US1758496A - Method for handling sinter - Google Patents

Description

May 13, 1930.

A. J. BOYNTON 1,758,496

IBTKOD FOR HANDLING SINTER 2 ShaetkSheet 1 Filed March 16, 1925 May 13, 1930. A. J. BOYNTON 1,758,496

'IETHOD FOR HANDLING SIN'I'ER Q Filed March 16, 1925 2 Sheets-Sheet 2 irzoarzzbr' 545 LPQrflzar Jliqy t 9: l J y I Patented May 13, "1930 UNITED STATES PATENT OFFICE El-ml. BOYIN'TON, OF'CHICAGO, ILLINOIS, ASSIGNOB TO H. A. BRASSERT, INQ, OF

' CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS METHOD FOR HANDLING SIHTER Application filed March 16, 1925. Serial No. 15,962.

This invention relates to a new and improved method for handling material and more particularly, to a. method adapted to screen and cool the product of a sintering process.

The invention has particular application to the handling of sinter made by processes well known in the art, the sintering having for its object the agglomerating of metalliferous ores and flue dust in its fine state of division. In somesintering processes themethod alsoserves to eliminate from the ores by combustion,

sulphur or other combustible substances. Usually the primary object of the sintering process is to increase in size the pieces of ore which are subsequently used in the charge of a metallurgical furnace.

In one sintering process as now carried out the metallic charge, generally in a fine state of division, is spread upon the grate bars of a so-called sintering pan mixed with a definite percentage of fuel. This fuel may be contained in the charge as a resultof previous introduction into a furnace, as in the caseof blast furnace. Flue dust, or the fuel may be added for the pur ose of sintering. After the'spreading of the charge, the fuel is ig nited and combustion is maintained by means of a current of air drawn down through the char e from the upper surface through interstices in the grate bars which support the charge, by a suction draft. At the conclusion of the process, the resulting sinter is an agglomerated mass in a more or less plastic state.

The pan is then inverted so that the sintered material falls on an inclined surface below the pan, part of which surface is usually provided with a screen or bars for the purpose of removing from the product any portion of the sinter which is in too fine a state of division to adapt it for use. The remainder of the sinter passes down an inclined surface without retardation into a freight car or other rece tacle. This dumping of the sinter on the inclined surface and the subsequent motion of the sinter over screens and into the car has the disadvantage of severe breakage. and abrasion of the plastic sinter, which reduces it in size and thus in part defeats the object of the sintering process. Also, the car or other receptacle is subject to damage by the residual heat in the sinter.

A further objection to this method lies in the fact that the screening which is ossible to effect by rapid motion over a steep y inclined screen is not suitable "for the objects of the sintering process since the rapid motion of the sintered products prevents the elimination of fines, except on a basis of screening so coarse that much sintered product suitable for use is allowed to pass through the screen with the fines. Also, this practice provides no means for reducing pieces of sinter which are objectionably large.

It is an object of the present invention to rovide a new and improved method for iandhng sinter whereb the sinter may be air cooled, crushed to re uce large pieces and screened at a slow rate of speed whereby the production of fines is reduced and the elimination" of fines more efficiently effected.

It is a further ob'ect of the invention to provide a method 0 this character whereby the sintered mass is air cooled before being crushed, or screened, whereby its hardness is increased and the product-ion of fines reduced.

It is an additional object to provide a method of this character which is simple and adapted for commercial application to existin sintering apparatus.

t is also an ob'ect to provide a new and improved metho of handling sinter by which the sinter is air cooled before crushin crushed and screened, the fines produced being reduced in quantity by the cooling preliminary to the crushing.

Other and further objects will appear as the description proceeds.

I have illustrated a preferred form of apparatus somewhat diagrammatically in the accompanying drawings, in which- Figure 1 is aside elevation, and

Figure 2 is a front elevation of the apparatus.

Referring to the drawings,-

The sintering pan 11 is supported on trunnions 12 about which it may be rotated to dump the sinter into the hopper 13. The

lateral walls of this hop er are ai f ht and its bottom is formed rom a p ur a lity of downwardly inclined overlapping plates 14, which are separated suificiently to permit the passage of air into the hopper but to prevent discharge of the sintered product. The passage 15 extends from the upper end of the hopper and leads to any source of draft, such as a stack.

The lower end of the hopper 13 is closed by the gate 16 operated by lever 17. The feed roller 18, which is diyided into a plurality of compartments 19, is located below the gate 16. Below the feed roller'l8 are located the pair of crusher rolls 20 and 21. These rolls discharge onto the screen 22, which has been shown in the form of a bar screen or grizzly. Below the screen 22 is located a opper 23 having thebottom 24 similar in construction to the bottom 14 of the hopper 13. The discharge and of the hopper 23 is controlled by gate Below gate 25 is located the screen 26, which may be vibrated electricallyor mechanically by any known process. Material passing over the screen 26 is discharged throu h chute 27 intocajr 28. Material passing t rough the screen 26 is discharged through spout 29 into receptacle 30. Material passing over the bar screen 22 passes down the upper surface 31 of the chute 27 into the car 28.

In the operation of the apparatus, the sintered material is dumped from the sintering pan into the hopper 13 and the heat of the material induces a draft through the bottom 14 and up the stack 15. This flow of air is distributed through the material by the nature of the bottom and serves to cool and harden the sinter. The gate' 16 is opened to discharge the material as desired and the flow is further controlled by the feed roller 18, which ma be rotated at any desired speed suitable for t e purpose. The material pass- 'ing through the rollers 20 and 21 has the lar er pieces reduced to a suitable size.

he material passing over the bar screen 22 has the larger ieces fed directl to the car 28. The sma ler pieces and the fines which are too small for usepass through the screen 22 and are further cooled by air coming through the bottom24. This material is passed over the screen 26 at a rate of flow controlled by the gate 25. As has been stated, the screen 26 may be vibrated to give a more eflicient screening action. The screen 26 eliminates the fines and the remaining material is discharged to the car. 1

This apparatus serves to cool the material thus hardening it and minimiz' the breakage of the material into finea he cooling also serves to revent damage to the car or other receptac e. The crusher rolls prevent the passa e of material in larger pieces than is desirab e. The gates and feed roll control the rate of passage of material, so that it may be caused to pass over the screens slowly in a thin layer. he screens may therefore, be of a proper size to eliminate only the undesirable fines and all of the usable material will be passed to the car.

It is to be understood'that the showing of the drawings is somewhat diagrammatic, and I contemplate such changes and modifications as come within the spirit and scope of the accompanying claims.

I claim:

1. The method of handling sinter which comprises air cooling the material and passing it at a controlled rate of flow over screens to remove the fines.

2. The method of handling sinter which comprises air cooling the material, crushing it to reduce the larger pieces and passing it at a controlled rate of flow over screens to remove the fines.

' 3. The method of handling sinter which comprises air cooling the material, crushing it to reduce the larger pieces, passing the [ll-lterial over a coarse screen to remove the larger remaining pieces, and passing the material which passes through the first screen over a second screen to remove the fines.

4. The method of handling sinter which comprises air cooling the material, crushing it to reduce the larger pieces, passing the material over a coarse screen to remove the larger remaining pieces, and again air cooling,,the material which passes through the first screen over a second screen to remove the fines.

Signed at Chicago, Illinois, this 5th day of February, 1925.

ARTHUR J. BOYNTON.

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