized by containing 100 parts by weight of one or two or more basic aggregates selected from the group consisting of magnesia clinker, dolomite clinker, lime clinker, limestone, dolomite stone, calcium hydroxide, and brick scraps, and 0.1-30 parts by weight as of modified sodium silicate made from acidic china clay calculated as a powder, or 0.1-30 parts by weight as of said modified sodium silicate calculated as a powder and 0.01-10 parts by weight as of a curing agent for said modified sodium silicate, the resulting basic refractory containing at least 1% CaO, and ##EQU1##
By utilizing various types of basic aggregates together with modified sodium silicate made from acidic china clay, the present inventors were able to obtain a basic refractory containing no components which are harmful to steel and having a high hot strength.
The present invention can be used in basic unburned bricks and castable refractories such as stamping materials, gunning materials, trowelling materials, and castable materials, and it is a basic refractory composition to which can be admixed a plasticizer or a curing agent for modified sodium silicate, or both, depending on which of the above-mentioned applications it is used for.
The present inventors discovered that as a result of the above-mentioned admixture, a high hot strength which can not be obtained with a conventional sodium silicate-containing refractory and which is equal to that of a phosphate bond-containing refractory can be achieved.
In particular, among the above-mentioned basic aggregates, those aggregates containing CaO react with modified sodium silicate, and as a result a high hot strength is obtained. It is thought that the reason for this is that the CaO content of the basic aggregate reacts with the SiO.sub.2 in the modified sodium silicate, and at high temperatures the compounds 2CaO.SiO.sub.2 or 3CaO.SiO.sub.2 are formed. It is thought that conventional sodium silicate produces the same sort of reaction, but ev
REFERENCES:
patent: 2568237 (1951-09-01), Lathe
patent: 3656977 (1972-04-01), Dreyling et al.
Ichikawa Kenji
Morita Akihiro
Nakamura Ryosuke
Sugimoto Hiroyuki
Capella Steven
Shinagawa Refractories Co. Ltd.
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