US1303411A - Pkogess of treating concentrates - Google Patents

Description

W. G. SWART AND B..G. KLUGH.

PROCESS OF TRE ATING'CONCINTRATES. APPLIC-ATIOP} FILED NOV.-17, F9]?- 1,308 ,41 1 Patented May 13, 1919.

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"WALTER. G. SWART, F DULUTH, MINNESOTA, AND BETHUNE Gr. K'LTJ'GH, 0F ANNISTUN,

ALABAMA. i

PROCESS Oil TREATING CONCENTRATES.

Specification of Letters Patent.

Patented an is, rare.

Application filed November 17, 1917. Serial No. 202,455.

To all whom it may concern:

Be it known that we, WALTER G. SWART,

- a citizen of the United States, residing at ti l Duluth, in the county of St. Louis and State of Minnesota, and Bernese Gr. KLUGH, a citizen of the United States, residing at Anniston, in the county of Calhoun and State of Alabama, have invented certain new and useful Improvements in Processes of Treating Concentrates, of which the folloiving is a specification.

This invention relates to improvements in processes of treating metalliferous ores, and has for its especial object the preparing of finely divided iron-bearing material, for example, such as concentrates of ores; ores naturally existing as very fine sand, earth, dust, or clay, or artificial ores; or by-products carrying iron values, for sintering or other agglomerating processes, and also natural or artificial ores requiring desulfurization, dehydration, or elimination of any volatile constituents by volatilization of such constituents.

Finely divided or clayey iron-bearing materials, require some form of agglomeration before they can be e iciently treated in blast furnaces. Agglomei ation by such blast roasting processes as the Heberlein, the lDwightv and Lloyd, and the Grecnawalt, for instance, requires, first, that the finely divided or clayey iron-bearing material. to be agglomerated shall be intimately and thoroughly mixed with solid fuel, preferably carbonaceous and finely divided, prior to its delivery to the blast roasting or sintcring apparatus; and, second, that such mixture of solid fuel and finely divided or clayey iron-bearing material be delivered to such sintering apparatus containing a definite percentage of water or other iiuid, which so tempers it, or brings it to such a'state of plasticity, tl' it contains the largest possible volume or percentage of voids, which is desirable for best sintering practice.

it happens that much of the finely divided and clayey iron-bearing material occurring naturally and the concentrates made artificially contain approximately the right amount'of moisture to give them the proper degree of plasticity, or can be brought easily to this condition, but it also happens that this condition or degree of plasticity is that at which it is most difficult to secure the necessary intimate mixture of the material or concentrate with the solid fuel. The gummy, sticky nature of the mass is such as to interfere seriously with the successful operation of any mixing device now in use, requiring a heavy excess of power, giving much trouble from breakage of machine parts, necessitating frequent stopping of machines for cleaning out caked and packed masses, and delivering a product imperfectly mixed..-

In the case of the pug mill or blade type of mixer, theplastic material builds up into hard cakes on all surfaces adjacent to the peripheral path of the blades, thus causing a braking action on the blades with enormously increased power consumption and wear on the blades. In the ctise of the drum or cylindrical type of mixer the gummy material builds up on all surfaces with which it comes in contact, forming cakes or masses difficult to dislodge, causing an excess power consumption, reducing the mixing area and volume of the apparatus, and giving poor mixing. lit intervals the mixers must be stopped and cleaned or all mixing stops. Such finely divided iron-bearing materials as fine magnetiteconcentrates, now being eX- tensively produced, and ores naturally plastic, such those Cuban ores known as Ma yari ores, are especially productive of difiiculty and expense as just described.

By our invention we propose to eliminate the mixing devices as abovedescribed with theirattendant diiiiculties and expense.

i Vhcn finely divided oreis concentrated on tables, or in magnetic and other separators, the concentrates arc ci'lstomarily delivered from the concentrating machines in a semi-fluid condition, due to the ex )8 of Water contained therein. This excess of water must be removed before sii'itering, and this removal may be effected in several ways, but filtering machines of thc Oliver or Portland type ofler a desirable method.

in our process the finely divided fuel, which if necessary has been previously crushed or ground, while either dry or wet, in suitable machines such as ball mills, is introduccd'into the fluid mass of concentrates and thoroughly mixed thercwith by any suitable means, such as a ccn ifugal pump, while the concentrates are still fluid; and tl excess water is then removed by any suitable apparatus, such as a revolving filter, which delivers a plastic mass with fuel lilvli already intimately mixed therewith, and in the best physical condition for sintering, without further mixing.

In the case of a sticky, gummy, or clayey ore occurring naturally, like the Mayari Cuban ores already mentioned, we vary our process only by first adding sufficient water to the natural ore to bring it to a semi-fluid condition, then adding the finely divided fuel, as before, then thoroughly agitating and mixing the semi-fluid mass and filtering same to the desired degree of plasticity. It has heretofore been found impossible to get a suitable mixture of fuel with this kind of ore to allow good sintering except at a prohibitive cost.

Certain (natural) ores and by-products (natural or artificial) contain sulfur, combined water, or other volatile constituents, to an amount which renders them undesirable, or even totally unfit, for blast furnace use. When such ores occur massive they do not require agglomeration for the purpose of keeping fines out of the blast furnace, but for the equally necessary purpose of removing the objectionable elements mentioned. It is therefore necessary to crush such ores and sinter them, which sintering not only eliminates the fines, but at the same time removes these objectionable elements. Such procedure is now being followed commer cially at several plants. The practice is to grind the ore dry, add the necessary fuel, moisten to sintering consistency in the mixer, then sinter the mass. Wet grinding is preferable, but not used, because an excess of water niust be added which would haveto be subsequently removed by drying, leaving the same sort of plastic mass as described above, with which it is difficult to mix the necessary fuel.

Under the invention described herein, such ores may be ground Wet, have the neces sary fuel added and mixed While the mass is still fluid, then filtered and sintered, as already described.

The fuel may be added to such ore previous to, or simultaneous with, or subsequent to, the grinding of the ore, the mixed ore and fuel being then filtered and sintered.

Iron-bearing ore and other products are sometimes leached for the removal of copper, zinc, or other substances, either in a natural state or subsequent to roasting. Such leached n'iaterial is usually plastic and difficult to mix with fuel for subsequent sin tering. By our method, Water is added until the mass is fluid. Fuel is then added and easily mixed, the resulting mixture being fil tered and sintered, as herein described.

As a further feature of this invention, we contemplate the use of peat, which to our knowledge has not heretofore been used as a fuel in sintering or otherwise agglomerating ores. Peat usually occurs naturally in such form that it must be maceraieu and dried before being used as fuel. It is not uncommon for it to be taken from the bogs carrying to water, most of which it is difficult and expensive to remove. in our invention we introduce the peat into the semi-fluid mass of concentrates or ore, without necessarily drying the peat, then agitate and mix the semi-fluid mass of ore or concentrates and peat, and then filter the lluid mass, the result being a plastic mass containing' the necessary fuel intimately mixed, ready for sintering, just as though finely divided coal or coke, or other solid fuel, had been used.

Peat often occurs in swamps in a naturally semi-fluid condition. Our invention also covers the inverted procedure of int reducing the finely divided iron-bearing materials into the fluid or pulpy peat, and then sul jecting the mixture to a filtering or dewatering operation, substantially as decribed, before agglomeration.

It is evident that in the ease of fuels other than peat, also, it makes no difference in the final result whether the ore is added to the fuel or the fuel to the ore, either or both being in the same liquid pulpy condition, or in the dry state.

To illustrate one method of carrying out our process, we have shown one form of apparatus in the accompanying drawing. in which- A designates a crushed ore bin or hopper from which the finely crushed ore is delivered to a concentrator indicated by B, the embodiment shown being of the type known as the Davis type, in which the ore is magnetically separated and at the same time conveyed to the upper end of the concentrator, where it is discharged in the form of a pulp or fluid mass into the launder C. Located above the latter is a bin D, in which is located the fuel in the desired condition, such as peat, comminuted or ground to de sired condition, a feed roller D being locat-ed beneath the open end thereof to deliver the fuel in desired proportion to the launder G, as indicated by dotted lines. A valve D may be utilized to control the amount of fuel delivered. This fuel, together with the fluid pulp, floi '5 through the medium of the launder O, and (l, to a centrifugal pump E, where the fuel and fluid ore particles are thoroughly mixed and commingled and delivered through the conduit E to a filtering machine, generally indicated by the letter F, and shown as of the Oliver or Portland type, the excess moisture being pumped out by the filtering machine in a manner well known to those skilled in the art, and the de-watered mixture of ore and fuel is carried over on the lip or chute F to the feeding hopper G which is located above the endless belt ll of a sintering apparatus, for

example, generally indicated by the letter H. A slide valve G may be used to regulate the delivery oi the mixture to the sintering belt H The apparatus for shite-ring shown here is of the Dwight and Lloyd type, although as in the case of the apparatus diagrammatically illustrated in the drawing, we do not Wish to be restricted to any specific type or form of apparatus in the carrying out of this process, H indicates the suction hex oi the sintering apparatus through the medium of which combustion carried through the mixture after ignition thereof and during the passage of the ex haust box H It will be apparent that, by the addition of the fuel in the manner and at the time described, a thorough homogeneity of the mixture is obtained With a minimum of labor and expense by utilizing a necessary step in the handling of the concentrates.

It Will be obvious that While the carrying out of our process in the above-descril'ied apparatus delivers the connninuted ore in a pulpy or fluid condition so as to flow readily, it is possible that we may treat line or plastic ores by reducing them to a fluid or pulpy condition previous to the mixture of the fuel therewith.

Further modifications and changes in our process as described are possible and contemplated, and 'WG do not Wish to be restricted to the herein-described process save as defined in the appended claims.

What We claim is:

1. A. process of the class described conr prising the steps of mixing fuel and metallit'erous particles with Water to obtain a fluid mixture, then removing the excess water content, and then agglomerating the mixture.

A. process of the class described cornrising the steps of mixing fuel with metal.- liferous particles in a fluid state,-then moving the excess Water content, and then agglomerating the mixture.

A process oi the class described, consisting in first mixing metalliterous particles of desired size with Water or the like, to

a state of fluidity, then adding fuel, next mixing said fuel and fluid, then removing" superfluous Water content, and finally gloinerating said mixture.

l. A. process of the class described, con-- sisting in first mixing nietalliterous particles of the desired size with Water or the like to a state of fluidity, then adding peat thereto, next mixing said peat and 1netallifero'us tluhr, then removing; superfluous water content from said mixture, and finally agglonierating the same.

lln. testimony whereof, we have subscribed J. Kerr, ill l E,

Nicr-rotts ti ll

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