US1291824A

US1291824A - Process of recovering metals from ores.

Info

Publication number: US1291824A
Application number: US20093117A
Authority: US
Inventors: Rudolf Gahl
Original assignee: Individual
Current assignee: Individual
Priority date: 1917-11-08
Filing date: 1917-11-08
Publication date: 1919-01-21
Anticipated expiration: 1936-01-21

Description

- 1,291,824. Patented 1311.211919.

R. GAHL.

PROCESS 0F RECOVERING METALS FROM ORES.

APPLICATION min Nov. e.' 1911. v

mamada-m Tosmd Jan/mz@ @not "cul/ RUDOLF GAHL, OF MIAMI, ARIZONA.

PROCESS OF RECOVERING METALS FROM ORES.

Specification of Letters Patent.

Patented Jan. 21, 1919.

Application led November B, 1917. Serial No. 200,931.

To all whom t may concern:

Be it known that I, RUDOLF GAHL, a citizen of the United States,residing at Miami, in the county of Gila and State of Arizona, have invented certain new and useful Inlprovements in Processes of Recovering Metals from Ores, of which the following is a specification.

My invention relates to a process of recovering metals from ores. For the beneficiation of certain ores, especially porphyry copper ores by means of concentration processes, very line grinding is necessary to liberate the economic mineral from the gangue particles and from particles'of such minerals as cannot be recovered by the concentration process. The cost of grinding, therefore, often constitutes theheaviest item of the reduction cost by the processes in' question.

For this and other reasons, it has been customary to reduce the grindingexpense by not attempting to carry the grinding as far as is necessary for freeing all mineral from gangue particles, but to apply the concentrating process to what may be called insufliciently crushed ore. The products which the concentration' process yields in this case are so-called concentrate containing essentially those mineral particles that have been liberated largely from the gangue and a middling product containing particles consisting of gangue and mineral combined, in addition to a 'waste product called tailing,

It has been customary in such cases to i regrind the middling product and -then to l attempt another concentration.

s high-grade product.

While the procedure just described has been successful in a measure, it does not permit essentially completerecovery of the mineral contents of the. ore in the form of a y The two principal causes for this shortcoming-are (1) a great number of insufliciently round particles find 'their way into the tailing` product instead of going'into the middling product; and '(2) the-treatment of the reground middling product by a concentration process is rarely satisfactory, inasmuch as the resulting tailing,I always carries `high mineral values.V The reason seems'to lie in the fact that altered or partly decomposed minerals leaching,

4which the Slime has which offer difficulties in concentration processes accumulate to some extent in the middling product.

In speaking of concentration processes so far, I have been referring to gravity concentration processes only. As a matter of fact, the flotation process which has recently come into use is also a concentration process..

In applying the flotation process, metallurgists have .generally confined themselves to applying the s a-me to slimes, i. e., very fine crushed ortions of ore; or when they have applied 1t to ore ulps as a Whole, i., c., sand and slime mixed), have specified that the crushing should be very fine.

I have discovered, however, that the flotation process may be so carried out that it is Well adapted to the treatment of insulliciently crushed ore, and that when so applied, in the manner hereinafter described.

there will be produced, in c'ontradistinction to the gravity process, a tailing product practically free from mineralvalues, while the flotation concentrates contain mineral particles essentially free from gangue and the middlings contain mineral particles com-- bined with the'gangue. The separation into these three products is not necessarily made in one operation. As in the example quoted below, the first flotation may, for instance. separate out the concentrate and an additional treatment of the balance of the pulp result in the middling` and tailing product.

" My experience is further, that flotation, .l like the gravity concentration process, does' not permit the separation of the middling'l product into a mineral free secondarytailing product and' a high-grade secondary concentrate Vproduct even after regrinding. On the other hand, I have discovered that the middling product can be obtained in a granular form suitable forY roasting an if the flotation in which the middlng is produced is ap lied to a pulp from lbeen previously removed by means known to the art, as for instance, a' drag classifier. Such roastmg treatment followed by leaching permits a high extraction of the values contained in the middlings product. y It has been mentioned before that. the

flotation' process will produce a telling prtduct practically from mineral 35 leaching with sulfuric per, 0.3% being in oxid combination.

values in addition to a concentrate and a middling productA refractory lto further treatment by dotation. The term practically :tree from mineral values is meant to `apply only to such mineral values as are amendable to dotation. YWhere, for instance, oxidized copper ores are treated it' is only possible to remove the copper suldds with a very high degree of extraction, While the copper carbonates are extracted to a smaller` extent, and silicates to a smaller extent yet. Where the oxid minerals 'exist in a suiiciently large percentage, another method may have to be used to supplement the flotation treatment, and l prefer leaching for this purpose.

As an example of my process, a copper A ore was ground so that practically all the product was fine enough to pass a 48-inesh screen, Which though comparatively une grinding is by n o means ysufficient to liber- `ate all the mineralparticles.' 'llhe ore treated contained approximately 1.5% cogs the result of a combined gravity and iotatlon concentration, a concentrate contain- 111%` abou.t 30% of copper was produced.

he tailings Jfrom thls concentration proc# ess, which would ordinarily be considered Waste product, were then, after the removal separated into a middling and ofthe slime, telling product in a dotation machine.

While thel material fed to this dotation inachlne carried 0.26% copper, the tailing product contained only 0.11% copp', and .after acid contained only 0.04% copper. y I

The middling product, containing 1.70% cop er was roasted with salt and then leac ed with sulfuric acid, and by this process the copper content reduced to 0.09% copper. ln other Words, the loss originating from this Waste product was also very small. 'l`l1ecopper solutions produced by leaching the tailings and .by leaching the roasted mlddlings can then be treated either by preoipitating the copper on iron to produce cement copper, or by electrolytic deposition. The attached gure represents part ont a of the residue wask nennen@ dlings produced `by flotation in this niachine are sent to a roasting furnace in which lthey are Igwen a kchloridizing roast,

this otv sheet, ltere, feeders,

and then together with the unroasted tailp ings sent to the leaching plant. From the resulting solutions, the copper is recovered either by precipitation as cement copper or.

as electrolytic copper, and the residues from the leaching are discarded.

' The slimed product from the desliming classier may he treated in any of the Well known Ways.

i claim:

1.l The process oi treating ores which consists in subjecting desliined pulp to @otation to produce .a nriddling product, roasting the middling product, :and leaching the roasted product to obtain a metalliierous solution.

2. rlhe process oit treatings ores which vcon-l siste in subjecting deslinied pnl to dotation to produce a nciddling pro uct, roast ing. the middling product., and leaching the roasted product and `the tailings to obtain a metallilerous'solution.,

3. The process of treating ores which consists in lsubjecting deslinied pulp to @otation to produce concentrates and tailings,

subjecting such tailings to dotation to prol ducea middling product, roasting the iniddlin product, and leaching the roasted prodguct to obtain a metalliierous selution. 4l. The process as claimed1 inl claim 3 1ncludingthe step of also lea-ching the tailings trom the :flotation process in which the middling product was obtained.

. lin testimony whereof l iny signature.

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