US3284325A - Production of alkaline earth metals - Google Patents

Production of alkaline earth metals Download PDF

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Publication number
US3284325A
US3284325A US230466A US23046662A US3284325A US 3284325 A US3284325 A US 3284325A US 230466 A US230466 A US 230466A US 23046662 A US23046662 A US 23046662A US 3284325 A US3284325 A US 3284325A
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US
United States
Prior art keywords
alloy
alkaline earth
calcium
cell
sulphide
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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
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US230466A
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English (en)
Inventor
Gibson Allan Robert
Lang Jan Zbigniew
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.)
Elgar Trading Ltd
UK Atomic Energy Authority
Original Assignee
Elgar Trading Ltd
UK Atomic Energy Authority
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Publication date
Priority claimed from GB3818861A external-priority patent/GB950889A/en
Application filed by Elgar Trading Ltd, UK Atomic Energy Authority filed Critical Elgar Trading Ltd
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Publication of US3284325A publication Critical patent/US3284325A/en
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B26/00—Obtaining alkali, alkaline earth metals or magnesium
    • C22B26/20—Obtaining alkaline earth metals or magnesium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/10—Vacuum distillation
    • 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
    • C25C3/02—Electrolytic production, recovery or refining of metals by electrolysis of melts of alkali or alkaline earth metals

Definitions

  • the present invention relates to the production of the alkaline earth metals calcium, strontium and barium from their salts.
  • a process for the production of alkaline earth metals comprising dissolving the sulphide of such metals in a fused salt bath, electrolysing such sulphide using a cathode formed by a molten alloy of the alkaline earth metal with copper, causing alloy enriched by the electrolysis to flow upwardly to a vacuum distillation apparatus.
  • alkaline earth metal selected from the group of calcium, barium and strontium is removed therefrom, and causing such depleted alloy to return under gravity for further enrichment by electrolysis.
  • Said electrolyte may conveniently comprise a mixture of calcium chloride and potassium chloride and is preferably the eutectic mixture containing 81% by weight of calcium chloride.
  • the dissolved calcium sulphide may be present in amounts up to 4% by weight.
  • the calcium is removed from the copper-calcium alloy by vacuum distillation and, although the distillation may be effected batch-wise, the copper-calcium alloy is preferably continuously removed from the electrolytic cell by making use of the differing specific gravities. of alloys containing differing proportions of calcium. Consequently the electrolyte is preferably continuously renewed by the continuous addition of calcium sulphide thereto. The sulphur liberated by the electrolysis will be in the vapour phase and may readily be removed.
  • the invention also includes apparatus for carrying the aforesaid method into effect.
  • apparatus for the production of alkaline earth metals comprising an electrolytic cell having a molten alloy cathode pool at the lower part thereof, vacuum distillation apparatus located above said electrolytic cell, a flow pipe leading from the upper part of said pool to said distillation apparatus, a return pipe leading from a point in said distillation apparatus lower than the entry of said flow pipe and terminating in the lower part of said pool and means to maintain such a pressure differential between said electrolytic cell and said distillation apparatus that said pipes are maintained full of alloy.
  • the spacing of the still head (forming the distillation apparatus) from the electrolytic cell Will depend on the temperatures of operation, vacuum differential and composition of the two copper-calcium alloys, but once these physical dimensions are fixed, a change in one of the operating conditions will cause a compensating change in the 3,284,325 Patented Nov. 8, 1966 other conditions. Thus, for example, a change in vacuum differential will cause a compensating change in the alloy composition.
  • the preferred arrangement is described in detail hereinafter.
  • FIG. 1 is a diagrammatic layout of the apparatus
  • FIG. 2 is a diagrammatic outline section through an electrolytic cell.
  • an electrolytic cell 1 (shown in more detail in FIG. 2) is provided with a gas connection 2 and is also provided with alloy inlet (return) and outlet (flow) pipes 3 and 4.
  • the alloy pipes 3 and 4 are connected to a still head 5, this still head having a condenser 6 which is cooled by a gas line 7, while the still head itself has a gas conmotion 8'.
  • All parts of the apparatus are constructed so as to be gas-tight, for reasons which will appear, and unless otherwise specified may be made of mild steel or chrome iron.
  • Gas, e.g. argon, and vacuum pipe lines 9 and 10 respectively are provided and are connected to the gas connections 2 and 8 by three-way valves 11 and 12 respectively.
  • the gas connection 2 from the cell 1 acts as an air condenser for sulphur vapour and a branch line 13 runs to a sulphur well 14 in which molten sulphur seals the end of the line 13.
  • Fresh calcium sulphide for making up the electrolyte is admitted to the cell 1 from a hopper 15 through a pipe 16, this pipe having a valve 17.
  • the electrolytic cell 1 is shown in more detail in FIG. 2 and comprises a brickwork body 20, an alumina brick liner 22 and an outer mild steel shell 21.
  • the cell has a gastight lid 23.
  • the base of the cell supports a mild steel cathode cup 24 on an insulating spacer 25, this cup having a central weir 26.
  • the anode is in the form of a graphite block 27 supported from the lid 23 of the cell by current carrying rods '35, these rods being joined at their upper ends by a terminal ring 36.
  • the pipes 3 and 4 also enter the cell through the lid 23 and extend into the cup 24 and it will be seen that they terminate at different levels, the return pipe 3 extending to nearer the bottom of the cup.
  • the pipes 3 and 4 are shrouded and effectively electrically insulated by alumina tubes 28, 29 respectively.
  • the calcium sulphide feed pipe 16 is also shown in more detail in FIG. 2 and it will be seen that the valve 17 is in the form of a screw-conveyor driven by a motor 30 on the end of a shaft 31.
  • the cell is filled with electrolyte to the level 32, the electrolyte being a fused mixture of calcium chloride, potassium chloride and calcium sulphide.
  • the electrolyte is preferably a eutectic mixture of 81% by weight calcium chloride and 19% by weight potassium chloride and may conveniently contain approximately 4% by weight of calcium sulphide.
  • the cathode cup 24 contains molten copper-calcium alloy to the level 33 and under the conditions chosen only the calcium sulphide is electrolysed, the calcium entering the alloy and the sulphur being discharged from the cell via the gas connection 2.
  • the mode of operation of the apparatus is to fill the cup 24 with copper-calcium alloy containing 30% by weight calcium (melting point 705 C.) and to fill the cell 1 with molten electrolyte.
  • the valve 11 By operating the valve 11 the cell is purged and filled with argon, and electrolysis may now begin using, for example, a voltage of 7.5 volts. After a period of electrolysis and due to the configuration of the cell 1, the upper layer of alloy in the cup 24 becomes enriched to 40% calcium (melting point 665 C.).
  • the specific gravity of the 40% alloy at 800 is approximately 2.9 while that of the 30% alloy is approximately 3.5. If, under these conditions, the stillhead is connected via the valve 12 to the vacuum line (after a suitable purge with argon), the alloy will flow up the pipe 4 into the heated still-head 5, a proportion of its calcium content will be vaporised to be condensed on the condenser 6 and the depleted alloy will return down the pipe 3. Assuming that the cell 1 is at substantially atmospheric pressure and the still-head 5 at 0.1 mm. of mercury, the pipe 3 may be approximately 3 meters high and the pipe 4 approximately 3.5 meters.
  • the vacuum to the still-head 5 is broken by admitting argon via the valve 12 so that all the alloy in the still-head drops down the pipe 3 into the cell 1.
  • the condenser 6 may then be removed with the calcium thereon, a new condenser fitted and, after a purge, the distillation restarted.
  • a plurality of stillheads may be connected to a single cell by suitable valves or provision may be made for the continuous removal of calcium.
  • the cell 1 is conveniently operated at 700 C. to 800 C. and the still-head 5 at 800 C. to 850 C., and it is preferred to use electrical heating; the pipes 3 and 4 must also be heated. No details are given of the arrangement of the heaters or of the necessary temperature measuring and controlling circuits.
  • the invention provides a continuous electrolytic method of forming a copper-calcium alloy from calcium sulphide and a semi-continuous method of removing the calcium from the alloy.
  • the starting material, calcium sulphide may readily be made from calcium sulphate by reduction with town gas.
  • a process for the production of alakline earth metals comprising the steps of (a) dissolving the sulphide of an alkaline earth metal selected from the group consisting of calcium, strontium and barium metal in a fused salt bath,
  • said fused salt bath consists of 81% by Weight of calcium chloride and 19% by weight of potassium chloride and said sulphide is calcium sulphide.
  • Apparatus for the production of alkaline earth metals comprising (a) an electrolytic cell,
  • the apparatus of claim 5 including means for providing continuous addition of alkaline earth metal sulphide directly to the electrolyte in the cell.
  • the apparatus of claim 6, including a pipe scaled by molten sulphur for the continuous removal of gaseous product sulphur from the cell.
  • the apparatus of claim 5, including, in the vacuum distillation apparatus, a plate capable of being heated and located so that alloy flows over it from the flow pipe.
  • the apparatus of claim 5, including a cathode pool container and a weir therein separating the alloy flow and return pipes.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Electrochemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Electrolytic Production Of Metals (AREA)
US230466A 1961-10-25 1962-10-15 Production of alkaline earth metals Expired - Lifetime US3284325A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB3818861A GB950889A (en) 1961-10-25 1961-10-25 Improvements in or relating to the production of alkaline earth metals
GB3960662 1962-10-19

Publications (1)

Publication Number Publication Date
US3284325A true US3284325A (en) 1966-11-08

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US230466A Expired - Lifetime US3284325A (en) 1961-10-25 1962-10-15 Production of alkaline earth metals

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US (1) US3284325A (pt)
BE (1) BE624084A (pt)
CH (2) CH435765A (pt)
DE (1) DE1176877B (pt)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986002108A1 (fr) * 1984-10-05 1986-04-10 Extramet S.A. Procede de production de calcium ou d'alliages de calcium de haute purete
FR2573442A1 (fr) * 1984-11-21 1986-05-23 Extramet Sa Procede de production d'alliages de calcium de haute purete
WO1998014622A1 (en) * 1996-09-30 1998-04-09 Kleeman, Ashley Process for obtaining titanium or other metals using shuttle alloys
US20050161340A1 (en) * 2004-01-26 2005-07-28 Ceramatec, Inc. Process for the recovery of materials from a desulfurization reaction
US20080053838A1 (en) * 2004-10-12 2008-03-06 Toho Titanium Co., Ltd. Method for Production of Metal by Molten-Salt Electrolysis and Method for Production of Titanium Metal
US9475998B2 (en) 2008-10-09 2016-10-25 Ceramatec, Inc. Process for recovering alkali metals and sulfur from alkali metal sulfides and polysulfides

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB494702A (en) * 1937-05-04 1938-10-31 Allan Robert Gibson Improvements in or relating to the electrolytic production of alkaline earth metals or alloys thereof with base metals
US2913382A (en) * 1957-01-28 1959-11-17 Union Carbide Corp Method for producing metals electrolytically
US3119664A (en) * 1961-03-08 1964-01-28 Chlormetals Inc Production of alkali metal oxides

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB494702A (en) * 1937-05-04 1938-10-31 Allan Robert Gibson Improvements in or relating to the electrolytic production of alkaline earth metals or alloys thereof with base metals
US2913382A (en) * 1957-01-28 1959-11-17 Union Carbide Corp Method for producing metals electrolytically
US3119664A (en) * 1961-03-08 1964-01-28 Chlormetals Inc Production of alkali metal oxides

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986002108A1 (fr) * 1984-10-05 1986-04-10 Extramet S.A. Procede de production de calcium ou d'alliages de calcium de haute purete
US4738759A (en) * 1984-10-05 1988-04-19 Extramet S.A. Zone Industrielle Method for producing calcium or calcium alloys and silicon of high purity
FR2573442A1 (fr) * 1984-11-21 1986-05-23 Extramet Sa Procede de production d'alliages de calcium de haute purete
WO1998014622A1 (en) * 1996-09-30 1998-04-09 Kleeman, Ashley Process for obtaining titanium or other metals using shuttle alloys
US20050161340A1 (en) * 2004-01-26 2005-07-28 Ceramatec, Inc. Process for the recovery of materials from a desulfurization reaction
US7897028B2 (en) 2004-01-26 2011-03-01 Ceramatec, Inc. Process for the recovery of materials from a desulfurization reaction
US20080053838A1 (en) * 2004-10-12 2008-03-06 Toho Titanium Co., Ltd. Method for Production of Metal by Molten-Salt Electrolysis and Method for Production of Titanium Metal
WO2006078901A2 (en) * 2005-01-20 2006-07-27 Ceramatec, Inc. Process for the recovery of materials from a desulfurization reaction
WO2006078901A3 (en) * 2005-01-20 2007-02-15 Ceramatec Inc Process for the recovery of materials from a desulfurization reaction
US9475998B2 (en) 2008-10-09 2016-10-25 Ceramatec, Inc. Process for recovering alkali metals and sulfur from alkali metal sulfides and polysulfides
US10087538B2 (en) 2008-10-09 2018-10-02 Field Upgrading Limited Process for recovering alkali metals and sulfur from alkali metal sulfides and polysulfides

Also Published As

Publication number Publication date
CH435765A (de) 1967-05-15
DE1176877B (de) 1964-08-27
BE624084A (pt)
CH435206A (de) 1967-05-15

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