US2808325A - Process of refining pulverized metallic ores involving the production and use of ore pellets - Google Patents

Description

Us E 'on one PELLETS Andre Raymond Snbervie, CastreS-Gironde, Renonville,

France, assignor to Metal Sub'erdop S. A., Casablanca, Morocco, a corporation of Morocco NoDjrawing. Application February 24,1953, Serial No. 338,598

' Claims priority, application France March 21, 1952 Claims. or. 75-29 The present invention relates to the agglomeration of granular or pulverized materials, such as the residues, wastes or dusts of the metallurgical, chemical or extracting industries, for the purpose of making such materials suitable for industrial uses or treatments, and especially in metallurgy.

It is an object of this invention to provide a process for efiecting such agglomeration in the cold or at low temperatures employing the usual equipment, such as pug mills, agglomeration presses, etc.

It isanother object of this invention to provide such process of agglomerating raw materials of a nature and composition appropriate for metallurgical operations, in particular for feeding blast furnaces.

The process of agglomeration according to this invention is characterized in that the binder for the granular or pulverized materials results from the admixture of a pulverized heavy hydrocarbon pitch, a support, such as a hydraulic binder, and a hydrocarbon oil. The pulverized mixture of heavy hydrocarbon pitch and support are preferably-introduced into the mixer in equal parts, although, if desired, up to about three parts of a heavy hydrocarbon pitch may be mixed with each part of the support. In this specification all references to parts are by weight.

The heavy hydrocarbon pitch may be a coal tar pitch of coke oven or gas house tar origin, a water gas tar pitch or asphalt. It should have a softening point of from 150 F. to 200 preferably about 160 F. to 170 F. in' the case of a coal tar pitch and about 250 F. or higher in the case of asphalt.

The hydrocarbon oil is substantially non-volatile at atmospheric temperatures. This assures that the final viscosity of the binder remains substantially constant, i. 0., does not vary with time. This oil is preferably in the form of a bitumen or a tar emulsion or a soluble oil. By soluble oil ismeant a mixture of oils in such proportions that the density of the mixture is substantially equal to fat 70 C. Such oil, after the treatment described below, mixes with water in all proportions.

By mixing the hydrocarbon oil, as defined above, with the pulverized mixture of heavy hydrocarbon pitch and support, a synergistic action takes place between the heavy hydrocarbon pitch and the support. The pitch is absorbed or fluxed by the oil; this results in the formation of a plastic binder of high viscosity. The viscosity is easily regulable by the proportion of oil employed. There is thus obtained a binder having good bonding properties which assures excellent agglomeration. At the same time, the water originating from the breaking up of the emulsion, when such emulsion is employed or added with the soluble oil when the latter type of oil is used, reacts with the hydraulic binder to form a hydraulic skeleton when the'binder sets resulting in agglomerates of improved hardness and impermeability. The water of demulsification is, in fact, slightly alkaline and hence 2,808,325 Patented Get. 1, 1957 2 favors the formation of the hydraulic binder, which, as is known, is formed more readily in a slightly alkaline medium.

It must be stressed that these transformations of the constituents of the binder, i. e., pitch, hydraulic binder serving as support and oil, occur even in the cold, i. e., at atmospheric temperatures or at temperatures at which the pitch is in a non-molten state. Solid pitches are commonly used as agglomerants. Such pitches, however, achieve agglomeration only in the molten hot state and by mixture in a liquid, pasty form with the materials to be agglomerated. In, the present invention the pitches are transformed into a binder within the body of the mass being agglomerated, due to absorption or fluxing onthe part of the pitches with the oil which has covered each grain to be agglomerated.

It will be noted also that this process is different to or independent of the quantity of water employed. While in the usual agglomeration, water is generally undesirable, as it dilutes the binding materials and prevents their adhesion, in the present invention it is employed to react with the hydraulic binder. Because of the affinity of the pitch .with the oil introduced, for example, in the form of an emulsion, the excess quantity of water separates and does not hinderthe agglomeration in any way. Furthermore, the agglomerates obtained. are insensitive to the presence of water in excess or derived from an outside source, such as rain water, both during the agglomeration and subsequently when stored or handled.

It.is an important feature of this invention to start with the constituents, namely, heavy hydrocarbon pitches, hydraulic binder, oil and water, which separately have no agglomerating properties in the cold and to obtain by their mutual interaction ,an effective binder affording many advantages over prior known binders. These advantages are the ease and convenience of employing the binder of this invention, the quality of the agglomerates obtained and also the reduction in the amount of binder required. It should be further noted that the binder of this invention, which is produced by absorption or fluxing of the heavy hydrocarbon pitch and oil and the interaction between the hydraulic binder and the water, is substantially non-volatile at atmospheric temperature and hence does not change with time, and the viscosity thereof is easily regulable by varying the proportion of hydrocarbon oil. 7

The support used in accordance with this invention preferably contains lime. Lime alone may be used as the hydraulic binder, or it may be a constituent of the binder as in the case of hydraulic cement. The support may be in the form of limestone, dry and ground, for example, in the form of limestone flux, or other flux, such as that known as Fondant in France, or those used in the metallurgical industry. The choice of the support thus added to the heavy pitch depends on the applications envisaged. Its nature may be determined according to the uses anticipated for the agglomerates obtained by this invention. The expression hydraulic binder" is used herein and in the claims to mean a binder, such as, cement, limestone, lime, etc., which 'sets when admixed with water.

To transform at atmospheric temperature the mixture of heavy hydrocarbon pitch and hydraulic binder into a mixture having bonding properties, the hydrocarbon oil is employed, preferably in the form of an emulsion. The emulsion may be of the water-in-oil type, or the oilin-water type.

The oil-in-water type of emulsion is obtained by mixing in a suitable apparatus, such' as a colloidal mill,.oil, bitumen or tar which maybe asp-halt, coke oven 1tar,i water gas tar, gas house tar, etc.,"- previously heated to about 90 C. and hot water in substantially equal parts with addition to the water of an emulsifying or a surface active agent, such as an alkaline resinous soap. The stability of such emulsion is improved by adding thereto suitable stabilizers, "such for example, as ammonia in the proportionof about 5 parts of the stabilizer per 1000 parts of the emulsion] On contact of the emulsion with alkali, originating, for example, from the hydraulic'binder, or specially introduced, breaking of the emulsion occurs with closing up on. the micelles and consequent formation of an oil film having a great afiinity for the pitch grains of the binder.

The Water-in-oil emulsion is obtained by admixing with the oil brought to a temperatureof between 60 to 90 C., water and an emulsifying or surface active agent along with alkalis, such as sodium carbonate, ammonia, etc. The sodium carbonate may be added in the proportion of from to 25% of the total weight of the emulsion. Such water-in-oil emulsions may be made by emulsifying crude tars, such as coke oven tars containing in suspension a small amount of amoniacal water or to which may be added a small amount of concentrated ammoniacal solution. For example, such emulsion" may be produced by mixing from 75 to 90 parts of a coke oven coal tar with from 10 to 25 parts of ammoniacal liquor and from 10 to 25 parts of sodium carbonate solution. The components may be mixed at a temperature not exceeding 140 F.

Such water-in-oil emulsions diffuse readily and immediately in the mass to be agglomerated. They are very adhesive; the water being exuded at the surfaces. They may be relatively concentrated in oil containing up to from 75% to 90% oil. Whenemploying such water-in-oil emulsions having high concentrationsof oil, they should be employed at a temperature suficiently high, e. g., about 90 C., to insure the necessary fluidity.

According to the process of this invention, it is advantageous prior to the introduction of the hydrocarbon oil, in the form of water-in-oil or oil-in-Water emulsions, to activate the materials to be agglomerated by a soluble oil. By soluble oil is meant an oil of a density equal to l or close to 1, capable of mixing with water in all proportions at room temperature to C.); such oil must be substantially non-volatile at atmospheric temperature.

Such soluble oil is obtained from oils containing substantially no constituents, distilling above 250 C. It can be obtained, for example, by mixing anthracene oils (den- I sity lll to 1.2), phenol oils (density close to 1), gas oil or light fuel oil (density 0.8 to 0.9). By suitably proportioning these oils a mixture of a density close to 1 or equal to l is obtained. To this mixture is added a'soap, such as an alkaline resinous soap, containing fatty acids.

Desirably the oil and soap are mixed in proportions of of the former to 30% of the latter, by weight. The soluble oil is used cold. The resultant mixture is agitated producing a mixture'which when placed in water disperses therein readily and homogeneously in the manner of cresol. An addition of sulfonated oil, for example, the sodium salt of sulfonated castor oil, in the proportion of 2 to 5 parts per 1000 parts of the mixture improves the Watermiscibility or solubility of the oil.

The soluble oil may also consist of an anthracene oil in the form of an emulsion containing an alkaline lye of the same'density as the oil.

The effect of the use of the soluble oil is to activate the material to be agglomerated so that the hydrocarbon binder more readily bonds therewith without being hindered by the water and the various clay fillers which may be present. The Water mixes with the soluble oil and the resultant mix is adsorbed by the filler, i. e., the finely divided solid particles present; the water then'exudes or is expelled from the resultant mixture. In short, the soluble oil cleans the material to be agglomerated and prepares them for bonding with each other by means of the binder formed by the mixture of heavy hydrocarbon pitches and hydraulic binder; the emulsion serves as an intermediary in the production of the final binder. The high final viscosity is obtained by proportioning the amount of heavy hydrocarbon pitch and support in the mixture. No heat need be imparted to the constituents of the binder during agglomeration. Heat, however, promotes the reaction, and, if desired, the duration of the agglomeration treatment can be reduced by heating.

The use of soluble oil is of particular importance when it is desired to agglomerate cold and dirty materials. When hot materials are agglomerated, whether they are not as a result of previous treatment or because they have been heated, the proportion of soluble oil to be employed may be reduced, and, if desired, the pretreatment of the material to be agglomerated with the soluble oil may be omitted. The application of this preliminary treatment of the material to be agglomerated will depend on the nature of the material-to be agglomerated, its temperature and also the degree of compression employed during agglomeration.

This invention may be carried out in the usual equipment, such as pug mills, agglomerating presses, etc.; special equipment is not necessary.

The pulverized materials to be agglomerated are placed in a pug mill and if needed, the soluble oil is introduced first, then the hydrocarbon oil in the form of an oil-inwater or water-in-oil emulsion. When the materials are coated with the soluble oil and the emulsion, the pulverized mixture of pitch and hydraulic binder is added. After mixing for a few minutes the coated materials containing the binder formed by reaction of the constituents are removed from the pug mill and conveyed into an agglomerating press, for example, a press of the type used for making coal pellets. The agglomeration may be carried out at any temperature below which the pitch is molten, say at a temperature of F. Under compression of the order of from 100 to 500 kilograms per square centimeter the materials assume their final form. The binder is obtained immediately in the plastic form (due to fluxing of the pitch with the oil) to which later, after setting, the skeleton of hydraulic binder is added. The water in excess, if any, over and above that required for reaction with the hydraulic binder and separated from any hydrocarbon constituent, such, for example, as the water present in the emulsion, is exuded whereby the removal of the agglomerates from the mold is facilitated.

This process is applicable to all pulverized or granular materials and the proportions of the constituents of the binder may vary according to the nature of the products to be agglomerated and their intended subsequent use. In general, in producing agglomerates embodying this invention the material that may be agglomerated may be treated with from 0.5% to 2%, soluble oil. In the agglomerate there may be incorporated from 1% to 6%, preferably 2, hydrocarbon oil emulsion and from 1% to 6% preferably from 2% to 3%, of a mixture consisting of heavy or solid pitch and a hydraulic binder, such as cement. The amount of water added may be from 7% to 20%, preferably 10%. All percentages in this paragraph are based on the Weight of the material to be agglom erated. s

An important application of the invention is in the prep aration from industrial wastes of agglomerates of powders or grains rich in iron oxide capable of being used as raw materials in the iron industry. For example, pyrite screening residues, blast furnace dusts, metal crushing wastes, and residual muds from the treatment of bauxites may be agglomerated by @heprocedure of this invention.

It is known that 'the screening 'of pyrites gives pulverized residues rich in iron which contain also an appreciable proportionoff'sulfur' which his desirable to eliminate for use in metallurgy. To extract the sulfur,

sidues at atmospheric temperatures without a binder to form cylindrical relatively thick blocks which are then with great precautions subjected to heating at temperatures of 1300 C. This'procedure apart from the fact that it results in the formation er excessive waste, requires prolonged heating; nor does it result in the completeextraction of the sulfur.

By means of the present process it is possible to obt-ain agglomerates of small dimensions, comparable to those of coal pellets of various sizes, which are readily heated'throughout their thickness with complete extraction of the sulfur. Agglomerates rich in iron oxide which are hard, strong, notlikely to be disintegrated into powder and free of sulfur result which form an excellent charge for blast furnaces.

It is also known that the dusts entrained by the exiting from blast furnaces, although rich in iron oxide and other metals, such as vanadium, are generally useless as charging stock for a blast furnace, because of their particle size. By agglomerating such dusts by the process of this invention, hard and stable agglomera'tes which may be charged directly into blast furnaces result.

in like manner the wastes from the crushing of iron and other ores and all other residues of industry production may be transformed into calibrated agglomerates.

The process of this invention may be used to agglomerate dusts of blast furnace gases with thewastes from ore crushing. Such agglomerates constitute a convenient means of enriching poor ores by addition of dusts rich in the metal in question to such poor ores and agglomerating the resultant mixture to produce a charge containing sufiicient of the metal in question to make its treatment economically profitable.

When agglomerating residues or wastes, whether they are those of pyrite screenings, the dust of blast furnaces, crushing wastes, etc., or mixtures thereof, it is advantageous to mix pulverized coke or coal fines with such dusts. By the incorporation of these combustible elements and also due to the presence of the hydrocarbon materials in the binder a self-burning agglomerate results which contains all the elements necessary for the reduction and for the production of cast iron.

It should be noted that the agglomerates have a regular well defined shape. Hence, when-placed into the blast furnace they form beds permeable to the blast, facilitating the reduction operations. Moreover, the agglomerates of this invention become porous due to combustion of the hydrocarbons they contain. This porosity facilitates the reactions taking place within the blast furnace with consequent improvement in the output of the blast furnace.

With this invention materials heretofore considered worthless maybe recovered and this may be accomplished in a manner which improves the capacity and operation of the blast furnace. By proper choice of the recovered agglomerated materials special cast irons may be produced which cast ironscontain constituents introduced in the form of agglomerates into the blast furnace which constituents improve the chemical and physical properties of the cast iron including its strength. Thus, by :agglomerating pyrite residues or crushing wastes with blast furnace dusts rich in vanadium and/ or bauxite-treatment muds rich in iron oxide and containing an apprecibale prcportion of titanium and charging the resultant :agglomerates into the blast furnace titanium vanadium castirons, may be produced. The agglomerates thus charged into the blast furnace may also contain the fuel necessary for the transformation of the iron constituents into the form of molten iron which may be cast to produce the desired cast iron.

By proper choice of the support mixed with the heavy hydrocarbon pitches to form the pulverized mixture which cooperates with the hydrocarbon oil and water to formthefinzil binder of the agglomerates, agglomerat'es may be produced containing desired additives for the molten metal. Employing this technique the nature and proportion of these additives may readily be controlled accordingto the'quality of the metal it is desired to produce. Thus, by using a support of limestone or limestone flux or other flux, agglomerates may be produced which contain the iron ore, the fuel necessary for its reduction, as well as the compounds intended to constitute the slag. While limestone and coke are added for obtaining agglomerates containing additive fluxinlg and combustible products, the amounts "are 2to 10%, preferably 5% of coke or coal and 2 to 10%, preferably 5% of limestone of the agglomerant, said percentages being by weight.

It will be further noted that the constituents required for the practice of this invention are normally found near metahurgical plants. Thus, from the coking plants and the coal mines generally near the blast furnaces, not only the coke dust, fines or fsc'hlamms required for t'he production 'of self-burning a gglomerates, are available but also the tars and ammoniacal liquor serving for the preparations of oil-in-water or water-'in-oil emulsions, as well as the heavy hydrocarbon pitch required for the production of the binder are available. One of theimportant advantages of this invention is that it enables the production of agglomera'tes of metallurgical products employing raw materials'which are by-products of metallurgical industries or related industries.

Example I.' Pyrite screening residues duced byf'mixing the oil hereinbelow described with a resinous alkaline soap in the proportions hereinafter indicated. This oilhas a density of about '1 and is produced by mixing from 30% to 40% anthracene oil, 10% to 20% phenol: oil and from 30% to 40% light fuel oil. to parts of'this mixture are added to 20 to 30 parts resinous alkaline soap containing 50% fatty acid.

When the soluble. oil is distributed throughout the residues there is then added 3 to 4 kilograms of water-in-oil tar emulsion at a temperature of from 60 to C. The tar emulsion may, for example, be a crude coke oven tar containing ammoniacal Water. 7 7 After mixing the constituents noted there is intro duced 3 to 4 kilograms of a' mixture of dry pulverized pitch and hydraulic cement. Thereafter the water necessary to supply the water required to hydrate the cement is added; from 5% to 6% water based on the material subjected to agglomeration is added.

The resultant mixture isconveyed to a press of the type of a coal pellet press. Ovoid agglomerates each weighing from 60 to 80 grains are thus obtained.

Immediately after the agglomeration these agglomerates easily withstand a free fall'of 2.5 meters; on a double rail. Under a more. violent impact they break into compact fragments without formation of dust. Heated to 1300 C. these agglomerates give off substan tially completely all sulfur and arsenic. They are heated uniformly throughout their thickness. The products obtain'ed' after such heating retain their shape and are hard and strong; they contain a large proportion of iron oxide and are'admirably suited for use in charging blast furnaces.

Example [Ir-Blast furnace-dusts .The dust agglomerated .in this example is extracted from blast furnace gases which represent from 7% to 10%;of the, ore treated and containing 50% oxide.

These dusts collected hot or if previously collected reheated to 80' C. are introduced into a pug'mill; Into this pug millis introduced successively 1% to 1.5% by 7 weight of soluble oil as hereinabove defined, 4% to 6% of water-in'oil tar emulsion, and 4% to 6% of a mixture of equal parts of pulverized pitch and limestone.

The resultant paste is conveyed into 'a pellet press. The ovoid agglomerates obtained are hard, strong and do not soil the hand when touched. They are weather resistant and hence can be stored without risk of destruction. They are admirably suited for use in charging blast furnaces.

Examples III.Wastes from iron ore crushing I In addition to the waste from iron ore crushing there is introduced into a pug mill successively 0.5% by weight of soluble oil, 2% to 3% of water-in-oil tar emulsion, and 2% to 3% of pitch limestone mixture.

The resultant paste pressed in a pellet press furnishes ovoid agglomerates which can be charged directly into the blast furnace and which already contain the necessary fluxing constituents.

Examples IV.Mixture various metallurgical wastes There is introduced into a pug mill equal parts of blast furnace dust and crushing wastes and then added thereto 0.5% to 1% of soluble oil, 3% to 5% of a water-in-oil tar emulsion, and 3% to 5% of a pitch hydraulic mixture.

The paste formed is conveyed into the pellet press. The agglomerates thus produced may be charged directly into blast furnaces.

Example V.Additi0n of coke, coal fines or schlamms There is introduced into a pug mill, 90 kilograms of blast furnace dust, kilograms of coke dust, fines or schlamms, dust extracted from blast furnace gases, soluble oil, water-in-oil tar emulsion and a mixture of equal parts'of dry pulverized pitch and limestone in'th'e'p'roportions and following the procedure outlined in Example 11 above. 0 i

The resultant paste is pelleted producing agglomerates which are self-burning in that they contain the fuel necessary for the reduction of the iron oxides.

By employing in the pug mill a mixture of equal parts of hard pitch and ground limestone flux the resulting agglomerates possess the necessary elements for the formation of the desired slag. 1

Example VI.C0mplex mixture There is introduced into the pug mill wastes from iron ore crushing, 10% blast furnace gas dust, 10% red mud from bauxite treatment, and 10% coke dust. iTo'this mixture is added soluble oil, water-in-oil tar emulsion and a mixture of equal parts of heavy pulverized pitch and limestone as in Example H above. The resultant paste is then agglomerated also as in Example 11 above. The agglomerates thus produced are self-burning and maybe employed directly for charging blast furnaces to produce a titanium-vanadium cast iron.

Since certain changes may be made in carrying out the above process and in the product, without departing'from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is: Y j

1. A method of refining pulverized metallic ores, which method comprises adding to the pulverized ores an emulsion of water and hydrocarbon oil while agitating to coat said ores with'said emulsion, then adding to the coated ores a mixture containing powdered bitumen and a hydraulic binder in approximately equal proportions by weight while agitating to uniformly distribute said mixture throughout the coated ores to cause (41) said hydrocarbon oil to flux with said bitumen and form a bituminous binder for said pulverized metallic ore particles and (b) said water to react with said hydraulic binder to form 'an inorganic binderforsaid pulverized metallic ore particles, compressing the'resultant mixture to produce individual pellets and introducing the pellets into a metallurgical furnace and subjecting them to reduction in saidfurnace' by combustion, the combustion of said bituminous binder in said pelletsduring the initial stages of said reduction enhancing the porosity of said pellets which are then retained in pellet form by said inorganic binder and thus facilitating the refining of the metallic constitutents of said pellets as said reduction continues.

2. A method of refining pulverized metallic ores, which method comprises adding to the pulverized ores from 1% to 6% by weight based on the weight of said ores, of an emulsion of water and hydrocarbon oil while agitating to coat said ores with said emulsion, then adding to the coated ores from 1% t0 6% by weight based on the weight of said ores of a mixture of powdered pitch and a hydraulic binder, said mixture containing said pitch and hydraulic binder in approximately equal proportions by weight, agitating said mixture to uniformly distribute said pitch and hydraulic binder throughout the coated ores and to cause (a) said hydrocarbon oil to flux with said pitch to form a pitch binder for said pulverized metallic ore particles and (b) said Water to react with said hydraulic binder to form an inorganic binder for said pulverized ore particles, compressing the mixture to produce individual ovoids, and introducing the ovoids into-a metallurgical furnace and subjecting them to reduction in said furnace by combustion, the combustion of said pitch binder in said ovoids during the initial stages of said reduction enhancing the porosity of said ovoids which are then retained in ovoid form by said inorganic binder and thus facilitating the refining of the metallic constituents of said ovoids as said reduction continues.

3. A method of refining pulverized metallic ores, which method comprises adding to the pulverized ores from 1% to 6% by weight, based on the weight of said ores, of an emulsion of water in a hydrocarbon oil, said emulsion containing from to by Weight of oil, While agitating to coat said ores with said emulsion, then adding to the coated ores from 1% to 6% by weight, based on the weight of said ores, of a mixture of powdered pitch and a hydraulic binder, said mixture containing said pitch and hydraulic binder in approximately equal proportions by weight, agitating to uniformly distribute said mixture throughout the coated ores, and to cause (a) said hydrocarbon oil to flux with said pitch to form a pitch binder for said pulverized metallic ore particles and (b) said water to react with said hydraulic binder to form an inorganic binder for said pulverized ore particles, compressing the resultant mixture to produce individual pellets and introducing the pellets into a metallurgical furnace and subjecting them to reduction in said furnace by combustion, the combustion of said pitch binder in said pellets during the initial stages of said reduction enhancing the porosity of said pellets which are then retained in pellet form by said inorganic binder and thus facilitating the refining of the metallic constituents of said pellets as said reduction continues.

4. A method of refining pulverized metallic ores, which method comprises mixing the pulverized ores with a hydrocarbon oil having a density about equal to that of water while stirring to coat said ores with the 'said oiL'thereafter mixing the oil-coated ores with an emulsion of water and hydrocarbon oil while stirring to coat the oil treated ores with said emulsion, thereafter adding to the coated mixture, a mixture containing approximately equal proportions by weight of dry powdered pitch and a hydraulic binder while stirring to uniformly distribute the said mixture of pitch and binder throughout the emulsion coated ores and to cause (a) saidhydrocarbon oil of saidemulsion to flux With said pitch to form a pitch binder for said pulverized metallic ore particles and. (b) said water to react with said hydraulic binder to form an inorganic binder for said pulverized ore particle s, compressing said mixture to form individual pellets, and introducing the pellets into a metallurgical furnace and subjecting them to reduction in said furnace by combustion, the combustion of said pitch binder in said pellets during the initial stages of said reduction enhancing the porosity of said pellets which are then retained in pellet form by said inorganic binder and thus facilitating the refining of the metallic constituents of said pellets as said reduction continues.

5. A method of refining pulverized metallic ores, which method comprises mixing the pulverized ores with from 0.5% to 2% by Weight of a hydrocarbon oil having a density about equal to that of water while stirring to coat said ores with the said oil, thereafter mixing the oil-coated ores with from 1% to 6% by weight of an emulsion of water and a hydrocarbon oil while stirring to coat the oiltreated ores with said emulsion, thereafter adding to the emulsion coated ores from 1% to 6% by Weight of a mixture containing approximately equal proportions by weight of dry powdered pitch and a hydraulic binder while stirring to uniformly distribute the said mixture of pitch and binder throughout the emulsion coated ores and to cause (a) said hydrocarbon oil of said emulsion to flux with said pitch to form a pitch binder for said pulverized metallic ore particles and (b) said water to react with said hydraulic binder to form an inorganic binder for said pulverized ore particles, compressing said mixture to form individual pellets, and introducing the pellets into a metallurgical furnace and subjecting them to reduction in said furnace by combustion, the combustion of said pitch binder in said pellets during the initial stages of said reduction enhancing the porosity of said pellets which are then retained in pellet form by said inorganic binder and thus facilitating the refining of the metallic constituents of said pellets as said reduction continues, all of said weight percentages being based on the Weight of said ores.

6. A method of refining pulverized metallic ores, which method comprises preparing a hydrocarbon oil having a density equal to that of water and miscible with water in all proportions by mixing 30% to 40% by weight of anthracene oil, to 20% phenolic oil and 30% to 40% by weight of light fuel oil with a small amount of resinous alkaline soap, coating the said pulverized ores with 0.5% to 2% by weight, based on the weight of said ores, of said hydrocarbon oil, adding to the thus coated ores from 1% to 8% by weight, based on the Weight of said ores, of an emulsion of water and hydrocarbon oil while agitating to coat the oil coated ores with said emulsion, adding to the emulsion coated ores from 1% to 6% by weight, based on the weight of said ores, of a mixture containing equal parts by weight of dry powdered pitch and hydraulic binder, agitating to distribute said mixture throughout the emulsion coated ores to cause (a) said hydrocarbon oil of said emulsion to flux with said pitch to form a pitch binder for said pulverized metallic ore particles, and (b) said water to react with said hydraulic binder to form an inorganic binder for said pulverized ore particles, compressing the resulting mixture to produce individual pellets, and introducing the pellets into a metallurgical furnace and subjecting them to reduction in said furnace by combustion, the combustion of said pitch binder in said pellets during the initial stages of said reduction enhancing the porosity of said pellets which are then retained in pellet form by said inorganic binder and thus facilitating the refining of the metallic constituents of said pellets as said reduction continues.

7. A method as defined in claim 5, in which the emulsion is a water-in-oil emulsion and contains from to by weight of oil.

8. A method of refining pulverized metallic ores, which method comprises mixing with the pulverized ores from 2% to 10% by weight, based on the weight of said ores, of a powdered fuel, adding to this mixture from 1% to 6% by weight, based on the weight of said ores, of an emulsion of water and hydrocarbon oil while stirring to coat said mixture with said emulsion, adding while stirring to the emulsion coated ores from 1% to 6% by weight, based on the weight of said ores, of a mixture containing approximately equal parts by weight of dry powdered bitumen and hydraulic binder while agitating to uniformly distribute said mixture throughout the coated ores to cause (a) said hydrocarbon oil to flux with said bitumen and form a bituminous binder for said pulverized metallic ore particles and (b) said water to react with said hydraulic binder to form an inorganic binder for said pulverized metallic ore particles, compressing the resultant mixture to produce individual pellets, and introducing the pellets into a metallurgical furnace and subjecting them to reduction in said furnace by combustion, the combustion of said bituminous binder in said pellets during the initial stages of said reduction enhancing the porosity of said pellets which are then retained in pellet form by said inorganic binder and thus facilitating the refining of the metallic constituents of said pellets as said reduction continues.

9. The method as defined in claim 8, in which the hydraulic binder is limestone.

10. The method as defined in claim 8, in which the powdered fuel is from the group consisting of coal and coke, the emulsion is a water-in-oil emulsion and the hydraulic binder is limestone.

References Cited in the file of this patent UNITED STATES PATENTS 1,166,171 Baltin Dec. 28, 1915 2,025,945 Forrest Dec. 31, 1935 2,086,581 Smith July 13, 1937 2,131,074 Schulze Sept. 27, 1938 2,322,641 Jaros July 22, 1943 2,399,411 Watts et a1 Apr. 30, 1946 2,411,634 Pearson Nov. 26, 1946 2,482,586 Hersberger et al Sept. 20, 1949 FOREIGN PATENTS 2,297 Great Britain of 1873 3,356 Great Britain of 1874 2,134 Great Britain of 1875 6,894 Great Britain of 1885 21,245 Great Britain of 1894 10,066 Great Britain of 1904 205,063 Great Britain Feb. 18, 1925 406,563 Great Britain Mar. '1, 1934

Claims (1)

1. A METHOD OF REFINING PUIVERIZED METALLIC ORES, WHICH METHOD COMPRISES ADDING TO THE PULVERIZED ORES AN EMULSION OF WATER AND HYDROCARBON OIL WHILE AGITATING TO COAT SAID ORE WITH SAID EMULSION, THEN ADDING TO THE COATED ORES A MIXTURE CONTAINING POWDERED BITUMEN AND A HYDRAULIC BINDER IN APPROXIMATELY EQUAL PROPORTIONS BY WEIGHT WHILE AGITATING TO UNIFORMLY DISTRIBUTE SAID MIXTURE THROUGHOUT THE COATED ORES TO CAUSE (A) SAID HYDROCARBON OIL TO FLUX WITH SAID BITUMEM AND FORM A BITUMINOUS BINDER FOR SAID PULVERIZED METALLIC ORE PARTICLES AND (B) SAID WATER TO REACT WITH SAID HYDRAULIC BINDER TO FORM AN INORGANIC BINDER FOR SAID PULVERIZED METALLIC ORE PARTICULES, COMPRESSING THE RESULTANT MIXTUTE TO PRODUCE INDIVIDUAL PELLETS AND INTRODUCING THE PELLETS INTO A METALLURGICAL FURNACE AND SUBJECTING THEM TO REDUCTION IN SAID FURNACE BY COMBUSTION. THE COMBUSTION OF SAID BITUMINOUS BINDER IN SAID PELLETS DURING THE INITIAL STAGES OF SAID REDUCTION ENHANCING THE POROSITY OF SAID PELLETS WHICH ARE THEN RETAINED IN PELLET FORM BY SAID INORGANIC BINDER AND THUS FACILITATING THE REFINING OF THE METALLIC CONSTITUENT OF SAID PELLETS AS SAID REDUCTION CONTINUES.