US1906557A - Furnace lining - Google Patents

Description

May 2, 1933. (3 Dr EVANS 1,906,557

FURNACE LINING Original Filed March 14 1928 FIG. I.

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f This invention relates "to 'furnaees and more particularly to furnace linings anda methodfof forming the same. H I

- This application is a division of my conding application Serial No. 261,497, filed arch 14, 1928, for Furnace lining.

' This invention may be applied specifically" to refining furnaces; for example furnaces h furnaces used in the refining of copper. Sue are commonly constructed with, their. inner walls of magnesite, brick, which becomes worn during use as't heresult of the chemical action of the charge and of the mechanical forcesres'ulting from-the great temperature range to which a furnace of this type is sub jected.= The invention rovides a lining which may be applied tot e face of the magnesite brick and will serve as a protection therefor, both against the chemical action of the charge and against the intense heat of the interior of the furnace.

In accordance with the present invention a coating of protective materials is applied to the face of the magnesite brick and caused to be impregnated therein. This coating is gradually applied while the charge is being withdrawn fromthe furnace and while parts of the charge still adhere to the walls. a

The invention also consists in certain new and original features of construction and combinations of parts hereinafter set forth and claimed.

Although the novel features which are be-. lieved to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of its operation and the manner of its organization theretoin accordance with the'present in-v vention;

Fi 2 is an enlarged detail view showing the lining and illustrating the bonding action between the lining and the wall; 'and Fig. 3 is an enlarged detail view showing the liningabuilt up. substantial-.lthi'ck in the several: figures of thedraw-ing.

In the following description and in the claims parts will be identified ,by specific names for convenience,but they are intended to beas generic in their applicationto sim ilar parts as the art will rmit; v.

Referring tothe drawlng more in detail-,-

the invention is shown as applied to-a furnace comprising-an archland a pair of side walls 2, which may be formed ofany suit;

ablev material, as, for examplesilica, or

magnesite brick. Suitable=doors,l3 are prosuitable material, vsuch as brick or burned-in .10

quartz.

- Like reference characters denote like parts n.,, Y.. a jcoaroaanon or new In the operation of a furnace ofthis'type, 1n the refining of copper, a bath of moltencopper is maintained at an elevation slightly below the bottom of doors 3 until the desired metallurgical reactions have taken place.

The charge is then tapped for subsequent treatment and the operation repeated with ated as above the molten copper adheres to v the walls and entersinto the bricks themselves, which become impregnated to .a substantial depth. The copper becomes oxidized, due to-the stron ly oxidizing conditions maintained in the urnace, and forms tenoriteandcuprite. 1 w

The present inventiongtakes advantage of the above mentioned coppercoating' an uti-' lizes-the same for forming a protectlvecoverin over the furnace walls.

This is aceom-;'

plished by forcing finely divided silica against the furnace walls while the charge is being withdrawn. 7 The 'silicatadheres' to the film of molten copper and becomes firmly embedded'thereimwhile the heat of the fur nace changes substantial amounts ofthesilica to tridymlte, in. which. form 'it is stable-between the temperatures of-870 and-1470"C. 'The'silica is=sprayed, or otherwise thrown upon the walls just above the moltenbath as the charge is withdrawn until substantially the entire surface of the wall has been covered by the protective coating. The operation is repeated for subsequent char es and the coating 5 built up to the desire thickness due to the bonding action of the molten copper. A homogeneous mass of the composition above mentioned is obtained, which may be made to cover the entire inner wall of the furnace and prevent the magnesite brick from becoming worn. It has been found in practice that the life of a brick when used in a furnace wall, as above mentioned, is materially increased, thereby increasingthe total time during which a furnace may be operated and decreasing the maintenance charge.

Although applicant is not aware of the exact nature of the changes undergone by the various elements in carrying on this process, it is believed to take place in two stages, namely the silicious material is firmly bond-- ed to the magnesite brick and enters into the interior thereof, while successive layers or accumulations of this material are bonded upon the previous layers. This is though to be accomplished by an assimilation of silica in the copper oxide with which the magnesite brick'or the silica material is impregnated. Analysis of the furnace lining has revealed, however, that definite quantities of cuprite, tenorite,tridymite and quartz are present. The amount of metallic copper remaining is comparatively small, since under furnace conditions the above mentioned oxides have been formed. Because of the hi h temperature the quartz grains have been highly fractured and have been largely converted into tridymite.

. 7 It is obvious that a lining formed as above provides a strong protective coating for the furnace walls in the form of a single uniform mass. A copper refining furnace having a magnesite brick lining has been described for purposes of illustration. It is to be understood, however, that the invention is not limited thereto but may be applied to other furnaces and to other lining materials.

While certain novel features of the invention have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. The method of forming a furnace lining which comprises impregnating'thefurnace walls wit molten copper, subjecting the interior of the furnace to oxidizing conditions whereby said copper is partially converted to copper oxides, adding finely divided silica to the molten copper and copper oxides whereby the silica becomes bonded in a matrix of said oxides and repeating said operation until a coating of substantial thickness has been built up.

2. In lining furnaces the improvement that comprises establishing a bath of molten copper within the furnace to be lined, tapping the molten co per from said furnace whereby a layer 0 co per adheres to the furnace walls and app ying finely divided silica to said layer of copper while same is in a molten condition whereby a protective lining is formed.

3. The method of operating a furnace in the refining of copper, which comprises forming a bath of molten copper within said furnace, gradually withdrawing the bath therefrom, whereby a film of copper remains on the furnace walls, and forcing against said film while still in a molten condition a quantity of finely divided silica, whereby said silica becomes firmly embedded therein and forms a protective coating for said walls.

4. The improved method of lining a metallurgical furnace having magnesite brick walls which comprises applying silica to said walls in the presence of molten copper and copper oxides whereby a protective lin ing is formed on said magnesite brick.

In testimony whereof I have hereunto set my hand and seal.

GEORGE DAVID EVANS.

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