US1581479A - Recovery of values - Google Patents

Description

' PatentedA'pr. 1926.

u 1TED *-S A E$. PA NT. OFFICE i enonen'n. VAN ARSDALE, OFLOS ANGEIQES, onmr'onnrnynnn HAROLD W. ALDRICH AND WALTER e. scor'r, F msrrnn'rron, ARIZONA, ASSIGNORS'TOMINSPIRATION N. Y'., a CORPORATION or CONSOLIDATED COPPER-COMPANY, 0F YORK, MAINE. I

- RECOVERY OF VALUES.

Ito Drawing.

use in connection with leaching processes applied to ores, such as copper ores, or the like.

Although our present invention provides a highly efficient method for washing out dissolved copper after the application of anydesired leaching process to copper ores, orthe like, this invention, in one of its aspects, may be regarded as comprising a novel combination of. a countercurrent method of washin with an exhaustive or circulation method of Washing, involving cementation, orthe like; and it may also'be regarded as comprising a combination of countercurrent methods of washing with a subsequent precipitatioinas hereinafter 'described.

, The usual leachingmethods applied to copper ore may be divided into two classes: 7 e

and also in View of installation expense for I which the ores are treated by percolation, and (2) those in which agita tion is used. In either case, after contact with the leaching solution has been sufficient to dissolve the copper, it is necessary;-v to separate the resultant solution or rich-liquor, and subsequently to remove, by washing methods, that dissolved copper which-would otherwise remain associated with the residual moisture inthe tailings, after separation of the main body ofsolution therefrom,

For example, in washing by percolation, a number of successive washes arevapplied, each of which removes a fraction of the re maining copper. v have the volume of the respective washes so adjusted that the total volume of solution re mains practically a constant. To do this, the unit volume of washxwatermay be adjusted to be approximately equ'al' to the volume of liquid finally discharged, as re- (1) those in sidual moisture, in the tailings, allowance ,ble number of' individual. washes.

Usually itisdesirable. to

Application filed septemb er 7, 1923. Serial No. 661,631.

beingmade for such inoistureas comes into the system with the ore, andfor evaporation during the cycle of operations. I When'thetotal volume of solution is controlled in the manner above referred to, the strongest wa'sh water being finally added tov the main solution ofrich liquor to b'e -treatedfor the recovery of a metal, or regeneratlon, subsequent washes are successively adi anced, in the next; following cycle.

In some cases, by reason of the accumulation of dissolved impurities, a solution discard is required; but when'the ores underpurpose referred to.

going treatment do not yield, per cycle, more It has heretofore been recognized and it can be shown mathematically that, for any system of washing, the total percentage of dissolved valueswashed out increases with the number of successive washings; and al.- so that, with a suflicient-number of washings, the removal of values will approach,

but can neverequal, one hundredpercent. It has also been recognized that, for, any

such total volume into the greatest practica- However, fromflan operating standpoint,

iven'total volume of Wash liquid, the highest eificiency will be'obtairied by dividing storage of washes, it is not practicable to carry more than limited number o'f stock Washes. For example, in leaching' copp'er ores, the last wash in a system'of 'say six to eight washes may carry from 0.15% to 0.25% or more of copper; and the discharge 'oftailings carrying residual moisture with narily comparativelylow andthat cementa 7 tion costs are per-pound costs.

In' connection with the new" system of 5 10 washing herein described and. claimed, we point out that our novel method of washing may obviously be applied in connection with,

.variousmet-hods of leaching copper ores, or

the like, for example, agitation methods of leaching; and it may also be applied with advantage in other wet methods of removing Tvaluesffrom subdivided solid materials; for

example, in cyaniding gold andsilver ores; and it may indeed be generally applicable as a method of treating subdivided solids containing soluble values by the employment of a circulating wash liquid brought alternately into contact with such subdivided solids and intoa system capable of precipitating or removing the values therefrom.

As appliedin connection with a leaching of copper ores-by percolation, our method is as follows: After the application of a sufiicient number'of washes to leached ore residues, as in usual practice, which may be substantially 'as out-lined above, the washed ore is drained; and thereafter wa ter, in any quantity suitable to convenient manipulation, is pumped onto the cm. The 'water takes up remaining dissolved values, and it is then-removed from the leaching or other tank and passed through aniron launder system orother means ot precipitating copper, and is then returned to the ore.

' This operation, which may involve a continuous or intermittent circulation,is repeated until a complete or exhaustive extraction is obtained,- or until the extraction is as nearly complete as is economically practicable, it being understood that when a cementation process, in which the more electropositii'e metal goes into solution, isemployed, the circulated wash liquor tends to become increasingly rich in iron salts, in proportion as copper is precipitated therefrom.

It will be appreciated that there are nu merous cases in which use is made of leaching systems employing iron salts as an essential constituent of the leach liquors; and, in treating certain copper ores, use mayadvantageously be made of a liquid whose iron content may be due to its previous employ- 'ment in" our method of exhaustive washing,

various processes involving leaching or electrodeposition and in connection with which our, invention may be employed having been 7 described in copending applications by George D. van Arsdale, Serial Nos. 639,968 and 639,970, filed May 18,1923, and Ser. No. 665,463, filed September 28, 1923. There are, of course, numerous ways in which such a circulating or exhaustive wash as we have herein described may be applied. For example, it may follow either say 'four, five, six or another numberof ordinary countercurrent washes, the preferred number of washes depending upon the amount of copper that it maybe economical'to leave .for precipitationby cementation and final recovery by known methods applicable to cement copper, Usually, however, our

manna A system of exhaustive washing aims to recover approximately that amount of copper which would otherwise be lost after the employment of acountercurrent or other known washing system. 7

As a practical proposition, ourwashing system as described and consisting essentially' of a countercurrent washing followed by a circulation orexhaustive washing has shown very considerable advantages. It

has been shown to be practicable and economical to wash ore, by our new method,

down to 0.01% dissolved copper, correspond ing to less than one-fourth pound of copper lost per ton of ore; and even more complete recovery is possible. In fact, as implied above, pumping costs are often sufficiently low to render economical a practivcally complete recovery of dissolved values.

As a comparison, the application ot the ordinary leaching systems with a practicable number of the usual countercurrent washes has been found to resultin tailings, 'ongthe same oreon which the above results were pendently employed, and various modifications might obviously be made, without de .parture from the spirit and scope of our invention as the same is indicated above and in the follow-"ingclaims.

lVhat is claimed is:

1 In the recovery of values, the steps which comprise washing residual subdivided solids by a countercurrent method to obtain a solution suitable to be added to a rich liquor for a usualtreatment,andthereafter removing residual values by circulating a body of liquid therethrough and precipitatingvalues from said body of liquid during itsv circulation, in a form permitting of'a substantially complete recovery. I

2; In a recovery of values, the steps which comprise washing residual subdivided solids by a countercurrent niethodto btain a solution suitable to be addedto a rich liquor for a usual treatment, and thereafter removing residual values by-circrilating a body of liquid 'therethrough and precipitating tion during such circulation.

In testimony whereof we have signed our names to this specification.

cno'aen'n. VAN ARSDALE.

HAROLD 'w.;aLD icn.- WALTER s. scorn