US1379023A - Metallurgical process - Google Patents

Description

UNITED STATES PATENT OFFICE.

JOHN TYLER JONES, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 THOMAS J.

HOWELLS, OI IITTSBURGH, PENNSYLVANIA.

METALLURGICAL PROCESS- No Drawing.

To all whom it may concem:

Be it known that I, JOHN TYLER JONES, a citizen of the United States, and a resident of Pittsbur h, in the county of Allegheny and State 0 Pennsylvania, have invented a new and useful Improvement in Metallurgical Processes, of which the following is a specification.

My invention relates to improvements in metallurgical processes, more particularly 1 those processes which relate to the reduction of ores and the production of metal in the form of the pure elements such as iron, aluminum, etc., or the production of alloys such as ferroman'ganese, and it consists in the steps hereinafter described.

An object of my invention is to provide a process by means of which metals may be economically reduced from the1r ores.

A further object of my invention is to provide a process which can be carried out quickly, thereby resulting in a saving of time as well as in cost.

A further object of my invention is to provide a process for reducing ores which does not require the use of specially designed machiner to carry out the process, but which may e carried out through the use of ordinary apparatus such as a regenerative coking oven and a regenerative furnace.

Other objects and advantages will appear in the following specification, and the novel features of the invention will be particularly pointed out in the appended claims.

In various parts of the countries are lar e deposits of relatively low grade ore. 11 many instances the ore is of such low grade that it has not up to the present time been profitably handled. Man of these deposits are in what is known as lanket formation, that is to say, the ore is found just beneath the top soil at distances approximating twenty feet (20), and is substantiall level with the surface of the ground instea of being inclined in veins. Other veins occur which are inclined. As an instance of a blanket formation, I may cite the deposit ofmanganese ore in the Cuyuna range in Minnesota. Iron ore will occur in veins and there are large deposits of bauxite from which aluminum may be obtained at a relatively low cost.

The present process may besuccessfully carried out or used in connection with the Specification of Letters Patent.

Patented May 24, 1921.

Application iiled October 26, 1917. Serial No. 198,674.

recovery of a variety of metals such as iron, alum1num,-silicon, etc. A specific instance W111 suffice to show the manner in which the process 1s carried out. Let us take the case of aluminum. Hitherto it has been necessary to subject the aluminum ore to a high heat 1n an electric furnace in order to effect the reduction. In carrying out the invent1on, the bauxite is first crushed in any suitable crushing device, to a fineness approximating from twenty to one hundred mesh. Crushed bituminous coal of a fineness substantially equivalent to that of the ore is intimately mixed with the bauxite. Instead of coal, any other hydrocarbon havin volatile matter capable of bein driven 0 under heat and of being ignited for furnishing the heat with which the ore is reduced, may be used instead of the coal. Any such material is reduced to a state of fineness correspondmg with that of the ore. In mixing the crushed ore and hydrocarbon, any suitable mixer may be used, such as a rotating barrel or the like. It is necessary that an excess of the coal or hydrocarbon bearing element'be used, and to this end, I make use of a mixture of one-third of ore and substantially two-thirds of coal or its equivalent hydrocarbon bearing material, although these proportions may be varied without de- .partmg from the spirit of the invention.

The mixed material is put into a furnace or retort and heated. The particular form of retort does not constitute a part of the present invention. An ordinary Siemens regenerative coking oven or an ordinary by-product oven may be used and the temperature at which the mixture is heated is preferably the highest'temperature ordinarily used in making coke.

he material, that is to say, the mixed coaland ore, or the mixed hydrocarbon bearing material and ore, is left in the oven long enough to thoroughly coke the mass. The time depends, of course, upon the size of the oven. In the case of bituminous coal, some ovens require twenty-four hours while others require forty-eight, and others perhaps, seventy-two. When the mixed ore and coal is ut in a small crucible and heated the mass is coked in a few minutes.

Assuming that coal has been used, after the material has been coked it is taken out of the oven in a red-hot condition and water is turned on it as in the ordinary process of making coke. The product is a substance which has very much the appearance of coke. ()n close examination, however, it will be found that the metal is in a metallic state, that is to say, instead of being in the ox d form, it is in the metal form and the end has been substantially driven off. In the case of aluminum, the aluminum has been deoxidized at the temperature at which coal is ordinarily coked. This temperature is greatly below that required in the reduction of the metal in an electric furnace. The precise reasons for such action are not definitely known. It may be that the nascent gases such as hydrogen which are more active in their nascent state, have a greater affinity for the oxygen than such gases would have when they are not in the nascent state. In any event, I have found that the metal exists in the coked mass in the metallic form and is scattered throughout the mass, the particles of aluminum apparently being separated by particles of coke.

The product is now in a state from which the aluminum can be readily removed. This is done by placing the coked mass in an ordinary melting furnace such as an open hearth, a blast furnace, or any ordinary form of melting furnace, In the case of aluminum, the coal or rather the coke, is burned away, the metal melts and may be collected in any suitable form. In a co-pending application I have described a process of producing ferromanganese, in which iron oxid and manganese oxid are reduced to the metallic form, so that the coked product is a mixture of iron and manganese in the metallic form separated by particles of coke. In such a product, I may separate the iron by crushing the mass and then treating it magnetically. The manganese may be subsequently separated, and the coke is recovered as such. Right here, I desire to call attention to the fact that approximately as much coke is recovered as would be produced by the same amount of coal. In other words, it is not the coke itself which is consumed to deoxi- (llZG the metals, but it is the volatile constituents of the coke which produce the reduction. This in itself is a very important economical advance in the art, since in roducing ferromanganese, the coked pro uct may be separated into its metallic elements and the remaining coke may be sold. Furthermore, when a by-product oven is used not only are the volatile portions of the coal used in bringing the metals to the metallic state, but certain constituents of the excess of volatile matter may be recovered in addition. This again renders the process still more economical.

In the case of aluminum, the reduction in the cost of producing the metal is such that the burning away of the coke plays a very small part.

The process described herein, it will be noted, requires that the ore be in a finely divided state. It is also necessary that the hydrocarbon bearing material such as coal, be in a correspondingly divided state. The Whole tendency of modern metallurgy, at least up to the time of applicants invention, has been to get away from the finely divided state, that is to say, to carry out the operation with lumps of ore, not small particles of ore or ore dust. The reason is obvious; in the ordinary operation, dust is blown out of the furnaces. Whole sections around metal reduction works are covered with this fine dust and, therefore, the tendency has been to exert every effort to keep down the dust, because not only does it form a nui-' sance in the surrounding community, but it causes an actual loss of material. In my process .I make use of every bit of the crushed material. The crushed material is put into an air-tight heating device, no dust can possibly escape, the finer the material, the better is the coked product, and the quicker the reduction takes place. The coked product is an agglomerated mass which may be handled without inconvenience and which is in the state from which the metal may be easily obtained as described.

The agglomerated mass or coked product has very much the appearance of ordinary coke, but on microscopical examination, it is found to consist of articles of metal separated by particles of coke. The material itself is novel, as far as applicant is aware, and the bringing of the metal into the pig form is very readily accomplished.

In carrying out my process it will be observed that the mixed ore and hydrocarbon bearing material isaccomplished substantially out of the presence of air. As a matter of fact, only enough air is admitted to insure the combustion of a sufficient quantity of the coal to coke the remaining mass, substantially as in the ordinarycoking operation, when the air is shut off.

In the final melting of the metal as, for instance aluminum, into the pig, air is admitted so as to provide for the combustion of the coke during the melting step.

I claim:

1. The herein described process of treating metalliferous ores, which consists in crushing the ore to a fineness approximating twenty to one hundred mesh, mixing with the crushed ore an excess of crushed coal having substantially the same fineness, heating the mixed ore and coal together, substantially out of the presence of air, to a temperature sufficient to coke the coal and to produce an agglomerated mass resembling coke, and subsequently separating the metals from the coke.

2. The herein described process of treating metalliferous ores containing a metal heating the mixture to a coking temperature oxid, which consists in crushing the ore to to form an agglomerated coke mass cona fineness approximating twenty to one huntaining the metals in metallic form and 10 dred mesh, mixing said crushed ore with coke, and subsequently separating the metals 5 hydrocarbon bearing material of a fineness from the coke.

approximating that of the ore, said hydrocarbon bearing material being in excess, JOHN TYLER JONES.