US2423898A

US2423898A - Refractory bottom for metallurgical furnaces

Info

Publication number: US2423898A
Application number: US522948A
Authority: US
Inventors: Mclain William Rex
Original assignee: Carnegie Illinois Steel Corp
Current assignee: Carnegie Illinois Steel Corp
Priority date: 1944-02-18
Filing date: 1944-02-18
Publication date: 1947-07-15
Anticipated expiration: 1964-07-15

Description

w. R. mum 2,423,898

REFRACTORY BOTTOI FOR IBTALLURGICAL FURNACES Filed Feb. 18, 1944 July 15', 1947.

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IV/um! P5X TTORNEY Patented July 15, 1947- REFRACTORY BOTTOM FOR METALLURGICAL FURNACES William lie: McLain, Chicago, Ill., assignor to Carnegie-Illinois Steel Corporation, a corporation of New Jersey Application February 18, 1944, Serial No. 522,948 I This invention relates to furnace bottoms, and particularly to an improved refractory bottom for the hearth of metallurgical furnaces, such as blast furnaces and the like.

The bottom for the hearth of blast furnaces and other similar metallurgical furnaces is made generally of standard brick shapes of fire clay,

usually rectangular parallelepipeds. In a blast furnace bottom, the brick work consistsgenerally of a plurality of courses of fire bricks which are disposed in staggered relation so as to provide a solid bottom from approximately 9 to 12' feet thick and from 25 to 30 feet in diameter. Heretofore, the brick work was usually installed by cutting or rounding the outer sides of'the outermost bricks next to the water cooled hearth jacket so that the same would fit tightly thereagainst. The hearth jacket is usually shaped like the frustum of a cone,v and thus considerable cutting of the outer bricks was necessary in order to obtain a good fit. It will be seen that such procedure was not only laborious but tedious and expensive.

Also, if the outer bricks of the bottom do not abut firmly against the water cooled jacket. the full cooling effect of the hearth jacket is .not realized because any air spaces between the outer bricks and the water cooled jacket are not good conductors of heat. In other words, in such a case the heat in the center of the. hearth was not transmitted rapidly enough to the water cooled jacket and the metal collects on the center of the bottom of the hearth tending to erode and replace the bricks therein with a solid mass of metal which is known as the salamander. Such a condition consequently makes the bottom of less depth and increases the danger of molten metal breakouts through the furnace bottom.

Accordingly, it is one of the objectsof the present invention to provide arr-improved refractory bottom for blast furnaces and the like wherein standard fire brick is used and cuttingof the outer sides of the outer bricks of the bottom is eliminated thereby reducing maintenance and replacement costs to aminimum. 4

It is another object of the invention to provide an improved refractory bottom for blast furnaces 2 Claims. (Cl. 266-43) and the like wherein the bottom is continuous from the center of the bottom to the water cooled jacket therearound thereby insuring an effective and rapid transmission of heat from the center of the bottom to the water cooled jacket so as to prevent the formation of an\ excessive salamander.

It is a further object of this invention to protom for blast furnaces and the like having a center portion of standard brick shapes and an outer portion adjacent the water cooled hearth jacket, of a relatively high heat conducting refractory rammed into place between the fire brick and the cooling jacket so as to entirely fill the space therebetween thereby eliminating any voids.

Various other objects and advantages of this invention will be more apparent in the course of the following specification and will be particularly pointed out in the appended claims.

In the accompanying drawings there is shown, for the purpose of illustration, an embodiment which my invention may assume in practice.

In these drawings:

Figure 1 is a vertical section through the hearth of a blast furnace showing the improved refractory bottom of my invention incorporated therewith; and

Figure 2 is a sectional view taken on line IIII of Figure 1.

Referring more particularly to the drawings, there is shown the lower portion of the hearth of a blast furnace comprising a bottom 2 and a side wall 3 having a water cooled jacket 4 circumferentially arranged therearound. The bottom 2 and the cooling jacket 4 rest preferably on a suitable concrete base 5 in a manner well known to those skilled in the art.

According to the present invention, the center portion of the bottom 2 consists of a plurality of courses of fire bricks 6 which are disposed in staggered relation so as to provide a solid center column of brick work. The fire bricks 6 are preferably standard brick-shapes, or brick shapes of fire clay. The brick work of the center portion fills substantially the space within the inner periphery of the water jacket 4, as shown in Figure 2 of the drawing. However, it will be seen there is disposed a refractory material I which fills entirely the space therebetween so as to eliminate any voids between the outer side of the column of brick work and the water Jacket. It isimportant that the refractory material used have terials are preferable so that the refractory will not flux the adjacent firebrick S; Refractories most suitable for use are graphite, amorphous carbon, coke, or any other highly carbonaceous material, or a combination thereof, mixed with up to approximately 97 per cent of a suitable bonding material, such as flre clay, bentonite, hot tar, or any other similar material or any of the organic bonds. Also, 'magnesite-cement, or magnesite clay mixtures are suitable refractories rammed into place.

It has been found that a mixture having good heat conducting properties and also'one which may be easily rammed into place, i. e., good workability. consists of approximately 40 per cent fire clay and 60 per cent graphite crushed to pass a 4 mesh U. 8. standard sieve. It has been found also that a mixture of one part of hot tar, six parts of graphite, or amorphous carbon, or coke, or other highly carbonaceous material, or a combination thereof provides a satisfactoryrefractory for such use. It is important that the amount of graphite in the mixture be sufiiciently high so that the mixture will have a coefllcient of heat.

conductivity at least equal to the fire clay brick 6. It will be understood that any combination of a refractory gregate and a bonding agent which will provide a relatively high coefllcient of heat conductivity equal to or greater than the standard fire brick 6 used for the center portion of the bottom and which will not flux therewith can be conveniently used in the practice of this invention.

When installing the bottom of the present invention, it will be understood that the bricks 6 are laid as in the standard practice except that enough space is provided between the center.column of brick work and the water cooled hearth jacket so-asto permit the pla insand ra in of the refractory material I therebetween. It is preferable that the refractory material be placed between the brick work and the cooling jacket after each course of brick work is laid. However, the refractory may be placed between the brick work and the cooling jacket after all of the courses of brick work have been laid, but under such circumstances it is necessary to insure that the refractory is properly rammed into place at all courses in the brick work so as to eliminate the danger of any spaces or voids being left between the brick work and the water jacket.

As a result of my invention, it will be seen that it is not necessary to cut the outer sides of the outermost bricks 6 so that they flt tightly and possess the characteristic ofbeingeaslly against the inner periphery of the water cooled jacket 4. In other words, standard brick shapes may be used, thus eliminating the cutting thereof. Also, it will be seen that by using the improved bottom of my invention, that the heat to which the center of the bottom is subjected will be rapidly transmitted from the brick work 8' through the refractory I to the water cooled Jacket 4 thereby tending to prevent the formation of an excessive salamander in the center portion of the furnace bottom.

While I have shown and described a specific I embodiment of my invention, it will be understood that this embodiment is merely for the purpose of illustration and description and that various other forms may be devised within the scope of my invention, as defined in the appended claims.

I claim:

1. A bottom for the hearth of blast furnaces and the like having a water cooled hearth jacket arranged therearound comprising a center portion made of a plurality of courses of fire brick, and an outer portion arranged between said fire brick and the water cooled jacket made of a refractory material which is rammed into place therebetween having a coefficient of heat conducitivity at least as great as that of the fire brick, aid refractory material adapted to transmit rapidly the intense heat to which the center portion of the bottom is subjected to the water cooled jacket, thereby tending to prevent the formation of a salamander in the bottom of the furnace.

2. A bottom for the hearth of blast furnaces having .a water-cooled jacket arranged therearound comprising a center portion made of a plurality of courses of fire brick, and an outer portion arranged between said fire brick and the water-cooled jacket made of a refractory material, which will not flux the fire brick at smelting temperatures, and which is rammed into place therebetween, said refractory material consisting of a finely crushed mixture of a bonding material such as fire clay and suificient carbonaceous material to provide a coefficient of heat conductivity at least as great as that of fire brick. whereby said refractory material will rapidly transmit heat away from said bricks thereby tending to prevent the formation of a salamander in the bottom of the furnace.

- WILLIAM REX McLAIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,256,179 Thomson Sept. 16, 1941 1,777,617 Jack Oct. 7, 1930