Compositions: ceramic – Ceramic compositions – Refractory
Patent
1992-12-21
1994-05-10
Klemanski, Helene
Compositions: ceramic
Ceramic compositions
Refractory
501154, C04B 3516
Patent
active
053107080
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The present invention relates to a method of producing silica brick and, more particularly, to a method of producing a silica brick which can suitably be used in building up or repairing various industrial furnaces such as a coke oven, hot blast stove and glass kiln.
2. Background Art
Silica brick is a very important material which is used as refractory for building up and repairing industrial furnaces, mainly coke ovens, hot blast stoves and glass kilns. It is well known that silica, which is the main component of siliceous stone as the principal material of silica brick, is changed into cristobalite and tridymite due to crystalline transformation in the course of firing for production of the silica brick. Any silica brick having large non-transformed silica content is undesirable because it exhibits extraordinary expansion so as to impair stability of industrial furnace which employs such brick as the refractory. Therefore, the extent of transformation of silica is one of very important factors which have to be considered in designing an industrial furnace in regard to selection of material and evaluation of adequateness of the use of the selected material.
As is well known, an ordinary process for producing a silica brick employs the steps of pulverizing a silica material such as red-white silica or blue-white silica into particles of a suitable level of particle size and mixing such particles with lime (CaO) which is an additive effective also as a binder.
A silica brick for use as a material of glass kiln is also known which contains for the purpose of preventing generation of frost-like matter on the brick surface of upper structure of glass melting cell, 0 to 1.5% of CaO, 0.3 to 1.5% of K.sub.2 O, the sum of the CaO and K.sub.2 O contents being not more than 1.5%. (Japanese Patent Publication NO. 49-16087). It has been attempted also to further add elements such as Fe, Fe.sub.2 O.sub.3, Cu.sub.2 O, TiO.sub.2, Si and so forth.
The degree of ease of transformation of silica in silica material into cristobalite and tridymite caused by heating tends to be affected by factors such as the crystal grain size of silica and impurities in the siliceous stone material, and varies also according to the place where the siliceous stone material is yielded.
In general, greater crystal grain size of silica, as well as smaller impurity content, tends to hamper the transformation of silica.
Hitherto, there has been no proposal in regard to any additive which promotes transformation of silica in silica material with which transformation of silica is not easy, and any method of producing silica brick by using such additive.
DISCLOSURE OF THE INVENTION
The present invention has been accomplished in view of the above-described problems of the prior art, and is aimed at providing a method which can make silica brick with small residual silica content by a process similar to a conventional method with same degrees of ease and efficiency as those in the conventional process, even from a siliceous stone material with which transformation of silica is not easy.
The invention provides a method of producing a silica brick by firing siliceous stone containing silica as the main component, characterized by adding 0.2 to 5 wt % of Na.sub.2 O--CaO--SiO.sub.2 fused and solidified material to the siliceous stone.
Preferably, the siliceous stone material contains 97.5 wt % of SiO.sub.2. Substances which may be contained in the siliceous stone, besides SiO.sub.2, are Al.sub.2 O.sub.3, Fe.sub.2 O.sub.3, CaO, MgO, Na.sub.2 O and K.sub.2 O.
Na.sub.2 O--CaO--SiO.sub.2 fused and solidified material promptly reacts with silica which is the main component of siliceous stone and promotes transformation of silica into cristobalite and tridymite.
According to the method of the present invention, it is possible to reduce the content of residual silica in siliceous stone to 1 wt % or less. The Best Mode for Carrying Out the Invention
The Na.sub.2 O--CaO--SiO.sub.2 fused and solidified material used in the present
REFERENCES:
patent: 258661 (1882-05-01), Martin
patent: 982252 (1911-01-01), Collins
patent: 2066366 (1937-01-01), Salmang et al.
patent: 3144345 (1964-08-01), McCreight
patent: 3660123 (1972-05-01), Smith
patent: 4143104 (1979-03-01), Konijnenburg et al.
patent: 4230498 (1980-10-01), Rueckl
PCT International Search Report Sep. 1992.
Akahori Shushi
Harako Hisayuki
Klemanski Helene
Sample David R.
Shinagawa Refractories Co. Ltd.
LandOfFree
Method of producing silica brick does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of producing silica brick, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of producing silica brick will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2412285