US2838454A - Electrolytic cell - Google Patents

Electrolytic cell Download PDF

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Publication number
US2838454A
US2838454A US461740A US46174054A US2838454A US 2838454 A US2838454 A US 2838454A US 461740 A US461740 A US 461740A US 46174054 A US46174054 A US 46174054A US 2838454 A US2838454 A US 2838454A
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United States
Prior art keywords
cathode
metal
cell
anode
cup
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US461740A
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English (en)
Inventor
Malcolm E Washburn
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Saint Gobain Abrasives Inc
Original Assignee
Norton Co
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Publication date
Application filed by Norton Co filed Critical Norton Co
Priority to US461740A priority Critical patent/US2838454A/en
Priority to DED21279A priority patent/DE1093998B/de
Priority to GB27059/55A priority patent/GB780785A/en
Priority to FR1136472D priority patent/FR1136472A/fr
Application granted granted Critical
Publication of US2838454A publication Critical patent/US2838454A/en
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B35/00—Boron; Compounds thereof
    • C01B35/02—Boron; Borides
    • C01B35/023—Boron
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/26—Electrolytic production, recovery or refining of metals by electrolysis of melts of titanium, zirconium, hafnium, tantalum or vanadium
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
    • C25C7/005—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells of cells for the electrolysis of melts

Definitions

  • the invention relates to electrolytic cells and particularly to cells for extraction of metals from metal carbides by methods in accordance with the disclosures of my colleagues Ervin and Ueltz, Serial Nos. 356,423 to 356,428, inclusive, filed May 21, 1953, Serial No. 313,171, filed October 4, 1952, and Serial No. 394,753, filed November 27, 1953, in which the metal carbide is the anode in the cell, which employs an electrolyte of Another object of the invention is to provide a cell of general application for the extraction of refractory metals of the subgroups of groups IV, V and VI of the periodic table as follows from their carbides.
  • Another object of the invention is to provide an efficient electrolytic cell of the character indicated. Another object of the invention is to provide a cell having cell elements which are not too expensive and are easily made.
  • Figure l is a vertical axial sectional view of a cell
  • Figures 2 to 5 inclusive are horizontal sectional views illustrating the metal cell, graphite container, the anode or anodes and the cathode or cathodes in further embodiments of the invention.
  • a cylindrically shaped cell 1 made of nickel or other suitable material has a bottom to which an integrally depending drain pipe 2 is attached.
  • the cell 1 has a hollow head 3 to which is bolted by means of studs 4 a hollow head 5, each stud 4 being insulated from the head 5 by means of a sleeve 6. Nuts 7 on the studs 4 hold the parts together.
  • the peripheries of-the heads 3 and 5am drilled and tapped and pipes 8 and 9 are screwed thereinto one of which conducts water into one head and the other of which is the drain from the other head.
  • the heads are drilled and tapped on the periphery ice at another location and pipes 10 and 11 connected by a rubber tube 12 conduct the water from the inside of the one head to the inside of the other head. Thus the heads 3 and 5 are kept reasonably cool.
  • a sealing ring 13 of rubber or the like is provided between grooved flanges 14 of the heads 3 and 5.
  • an upwardly extending pipe 15 which is externally threaded at the top to receive "a cap 16 which has a central hole plugged by an insulating bushing 17 preferably made of refractory material such as asbestos cement through which extends a cathode 18.
  • a cap 16 which has a central hole plugged by an insulating bushing 17 preferably made of refractory material such as asbestos cement through which extends a cathode 18.
  • the cathode 18 is preferably a titanium tube.
  • the cathode 18 might be a nickel tube but preferably the cathode 18 is made/of the same metal which 'is being extracted.
  • Zirconium with its almost inevitable content of hafnium can be drawn into tubes and so can vanadium, chromium, niobium (columbium) and tantalum although the last two are rare at present. Molybdenum and tungsten cannot at present be had in the form of tubes but solid rods can be had andused in this invention. Titanium can readily be drawn into tubes and I have used a titanium tube cathode 18. The advantage of using a tube is that a thermocouple rod 19 having thermocouple wires 20 can be inserted in the cathode 18 to keep careful check 011 the temperature deep in the cell.
  • the bushing 17 is sealed to the pipe 15 by means of a sealing ring 21 and the bushing 17 is also sealed to the cathode 18 by means ofa short section of rubber tubing 22 so therefore, since the heads 3 and 5 are sealed by the ring 13 and the head 3 is integral with the cell 1, the inside of the cell 1 is hermetically sealed from the atmosphere except for pipes 24 which extend through both walls of the head 5 and are welded thereto.
  • These pipes are connected to rubber hoses, not shown; one hose leads to a bottle of gas and the other hose leads to a needle valve to throttle the flow to keep a low pressure of gas within the cell, for example of the order of one or two inches of mercury which is sufficient to keep out the air and to avoid wasting the gas.
  • the gas is an inert gas of which the common examples are helium, neon, argon and krypton and from many practical points of view I prefer argon. It is not too expensive and it is heavier than air so it has less tendency to diffuse then helium which is much cheaper but is very much lighter than air. The molecules of helium are of course very small and they diffuse readily, that is to say they escape through minute cracks or pores. Nevertheless helium in some cases might be preferred.
  • the cathode is connected to negative electricity by means of a clamp 26 while the cell 1 is connected to positive electricity by means of a clamp 27.
  • the pipes 8 and 9 can readily be insulated by connecting them to rubber hoses while the lower head 3 rests upon an annular plate of asbestos fibre material 30; thus the cell 1 and conveniently shaped into cylindrical form.
  • the outside thereof there is preferably a helical groove in which is a winding of wire 38 having suitable electrical resistance and being refractory enough to withstand the temperature involved.
  • Nichrome U. S. Patent 811,859
  • the grooving of the cylinder 36 can be dispensed with and is a matter of choice.
  • Outside the winding 38 is a coating of refractory cement 40 which can be applied after the Wire is wound.
  • Alumina cement is satisfactory for this purpose.
  • Between the cement 40 and the inside of the can 32 is a filling 41 of any suitable insulating material which is refractory enough and there are many such materials such as fullers earth and diatomaceous earth. This material 41 can be simply loose material poured into the space.
  • One end 42 of the Winding 38 extends to a binding post 43 connected to a wire 44 and the other end 45 of the winding 38 extends to a binding post 46 connected to a wire 47.
  • the binding posts 43 and 46 extend through the fibreboard 30 as shown.
  • the wires 44 and 47 are connected to a suitable source of electrical energy, either direct current or alternating current although the latter is usually more readily available, and suitable controls are provided for heating the apparatus to the required temperature. Such electrical apparatus is well known and need not be further described.
  • the cup can be formed by taking grains or lumps of the carbide and bonding with a carbonaceous binder such as coal tar pitch. This operation is conveniently carried out in an inert atmosphere, such as argon, at 900 C. to 1000 C.
  • an inert atmosphere such as argon
  • Other binders could be used, and it is even possible to produce satisfactory anodes by pressing, sintering or hot-pressing without the presence of added residual binding material, so long as the particles are in good electrical contact to constitute an electrically-conducting structure.
  • titanium carbide there should be neither oxygen nor nitrogen in the atmosphere. Titanium and its carbide react quickly with nitrogen.
  • the carbide cup 50 will in most cases be somewhat porous so I provide an outer cup 51 made of graphite which fits snugly between the cup 50 and the cell 1. Graphite is inert to the hot salt.
  • a clamp 55 held by an insulating bushing 56 on a screw stud 57 which is supported by a thumb nut 58.
  • the lower end of the screw stud 57 is screwed into and is supported by a clamp 62 secured to the pipe 15.
  • titanium metal was made therein in accordance with the following examples.
  • Example I Titanium carbide of grit size from 12 to 90 was mixed with ten percent of pitch. The mixing was accomplished by heating the pitch in a metal container on a hot plate until molten and then adding the titanium carbide to the molten pitch, heating continuously while mixing with a spatula until the mass was homogeneous. A total of 421 grams of carbide was used. This mixture was used to line the inside of the graphite cup 51, which was 3 inches outside diameter by 2 /2 inches inside diameter and 7 /2 inches deep. The graphite cup 51 was lined by tamping the hot mixture in it around a slightly tapered graphite plug that had a A inch clearance. The A inch lining over the bottom of the cell was tamped in before the plug was inserted.
  • This titanium-carbide-lined cup was then placed in the cell 1 and was filled with a eutectic mixture of mols of potassium chloride and 60 mols of lithium chloride in accordance with the disclosure in the application of my colleagues Dr. Ervin and Dr. Ueltz, Serial Number 394,753 filed November 27, 1953.
  • the quantity of this eutectic mixture was 466 grams, which melted to form molten salt about 6 /8 inches deep.
  • the apparatus was then completely assembled, heated to the operating temperature, the water was turned on and the argon caused to flow from one pipe 24 to the other pipe 24, thus driving the air out of the cup and the space above it.
  • the titanium tube 18 was adjusted so that it extended four inches into the molten salt.
  • the apparatus was energized with electricity at 3.4 volts E. M. F., causing electricity to flow from the cup 1 through the cup 51 and anode cup 50, through the salt bath to the cathode rod 18, and so out of the cell.
  • the temperature of the molten salt was raised to 900 C. by control of the electric current from the wire 44 to the wire 47.
  • the exposed surface area of the cathode rod 18 in the salt bath was 30.4 square centimeters.
  • the electric current was amperes, giving a current density at the cathode of 164 amperes per square decimeter. After minutes the electric current was turned off, both between the clamps 27 and 26 and between the wires 44 and 47, and the apparatus andcontents were allowed to cool.
  • the cathode 18 was raised out of the salt bath soon after the apparatus was de-energized. After allowing to cool to the vicinity of room temperature, the apparatus was disassembled. Up to this time, argon had been continuously flowing from one pipe 24 to the other one.
  • This cup 51 sticks in the cell 1 because of the salt which penetrates every crevice and freezes therein, but I am able easily to loosen the graphite cup 51 with a steel rod through the pipe 2 and a hammer. Of course, the head 5 has to be taken off before the cup 51 can be removed.
  • the deposit of metal on the cathode tube 18 was then scraped off and was placed in dilute sulphuric acid.
  • the sulphuric acid was then poured off and the salt was leached from the metal with distilled water.
  • the weight of the sponge metal titanium produced was 7.6 grams, giving an efficiency of 34 percent, based on the electric current value and total time involved,
  • Example II Using the same apparatus as in Example I, the cup 50 was prepared in the same manner out of 374 grams of titanium carbide, grit size from 12 to 90, with ten percent of pitch. Four hundred and eighty-six grams of the eutectic mixture of lithium chloride and potassium chloride were placed in the cup and melted. The molten salt was 6 inches deep.
  • the cathode tube 18 being the same one previously used, was immersed 4 inches deep in the molten salt and the cell was operated for 60 minutes at 1,000 C. at 50 amperes under an electromotive force of 3.3 volts.
  • the current density was 164 amperes per square decimeter.
  • ExampleIII In this example of the use of the apparatus, the anode cup was prepared out of 391 grams of titanium carbide of grit size from 12 to 90 with ten percent of pitch added. The baking was done in an inert atmosphere of argon at 900 C. Four hundred and seventy-four grams of the lithium chloride-potassium chloride eutectic mixture constituted the salt bath, which had a depth of .six inches. The voltage was 4.1 and the current 50 amperes, giving a current density of 164 amperes per square decimeter, the cathode tube 18 being immersed four inches in the salt bath, as in the other examples. The procedure was the same as previously described and 11.8 grams of titanium metal was collected, giving an efficiency of 52 percent.
  • Example IV current density was 246 amperes per square decimeter.
  • Example V Procedure, similar to Example I, was used for a series of consecutive runs using the same anode, and a sample of the product had the following analysis:
  • a larger weight of the metal carbide which is the raw material for producing the metal, can be provided.
  • the centrally located cathode rod or tube and its deposit of metal can be conveniently lifted out of the molten salt without opening the cell.
  • the cathode is centrally located, it can hold a larger deposit of metal sponge before bridging over to the anode.
  • Another factor is the larger anode area in comparison to that of the cathode. This gives a lower anode current density which in turn gives improved electrical efficiency.
  • anode of cylindrical shape many other shapes would be effective, the only requirement being that the cathode is partially or completely surrounded by the anode.
  • the cathode is partially or completely surrounded by the anode.
  • the anode shape might be that of a hollow prism.
  • the requirement is that at least 80% of the submerged area of cathode shall be surrounded by carbide anode.
  • the cathode can be in several parts and so can the anode.
  • metal carbide is used here to include material that contains more than 50% by'weight of chemically combined metal and carbon, and which is electrically conducting.
  • the metal carbides have variable ratios of metal to carbon and are frequently contaminated with oxygen and nitrogen, but can be used effectively for raw materials for this process.
  • the structure is square in cross section except for the cathode 89 which is hollow and the anode completely covers the interior of the graphite container 81 so it can be in contact therewith as shown.
  • FIG 4 the structure is octagonal except for a solid cylindrical cathode 99.
  • An octagon approaches a cylinder and because of symmetry is preferable to a square.
  • Figure 5 four anodes 100 in the form of plates and four cathodes 109 in the form of rods are illustrated and it will readily be seen that the structure complies with the rule above given.
  • the metal cell contains a graphite cup 1 81 which contains a titanium carbide cup 50, so therefore the bottom of the cell is titanium carbide which is of course in electrical contact with the graphite and with the metal illustrating an arrangement similar to Figure 1 except that the cross section is square.
  • Figure 4 I choose to illustrate the condition in which the metal cell 95 contains a graphite cup 91 whereas the carbide anode 90 has no bottom so therefore the bottom of the cell is graphite which is electrically energized. l find that this results in little loss of electric efficiency because the affected area of the bottom of the cathode rod 99 is relatively small. Nevertheless it would be better to have the bottom of the cell of Figure 54 covered with the carbide anode but the foregoing description of Figure 4 is given to illustrate what may be done and there may be some mechanical reasons in some cases for lining the graphite with carbide on the sides but not on the bottom.
  • Figure 5 shows an arrangement almost the same as that of Figure 2 the difference being that the anode in Figure 5 takes the form of a plurality of rods 109 whereas in Figure 2 only a single rod 79 is shown.
  • Figure 5 there is some masking of some of the area of the cathode rods 199 as will readily be seen by drawing radial lines from the rods to the anode plates 100. This masked area does not count in the application of the rule of 80% as previously stated.
  • the electrolyte in this invention is composed of fused salt which is halide of metal selected from the group consisting of the alkali metals and alkaline earth metals including magnesium.
  • the alkali metals are sodium, potassium, lithium, rubidium and cesium.
  • the alkaline earth metals are magnesium, calcium, strontium and barium. Mixtures are definitely included and at present I prefer a eutectic mixture hereinbefore specified of potassium chloride and lithium chloride.
  • An electrolytic cell for the extraction of metal from metal carbide which comprises a metal container, a graphite container within said metal container, said graphite container being adapted to contain fused salt, means for maintaining a controlled inert atmosphere inside said metal container including a head secured to said metal container and an orifice for the introduction of said inert atmosphere, a cathode within said graphite container, a metal carbide anode within said graphite container surrounding at least of the submerged unmasked area of the cathode as determined by projecting the submerged area of the cathode radially in a horizontal direction from its surface to the submerged area of the anode, the area of said anode being considerably greater than the area of said cathode, and electrical leads for the anode and for the cathode whereby the cathode can be made negative and the anode positive.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Inorganic Chemistry (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)
US461740A 1954-10-12 1954-10-12 Electrolytic cell Expired - Lifetime US2838454A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US461740A US2838454A (en) 1954-10-12 1954-10-12 Electrolytic cell
DED21279A DE1093998B (de) 1954-10-12 1955-09-13 Elektrolytische Zelle zur Herstellung von Titan
GB27059/55A GB780785A (en) 1954-10-12 1955-09-22 Electrolytic cell
FR1136472D FR1136472A (fr) 1954-10-12 1955-10-05 Cellule électrolytique

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US461740A US2838454A (en) 1954-10-12 1954-10-12 Electrolytic cell

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DE (1) DE1093998B (fr)
FR (1) FR1136472A (fr)
GB (1) GB780785A (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2920021A (en) * 1957-07-02 1960-01-05 Norton Co Processes and anodes for the electrolytic extraction of the metals ti, v, cr, zr, nb, mo, hf, ta and w from their carbides
US2981666A (en) * 1957-08-09 1961-04-25 Ciba Ltd Process for the production of metallic niobium or tantalum by an electrolytic method
US2987462A (en) * 1956-06-07 1961-06-06 Commissariat Energie Atomique High temperature electrolytic cell
US3078218A (en) * 1958-08-04 1963-02-19 Union Carbide Corp Hydrogenation of halogen compounds of elements of groups iii and iv of the periodic system
US3226310A (en) * 1960-12-19 1965-12-28 Ciba Ltd Electrolytic fusion cells and method of operating the same

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114752967B (zh) * 2022-02-25 2024-06-18 包头市玺骏稀土有限责任公司 一种集群式稀土金属熔盐电解装置
CN116695185B (zh) * 2023-08-04 2023-10-17 四川澳晟新材料科技有限责任公司 一种金属锂熔盐电解工艺参数模拟仿真测试装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2014566A (en) * 1931-05-27 1935-09-17 Fansteel Prod Co Inc Bimetallic articles of manufacture
US2519792A (en) * 1942-04-10 1950-08-22 Rosen Raphael Electrolytic production of metallic uranium

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE508036A (fr) *
DE319530C (de) * 1916-08-03 1920-03-08 Henry Charles Morris Ingeberg Verfahren zur elektrolytischen Herstellung von Metallen mit Hilfe geschmolzener Elektrolyte
DE334475C (de) * 1919-05-29 1921-03-14 Metallbank Verfahren zur Gewinnung von Metallen und Legierungen durch schmelzfluessige Elektrolyse
DE701785C (de) * 1938-07-27 1941-01-23 Franz Landler Vorrichtung zur schmelzelektrolytischen Gewinnung von Leichtmetallen

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2014566A (en) * 1931-05-27 1935-09-17 Fansteel Prod Co Inc Bimetallic articles of manufacture
US2519792A (en) * 1942-04-10 1950-08-22 Rosen Raphael Electrolytic production of metallic uranium

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2987462A (en) * 1956-06-07 1961-06-06 Commissariat Energie Atomique High temperature electrolytic cell
US2920021A (en) * 1957-07-02 1960-01-05 Norton Co Processes and anodes for the electrolytic extraction of the metals ti, v, cr, zr, nb, mo, hf, ta and w from their carbides
US2981666A (en) * 1957-08-09 1961-04-25 Ciba Ltd Process for the production of metallic niobium or tantalum by an electrolytic method
US3078218A (en) * 1958-08-04 1963-02-19 Union Carbide Corp Hydrogenation of halogen compounds of elements of groups iii and iv of the periodic system
US3226310A (en) * 1960-12-19 1965-12-28 Ciba Ltd Electrolytic fusion cells and method of operating the same

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FR1136472A (fr) 1957-05-23
GB780785A (en) 1957-08-07
DE1093998B (de) 1960-12-01

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