US1755380A - Method and means for electrolytic production of light metals - Google Patents

Description

April 22, 1930. E. o. BA STQW I 1,755,380

METHOD AND MEANS FOR ELECTROLYTIC PRODUCTION OF LIGHT METALS Filed Nov. 1925 GLOISULES F06 ED ELETROL YTE.

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I XV EN TOR.

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Apr, 22, lld33 see EDWIN 0. BARSTOW, OF MIDLAND, MICHIGAN, ASSIGNOR TO THE DOW CAI: COMPANY, 018 MIDLAND, MICHIGAN, A CORPORATION OF MICHIGAN METHOD AND MEANS FOR ELECTROLYTIC PRODUCTION OF LIGHT METALS Application filed November In the electrolytic production of metallic magnesium, by passing an electric current through a suitable fused electrolyte, one of the difliculties encountered is the collection of the separate molten globules of the metal. These, as they are set free, rise to the surface due to their lighter specific gravity, but do not readily coalesce, at least until a considerable mass of the molten metal has accumulated.

3 The-object of the present invention is to provide an improved method and apparatus whereby such free molten globules of the "metal may be positively collected together at a selected point in the electrolytic cell, thus facilitating the removal or discharge of the metal.

, To the accomplishment of the foregoing and related ends, the invention then consists of the steps and means hereinafter described and particularly pointed out in the claims, the annexed drawing and following description illustrating but several of the various ways in which'the principle of the invention 2 may be carried-out. 4

. In said annexed drawing Fig; 1 is a more or less diagrammatic plan view of one type of electrolytic'cell such as is used in the production of metallic magne- 80 sium, the construction of such cell being modified to adapt the same for the collecting together of the molten metal inaccordance.

with the present invention; and Fig. 2 is a vertical section of such cell, partly on an axial plane and partly onv a plane in front of such axial plane, as indicated by the line 2. 2,Fi .1. q

The principal element in the apparatus,

illustrated in the drawing is a cast-iron or steel vessel (1) that constitutes the cell-proper and in which the electrolyte is placed and maintained in molterr conditipn. This vessel at the same time constitutes the cathode and,

for the purpose of initially melting the elec- 7 trolyte, the vessel may be supported in a suitable furnace chamber (not shown).

' Supported in any suitable way within vessel l is an annular diaphragm orpartition (2) of porcelain, fire clay, or equivalent material that serves to laterally surround the centrally 9, 1925. Serial No. 67,780.

disposed, depending carbon orgraphite anode (3). Neither. the latter, nor such annular diphragm extends entirely down to the bottom of the vessel. The anode, however, extends downwardly beyond the lower edge of the diaphragm. A suitable duct, not shown, may be provided if desired for supplying the electrolyte to the cathode compartment of the cell, i. e., that portion lying between the wall of the vessel (1) and the an-' nular diaphragm (2); while-a duct (4) is connected with the upper portion of the space within the diaphragm in order to conduct away any gases arising from the anode compartment defined by such diaphragm.-

In the operation of a cell such as the foregoing, the particles of free molten magne-. sium; many quite small in size, rise to the surface of the electrolyte in the aforesaid cathode compartment, and there float as separate globules which do not readily coalesce and, at the best, form a thin film only of the metal, which is dificult to remove either by dipping or through a spout or'equivalent discharge opening. The present 1mprovement consists as previously indicated inthe provision of means for collecting these free molten globules of metal and in the preferred form illustrated, such means comprise a boxlike chamber (5), lying between the diaphragm (2) and the wall of vessel The respective end walls of thischamber are submerged below the bath level, but'the lateral walls rise-well above such level. Two transverse partitions (6) and (7) in said chamber (5) form a sub compartment 8) that is open both above and below The second of these partitions (see Fig. 2), it willbe noted, extends downwardly further than the first and in the portion (9) of the chamber adj acent'to the sub-compartment (8) there is located a propeller (10) carried by an externally driven vertical shaft (11), such propeller serving when operated to induce a flow of the electrolyte through the several compartments of chamber (5) in the direction indicated by the arrows.

Only the upper stratum of the electrolyte lying, between the annular "partition (2% and the surrounding Wall of vessel (1) will e af- 1% fected, and, depending upon the size and rate of rotation of propeller (10) this stratum may be circulated at any desired rate of speed so as to be entirely caused to pass through chamber (5) within a stated time. Due to the arrangement of the transverse partitions (6 and 7) within the chamber, as clearly shown in Fig. 2, the particles or globules of molten metal are entrapped in the sub-compartment defined by said partitions and are there collected together to form a mass of molten metal of substantial thickness. From this sub-compartment the metal ma be removed either by dipping or a suita ly controlled laterally opening sprue or discharge spout may be provided to conduct the metal from said compartment to a point without the cell.

It will be understood that the propeller (10) may be operated either continuously or intermittently. Thus, it may be found satisfactory to induce a circulation of the upper described and, similarly, I do not limit myself" to any precise form of trap chamber for collecting together the globules or particles of molten metal as they are thus carried around by the circulating electrolyte.

Oher modesofapplying the principle of my invention may be employed instead of the one explained, change being made as regards the means and the steps herein disclosed, provided those stated by any of the following claims or their equivalent be employed.

ll therefore particularly point out and distinctly claim as my invention 1. 'lhe method of aggregating light metal floating on a fused electrolyte, which comprises mechanically circulating sa id electro iyte through a trapped zone in which the oating metal is arrested.

2. in a method of electrolyzin a fused electrolyte for the production 0' a metal which will float thereon, the step which comprises mechanically circulating the surface portion of said electrolyte through a trap adapted to arrest metal floating thereon.

3. A method of electrolyzing a fused electrolyte containing magnesium chloride for the production of magnesium. metal, which comprises .mechanically circulating the surface layer of said electrolyte through a trap adapted to arrest and retain such floating;

metal.

4. A method of producing a light metal which comprises electrolyzing a suitable fused electrolyte, mechanically driving the upper stratum of such electrolyte about in an approximately circular surface path, and entrapping at one point the free molten globules of metal therein.

5. In a method of electrolyzing a fused electrolyte for the production of a metal which will float thereon, the step which comprises liberating said metal as such,permitting it to rise to the surface of the electrolyte, and collecting such metal by mechanically circulating the electrolyte upon which it floats through a trapped zone.

6. In an electrolytic apparatus for liberating a light metal upon a non-fluid cathode from a fused electrolyte heavier than the metal liberated, the combination with a vessel adapted to contain the fused electrolyte, of means to mechanically circulate said electrolyte through a trap within said vessel to arrest metal floating on said electrolyte.

7. In an electrolytic apparatus for liberating a light metal upon a non-fluid cathode from a fused electrolyte heavier than the metal liberated, the combination with a vessel adapted to contain the fuesd electrolyte and act as cathode, of an anode depending in said electrolyte, means to separate products liberated upon the anode from those lib erated upon the cathode, and mechanical means to circulate the catholyte througha trap to skim and arrest metal floating upon the surface.

8. In an electrolytic apparatus for pro ducing a metal lighter than the electrolyte,

the combination of a vessel adapted-to contain a fused electrolyte, means for passing an electric current therethrough, means for positively driving in a surface circuit the portion of such electrolyte containing free molten globules of metal, and a trap located in such circuit to collect the globules together.

9. In an electrolytic apparatus for producing a metal lighter than the electrolyte, the combination of a vessel of general circular form adapted to contain a fused electrol to and constituting one electrode, a second e ectrode disposed approximately centrally within said vessel, means for driving the upper stratum of such electrolyte around said second electrode, and a trap-chamber within said vessel disposed in the ath of such circulating electrolyte and aa ted to collect together the free, molten glo ules of'metal therein.

10. In an electrolytic apparatus for producing a metal lighter than the electrolyte, the combination of a vessel of general circular form adapted to contain a fused electrolyte and constituting one electrode, a second electrode disposed approximately cen- 3 trally' within said vessel, means adapted to cause a circulation of the upper stratum of such electrolyte around said second electrode, a chamber lying between the wall of said vessel and said second electrode so as to permit msasso 3' such circulating electrolyte to flow therethrough and having a transverse partition arranged to tra and so collect together the ree, molten glo ules of metal in the electro- 5 11. In an electrolytic apparatus for pr duoing a metal lighter than the electrolyte, the combination of a vessel of general circular form adapted to contain a fused electrolyte and constituting one electrode, a second electrode disposed approximately centrally within said vessel, a chamber lying between the Wall of said vessel and said second electrode, the end walls of said chamber being submerged so as to permit the upper stratum of such electrolyte to flow thereover, transverse partitions in said chamber forming a sub-compartment open at the top and bottom, and a propeller in said chamber adjacent said sub-compartment.

12. In an electrolytic apparatus for producing a fused metal lighter than the fused electrolyte employed, the combination with a suitable vessel adapted to contain said fused 5 electrolyte, of a trap disposed within said vessel in said electrolyte to arrest and retain floating. metal, and a mechanically driven means in said vessel to circulate the electrolyte upon which the metal floats through said tra igned by me this 6th day of November, 1925. i

EDWIN O. BARSTOW.

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