US1344869A - Electrolyzing cobalt solutions - Google Patents

Description

-Il'o Drawing.

PATENT OFFICE.

ELISHA BARTON CUTTEN, 0F KOKOMO, INDIANA.

ELECTROLYZING COBALT SOLUTIONS.

T 0 all whom it may concern:

Be it known that I, ELISHA B. CUTTEN, a citizen of the United States, and resident of Kokomo, county of Howard, State of In diana, have invented certain new and useful Improvements in Electrolyzing Cobalt So,- lutions; and I do hereby declare the follow ing to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The invention relates to a method of separating and extracting the metal cobalt from solutions containing salts or cobalt by electrolysis. Many attempts have been made heretofore to extract cobalt from ores and compounds containing the same and to deposit the substantially pure metal by electrolysis, either to form a protecting coating for other metals, or to admit of the deposited metal being recovered for subsequent use but, so far as applicant is advised, none of these attempts have been commercially successful, nor have any of the previously employed attempts to electrolyze solutions of cobalt salts been found capable of practical application except for very brief runs, as the deposit tends to blacken after a short period of operation, or it has been found that the efficiency of the method, measured by the percentage of recovery or deposit, cobalt has fallen off so rapidly as to render the operation practically valueless from a commercial standpoint. In most instances, the same mode of procedure has been attempted, in respect of electrolyzation of cobalt, that has been successfully practised in depositing nickel electrolytically, but, except in cases of relatively short runs, the results have been entirely unsatisfactory and of no permanent commercial value.

I have discovered that the heretofore insurmounted difficulties in the successful application of-electrolytic methods of the re covery and deposition of cobalt have been due primarily to the lack of permanency and stability of the electrolyte, due either to the presence of free acid or alkali in the solution, or the production of acid or alkaline conditions therein during the electrolyzing operation.

I have discovered that all of these difiiculties may be obviated and an entirely satisfactory recovery and deposition of cobalt on a commercial scale and-without'any material falling off in efliciency, by the employment Specification of Letters Patent.

Application filed October 20, 1919.

Serial No. 331,966.

of a neutral solution,-.of a suitable salt of cobalt, employed as electrolyte, the neutrality being maintained constant throughout the operation by the presence of a salt reagent that forms an insoluble and innocuous precipitate with the liberated acid radical which is produced during the electrolytic actlon.

A particularly efficacious arrangement which I have employed for carrying out the new method includes an electrolyte consisting of a solution of sulfate of cobalt which is maintained in a constantly neutral condition by the presence of calcium carbonate. The latter may be added from time to time. or it may be applied in suitable quantities to maintain the neutrality of the electrolyte for a long time, thereby avoiding the re-- peated additions of the neutralizing agent. Entirely satisfactory results have been had from the use of an electrolyte made by dissolving about six ounces of sulfate of cobalt per gallon of distilled water, although relatively stronger or weaker solutions may be employed as desired. Into the solution thus obtained, a small quantity of pure calcium carbonate is stirred, one-half ounce per gallon of electrolyte is generally sufiicient, to completely neutralize the electrolyte and precipitate any foreign matter that may tend to obstruct the normal operation. This solution when filtered is ready for use. The electrolyte as thus constituted, works satisfactorily and produces a bright uniform deposit of cobalt for a period of one or two days, provided the E. M. F. employed does not exceed one volt and is preferably maintained at about eight tenths of a volt. As soon as the deposit shows a tendency to blacken, a further quantity of calcium carbonate is added to the electrolyte which immediately corrects the tendency and the normal bright deposit of cobalt is continued. In order to avoid the necessity of repeated additions of the neutralizing agent to the electrolytic bath it has been found advantageous and effective to surround the anode, preferably consisting of or containing cobalt, by a porous sack in which the neutral izing agent is contained, and which is, therefore, available for maintaining the electrolyte in a strictly neutral condition for relatively long periods of operation.

In lieu of the-calcium carbonate as a neutralizing agent, barium carbonate may be employed, as the latter, like the calcium Patented J line 29, 1920.-

salt, forms with the acid liberated during the electrolytic action, an insoluble precipitate which is entirely innocuous and produces no effect whatever upon the metallic deposit of cobalt and which offers no other objections than that it must be removed from time to time from the electrolytic cell. I have also found .that oxid of cobalt or carbonate of cobalt may be employed as the neutralizing agent, and when the latter is employed, care must be taken that no caustic alkali, soda, potash, or ammonia, is present to produce a double salt of cobalt, analogous to the double nickel salt employed in electrolysis of the latter metal, which would defeat the purposes of the present invention by causing a deposition of hydrogen at the cathode, which tends to alloy or mix with the deposit of cobalt to the impairment of the latter. l

Instead of employing sulfate of cobalt as the electrolyte, the chlorid of cobalt may be substituted and, if used, must be neutralized by the addition of a salt which will produce an insoluble and innocuous precipitate with the liberated hydrochloric acid radical, such carbonate of lead, which would result in the formation of lead chlorid and would be in no wise harmful to the solution or the normal electrolytic action.

In carrying out the invention, therefore, it is necessary and desirable that the elec trolyte be not only neutralized at the initiation of the electrolytic action, but that it be maintained continuously neutral, which result may be effected by either adding successive portions of the neutralizing medium whenever the bath tends to show either an acid or an alkaline condition, or surrounding the anode with a suitable porous sacking which contains a sufficient quantity of the neutralizing agent to maintain the electrolyte strictly neutral throughout a long and continued operation.

lVhat I claim is:

1. The method of depositing cobalt which includes in electrolyzing a solution of a suitable salt of cobalt, andmaintaining the neutrality of the electrolyte by the action of a reagent that forms an insoluble and innocuous precipitate with the liberated acid radical.

2. The method of depositing cobalt which includes electrolyzing a solution of sulfate of cobalt, and maintaining the neutrality of the electrolyte by the action of a reagent that forms an insoluble and innocuous precipitate with the liberated sulfuric acid radical. l

3. The method of depositing cobalt which includes-electrolyzing a solution of sulfate of cobalt, and maintainin the neutrality of the electrolyte by the presence of a carbonate which forms an insoluble and innocuous precipitate with the liberated sulfuric acid radical.

4. The method of depositing cobalt which includes electrolyzing a solution of sulfate of cobalt, and maintaining the neutrality of the electrolyte by the, presence of calcium carbonate.

In testimony whereof I allix my signature in presence of two witnesses.

ELISHA BARTON GUTTEN.

Witnesses: I

H. M. IVOYcHECK. S. K. HAUPERT.