US1030676A - Zinc distillation. - Google Patents

Description

J. U. MOUL & H. W. WEBSTER. ZI STILLATION. APPLICATION FILED DEC. 29, 1910.

Patented June 25, 1912.

to those; ores of zinc. which contain" sensible UN TED sTAirEs PATENT OFFICE.

JOHN COLLET'IIMOULDEN AND HAROLD WOLSTAN WEBSTER. or "sm'roN cAnEwQ ENGLAND, assreNoa's TO CENTRAL ZINC ooMrANY LIMITED, or sne'roN-"cannw,

ENGLAND.

ZINC. Drs'rILLA'rIoN.

Patented June 25, 1912.

Application filed December 29, 1910. Serial 1V0. 599,832. I

*useful Improvements in Zinc Distillation,

of which the following is a specification.

This invention is for improvements in or relatin to zinc distillation, the object beingto ten er the distillation more efficient and particularly to increase the amount of spelter formed and to avoid the; formation of zinc oxid-.- v y The invention is particularly. applicable proportions of lead: and silver and the residues of'which have tobetreated after distillation for the recovery of their lead and silver contents. V i v Y The, ores to be treated according to the present method must be oxidized ores, either as vfound in nature or otherwise oxidized.

.In the. distillation of zinc this invention consists in bringing into contact with the" retort vapors a haloid salt such as sodium chlorid which in the presence of carbon monoxid tends to. prevent the formation of [More particularly in the distillation of zinc from products which contain other metals such as lead and silver this inventionconsists' in placing a haloid salt. such 'as' sodium chlorid in the path of the 2 retort vapors i. e. in the vfront of the retort. or in the back of-the condenser to diminish the production of zinc'oxid and to increase the production of-metallio zinc.

Hitherto it-has been proposed in'the distillation of certain zinc ores to mix common salt with the retortchargewiththe object of improving the distillation. It is found however-that the salt has no beneficial effect in the actual decomposition of the orebut on the other hand the presence of salt in the charge is detrimental where the ore contains metals other than zinc (such as lead and silver) because the presence of the salt resultsin a chloridizing roast by which metals other than zinc are driven off 'in the form of volatile chlorids, thereby contaminating the zinc products and depleting the residues.

According to this invention the haloidsalt such as sodium chlorid is not mixed with the retort charge but is so placed that containing say two cwt-s. of a mixed charge containing anore comprising compounds of zinc'with some lead and silver, about 4 .ozs. of salt are placed. in the mouth of the retort in order to separate the. salt from the retort charge, alayer of coke breeze may be introduced into the mouth of the-retort be fore the salt. Alternatively,the small quantity. of salt may be placed at theback of thecondenser, and this invention includes the provision of a small pocket or receptacle for salt at the-back of the condenser and above .thelevel of ,the'condensed zinc. As the hot.

vapors'from the retort pass over the salt,

.the vapor from the salt comes in. Contact with the vapors. and the tendency. is to prevent the formation of zinc oxid and to increase the yield of spelter. a

Several advantages accrue from the invention. .In th'e first place the quantity of 'spelter obtained from each retort charge is materially increased, and from the investigations made up to the present it appears that any lead carried over with the-zinc readily settles out therefrom. The production of blue powder is diminished and the condensation is therefore better: and

.' owing to the decrease of ox'id fumes the furnace-main can more easily inspect the progressofdistillation. In cases where the fumesffrom the c'ondenserpass through a nozzle thefiam'e'is bright yellow and forms a useful source of illumination. The zinc products are found to be comparatively 'free of contamination.

Thetheoretical reasonsTfor the advantageous results are not positively deterk mined, but this invention would include the employment of any catalytic agent (such as other metallic chlorids) which in the presence of carbon monoxid will prevent the formation of zinc oxid.

This invention is applicable to" the distillation of zinc by any known means, electrical or otherwise. I i

The figure shows a form of apparatus for carrying this invention into. effect.

A is the retort into which the charge of zinc ore and carbonaceous material is inserted. The retort Ahas an opening B into which fits a condenser C, and is preferably arranged so that it has a slope as has also the condenser. The condenser C is provided with a pocket I) preferably of a shallow cup form, at a point nearthe opening intothe retort, and is also provided with an outlet E for thegases from the retort and an outlet F from which the zinc is run off. .The charge is introduced into the retort I and the condenser is placed in position with tit of'haloid salt G, as for example sodium its end in the opening B of the retort. A layer of coke breeze may be introduced into the mouth of the retort. The joint of the condenser with the retort is packed with clay or other suitable material as is also the outlet F from which the molten .zin'c is run oif. Into the pocket D is placeda small quanch orid. The retort is heated and the zinc vapors distil and pass into the condenserv thereby heating the salt in the cup D and causin it'to give: off vapors. The vapors mix wlth the zinc vapor and enable them to of zinc distillation which consists in bring-;

condense in the lower endof the condenser without formation of zinc oxid and blue owder When suflicient zinc is condensed t e plug of clay is removed from the openin F and the zinc is run 01]., another plug being placed in position to seal the condenser for a further time. The fumes from the retort pass through the condenser and out of thenozzle E.

' What we claim as our invention and desire to secure by LettersPatent-isz- 1. The herein describedstep in the process.

'Ofzinc distillation which consists. ing into contact with retort vs "rs a halo d salt to revent the formation 0 zinc oxid.

' 2. T e hereimdescribed step inthe process ing into contact with retort va rs common salt to prevent theforma-tion o zinc oxid.

3. The herein-described process for the" production of, substantially pure oxidizedi-oref which consists in heating the oxidized "ore with a reducing agent to 'generate zinc vapor therefrom, bringing the vapor into cont-act with a haloid salt to pre- .vent the formationof zine oxid,and-: condens= ing metallic zinc.

- 4. The herein-described processfor the .sists in placing common salt at the front of I 65 '1 g 7. The herein-described step in the process production of substantially pure -rinc from oxidized ore which consists in heating the oxidized ore with a reducing agent to generate zinc vapor therefrom, bringing the vapor into contact with common salt to prevent the formation of zinc oxid, and condensing metallic zinc.

5. The hereindes'cribed step in the process of zinc distillation from retorts which'conslsts in placing common salt in the pathof the-retort vapors for the purpose'described.

6. The herein-describedstep in the process of zinc distillation from retorts which conthe retort for the purpose described.

of zinc distillation from retorts which consists n placing common salt in the condenser at the back thereof and above the levelof 9. The ethod of treating complex oxi- 'dized ores containing zinc and other metals for the'recovery of metallic. zinc substantiall; free from zinc oxid, which consists in mixing the ore with a reducing agent, heatingthe .mixture to generate therefrom a va 1' of nine mixed with carbon monoxid, nging a vapor of common salt into con tact with the zin vapor to prevent the for.-

tallic zinc. v

Intestimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses. I JOHN COLLETT MOULDEN. HAROLD WOLSTAN WEBSTER.

Witnesses-z. Y

J no. I. DAVIES, E. W. WARING.

mation of zinc oxid, and condensing me-

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