US921372A - Process of separation of metals. - Google Patents

Description

, im rovement of, the

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Specification of Letters Zatent.

Application mammal 12}.1908,8or1a1No. 8 48,086.- macaw-su reme: 17, was. .semmdmasos.

To all whom it may concern."

Be it known :that I, RICHARD'D. DIVINE, citizen of the United -States,re's-iding at Ohh cago, in the county of Cook and State of Illinois, have invented new and useful Im rovements in Processes of Separation of etals, of which the following is a specification.

This invention is a (process for the separation of zinc from lea and antimony oxide, and the reduction of the metal oxids to the metallic state. I v

The invention is su plemental to, and an arkes process for the re notion of metals. In the Parkes rocess, for extracting precious metals from ead,

, zinc is added to molten lead containing gold,

, silver and copper, and these metals form 'an alloy with the zinc by reason of their greater alfinity for the zinc than for the lead, and this alloy is lighter than lead and rises to the top, carrying the precious metals with it, whence it can be removed by skimming. These skimmings are further treated for the separa tion of the zinc therefrom and the recovery of the recious metals, the zinc being driven off by eat and again used for another operation. But before the zinc which is added to the bullion has any action on the silver it has been found that a certain amount is necessary to saturate the lead, and the zinc so used remains with the desilverized lead, and does not skim off, and hence it is 'necessar togive said lead another treatment to free it from the saturating zinc. To do this it is heated with an oxidizing flame or steam is blown through it. This method will oxidize the zinc together with a small amount of the lead and antimony, leaving the lead free from zinc and antimony, and forming oxids of these metals, which rise to the top and are skimmed off. My rocess relates to the separation of the meta s in these oxids or skimniings. The skimmings or oxids are first cooled and then crushed, and to the crushed product is added carbonate of soda in the proportion of two hundredpounds to one ton of the oxids, and there is also added pulverized oil cake in the proportion of one hundred pounds to the ton. These are thoroughly mixed and placed in a suitable retort and heated to a temperature which will expel the zinc which volatilizes at a lower heat than the lead and antimony. The heat is therefore not intense enough to remove the lead and antimony, but by the action of the carbonate of soda and oil cake said oxids are reduced to a metallic state. The g zine is then easily driven off, and is condensed and col- '-lectedin' a suitablaroom as commercial zinc -ox1d.

The carbonate of soda greatly assists the duction ,in consequence ofits dissolving and decom osing effect, adn it generally facilitates t e action. residue thereof after the zinc is driven off,

.and it is evident that the sodium carbonate is decom osed. Its action is probably as follows: he hot carbon acts upon the sodium carbonate, producing by its reduction a certain amount of sodium which by its strong attraction for oxygen combines with that contained in the metallic oxids. In. the reaction carbonic oxid is formed, and this acting upon the vapors of zinc assists somewhat in the oxidization of the volatile zinc. The reaction may be written as follows:

then

Zn C0 ZnO CO.

This cake has many advantages for the a current of air or oxygen,- and it is this fact which makes it more valuable than coal, charcoal or coke, all of which leaves ashes or deposits which'would have to be gotten rid of. The action of the oil cake and carbonate of soda is to reduce the OXldS'tO the metallic state, and by simply keeping the charge in the molten condition at a low heat the zinc is volatilized and again oxidized while the lead and antimony remain behind as metals practically free from impurities. Air is excluded to a reat extent from the retort as it would be iable to again oxidize the lead and antimony, and the tem erature is kept low for the same reason. T e extraction of the zinc by this method is practically perfeet, and the reduced lead and antimony contain only a small percentage of zinc, and are free from any deposit of silica or ashes which would result from the use of coal or the like.

Heretofore, the zinc oxid in the skimmings referred to has been lost, as there hasbeen no way of extracting it from the oxids of lead and antimony and saving it. This resulted in a certain ex ense which the present invention saves. A so the presence of the other oxids has been a nuisance in clogging the smelting There is very little lead, antimon and zinc, consisting in mixing which retain other metals, fluxes, etc. and said oxids wit oil cake and sodium carbongradually make the furnace smaller and curate, and heati'n said mixture sufliciently l5 tail the output. Even with its disadvanto reduce the oxids to the metallic state and 5 tages it has hitherto been chea er to lose the va orize the zinc.

zinc than to t to extract it, ut by the use 7 n testimony whereof I have signed my of a cheap re ucing agent such as oil cake name to this specification in the presence of and the process above described, the reductwo subscribing witnesses.

tion and separation can be made at asub- RICHARD D. DIVIN 10 stantial saving.

I claim: The process of separating the oxide of furnace by forming deposits on the sides Witnesses LEWIS M. RANDOLPH,

1 Joan MOCABE.