Carbon-containing refractory and process for producing the same

Details Carbon-containing refractory and process for producing the same Carbon-containing refractory and process for producing the same

1997-08-12

2000-10-24

Fiorilla, Christopher A.

Compositions

Solids with solution or dispersion aids

264 291, 264 295, 264239, 264299, 501 94, 501 99, B01F 300, C09K 300

Patent

active

061362271

DESCRIPTION:

BRIEF SUMMARY
FIELD OF THE INVENTION

This invention relates to a carbon-containing refractory and a process for producing the same. More particularly, it relates to a carbon-containing refractory which gives off little decomposition gas (offensive decomposition gas) and are excellent in spalling resistance, kneading properties, and molding properties and to a process for producing the same.


BACKGROUND OF THE INVENTION

A phenolic resin has been widely used for mixing in the kneading of carbon-containing bricks. A phenolic resin used as a binder in kneading a mixture containing carbon, such as graphite, exhibits excellent properties in kneading and molding and a high residual carbon on calcination.
However, use of a phenolic resin involves the following drawbacks or problems.
Firstly, a phenolic resin gives off decomposition gases, such as water, hydrogen, ethylene, phenol, cresol, and xylenol, when carbonized in a temperature range of from 350.degree. C. to 650.degree. C. Of these components, in particular, phenol, cresol, and xylenol cause odor. For example, carbon-containing unburned bricks for use as a furnace lining material are generally supplied as a product after only a drying treatment at about 200.degree. C., laid to form the inner wall of a furnace, and preheated to about 1000.degree. C. before actual use. In the preheating treatment, the phenolic resin decomposes to generate decomposition gas, which is discharged out of the furnace to cause air pollution and odor, etc.
Secondly, where a phenolic resin is used as a binder, the resulting structure is dense and has insufficient open cells because of the excellent molding properties of the phenolic resin. Therefore, the structure is liable to destruction due to evolution of decomposition gas on heating. That is, the brick after hardening by drying has a structure with fewer open cells and little air permeability. Such a structure, while contributing to improvement in brick strength after drying, hinders escape of gas generated by decomposition of the phenolic resin at temperatures higher than the drying and hardening temperature. It follows that the internal pressure increases, leading to destruction of the structure or cracking. This phenomenon becomes more conspicuous as the rate of temperature rise increases or the size of the brick increases. In order to prevent the phenomenon it is necessary to strictly control the rate of temperature rise until the temperature reaches a range in which the phenolic resin no more generates decomposition gas. In the case of unburned bricks, however, since the heat treating temperature for obtaining a product is generally from 200.degree. C. to 300.degree. C., it is difficult to have decomposition gas completely removed before the bricks are supplied as a product. In the production of carbon-containing burned bricks, too, strict temperature control in the drying and burning steps involves many technical and economical problems.
Thirdly, carbon produced from a phenolic resin is glassy carbon inferior in resistance to spalling. That is, where carbon-containing bricks are produced by using a phenolic resin as a binder, although the phenolic resin has a high residual carbon on burning, the resulting products have poor spalling resistance.
Therefore, use of a phenolic resin is not preferred in the production of carbon-containing bricks which are required to have spalling resistance, and carbon-containing bricks which do not use a phenolic resin have been sought. Pitch-bonded type bricks using pitch as a binder are known to meet the demand. However, pitch-bonded carbon-containing bricks, while excellent in spalling resistance, are disadvantageous in that pitch, which is solid at ordinary temperatures, must be heated above the softening point and kneaded (i.e., heat kneading). Besides, pitch is inferior to a phenolic resin in kneading properties and molding properties.
A process comprising uniformly mixing a refractory matrix material and fine powder of a carbon element, such as carbon black, together with an aqueous solution or su

REFERENCES:
patent: 4028186 (1977-06-01), Sakai
patent: 4552852 (1985-11-01), Manning
Database WPI, Week 8410, Derwent Publications Ltd., London, GB, AN 84-059839 (Abstract of JP 59 018173 A, Jan. 30, 1984).

Affiliated with

Also associated with

Rating

Carbon-containing refractory and process for producing the same does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Carbon-containing refractory and process for producing the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Carbon-containing refractory and process for producing the same will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1960241