US2355885A - Processes for chemically purifying and refining metals and other substances in fusion - Google Patents

Description

MERLE PROCESSES FOR CHEMICALLY PURIFYING AND REFINING 2 Sheets-Sheet 1 Aug. 15, 1944. J. M.

METALS AND OTHER SUBSTANCES IN FUSION Filed July 19, 1941 SWW? Weir/[ MM 15, 1944- J. M. MERLE I 2,355,885

PROCESSES FOR CHEMICALLY PURIFYING AND REFINING METALS AND OTHER SUBSTANCES IN FUSION Filed July 19, 1941 2 Sheets-Sheet 2 Patented Aug. 15, 1944 I ROCESSES FOR. CHEMICALLY PURIFYING AND REFINING METALS AND OTHER SUB- STANCES IN FUSION Joseph M. Merle, Pittsburgh, Pa.

Application July 19, 1941, Serial No. 403,124 In Brazil January 22, 1941 14 Claims.

This invention relates to processes for chemically purifying and refining metals and other substances in fusion.

Heretofore, the refining of metals has been relatively slow and has only been effective to a limited degree. This is exemplified by the refining of steel in the open hearth (Siemens Martin) and in electric furnaces. In these operations several hours are required to refine the steel after the charge has been melted. The reasons are that the depth of the molten bath is from 20 to 30 inches and the top surface area through which the various reagents, such as ores or slags, can chemically react with the metalloids is relatively small. Thus the rate of diffusion of these reactive elements throughthe mass treated, takes considerable time which is further lengthened and made uncertain and incomplete because some of the reactions are reversible and some metalloids recombine with the bath from the slag. As a result of this, a certain amount of impurities remain in all commercial metals and alloys and the refining operation besides being slow, utilizes more fuel, refractory materials and labor than is desirable.

The principal objects of this invention are to remedy these difiiculties by providing a new and improved method of refining metal and other sub stances in fusion in a more facile, economical and eflicient manner than formerly, which consists in continuously forming the molten unrefined metal or alloy into a thin film and at the same time continuously bringing one or both of its surfaces in contact with films of reagents at controlled temperatures.

Other objects of my invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings wherein:

Figure 1 is a view in side elevation of a film forming machine constructed to effect the refining process of my invention, with certain parts shown in vertical section, and showing a film of molten metal between two films of molten slag or reagent;

Figure 2 is an enlarged fragmentary sectional view taken through the rim of the film forming cylinder of them-achine illustrated in Figure 1 and showing afilm of molten metal sandwiched between two films of slag;

Figure 3 is a view in side elevation of a modified form of film forming device for effecting the refining process in accordance with my invention, with certain parts shown in section;

Figure 4 is a detail partial fragmentary plan view of the device shown in Figure 3, with certain parts broken away in order to show certain details of the opening between the two film forming cylinders and to show the collectors for excess slag;

Figure 5 is a vertical sectional view taken through a third form of device for effecting the process of my invention, illustrating the use of a vertical rotating cylinder for forming a film of molten metal over a film of molten slag and separating the refined metal from the used slag;

Figure 6 is a vertical sectional view taken through still another form of device for effecting the process of my invention; and

Figure '7 is a vertical sectional view taken through still another modified form of device for effecting the process of my invention, illustrating a multiple film forming machine with successive slag separators.

Referring now in particular to Figures 1 and 2 of the drawings, a rotary wheel I having a cylindrical film forming surface I0 is provided. As herein shown, said wheel includes two annular flanged pieces 2 and 3 having integrally formed spokes extending from central hubs 4, 4. Said hubs are preferably keyed to a drive shaft 6, and said annular flanged pieces are secured together by means of bolts 1, 1 extending through the spokes of said flanged pieces and through spacing sleeves 9, 9 interposed between said spokes of said flanged pieces. A spacing cylinder 8 fits in shouldered portions 8a, 8a of said flanged pieces and forms a cylindrical rim between said flanged pieces. Said cylinder may be of a segmental construction if desired. Said spacing cylinder is faced with a cylindrical metal propelling and film forming member H which may be made from any suitable refractory material. The out er periphery of said film forming member forms the cylindrical film forming surface I0. Side wall sections 10a, Illa of said film forming member extend along the insides of said annular flanged pieces and their outer peripheries are abutted by gibbed portions lob, illb, extending inwardly from the outer peripheries of said flanged pieces and held in engagement with said side walls by means of the bolts 1, l, which hold said annular fianged pieces together. Said side 7 wall sections may likewise be constructed from a suitable refractory material. Different widths of film forming members may be mounted between said annular fianged pieces by changing the spacing sleeves 9, 9 and the spacing cylinder 8.

The shaft 6 may be mounted on a supporting speed drive of any well known commercial form,

to vary the speed of rotation of said wheel as refining conditions vary. Said motor and drive are not herein shown or described in detail since they may be of any well known type and form no part of my present invention.

The rotary film forming surface may be enclosed by a casing generally indicated by reference character I3. The space between the inside of said casing and the rim of the cylinder may be utilized to permit the use of gas or oil flames to preheat the refractory facing or film forming surface l and to maintain it at the desired temperature. A Jet for said gas or oil flames is indicated generally by reference character [5. If desired, other jets may be positioned at other points along said casing. It should also be understood thatwhile a gas or oil burner is shown as being used'to preheat said refractory facing or film forming surface, that any other well known form of heating means may be used, if desired.

A pouring device ll having a nozzle I8 is supported above the refractory film forming surface It. Another pouring device l8a having nozzles l9 and 20 is also supported above the refractory film forming surface ill in such a manner that molten material from the nozzle l9 will be laid over the rim of the refractory film forming surface I 0 at, or very close to, its vertical center line. Immediately afterand slightly in advance of the nozzle l9, another molten material which may be molten metal, may be laid over the width of the film forming surface ill by the nozzle l8. Immediately in advance of said last mentioned nozzle, another molten material will be laid over the width of the film forming surface H) by the nozzle 20. Thus the film forming surface It after passing by the nozzle 20 will carry three films of molten material 2|, 22 and 23, distributed by the nozzles l9, l8 and 20, respectively.

Intimate contact of the three films 2|, 2: and

23 will be maintained as they travel with th film forming surface I 0 and the period of contact may vary according to the time required by the chemical reactions involved between the films by varying the speed of travel of said film forming surface.

After leaving the rim of the film forming surface, the three films 2I, 22 and 23 (two films of molten slag and one film of molten metal) can be directed into a separating receptacle 24 iiicluding a chamber 25 for receiving the triple film and a chamber 26 into which flows the heavier metal or substance through a bottom opening 21. From this chamber the metal or substance fiows throughan opening 28 into a ladle 29 or other receptacle, while the lighter molten substances fiow from the chamber 25, through an overflow 30 into a receptacle 3|. Thus the films are formed and kept in contact with each other and carried away in a continuous operation.

The above procedure provides favorable conditions for the rapid refining of most metals. For example, molten pig iron from a blast furnace or cupola can be supplied through nozzle I8 and molten iron ore or iron oxide can be supplied by nozzles l9 and 20 and the oxidation of the metalloids, phosphorus, silicon, manganese and carbon 76 contained in the film of molten pig iron will be immediat ly and thoroughly accomplished. The pure iron collected in ladle 29 can be immediately poured from the ladle or from opening 2| into another similar machine, set in cascade, which will distribute this molten iron through another nozzl it over a film laid by another nozzle is under another film laid by another nozzle 20,

which films in that case would be made of very fiuid molten calcium (lime) slag, which would remove whatever sulphur and phosphorus was left in the molten iron in the first operation. I

Another way of operating the machine is to feed molten pig iron through nozzle l8, molten iron ore and limestone through nozzle is and molten calcium (lime) slag through nozzle 20, thus accomplishing the whole refining operation in a single operation and collecting the refined pure iron in the ladle 29. Whatever additions are necessary for deoxidization and for bringing up such metalloids as silicon, manganese and carbon to desired composition to transform the pure iron into steel, may be added in this ladle. As, forexample, molten ferromanganese would be added in making manganese steel.

In the same manner, a stream of molten steel. or molten pig iron, or molten nickel, etc.. may be supplied through the nozzle l8, to be desulphurized and dephosphorized, and a different molten material capable of quickly combining with the above two elements may be supplied through the nozzles l8 and 20. These other materials may be a molten slag made of Geo, 25% iron oxide, 10% MnO with balance made of silica and fiuorspar to make this slag very fiuid and enable it to form very thin films. The composition of the slag mixtures will vary and will be determined and adjusted according to the impurities contained in the molten metals to be refined. The amount of molten slag required is small, generally between 3 to 5% of the weight of the molten metal treated and the phosphates and sulphates resulting from the refining operation are entirely collected and have a. market valve;

Besides the thoroughness of the refining operation, its rapid rate of action can be realized from the following example: One cylinder with a 12" wide rim forming a film of molten steel, iron or other molten metal can be run at a peripheral speed of 600 to 800 feet per minute in general practice, and when forming a molten metal film thick, will refine between 2400 to 3000 pounds of molten metal per minute. Furthermore with a film of molten refining slag on both sides of the molten metal film, the surface of contact created between the molten metal and the molten refining slag is about one square foot per two pounds of metal and this relation can be increased by forming thinner films of molten metal. This procedure .requires molten slag which is generally easily melted in a rotary furnace, a crucible furnace, an open hearth furnace or an electric furnace and carried to the machine to be poured at the exact temperature required to insure instantaneous chemical reactions with the impurities in the molten metal. Nevertheless and as the amount of slag required is as indicated above, only a small fraction of the weight of the metal to be treated, it is much more economical to melt the slag separately in a small immediately and continuously formed at the temperatures of operation selected and best suited for the metal treated and slag used, the desired reactions are fully under control at all times with none of the uncertainties occurring when this operation is made in a big furnace with a small area of contact betweenthe slag and the mass of molten metal to be refined, and further the time factor for difi'usion of the reactions involved is practically nil. As a result of the above, while the machine illustrated shows one film or layer of slag laid over each one of the surfaces of the molten metal film or layer, in practice, one layer of slag either laid under the molten metal film or over it, depending on the molten metal treated,,is generally sumcient to refine this molten metal within present specifications as to chemical composition and the use of two films of slag produces metals and alloys in a state of purity now commercially non-existent.

Figures 3 and 4' show a machine having two cylindrical film propelling rims instead of one and in which all the refining operations described in connection with Figure 1, as well as several other new refining operations, can be carried out. A cylinder 32 keyed to a shaft 33 is supported on a frame 34 on proper bearings supported on bearing supports 3411. Another cylinder 35 is keyed to a parallel shaft 36 and supported on the frame 34 on proper bearings supported on suitable bearing supports 31. Two meshing gears, not shown, at one end of the shafts are provided to rotate both cylinders in a usual manner. One of said shafts may be driven by the usual motor through a suitable geared reduction or variable speed drive (not shown). The bearing supports '31 may be moved in parallel adjustment to the bearing supports 34a by means of a suitable adjusting device (not shown), so that the width of a grooved opening 38 at the bight of the two cylinders can be adjusted as desired.

A cover It protects both cylinders against heat lossesand allows the use of gas burners or of some other suitable heating device to preheat the film forming rims of both cylinders and to keep their surfaces at a desired temperature during the refining operation. I

The cover l6 also serves to support a central pouring device 40 having two pouring nozzles or box with the nozzles 44 and 46 disposed closely adjacent the vertical centers of the cylinders 32 and 35.- Both pouring nozzles 44 and 45 can be provided with a fiow controlling device. not shown. The pouring device 40 has an apron 41 on each side allowing frictionless free running of the two cylinders but preventing air circulation. A channel 48 leads to molds 49 which may be billet molds, slab molds, or molds for continuous casting, or cylindrical molds for continuous tubes, or other molds such as sand molds or molds for pressure castings.

In the operation of the device, molten slag will fiow through nozzle 46 at a point near thevertical center line of the cylinder 32 or slightly downwards therefrom, to form a slag film 50 of the width of the groove 38. Immediately in advance of the nozzle 46 and on the portion of the cylinder 32 turning downwards, a stream of molten metal is distributed through nozzle 42, which forms a .into suitable containers.

film 5| over the film and of the same width as or slightly narrower than the groove 38. In the sam manner, astream of molten slag flowing through nozzle 44 will form a film 52 over the film forming rim 35 and a stream of molten metal flowing through the nozzle 4| immediately in advance of the nozzle 44, will form a film of molten metal 53 over the film 52. As the double films ar carried downwards by each cylinder, the

thickness thereof will be controlled by the speed. of discharge of the metal and slag and the speed of rotation of said cylinders. The slag used is only a fraction of the weight or volume of the molten metal treated, and the lighter slag is squeezed from the heavier metal when the streams meet at the bight of the two cylinders through adjustable openings 39 and is collected into side receptacles 54 which conduct the slag so expelled, This is caused by the fact that the centrifugal force exerted on the slag and molten metal layers formed on the rim is less than the force of gravity. The lighter molten slag thus diffuses through the layer of heavier molten metal and floats on top of it before or when these layers reach the bight between the two cylinders, and the pressure caused by the meeting of the two streams of metal at the bight between the two cylinders forces the lighter slag through said openings. At the same time, the aggregated film 55 of' refined metal is projected through the channel 48 directly into the molds 49 where it is molded under the velocity given to it and the resulting impact force. may be done without any contact with air, if desired.

It is apparent from th foregoing that the refining operations described with regard to Figures 1 and 2 can be carried out with this machine, with the added advantage that the used slag may be mechanically eliminated.

The device illustrated in Figure 3 may also be used to produce wrought iron in the following manner: Molten pig iron from a blast furnace or from a cupola is first refined into pure iron free of sulphur and phosphorus in a machine such as is shown in Figures 1 and 2 and the pure iron produced is poured into a receiving device 40. If this source of metal is not available, desulphurized iron obtained from a Bessemer converter may be poured into a receiving device 40. At the same time, a siliceous molten slag may be com tinuously supplied through the pouring device 43 and nozzle 44 and through the pouring device 45 and nozzle 46. In this manner a film of molten pure iron will be continuously formed on either cylinder over a film of siliceous slag. The required proportions of slag and iron may be maintained by controlling the thickness of these films.

Since the siliceous slag has a melting point several hundred degrees lower than the melting point of pure iron, the slag film contacting the molten iron film will rapidly and uniformly supercool the molten iron films. This will liberate the occluded gases with shattering force and on account of the fluxing effect of the siliceous slag the minute particles of iron and slag will be aggregated and Welded together under pressure at the bight of the two cylinders into a film 55 of pasty or supercooled metal, into which film slag lS finely and uniformly distributed. while the excess slag which may be supplied for the operation is squeezed out through the openin s 39. As the machine is preferably operated at high velocity. the film 55 is given this high velocity and will impact into molds of any shape to form solid This or tubular products with a uniform dense structur having 1 to 4% slag content, in the form of finely distributed minute particles. These products can be directly usedcommercially as such or can be further finished by rolling, unless used as a cast product. The pure iron can be alloyed before pouring in the above machine if convenient or required for certain properties.

Thus a simple procedure has been provided wherein all conditions are under constant control, which eliminates a quantity of costly operations at present used to make the product known as wrought or puddled iron.

The procedure just described can also be applied to produce wrought nickel, wrought copper and many other metals which cannot be obtained under present operating conditions which contain slag finely divided through their cross sections in much the same manner as wrought iron.

Figures 5 and 6 show a variation to the previously describedrefining machines in which the film of molten metal or the substance to be refined and the film or films of molten refining slags are formed on the inner cylindrical surface of a rotary cylinder instead of the outside rim of the rotary cylinder. Since the principle of operation of each of these refining machines is substantially the same, the same part numbers will be applied to like parts in each of these figures.

A rotary working cylinder A is herein shown as being vertical and as being built of two parts 56 and 51 made of steel or alloy steel, machined all over and well balanced for high speed rotation. In this metal cylinder various refractory linings, tubular or of other shapes, can be assembled,

such linings being indicated by reference characters 58, 59 and 60 in Figure 5 and 6|, 62, 63 and 64 in Figure 6. These linings can be insulated from the metal cylinder by an insulating lining or by an air space indicated at 65. These linings, either made in the machine byramming and compressed by centrifugal action, or made of assembled bricks, may have different compositions which may be best suited to withstand the action of the molten metals or molten slags coming in contact with their working surfaces or to participate in the refining action by combining with some of the metalloids or impurities existing in the metal treated. For example, lining 8| may be made of silica brick or rammed silica sand while lining 62 may be made of magneslte brick or rammed sintered magnesite and dolomite and lining 63 may be a brick of zirconium oxide to prevent erosion.

The working cylinder A is supported in a machine frame 66 by a self-aligning cradle 61 having a convex bearing surface engaging said frame to permit pivotal movement thereof about an axis perpendicular to the axis of rotation of said cylinder. A flanged retaining member 68 and bearings 69, B9 are provided to mount said cylinder in said cradle. A bevel gear ring I is bolted to the upper side of a. flanged lower portion II of the upper cylindrical portion 56 and is meshed with a bevel gear I2 on a shaft I3. Said shaft is mounted in a bearing I4 in the frame 68 and a pulley I is shown by broken lines as being keyed on said shaft for driving said shaft. Said pulley may be driven from a suitable motor (not shown) by means of a belt either directly from said motor or through a geared reduction drive Or a usual form of variable speed drive. Since the speed of rotation of said cylinder must be suflicient to hold the molten metals and substances treated in films or layers against the inside of the cylinder, it is readily apparent that the axis of rotation of sold cylinder may be horizontal or at various angles between the horizontal and vertical, as well as vertical, if desired.

The means for pouring the metal and reagents into the inside of said cylinder includes a chamber a divided into a pouring box I. having a nozzle 'II depending within said cylinder and a pouring box I8 having a depending nozzle ll extending within said cylinder a greater distance than the nozzle 11. Figure 6 shows a third nozzle or feeding tube 80 extending within its cylinder between the nozzles II and I8 and leading from another pouring box (not shown). The discharge ends of the nozzles 11 and I! are inclined downwardly to direct a regulated amount of molten metal, slag or other material employed in the process, against the inner wall of said working cylinder at a constant rate of speed and at selected levels so each material will be immediately picked up and formed into'a film by said cylinder as it isdelivered from its respective nozzle.

The delivery end of said cylinder freely rotates within a collector 16a which includes two receptacles, one of which receptacles 'I'Ia serves to receive the refined metal and the other of which receptacles serves as a skimmer 80a, for the slag.

The receptacle IIa is preferably of a circular form and as herein shown is sealed from contact with the air by means of a seal indicated generally by reference character 18a and disposed between the top of the collector 76a and the outer wall of the cylinder A. Said seal may be of any well known construction, such as asbestos composition, mercury or any other suitable form of sealing means.

The receptacle Ila may have an inclined bottom for quick aggregation and drainage of the continuously expelled molten metal through an opening 19a which conducts the metal to a ladle or mold. Said receptacle may also have a number of radial openings (not shown) leading to as many molds. The slag is drained through stationary circular skimmer "a, which collects the separated slag so it will run down through an opening 82 by gravity.

In Figure 6 the skimmer 80a is shown as having an integrally formed pipe 83 extending through the center thereof to permit a gas or oil fiame to preheat the refractory lining before operation of the device, to keep the treated metal at the proper temperature during the refining operation, if necessary.

The circular skimmer 80a may be made of any suitable refractory material capable of withstanding the action of the slag formed.

In the device shown in Figure 6, molten slag may also b delivered from the feeding end of the working cylinder A through an opening 84, which throws the slag into a special slag box ll provided with a drain 86 and stack pipe 81, for free elimination of the gases.

Referring now to several refining operations which can be made in th machine just described, in the desulphurization and dephosphorization of molten pig iron or of molten unrefined steel from an acid Bessemer or an electric furnace or an open. hearth furnace, a hot fluid molten calcium slagis supplied through nozzle 11. This slag is formed into a circular thin film moving downwards inside of slightly conical refractory lining 58 by rotatable movement of the cylinder A. The molten metal to be refined, eith r steel or iron, is then supplied through the nozzle 10 at a i e I v I vertical level slightly under the discharge level of the slag, and rotatabl movement of said cylinder forms said molten metal into a thicker circular film moving downwards over the film of calcium slag. On account of-the lighter specific gravity of the molten calcium (lime) slag, this slag will first contact the film of molten iron or steel on its outside surface and then will gradually b forced mechanically through it under the centrifugal action exerted, thus submitting every particle of the metal film treated to the action of the refining slag and eliminating all sulphur and phosphorus contained. On its further downwards motion, this slag containing all the sulphur and phosphorus in the form of sulphates and phosphates, as well as all impurities and inclusions contained, will be completely separated from the treated metal and the refined and centrifugally cleaned metal will continuously fiow away through the openings 8| and 19a to a ladle or mold, whil the used slag will be continuously drained through the skimmer sleeve 80a and received in a container for further use or sale.

By proper disposition of the conicity of lining 58 with the outside diameter of skimmer 80a and the diameter of circular outlet 8|, clean metal only is continuously expelled into collector 16a and a fixed quantity of molten metal is constantly held inside the refining machine in the form of a slightly conical film or layer whose weight is insignificant in relation to the total weight of the working rotary cylinder. This material being a liquid is self-levelling and hasa balancing effect on the rotation of the working cylinder.

Pig iron and some steel are now desulphurized with powdered. calcium carbide, also with soda ash or caustic soda and while these reagents have a quick and powerful effect, they must be evenly distributed throughout the metal in order to be effective. For this operation, molten pig iron or steel may be supplied through the nozzle ll, to form a circular film covering the lining 58 and either one of the above powdered reagents may befed through the nozzle 19 and be continuously impinged and evenly brought in contact with the inside surface of the thin film of molten metal to be treated, thus insuring maximum eifectiveness. In this operation, the resulting slag is continuously eliminated without coming into contact with linings 58 and 59, preventing all detrimental effect to these two linings.

In transforming molten pig iron into pure iron in the device shown in Figure 6, molten iron ore or a molten mixture high in iron oxide may be poured through .the nozzle 11 to form a film inside of the lining Bl. Molten pig iron may also be poured through nozzle 19 to form a film over the-molten iron oxide film. Besides the large surface contact between the two films, the molten iron ore, having less specific gravity, will be forced through the film of molten pig iron. This will oxidize by surface contact, diffusion and mechanical penetration, all metalloids, such as, phosphorus, silicon, manganese and carbon contained in the pig iron in a practically instantaneous manner under the conditions created. As a consequence of the centrifugal action used, three levels will be created inside of lining 6|, the outside metal being pure iron, which is more dense, inside of which will be a layer of pig iron less dense and in the course of being refined, and inside of this metal layer will be a film of slag, purposely kept very thin by providing a constant elimination of the slag through opening 84.

The refractory brick lining 64 has peripheral slots a which are so placed in relation to the internal diameter of the lining 62 that these levels are kept constant while the pure iron produced flows downward through said slots at a constant speed. Another series of slots 64b are provided in saidrefractory brick lining 64 to permit a thin running molten calcium slag, supplied through the tube 80, to be impinged over the film of pure iron moving downwards inside of lining 62 by the centrifugal action of the cylinder. This will thoroughly remove all traces of sulphur and phosphorus remaining in the iron. This slag is continuously expelled and drained through the skimmer 80a, as previously described, while the refined and pure iron are collected through a collector 16a, as shown in Figure 5, and drained into a ladle.

As a variation of the above operation, molten pig iron can be supplied through nozzle 11 to form a thin film insidev of lining 6| and instead of using molten iron ore to produce the oxidation of the metalloids to be eliminated, air can be blown through nozzle 19 to quickly oxidize all the metalloids contained, in the same way as in converters in which the air is blown by tuyeres located. above the bath of molten iron. As a result of this operation the same three levels of pure iron on the outside, pig iron not yet refined against the pure iron, and slag against the pig iron, are established with constant elimination of the oxides formed through opening 84 and with further desulphurization and dephosphorization accomplished exactly as previously described. This same operation can be applied to many other metals such as copper, nickel, etc. In the case of copper, powdered charcoal would be used in conjunction with the dephosphorizing slag to reduce the copper oxides formed and the oxygen free pure copper could be directly cast into molds in the resulting carbon monoxide gas atmosphere. For certain purposes, instead of blowing air over the surface of the thin moving molten metal film formed, more effective gas reducers such as dry hydrogen could be used to procure a complete reduction of unwanted metalloids.

Another variation of the process of my invention consists in feeding materials in powder form through the nozzle 19, which are capable of producing the desired reduction or oxidation. In the case of molten pig iron, iron ore in a fine powdered condition will be reduced by contact with the molten pig iron film, forming an exothermic reaction by combining with the silicon and carbon of the pig iron, and as the film is continuously formed and continuously presents a clean surface to the iron ore powder, the slag is also continuously eliminated.

If desired, a mixture of metal oxide and aluminum powder may be supplied through tube 8!] inside of the refractory brick 64 and ignited while the machine is rotated. A continuous supply of the above mixture may be kept supplied to the cylinder A through the nozzle 11. If the mixture is too unstable, the metal oxide can be supplied continuously through the nozzle 11 and aluminum or magnesium can be supplied through the nozzle 19. Under these conditions, the reaction can be continuous and as long as it continues, the molten metal reduced from the oxide, if a single metallic oxide or ore has been used, or the mixture or alloy of various metals, if several metallic oxides or ores have been purposely used in predetermined proportions, will form a film or layer against lining GI and fiow through the slots of refractory lining 64 after the controlled level has been established and downwards into the lining 62. The film formed in the latter lining can be subjected to the action of a selected molten slag supplied through holes 64b of refractory 64 and the balance of the operation will be exactly as previously described for the refining of pig iron into steel.

This procedure is generally applied to the reduction of metals of high melting point, such as, tungsten, chrome, tantalum, titanium, molybdenum, vanadium, platinum, uranium, etc. It enables these metals to be obtained individually not only in the molten state but also enables them to be refined and cast directly into appropriate molds. .By a mixing of the metallic ores or oxides used, it enables exact alloys or mixtures between these high melting metals to be obtained in a refined condition and to be directly cast in appropriate molds.

In the modified form of refining machine shown in Figure 7, a rotary shaft and hub 08 is supported on a machine frame 09 in a bearing 90. Said shaft and hub may be driven at any required speed by a pulley, a geared reduction drive,

or variable speed drive (not shown). The shaft 88 is preferably hollow, to permit air or hydrogen or any other gases or mixtures to be fed under pressure through a central hole 9|. An air chamber 92, whose volume is controlled by spacers 83 serves to distribute the air or gas under pressure to circular slots or tuyeres 04 and 95 so as to form two or more vertically blown curtains of gas or air under pressure. A bottom piece 96 fitting into an annular flanged ring 91 will support and rotate a circular disc 98, made of refractory brick or molded material. A circular frame 99 is fitted over the hub 08 and driven by keys indicated at I00. Said frame 99 has two or more vertical circular walls IM and I02 into which are fitted or molded refractory linings I 03 and I04, which have a number of slots or outlets I05 and I06 of adjusted and interrelated cross-sections. The outlets I05 are arranged to spread the molten metal treated, over distributing and spreading disc I01, also made of a refractory material. A collector I08 receives and drains the refined metal through outlet I09 into a ladle or a mold (not shown). Another collector I I0 is disposed above the collector I08 and is supported on the upper side thereof. Said collector is adapted to receive slag forced over a circular dam III and drained through an outlet IIZ. Over said collector II 0 is provided another collector II3, which receives the slag forced over circular dam I I4 and drains it through an outlet I I5, which is also made large enough to evacuate all the gases created as well as the air blown. These collectors support, in the center of the machine, a pouring device for molten metal IIS which may be made of a single, or of several distributing chambers. Over collector IIO may be supported one or more feeding hoppers II1, for supplying liquid or powdered materials to the spreading disc I01.

The operation of the machine will be understood by describing one specific refining operation. For instance, molten pig iron is continuously poured through pouring device IIi at a continuous rate per minute. This liquid iron upon contacting the fast rotating refractory disc 00 will be spread into a film becoming thinner as it reaches the periphery of the disc, where it is broken into a sheet-like spray, projected in a direction approximately perpendicular to its axis of rotation. This spray, made of droplets of molten iron, crosses under the velocity acquired, the curtains of air or other gases under pressure blown through the slots or tuyeres 94 and. ll, and the metalloids contained are instantly oxidized. This spray after crossing the air curtains hits the circular refractory I03, against which it forms a vertical film and in that condition, under the centrifugal force exerted, the molten iron separates and fiows at a constant rate through slots I05 while the slag and oxides flow also at a constant rate over circular dam I I4. The molten iron flowing from slots I0! is spread over circular disc I01 where it forms a film and this film receives through hoppers II1 one or more streams of molten calcium slag, or some other powder reagent, and both films leave disc I01 in a finely atomized condition in a sheetlike spray. as above, and are thrown against circular refractory I04 where they form a vertical film or layer, from which and under the centrifugal action, the refined metal is continuously separated and cleaned and expelled through slots I06 into collector I08, while the slag is continuously expelled over circular dam III into collector I I 0.

This same procedure'applies to most metals, using the proper slag mixtures or powdered materials to remove by chemical combination the elements which have to be eliminated from the molten metal treated. By forcing the molten metal treated to successively form horizontal and vertical thin films and to be successively atomized, the maximum division is obtained by presenting a maximum area of the metal in contact with the oxidizing and refining agents used, in relation to the weight of metal treated, and these conditions permit instantaneous and continuous chemical reactions to be obtained and maintained and permit a high rate of production.

The foregoing is intended as illustrative or exemplary rather than as limitative or restrictive and it will be understood that within the scope of my invention, I may resort to many variations, additions, omissions or substitutions without departing from the spirit and principles thereof. Those skilled in the art will readily appreciate and understand the possibilities and ramifications thereof, the scope of which is rather to be indicated by the appended claims.

I claim as my invention:

1. A process for refining a molten material which consists in providing a molten refining substance and in forming the molten material and the refining substance into contiguous rapidly moving thin films by pouring the molten material and the molten refining substance on a rapidly rotating film forming member in superimposed relation with respect to each other.

2. A process for refining a molten material which consists in forming a molten material into a thin film by pouring the molten material on a rapidly rotating film forming member, in depositing a controlled amount of refining substance onto this film to cause the film of material to draw the refining substance into a thin film superimposed on the film of molten material, and in separately collecting the products of the reaction. Y

3. A process for refining molten materials which consists in progressively depositing an unrefined molten material and a molten refining substance on a rapidly moving film forming surface, in drawing out the molten material and refining substance into superimposed thin films by said filmformingsurface, and in separately collecting the products of the reaction.

4. A process in accordance with claim 3 wherein the products of chemical reaction are separated by centrifugal action imparted .thereto by the film forming surface.

10. A process, for refining molten metals which consists in forming the molten metal into a thin film by centrifugal action, forming a chemical reagent into a thin film in adhesive contact with the film of molten metal and in centrifugally separating the refined metal from the refining substance and in collecting the products of reaction.

11. A process for obtaining chemically pure metals which consists in forming and propelling 6. A process for chemically modifying molten I metals which consists in forming the molten metal into a thin film by depositing it on a rapidly moving film forming surface, and in blowing a gaseous substance against the film of molten metal while in a'rapidily moving condition.

7. A process in accordance with claim 6 wherein the products of reaction are separated by centrifugal action and are separately collected in an impacted form,

8. A process for chemically removing dissolved and combined elements from molten metal which consists informing the molten metal into a thin film by depositing it on a rapidly rotating film forming surface, in continuously distributing over the film surface of the molten metal, a predetermined and constant weight of powdered reagents capable of chemically combining with the elements to be removed, and in continuously removing the products of chemical action and separately collecting the molten metal and the resultant slag by centrifugal action.

9. A process for chemically modifying a molten ferrous metal which consists in forming and propelling at a high velocity a film of molten slag and in forming and propelling at a high velocity a film of molten metal on this film of molten slag and in continuously squeezing the two films between vtwo rapidly rotating forming cylinders and projecting the unsupported film of metal and slag into a collecting means under the velocity of impact.

a molten metal into a thin film moving at a high velocity and in removing the impurities by forming and propelling a refining substance into a thin film moving at a high velocity in contact with the film of molten metal and in separating and collecting the products of reaction from the pure metal by centrifugal action.

12. A process for refining molten copper which consists in continuously forming the molten unrefined copper into a thin film, forcing a blast of air over the film of copper to oxidize the impurities therein, and in subsequently forcing a calcium slag and powdered charcoal through the film of molten copper to combine with the copper oxide and phosphorus contained and in continuously separating the refined pure copper from the products of reaction by centrifugal action.

13. A process for obtaining pure iron free from inclusions and impurities which consists in forming molten pig iron into a molten film moving at a high velocity, forcing a film of iron oxide through the film of molten pig iron by centrifugal action, in subsequently refining the molten iron by contact with a film of molten slag and in separating the impurities from the pure iron by centrifugal action.

14. A process for refining molten metals which consists in forming the molten metal into a thin film by centrifugal action, depositing an oxide powder onto the film of molten metal and forming this powder into a thin film in adhesive contact with the film of molten metal, in liberating the oxide powder from the molten metal by aluminothermic reaction which includes the introduction of aluminum powder, and in centrifugally separating the refined metal from the oxide powder and separately collecting the products of reaction.

, JOSEPH M. IWERLE.

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