US1658406A - Assighoe - Google Patents

Description

Patented Feb. 7, 1928.

UNITED STATES masses PATENT n mes.

WILLIAM A. FARISH, F BUFFALO, NEW YORK, ASSIGNOR 1'0 BUFFALO REFRAOTURY CORPORATION, OF BUFFALO, NEW YORK, A CORFORATION OF DELA'WARE.

METHOD OF MAKING REFRACTORY ZRODUGTS AND ARTICLES BODU$ED TI-IEBZEBY.

N 0 Drawing.

The general object of this invention is to provide a simple and effective method of forming refractory products in such a Way as to make them durable and prevent cracking,

5 disintegration, corrosion, and oxidization.

Moreover, my object has been to provide a method which can be asily and cheaply performed, and one which will make it unnecessary to raise the temperature to which the composition is subjected above that of recrystallization.

By using the method of my invention, I am able to create a product, which resists chemical action and which greatly increases the life of articlesmade in accordance with my invention.

By means of my method any heat resisting articles may be made such as crucibles, firebricks, retorts, furnace cores, tubes, furnace 2 linings, combustion boats, heat resisting cements, and any other form of product, which is subjected to very high temperatures.

In describing my method, it is to be understood that the exact proportions of elements entering into the composition and the exact sequence of steps performed in following the invention are only preferably stated and some modifications may be used which will attain the desired objects without departing from the spirit of the invention as herein disclosed.

In general, I first make a dry mixture of graphite, and a suitable electric furnace refractory product with or without a suitable solid fluxing agent. This compound is thoroughly mixed. Then a suitable carbonizing binder is added and the mixture is thoroughly impregnated with it until all of the ingredients of the compound have been intimately mixed together. Then I mold this compound in any suitable way and under any suitable pressure. The compound is then placed in a carbonizing kiln, and subjected to a temperature which will thoroughly carbonize it. While the compound, so carbonized, is still warm, it is dipped into a liquid fluxing agent. After being dipped it is subjected to a hightemperature in a suitable annealing furnace.

Preferably in the dry mixture, I employ about 17% of graphite; about 12% of silica, and about 71%of silicon-carbide. While these are the preferable proportions of the elements of this dry mixture, still it is to be Application filed August 31, 1922, Serial No. 585,522.

understood that for some purposes a satisfactory product may be obtained by employing a maximum of 55% and a minimum of 10% of graphite in such mixture; a maximum of and a minimum of 5% of the fluxing agent; and a maximum of 75% and a minimum of 20% silicon-carbide.

For the solid fluxing agent feldspar or some other suitable agentmay'be employed. In place of the silicon-carbide any electric furnace refractory product such as fused magnesite, fused aluminum oxide, or fused silica may be used With satisfactory results. In such cases the proportions as to maximums and minimums of these substitute elements will be substantially as hereinbefore stated.

For the carbonizing binder, molasses, pitch or tar may be employed. If molases is employed, I preferably use about 15%, but a maximum of 40% and a minimum of 10% of this binder may be advantageously used. If pitch is employed, the preferable amount is about 20% but a maximum of or a minimum of 8% may be advantageously used. If tar is used, the preferable amount should be about 15% but a maximum of 40% and a minimum of 10% can be advantageously used. It is to be understood that molasses, tar and pitch are only examples of suitable carbonizing binders, and that other carbonizing binders than those named can be advantageously used within the limits of maximums and minimums above set forth.

After removing the product from the carbonizing kiln, it is dipped, preferably while it is Warm, into a liquid fluxing agent, such as sodium borate or sodium silicate.

After being dipped the product is placed in an annealing furnace, and is preferably subjected to a heat of substantially 1200 F.

In carrying out my invention as hereinbefore described, I have found that the products formed and treated according to my disv closure will withstand extremely high temperatures and rough handling Without material damage.

Having thus described my invention what I claim is: i

1. A method of making refractory prod ucts' comprising forming an intimate dry i'nixture of graphite, and an electric furnace refractory product, then intimately impregnating such dry mixture with a carbonizing binder, then forming the product, then carhonizing the product, and then dipping the product into a liquid fiuxing agent.

2. A method of making refractory proclucts comprising forming an intimate dry mixture of graphite, a solid fluxing agent, and an electric furnace refractory product, then intimately impregnating such dry mixture With a carbonizing binder, then form ing the product, thencarbonizing the products, and then dipping the product into a liquid flaring agent.

Amethod of making refractory prodriots-comprising forming an intimate dry mixture of graphite, and an electric furnace refractor" "rocl-uct then intimatel im re i .Y a a qu'ant-ity of carbon-iz-ing 'hinder'equal to substantially 15% of the dry mixture, "t lien' forming the product, then 'carbonizing "s'uch product, andthendipping the product into a'li'q-ui'd flu xing agent.

A'ineth'od'ofmaliing refractory prod- -iict s'comprising the' formation of an intimate dry mixture of substantially 17% of graphite,substantially 12% of a suitable solid -firming agent, and substantially 71% of an -electrlc furnace refractory product, their int mately llilXlIlg With the dry mixture "a? quantity of carbonizing binder equal to "substantially 15% ofthedry mixturethen form-ingthe "product, then carbonizing. such product, and then dipp ng the product,

with ile still W'arm, into a saturated solution of 6. A method of making refractory prod ucts comprising the formation of an intimate dryinixture of substantially 17% "of graphite,- substantially 12% of a suitable solid fluxin' a entand substantiall 71% of an electric furnace refractory product, then intimately mixing With the dry mixture a quantity-of carbonizing binder equal to substantially 15% of the dry mixture, then forming the product, then carbonizing such product, then dipping the product into a liquld fluxm'g agent, and then subgectingthe product to heat 111 an annealing furnace.

P" a L L-A methodoiunakrng re'iractory prod- "ucts comprising the formation of an inti- "inate'dry mixture of substantially 17% of graphite; substantially 12% of a suitable 's'olidfhirzing agent, and substantially 7l% of an electric furnace refractory product, then intimately mixing with the dry mixture a quantity of carbonizing binder equal to substantially 15% of the dry mixture, then forming the product, then carbonizing such product, then dipping the product into a liquid luring agent, and then subjecting such product to a heat of substantially 1200 F. in a suitable annealing furnace.

8. A method of making refractory products comprising the formation of an intimate dry mixture "of not more than 55% and not less than "10% of graphite, and notmore than 75% and not'less than 20% of anelectric furnace refractory product, thenintimately mixing With the-dry mixture a-quantity of carbonizingibinder equal to n'ot'injore than 50% and not'l'ess than 8%"0f the dry mint ure, then forming the product, then carhonizing such product; and then dipping such productinto a suitable liquidi'iiuxing agent. v

9. A method of making, refractory products comprising the formation of an intimate dry mixture of not m'ore 'than 55% and not less than 10% of graphite, not more "than 25% and not less than 5% of asuitablesolid flaring agent, and not more than 75%and not less than'20% of an electric furna'ce'refractory product, then intimately mixing with the dry mixture a quant'ityfof "carbon izing binder equal to notmore"thani'50% and not less than 8% ofthe'dry 'mixtur'e, then forming the product, then carbonizing such product, and then 'dippingsuch product into a's'uitahle liquid fiuxing agent.

10. A method of making refractory products con'iprising theformationof an intimate dry mixture of not more th'an"55%and"not less than 10% ofgraphite, not more than 25% and not-less than 5% of asuitablelsoiid fiuxing agent, and not morethan""75% and not less than "20% "of an electric furnace 'refractory product, then intimately"mixing with the dry "mixture a quantity ofcarbonizing hinder equal tonot 1nore"tnan5O% and not less than"8% of the 'dry mixture, then ca'rhonizing such product, then forming the product, then dipping such product into, a suitable liquid agent, and then subjecting such product to heat in asuitable annealing furnace.

11. A method'of making refractory products comprising the formation of an intimate dry mixture of not more than 55% and not less than 10% of graphite, not more than 25% and not less than 5% of a suitable Solid fluxing agent, and not more't-han 75% and not less than'20% of an electric furnace refractory product, then intimately, mixing with the dry mixture a quantity ofcarboniz- 'ing binder equal tonothior than 50%'and not less than 8% of the dry ,inixture, then forming the product, then carbonizing such product, then dipping such product, While still Warm, into a suitable liquid fluxing salt, and then subjecting the product to a temperature of substantially 1200 F. in a suitable annealing furnace.

12. A dense hard refractory graphitic article of manufacture having a body bond and a continuous glaze of non-ceramic mate rial and of the same coefficient of expansion and other physical characteristics.

13. In the art of making graphitic refractory articles containing a refractory the improvement Which consists in diffusing silicon throughout the pores of the article by incorporation and heating, converting the diffused silicon into silicate by treating the article With an alkali, and exuding the silicate to the surface of the article by the application of heat.

In testimony whereof, I have hereunto signed my name.

WILLIAM A. FARISH.