US554184A - Process of and apparatus for refining zinc - Google Patents

Description

l 2 Sheets-Sheet 1. M. HOLSTEIN J. D. JAMES; P'ROGBSS OIAND APPARATUS FORBEFINING ZINC.

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G. M. HQLSTEIN x44. D. JAMES. PROCESS OP AND APPARATUS POR REPINING ZINC.

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Nirnn STATES ATENT Enron.

GEORGE M. HOLSTEIN AND JOHN D. JAMES, OF PULASKI CITY, VIRGINIA, ASSIGNORS, BY DIRECT AND MESNE ASSIGNMENTS, TO Tl-IE BERTH'A MIN- ERAL COMPANY, OF JERSEY CITY, NEYV JERSEY.

PROCESS OF AND APPARATUS FOR REFINING ZINC.

i SECIFICATION forming part of Letters Patent- No. 554,184, dated February 4, 18S-)6.v

Application filed May 27, 1895.

To @ZZ whom it ,1m/,y concern:

Beit known that we, GEORGE M. HOLSTEIN and JOHN D. JAMES, of Pulaski City, in the county of Pulaski and State of Virginia, have invented a new and useful Improvement in Processes of and Apparatus for Refining Zinc, of which the following is a speciiication.

The object of our invention is to provide a process and apparatus for reiining zinc spel- 1o ter, and more especially for separating therefrom the lead with which it may be contaminated and it consists in certain steps for carrying out the same based upon the relative specific gravity, the melting-points, and volar 5 tilizing-points of these two metals, and a special construction and arrangement of furnace and retorts for making the same practically available, as will be hereinafter more fully described with reference to the drawings, in zo Which- Figure lis a front elevation of aportion of the furnace; Fig. 2, a vertical section through a portion of the retorts, condensers, and their front and back supports; Fig. 3, a rear View 2 5 of a part of the back end wall or supportingshelves for the back ends of the retorts, partly broken away; and Figs. 4, 5, 6, and 7 are details of modifications.

In the drawings, Fig. 2, A A represent the 3o retorts made of clay and baked in the usual manner, and having their back ends c closed, and their front ends provided with the tapering conical condensers B, into which the volatilized zinc is condensed and collected when 3 5 distilled from the retorts. These condensers are luted or cemented temporarily in the open ends of the retorts with a paste of clay, and are of the usual construction, being made at the lower edges of their larger open end with 4o a semicircular bridge wall or dam b which prevents the boiling metal in the retorts from slopping over into the condenser, and also prevents the pure distilled and molten zinc in the condenser from running back into the retort.

The outer and smaller end of this condenser is partly closed with a'sto'pple b of clay, which is removed when the contents of the condenser are to be drawn off.. l l i The outer ends of the retorts are held in a Serial No. 550,811. (No model.)

front wall composed of an inner lining C, of fire brick and clay, and a facing of cast-iron boxes C through which the condensers protrude, the whole being arranged to form a bank or nest ofretorts, condensers and boX- frames, as shown in Fig. 1, which are secured in place in the usual manner by iron buckstays and tie-rods, and thus integrally organized.

At the back end the retorts are surrounded by a luting E2 ofclay and are entered into and supported upon a checker-work or skeleton frame of fire-brick composed of horizontal tile-blocks D of fire-brick and vertical standards E of the same material having concave side and tenons at top and bottom, as shown in Fig. 3. These iire-clay nests protrude beyond the back ends of the retorts far enough to receive an outer cap or covering of tire-clay tile or brick. This cap may be made in one piece, as shown at F, or be built up from bricks or sectional tile, as shown at F. In either case this closure or cap at the-back end of the retort only covers the upper portion of it,`

leaving the lower portion exposed for the purpose hereinafter described. In building this wall at the back end of the retorts in large furnaces We propose, for the purpose of greater stability, to incorporate an iron frame G therein, as shown in Figs. 5 and 6, which frame has the fire-brick packed in its cells.

Havingthus described the construction of the furnace, we will now show how the process is carried out therein, and first let it be understood that we cant or incline all of the retorts, so that their back ends are about four inches lower than their front ends, as shown in Fig. 2.

The zinc spelter in the form of bars having been rst charged into the retorts, the heat from the subjacent iire circulating up through the retort causes it to melt and assume a level, (shown by the dotted line in Fig. 2,) and then as the proper temperature is reached the zinc volatilizes, and, passing over into the condensers, is collected in the form of pure melted zinc.

The furnace lires are so regulated as to keep the retorts as nearly as possible at the temperature at which zinc volatilizes, (1,04E0O centigrade,)'lead, .the chief impurity which this process is designed to remove, requiring a slightly higher temperature to volatilize. As soon as the spelter begins to melt, the lead, owing to its lower melting-point (330O centigrade as compared with zinc i12o centigrade) and 'owing also to its greater specilic gravity, (lead, 11.37, Zinc, 7.3,) collects in the lowest part of the retort at the back end. This part of the retort, it will be seen, is partly exposed to the air, which chills or lowers the temperature of the metal within. This, it will be seen, by diminishing ebullition at this point, gives the necessary condition of quiescence in the molten metal,and the greater specific gravity of the lead has a chance to assert itself and carry the lead to the-bottom, andthe cooling of the exposed .end of the retort also so lowers the temperature as to get below the volatiliZing-point of lead, so that the latter is not carried over into the condenser with the zinc, -which is thus .distilled ina condition of almost perfect'purity, running from 99.80 4to 99.98 per cent. of pure zinc. A proper regulation of the temperature-of the furnace is all that is required from ,this stage of the treatment on to maintain and continue the separation of the lead from the zinc.

The zinc volatilizing passes over the bridge into the condenser, where it `condenses into the molten condition, and so `remains until drawn .offer ladled out.

Thelead kept-in the coolestpart of the retort .i-sinot volatilized, .but inpart is absorbed by the silica of the retort forming lead silicate, and in part remains at the lowest end ofthe retort, as metallic lead, and at intervals is yremoved with rabbles vthrough the vfront end of theretort. :In vour'vprocess it willfbe seen that there-are two (3o-operating and lnecessary features to our invention. One is the making of the backend of the retort lower than the front end, soas to cause the molten metal to `flow to that end, and the. other is thezexposure and chilling of that end of theretort, so. as to take advantage .of the distinguishing `physical qualities of lead-17. c. ,its greater specific gravity, its lower melting-point, -and its higher volatilizing-point-that .is to say, lead having alower melting-pointiirst melts and runs tothe back end of'retort, and, having'a higher volatilizing-point, the chilled end of the retort keeps it from volatilizing and also promotes such quiescence inthe molten metal at this point as to facilitate the separation of lead into a lower layer by virtue of its greater specific gravity.

Ordinarily the backends of the retorts are the hottest, because they are arranged centrally in the furnace. In our invention the back ends of the retorts are in an outside wall and exposed to the airat certainpoin'ts. Ve prefer to expose-the lower edge of the retort,

as shown in Figs. 2 and 3, for the reason that the molten metal is in this lower plane, while the volatilized pure zinc occupies the upper zone or layer and should not be chilled since its continuous volatilization is necessary to its separation. le also in some cases form a small channel d in the supporting-tile D beneath the retort, which lets air in and further chills this end. We find good results, however, following the chilling of any portion of the back end of the retort, and in some case we expose the upper edge of the back end of the retort, as shown in Fig. 4. This is not because it is most desirable in itself, but it affords us another means of charging the metal plates of spelter into the retorts, for in such cases we make an opening o in the upper part of the back end ofthe retort large enough to receive the full size pig or plate of spelter, whichis at .once charged into the retort without'beingA remelted intozsmaller bars, as is necessary when the spelter is charged into the retort through .the relatively .small opening of the `condenser at theotherend. This opening-o-isduring the process closed up witha mixture'of an equal bulk of clay andcoal-dust, which is made firm by ironing with a hot iron after being -applied to the opening.

As a further modification for chilling the back end ofthe retort we may employ a water-jacket, as shown in Fig. 7, in'which the water-chamber A2 is supplied with a flowing bodyof vwater through suitable inlet and outlet pipes.

We Vdo not confine our inventionto separating lead from zinc, as it is obvious that any other metals having similar relative characteristics may beseparated bythe/same process and apparatus,

Having thus described your invention, what we claim as new, and desire tosecure by Letters Patent, is-

l. The process'herein described of refining Zinc and separating it from lead, which consists in melting the spelter and causing the lead by its lower melting-point greaterspecc gravity and higher volatilizing-point to flow to a lpoint of lower level, chilling the metal at this point, to hold the lead below its volatilizing-point, and volatilizing andseparatin g the zinc ata temperature below the volatilizingpoint of lead substantially as shown and described.

2. A-rening-furnace for zinc having retorts with one end lower than the other, and having 4at their lower ends a supporting-wall with openings through it which` are opposite to the lower part of that end-of the retort, the said wall covering. and inclosing the upper part of saidend of the retort'substantially as andfor'the-purposes described.

3. .A refining-furnace for zinc having re torts with oneend lower than the other, and having at their lower ends a supporting-wall provided with an opening (l passing entirely IOO IIO

through the said wall below the bottom of the lower endof the retort substantially as and for the purposes described.

4. A refining-furnace for zinc having re torts with their back ends lower than their front ends, a back wall composed of horzontal tile D, and Vertical tile E with tenoned ends tted to the horizontal tile so as to form un open wall or support, and a. detachable cap or lling of tile or brick covering a por- 1o tion of the end of the retort substantially as and for the purposes described.

GEO. M. HOLSTEIN.y JoI-IN D. JAMES. Vitnesses T. L. MAssIE, D. W. BARNARD.

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