US2498904A - Apparatus for expanding slag - Google Patents

Description

Feb. 28, 1950 D. G. WHEELER APPARATUS FOR EXPANDING SLAGS 2 Sheets-Sheet 1 Filed April 15, 1948 Feb. 28, 1950 D. G. WHEELER APPARATUS FOR EXPANDING sues 2 Sheets-Sheet 2 Filed April 13, 1948 Patented Feb. 28, 1950 APPARATUSE'FQR EXPANDING- SLAG- Dee: Whe l r Chica 111., sien r to The (lclct x Corporation, ica o, 11L, acorpor tion.

fflle ware Application April: 13, 1948', SerialNo. 20,631

5. Cl im 1 This invention relatesto anew and improved apparatus for producinga; Slag; aggregate and in. particular the soecalledg expanded slag; aggregate, Such expanded slag; aggregate; is. usedin lieu of crushed rock, gravel, and the like, in; the preparation of: concrete to, provide light weight concreta. both monolithic and: shape term; thatis, as blocks or variousz'o her formed prod-.- ucts.

The, objects of this: inventiom are: to, provide a new animproved form; o apparatus for; use in expanding, slag for use as light Weight. slag segregate in particular, ta proizide suchan-v apparatus which is simple; in, operations, is rugged; and in which thereare notmovina p rts. involved in. he precedure of expand ng or cau ine' fi hg of he slag in. order hat he g: may be; ex-. panded to alight Weight; a

In, the drawings, wherein. like numerals; arev applied.- to. like parts in thevarious: figures,

Figure. 1, comprises. a se ction. taken on. line of Figure 2;

Figure-2 is a-sectiontalgen on. line 2! of Figure 1; and.

Figure 3. is a. section taken on line. 3-=3 of- Fig;- ure 1.

The. useof the apparatus disclosed herein. is not limited. to its use in expanding: slag from any particular source, but, in, general the most convenient: slag source is. the. steel: blast turn-ace, and for the purposes. hereoi the description and use of the apparatus will, be discussed: from the viewpoint oi apparatus for and production; of expanded slag from blast; furnace slag;., Other suitable slag-s of course, may bev used, as, for

example; slag from a. foundry 01111912. or slag from a. zinc smelter, or the like, or, some cases, suitahlerock and/or fluxes-may be. melted down and. then; expanded by the.- use of: the, ap-

paratus hereof fo providing expanded. a ate gate, that. is, one from What might. be termed a synthetic, slag.

The. apparatus. must. be, rugged and, capable, n particular, of standing up. under hightempeh atures, since slag froma blastiiurnacejis; usually pped off at atemperature or around. 2.40.0! and. due to. the conditions. to. which theapparatus is. subjected that. is, b.ecaus.e. of the. abrasive. con.- ditions, which exist with acccmrela g g tempera ures, it is substantially. imperative. hat he apparatus not, include, rotating parts requiring hearings. or close fit of any nature,

The device hereof. has no movin parts. and all, parts thereof may. readily be. construct d Of such. materials and: such. manner. that to. al

intents and purposes there is. nothing to wear out. due, to the abrasive and. high temperature, conditions, and thus the upkeepv and maintenance of the apparatus will be kept at, a minimum There is; provided, as part of the device, a slow movingconveyor which is provided at the bottom or the device for carry ng away the slag a r it is expanded, but this is, a; very' slow moving device and it ma readily" be designed so as to be; relatively unaffected by its (renditions. of operations, particularly so since this, conveyor is, not subjected; to. the extremely high temperature of; the molten slag, but is merely subjected to theI lower temperature of the somewhat. cQoled slag after it hasbeen expanded in the apparatus.

The apparatus comprises a suitable chamber constructed: of stone, brick, concrete, or-the like, and is;:0fa. considerable diameter with. the illustration, thereoii considered to. represent such con truction of: approximately 1Q feet in diameter'and. of a height or. about. 1.14: feet. This chamber or, rather, the; Walls-thereof are designailed on. the drawing; by; the numeral In; It is; o be un ersto d. f c.our.se,.. ha p ef r bly. at least the inner racing of: the walls of such construction are; composed of; suitable refractory material; which will Withstandi subjection to. high temperature, but as this is. merely a. matter of sel c ion well-wih n-thescope f; he knowl d of those skilled; in theart, there will be; no specific discussion of the particularnaa-terials to be used in the erection; of the walls to or the details of erection.

Breferably, and order that there may bea greater latitude intheselection of the materials comprising wall [,1]. inits' upper portion, there may beprovidedwithin, and as; a lining: therefor, an annular cooling chamber designed at. il Thechamber; as. willbe apparent f-rQm the illustration, is; preferably round. at thetop, that is, or circular outline. and i s lower par of a square outline. Itis not; critical asto; the exact point atwhi ch the shape, of the chamber should change from a. round shape to. asquare-1 Sh rpe, but for the purposes of construction it is. convenicnt. hat. just below the. lower water-cooled grid. 22. his. chan e occur, sothat he bafiles, eta. below this point may be fitted to. the rectangular shape rather than. involve dimculty were the c r ular, shape continued all. th way dowa.

It is no deemed ha any. detailed des r pt sv required. of. the wa er-cooled annular linin H, xcep t y a it i provided With; suit. ab e. coo ing, Wat r inl ts, a at. t. and. outlets,

as at M, or vice versa, depending on whether it is preferred to circulate the cooling water, respectively, downwardly or upwardly through the cooling chamber. The purpose is merely that of protecting the interior of the wall ID at its upper part from the high-temperature molten slag, and while a water-cooled chamber lining has been illustrated, it will be understood that there may be used in lieu thereof any suitable high-temperature refractory, and that the specific construction with respect to this feature is purely a matter of engineering design.

Located centrally of the structure, and slightly below the top thereof, there is provided what will be referred to as a target l2. Target 12 is shown as comprising a double-walled, watercooled basin having suitable piping connected thereto to support the structure and to provide for supplying cooling water thereto. The inlet and outlet for the cooling water which circulates within the target [2 are also designated by the numerals I3 and M, respectively, but here again, as will be well understood, the target may be formed of a suitable refractory material. For

example, such high-temperature refractory as has lately been developed in connection with jet turbines, and the like, or, if desired, the upper surface of the double-walled target l2 may be provided with a protective coating of a high-temperature refractory material.

One or more of jets 20 may be air-jets supplied with air at about 100 pounds per square inch. Such air jet will serve the same function as the water jets, but will be more effective in breaking up the slag stream into slag masses with less cooling at this stage of the process.

Also adjacent the top portion of the chamber, and extending through walls Ill, there are illustrated spray nozzles which will be referred to as primary sprays and designated by the numeral 20. There are shown a plurality of primary spray heads, specifically 6 being shown, but it is to be understood that here again, depending on design, there might be used substantially any other number of sprays which, by way of example, may conveniently comprise as few as three, or even a lesser number, or may conveniently comprise up to 10 or 12, although the desired result could be obtained with an even greater number of such primary sprays. The purpose of these primary sprays are to provide for a limited degree of cooling of the slag stream as it impinges on target [2 and, to a somewhat limited extent, to serve to break up the slag into separate masses. As shown in the drawings, and as is particularly evident in Figures 1 and 2, the primary jets 20 are directed downwardly, and more or less tangentially with respect to the upper surface of the target l2, and these should comprise jets rather than sprays since, as stated, it is the purpose of these jets 2!) to impinge upon the slag stream just about as it contacts the target 12, and part of the function of these sprays, to a limited extent, at least, is to assist in breaking up the cooling slag mass.

Positioned below primary jet sprays 20 there are provided a plurality of secondary sprays 2| which are also shown as being six in number, although here again the number may be varied in accordance with the design. That is, with large sprays, high pressure, etc., there may be used a smaller number of sprays 2!, or there may be a greater number of such spray heads of a smaller size and supplied with water at lower pressure. The function of these sprays 2i is to provide an actual spray rather than jets, and to spray the slag masses as they fall over the edge of target l2, and these sprays 2| serve to further lower the surface temperature of the slag masses that are falling from target I 2. Sprays 2| are also preferably arranged so as to spray, substantially, tangentially with respect to target l2, since, as is readily understood, there is nothing to be sprayed directly under the target.

Slightly lower down in the chamber, and shown as extending through the wall l0, there is provided grids designated by the numeral 22, which grids connect to suitable headers 23. Headers 23, at one end of each sets of grids, will comprise a cooling water inlet header, whereas, the header at the other end of the grid will comprise a coolwater outlet header. It is to be understood that these cooling water headers 23 will be suitably connected to a water supply and discharge so that cooling water may be circulated through the individual grid members 22. The grids 22, as is clearly shown, are spaced slightly, one below the other, and the individual grid members are respectively arranged at right angles, one to the other, so that a plan view thereof shows the checkerboard effect, clearly apparent in Figure 2 of the drawing. This grid will serve, to some extent, to slow up the fall of the slag masses which are formed above and fall from target [2, that is, some of such slag masses will hit the grids and be retarded so that overall the fall of the slag masses is slightly slowed down.

Below the grids 22 there are provided downwardly inclined bafiies 3| provided with perforations 32 and having their outer ends more or less overlapping, as is clearly indicated in the drawings. The baflies 31 are for the purpose of receiving the slag masses after they have passed through the grids 22, and these bafiles, being inclined downwardly, the slag masses falling thereon will tend to slide downwardly on the first bafile onto the second, and then from the second baffle to the next, should more of these baffles be provided. The function of these baffles 3| is to further slow up the falling of these slag masses. Since the inclination of the baffles is relatively small, that is, about 60, the slag masses may tend to lay on the surfaces of the baflle, but as there is a large volume of slag falling, this material which subsequently falls will tend to force downwardly along the surfaces of the baffles such slag masses as may have been arrested on the bafiles. Bafiles 3| are provided with openings 32 through which any excess water may drain.

The slag masses will eventually be discharged from the lower inward end of the lowermost baflie 3|, and below this baffle there is provided a low speed conveyor more or less similar'to a chain grate. This conveyor, positioned near the bottom of the chamber, comprises a chain or link belt 2'! which runs on sprockets 28, one of which may be driven by suitable power means. Preferably, between the runs of the conveyor 21, and in fact just under the upper run of conveyor 27, there is provided an additional downwardly inclined baffle, designated by the numeral 25, which baffle member is provided with drain openings 26. This baffle not only serves the function of supporting the upper end of the conveyor chain 21, but it also provides, due to the openings 26 therethrough, for the drainage of any free water away from the expanded slag masses which are deposited on chain 21. Of course, in lieu of chain conveyor 21, there may be provided other means for removing the expanded slag from the bottom of the chamber, and in fact, if desired, the expanded slag masses may be raked from the lower part of the chamber by hand, or any desired mechanical means may be provided for discharging the expanded slag from the lower part of the chamber.

In the operation of the apparatus hereof, molten slag from a blast furnace, or the like, is poured into the chamber at the top from any suitable ladle, or the like, and preferably the slag is poured therefrom as a stream impinging upon target l2. The slag stream, as it impinges upon target I 2, is impacted by the cooling jets from spray heads so as to be somewhat cooled down, and to some extent sub-divided into individual masses. Since the slag is preferably poured at quite high rate and continuously, while a pour is being made the material will rapidly pile up on target [2 and spill over the edges as slightly cooled masses which, as they start to fall, will be additionally sprayed and cooled by the spray heads 2| to be somewhat more solidified. These partially solidified masses then continue to fall, pass through grids 22, and then on to the first baflle 3| and from first bafile 3| to second baffle 3|, and finally, to discharge from the lower baffle onto conveyor chain 21.

The result of the operation, as above, is to form the hot molten slag into individual masses or asregates which have been somewhat cooled and have been slowed down in their fall so as to provide a time interval for expansion, and the slag masses which collect on conveyor chain 21 will be quite hot slag masses which have been expanded, it isbelieved, by gasses which are dissolved in the hot slag but which are forced out of the slag as it cools due to the fact that the slag as it cools becomes supersaturated, and such gases cause the formation of voids in the slag masses and thus puff the slag masses to provide a structure which will result in the desired light weight aggregate. It is also possible that some of the water with which the slag masses are sprayed, or steam formed therefrom, finds its way into the slag masses, and that the steam also has some effect in pufiing the slag masses or providing voids therein. It is immaterial as to just how or why the voids are formed in the slag masses, since the desired pufiing is a function of the treatment to which the slag has been subjected, as above described, and so far as the result is concerned, it is immaterial whether the pufling or expansion of slag is caused by dissolving gases or by steam or gases from some extraneous source.

The hot puffed slag which cools on chain conveyor 21, due to the slow speed of such conveyor, is subjected to annealing, at least to some degree. That is, due to the fact that the materil cools en masse on the conveyor and the'mass is a hot mass, cooling thereof will be at a relatively low rate, and thus there will be some annealing. When the expanded slag has been removed from the chamber it may be suitably crushed to provide aggregate of desired size, which crushing may be by passing the material through a cylinder crusher, through a swing hammer crusher, or any other suitable means for reducing the masses to aggregate size. After the expanded slag has been reduced more or less to aggregate size, it is then screened over suitable screens so as to obtain the desired gradation required for the particular use to which the expanded slag aggregate is to be put. The reduction of the expanded slag to aggregate, and the specific use thereof, not being pertinent to the invention hereof, such will not be further described or discussed, particularly so since those skilled in the art will well understand the procedures required. 1

The inventions hereof having been described in detail, both as to the apparatus and the procedure of its use, I claim:

1. Apparatus for the manufacture of expanded slag and comprising: a stack structure, a stationary target mounted substantially centrally of the stack and adjacent the top thereof, pressure jets positioned above the target directed downwardly toward the upper portion of the target and generally tangentially thereof, spray heads mounted at substantially the level of the target and directed toward the target, generally tangentially thereof, means positioned below the target, in the path of slag masses discharging from the target, and interrupting free fall of such slag masses, the said means comprising a substantially horizontal grid supported in the stack and below the grid, one positioned below another, plate members extending oppositely from the wall of the stack toward and overlapping adjacent the center of the stack. v

2. Apparatus for the manufacture of expanded slag and comprising: a stack structure, a highly refractory stationary target against which a poured stream of molten slag may impinge mounted substantially centrally of the stack adjacent the top thereof, fluid projecting nozzles mounted about the target, directed toward the target and discharging substantially tangentially thereto, a grid and downwardly inclined means positioned below the target in the path of slag masses discharged from the target, whereby the fall of slag masses discharging from the target will be retarded.

3. The apparatus of claim 2 wherein the downwardly inclined means intercepting slag masses discharging from the target comprise substantially plane surfaces mounted one below another, spaced apart vertically, oppositely inclined downwardly from the periphery of the stack toward its center and overlapping, whereby slag masses falling upon the upper of such means will be directed downwardly and discharged to the next succeeding downwardly inclined means.

4. The apparatus of claim 3 wherein the downwardly inclined means are provided with multiple drainage openings extending therethrough, whereby water accompanying the slag masses may drain away.

5. The apparatus of claim 4 wherein adjacent the bottom of the stack and below the lowermost downwardly inclined slag intercepting means, there is provided means receiving the slag masses and discharging them exteriorly of the stack.

DEE G. WHEELER.

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

UNITED STATES PATENTS Number Name Date 964,805 Passow July 19, 1910 2,210,999 Bartholomew Aug. 13, 1940 2,417,301 Hayes Mar. 11, 1947

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