US1169139A - Apparatus for and process of ore treatment. - Google Patents

Description

A. S. DWIGHT.

APPARATUS FOR AND PROCESS OF ORE TREATMENT.

APPLICATION FILED JUNE 30. I911.

Patented J an. 25, 1916.

2 SHEETS-SHEET l.

APPLICATION FILED JUNE 30, 1911.

Patented Jan. 25, 1916.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

ARTHUR S. DWIGHT, OF NEW YORK, N. Y.

APPARATUS FOR AND PROCESS OF ORE TREATMENT.

To all whom it may concern: I

Be it known that I, ARTHUR S. DWIGHT, a .citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Apparatus for and Processes of Ore Treatment, of which the following is a specification, reference being had therein to the accompanying drawing.

This invention relates to processes for treating ores, and more especially for the treatment of ore bodies which can be sintered or agglomerated by combustion within the mass or by external heat to form sinter cakes or blocks which are porous and which have relatively low specific gravities.

The invention relates more particularly to a process for preliminarily treating the sinter cakes or blocks after sintering to prepare them for smelting or other subsequent treatment.

The invention has as its object the provision of improved process steps" adapted to effect such changes as the partial reduction of oxids, or' the oxidation of one oxid to a higher oxid.

In the accompanying drawings, which form a part of this specification, I have shown for purposes of illustration several forms of apparatus, such as are adapted for use in carrying out my improved process. However, I desire it to be clearly understood that other apparatus or mechanisms may be used, if desired, and that my invention is not limited to be carried out by any particular mechanical structure.

Of the drawingsFigure lis a side elevation, partly in cross section, of an apparatus adapted for the formation of porous sinter cakes of the character referred to for subjecting the cakes to a preliminary treatment, for continuously passing them after treatment into a smelting region, and for subjecting them to smelting action. Fig. 2

is a cross sectional plan view taken along the line 22 of Fig. 1. Fig. 3 is an enlarged cross sectional view taken along the line 33 of Fig. 2. Fig. 4 isa side elevation of a sintering mechanism similar to that shown in Figs. 1, 2 and 3, but separated from the other parts of the apparatus. Fig. 5 is a Specification of Letters Patent.

Application filed June 30, 1911.

cross sectional elevation showing a furnace similar to that in Fig. 1, and also a device for effecting the preliminary treatment of the sinter cakes before smelting. Fig. 6 is a side elevation of a sintering machine and apparatus for preliminarily treating the sinbv means of a fan 2. Upon the upper edgesof the box are carefully planed wearing strips 3 upon which slide cast iron pallets 4:, the lower edges of which are likewise carefully planed so as to make air tight joints with the strips when the pallets are pushed along the top surface of the box. The pallets carry the grates 5 and are built with transverse members 6 which together with the sides of the pallets form four-sided boxes beneath the grates. Above the grates these transverse members are omitted so that when a number of pallets are adjacent each other an uninterrupted grate surface is provided. These lower transverse members also serve as partitions to cut off the air at certain points in a manner which will be described.

Each of the pallets may be considered as an independent or individual car provided with four wheels 7 7 attached by suitable bearing pins so arranged that the axes of the wheels are in the same plane with the lower edges of the pallets, each pallet being thus permitted to move around the curved track hereinafter described without interference with the other pallets. As the pallets are pushed across the suction box they are guided by the flanges of the wheels 7, v

7 which are in engagement with the longitudinal track rails 8, 8, the weight of the pallets being sustained on the wearing strips 3.

At each end of the suction box there is arranged a dead plate 9, the upper surface of which is flat and in alinement with the upper surfaces of the strips 3. The pallets move with an air tight joint over the sur: face of one dead plate 9 just before they pass to a position over the suction box and pass within an air tight joint over the surface of the other dead plate 9 after they pass the suction box. Each of these dead plates has a length slightly greater than the length of a pallet so that there will be no leakage of air during the time that a pallet is but partly over the suction box.

The pallets are elevated one by one and consecutively placed in position on the rails 8, 8 by means of a pair of sprocket wheels 10 which are so designed that their teeth engage the treads of the wheels 7, 7 in conjunction with the guide rails 11.

At the end of the suction box which is farthest removed from the sprocket wheels- 10 the track rails 8, 8 are curved suddenly downwardly. Outside of and concentric with the curved ends of the rails 8, 8 are rails 12 which are continued at a downward and backward incline at their lower ends and which join with the guide rails 11. It will be observed that as each pallet reaches the curved parts of the rails 8, 8 it will move downward out of alinement with the other pallets and into position on the rails 12 for engagement by the sprocket wheels 10.

A hopper 13 is mounted above the pallets 4 on the track rails 8 and serves to deposit on the pallet grates a uniform layer of the materialto be treated. The material supplied to the hopper 13 is preferably in a relatively finely divided condition and should contain a certain proportion of combustible substance, such sulfur or carbon. Many ores such as sulfid ores of copper contain in the natural state a sufficient quantity of combustible substance, such as sulfur. When it is desired to treat other ores, such as oxid iron ores, not initially containing a sufiicient combustible material, a quantity of combustible substance, such as powdered coal, coke or charcoal, can be added. \Vhen iron ore is to be treated, it is generally desirable to add to it before it is fed to the sintering machine, a supply of fluxing material, such as limestone. When this material is added it remains more or less inert until the smelting furnace is reached.

As the pallets are pushed slowly forward by the sprocket wheels 10 the layer of material on them is carried away from the hopper 13 and beneath an igniting device such as is indicated at 14. This igniting device serves to fire the combustible substance in the ore mass. The igniting device 14 may be simply a perforated pipe adapted for supplying gas to support flames which continually play upon the top surface of the ore layer. As the layer is further advanced, the combustion, which has been started by the igniter 14, is caused to progress slowly downward through the mass by the action of a combustion supporting gas such as air, which is drawn downward into the suction box 1 through the interstices between the particles of material of which the mass is composed. The heat of combustion is sufficient to cause certain constituent elements of the ore to be softened or partly melted with the result that these softened ore particles unite and harden upon cooling to form a rigid integral cake. This cake has its opposite top and bottom surfaces large, substantially parallel and practically smooth, that is, as smooth as results from feeding the material to a pervious support to form a layer thereon of uniform thickness, in the manner described. On account of the continuous passage of the air through the cake during the process of sintering, the cake is highly and uniformly porous from one of the said parallel surfaces to the other, and on this account well adapted for the smelting and other action which will be hereinafter described. It will be understood that the rate of movement of the pallets along the upper track rails 8, 8 is relatively slow and is so regulated that when the combustion and sintering at any one point has progressed downward entirely'through the layer that point will have moved beyond the suction box and substantially to the discharge end of the machine.

In the construction shown in Figs. 1 and 2 the sinter is moved continuously forward onto a shelf 15 which is adjacent and in alinement with an aperture 15 in the wall of a smelting furnace which is indicated as a whole by B. The pallets 4 after freeing themselves from the sinter cake return by gravity in the manner before described to be picked up and returned by the wheels 10.

From the sintering mechanism A the cake or layer, while still retaining the heat of sintering and before being delivered into the smeltering furnace, is passed across or through a duct 0. A grate (Z is preferably provided to support the sinter cake and to prevent any particles from becoming detached and falling into the duct. The duct is connected at one end, as for instance the lower end, with a pipe 0 which leads from a suitable source from which a gas, such as carbon monoxid, can be supplied in quantities. This gas, in moving along the duct 0 is forced to pass through the pores of the sinter cake. The cake is still hot and the gas produces certain chemical reactions to which further reference will be made hereinafter.

The continued movement of the ore cake carries it out of and away from the duct 0 and into the furnace. The furnace which has been selected for purposes of illustration is provided with a reservoir 16 adapted for retaining a lower bath or matte 17 of molten erably left open and is positioned to discharge into a car, such as that indicated at I 21. It is arranged to maintain the surface of the slag on a level with or slightly below the bottom surface of the incoming sinter cake or cakes.

The sinter cakes from the apparatus A are fed preferably continuously into the furnace and are permitted to break off by their own weight into irregular chunks or blocks, as indicated by 22 in Figs. 1 and 2. As has been before mentioned, the sinter cakes are light and porous because of the continuous passage through them during formation of air or-gas. In the case of iron ore, for instance, it has been found that the specific gravity of a porous sinter cake averages as low as 1.5; whereas the specific gravity of the solid material of which the sinter cake is formed averages between 5 and 6. As the specific gravity of slag ranges from about 2.4 to 2.9, it will be apparent that the broken sinter cakes will float buoyantly on the surface of the slag.

The smelting heat is applied to the sinter cakes or blocks within the furnace from two sources. In the first place, the cakes have large surfaces of exposure on account of their porosity, and the lower part ofthis surface of exposure is in intimate contact with the hot slag which gradually works its Way through the pores well into the interior of the mass. In the second'place, heat is supplied to the slag bath and tothe upper parts of the cakes themselves by means of a powerful blast of burning gases injected into the furnace through the nozzles 23. The blast serves not only'to heat the slag and to melt the sinter cakes but also to hold the sinter cakes in the region adjacent the entrance and to prevent them from drifting to other parts of the furnace outside of the range of the flames. By the combined heating effect of the slag and of the jets of flame the cakes are very rapidly melted. The metallic parts joining the lower metallic layer 17 in the reservoir and the slag parts joining the slag layer 18 and flowing out through the spout 20.

In Fig. 4 I have shown a sintering machine separated from the other parts of the apparatus. The construction and operation of the sintering machine has been fully described in connection with the ap aratus of Fig. 1, 2 and 3, and further description will be unnecessary. It will be understood that a separated sintering machine is necessary when it .is desired to store or ship the sinter cakes after formation and before further treatment;

In Fig. '5 I have shown an apparatus adapted for preliminarily treating and subsequently smelting sinter cakes which have been broken up and which have been allowed to cool. As in the other form of apparatus 0 represents a gas duct, 01 a rate for supporting sintered material within the duct, and 6 represents a pipe for conveying a suitable gas to the duct at its lower end. Adjacent the duct there is a furnace which, as indicated in the drawings, is similar to that shown in Figs, 1 and 2.

In order to secure proper chemical reactions by means of gas passing through the pores of the sinter cakes, it is necessary that these cakes be at a relatively high temperature. In the first described form of apparatus, this temperature resulted directly from the sintering action. In the present form of apparatus, however, it is necessary to provide other means for heating the sinter cakes. In the drawings I have shown one means which can be used to effect the heating. This consists of a duct 24, which is divided to avoid interference with the gas duct 0 and which serves to convey the heated gases from the furnace along the top of the sinter cakes not onlybefore they reach the duct 0 but also after they have passed the duct 0 and before they have reached the furnace. This waste gas duct 24: preferably communicates with a chimney 25. By means of the gases discharged through this duct 24 the sinter cakes are heated to a temperature suflicient to permit proper reaction within the duct 0 and after leaving the duct 0 are further heated to make them ready for rapid smelting.

In Fig. 6 I have shown a sintering mechanism and a duct for supplying gas for treating the sintered cakes, separated from a furnace. Under certain conditions the continuous preliminary treating and smelting is not desirable, and in such cases apparatus of this character can be used. As has been before suggested, the use of carbon monoxid, CO, for reducing iron oxid ores can be considered as a typical carrying out of my improved process. As has been before stated, iron oxid ores are sintered.

preferably by the combustion within the ore mass of artificially added carbon. After combustion and sintering some of the iron oxid may have been reduced either toalower oxid or to metallic iron. But as it is desirable to effect as complete reduction as possible before the final smelting action, further reduction can be accomplished by passing through the sinter cake a reducing gas, such as carbon monoxid, which unites with the oxygen of the ore to reduce a high oxid, such as hematite, Fe O to a lower oxid, such as magnetite, Fe O or to completely reduce some or all of the oxid ore to spongy metallic iron. In order that the reducing action may take place it is, of course, necessary for the cakes to be heated and, as shown in Figs. 1 and 2, the gas is preferably supplied while the heat of sintering is retained. But, if desired, the cakes can be permitted to cool and be re-heated by suitable means, as for instance, by the furnace gases, as indicated in Fig. 5.

-Another action which can be carried out by my process is the treatment of a lead ore, such as galena, PbS, with carbon monoxid after the sulfur has been removed by the sintering process, to reduce any oxids which may be formed to the metallic state.

Another action which may in certain cases be desirable is the oxidizing of an iron oxid, such as magnetite, to form a higher oxid, such as ferric oxid to be used for a purpose such as the decarbonizing of steel in the open hearth process. When such an action is desired it can be accomplished by passing superheated steam through the duct 0 in an apparatus such as is shown in Fig. 6, the oxidized cakes being discharged from the duct and subsequently carried to points of use as desired. Other actions which can be carried out by my improved process will suggest themselves to those skilled in the art, and I do not limit myself to the actions which I have described.

I do not claim as a part of my present invention the particular form of sintering mechanism, as this is disclosed and claimed in certain co-pending applications, among which are my applications Serial Nos. 544,507 an 558,621 upon which have issued Patents 1,027,110 and 1,027,111, dated May 21, 1912; nor do I claim the process herein disclosed consisting in floating masses of porous metal-bearing material such as sinter cakes, upon a bath of molten slag which acts thereon as described, as this is covered by my co-pending application, entitled Apparatus for and process of ore treatment, Serial No. 636,296, filed on even date herewith. I do not claim broadly as part of my present invention the apparatus or process for continuously treating ores to effect, first, sintering and, ultimately, smelting, as these are claimed in my co-pending application Serial No. 440,404, allowed May 11, 1911.

lVhat I claim is:

1. The hereindescribed process of treating a metalliferous material that is initially in a fine condition, which consists in forming it into coherent, rigid cakes having extensive substantially parallel smooth top and bottom surfaces and being highly and substantially uniformly porous between said surfaces, and then, preparatory to any smelting operation, passing through the pores of the said blocks While they are maintained intact and at a high temperature, a gaseous body adapted to react upon the material of the blocks causing chemical reactions to take place therein.

2. The herein described process of treating a metalliferous material that is initially in a fine condition, which consists in forming it into coherent, highly porous, pieces, subjecting these to a moving stream of gas adapted to react upon the material of the said pieces causing chemical reactions to take place therein, and after such reactions introducing the said pieces into a furnace and there smelting them.

3. The herein described continuous process of treating a metalliferous material that is initially in a fine condition to recover the metal, which consists in forming the material into a highly porous coherent mass, advancing the mass as formed and adding thereto, causing a gaseous body capable of reacting upon the material of the mass to pass through the pores thereof While in process of being advanced, and immediately thereafter passing the treated mass into a furnace and subjecting its end to smelting.

4. The herein described process which consists in agglomcrating fine metal-bearing material into highly and uniformly porous rigid masses, subjecting these to an intermediate treatmcnt by gas that reacts thereon and causes chemical changes therein to take place, and after such reactions have taken place introducing the material so treated into a reverberatory furnace and there immediately smelting it.

5. In an apparatus for ore treatment, the combination of a mechanism for forming a mass of .ore into a porous cake and for raising the temperature of the cake, a duct for the passage of reaction producing gas, means for supplying gas to the duct, and means for causing the cake to be moved from the forming and heating mechanism into and through the duct.

6. In an apparatus for-ore treatment, the combination of a mechanism for the formation of a mass of ore into a continuous porous cake by the action of heat, a duct for reaction producing gas, having alined openings, means for supplying gas to the duct, means for continually moving the cake away from the forming mechanism transversely across the duct through the said alined apertures, whereby the cake, while retaining the heat of formation, issubjected to the action of the gas in the duct.

7. In an apparatus for the treatment of ore, the combination of a mechanism adapted for the continual formation of a porous sinter cake by the action of heat, a duct for reaction producing gas having alined apertures in its sides, means for supplying gas to the duct, devices for causing the cake to be continually moved away from the region of formation across the duct I In testimony whereofI aflix my signature, through the sa1d ahned apertures, whereby in presence of two witnesses.

it is subjected to the action of the gas while ARTHUR S. DWIGHT. retaining the heat of sintering, and a smelt- Witnesses:

5 ing furnace, into which the cake of material CHARLES L. MONTAGUE,

1s directly passed as it leaves the said duct. JOHN KNOX.

It is hereby certified that in Letters Patent No. 1,169,139, granted January 25,

printed specification requiring correction as follows: Page 2, line 37, after the word smelting; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice.

Signed and seaied this 25th day of July, A. 1)., 1916.

[SEAL] i F. W.'ri. CLAY,

Acting Commissioner of Patents.

Corrections in Letters Patent No. 1,169,139

1916, upon the application of Arthur S. Dwight, of New York, N, Y., for an improvernent in Apparatus for and Processes of Ore Treatment, errors appear in the suc insert the word as; same page, line 109, for the word smeltering read

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