US3219561A - Dual cell refining of silicon and germanium - Google Patents

Dual cell refining of silicon and germanium Download PDF

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Publication number
US3219561A
US3219561A US179726A US17972662A US3219561A US 3219561 A US3219561 A US 3219561A US 179726 A US179726 A US 179726A US 17972662 A US17972662 A US 17972662A US 3219561 A US3219561 A US 3219561A
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US
United States
Prior art keywords
germanium
cathode
silicon
metal
cell
Prior art date
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
US179726A
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English (en)
Inventor
Monnier Robert
Barakat Dlawar
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.)
General Trustee Co Inc
Original Assignee
Gen Trustee Company Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to NL290208D priority Critical patent/NL290208A/xx
Priority to NL290209D priority patent/NL290209A/xx
Application filed by Gen Trustee Company Inc filed Critical Gen Trustee Company Inc
Priority to US179726A priority patent/US3219561A/en
Priority to US179725A priority patent/US3254010A/en
Priority to GB9363/63A priority patent/GB993192A/en
Priority to GB9362/63A priority patent/GB989452A/en
Priority to CH314563A priority patent/CH410441A/fr
Priority to CH319963A priority patent/CH409416A/fr
Priority to AT199163A priority patent/AT245273B/de
Priority to FR927910A priority patent/FR1351123A/fr
Priority to DEG37275A priority patent/DE1217077B/de
Priority to DEG37274A priority patent/DE1213627B/de
Priority to FR927909A priority patent/FR1351122A/fr
Application granted granted Critical
Publication of US3219561A publication Critical patent/US3219561A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • C22B41/00—Obtaining germanium
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/02—Silicon
    • C01B33/037—Purification
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/33—Silicon
    • 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
    • C25C3/34—Electrolytic production, recovery or refining of metals by electrolysis of melts of metals not provided for in groups C25C3/02 - C25C3/32
    • 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

  • This invention relates to the electrolytic production and refining of metals particularly of silicon and germanium, and, more particularly, to a new electrolytic method of producing these elements in a high purity state from their oxides.
  • Electrolytic methods of preparing silicon and germanium have been proposed heretofore. Nevertheless, so far none of these methods have been utilized in the industry for several reasons; among which are the low purity of the elements obtained rendering them unsuitable for further refining by zone-refining or the like and diflicult operating conditions involved in their production.
  • the electrolysis is conducted with one or two fused salt baths or electrolytes of any of the following type: (1) an alkali metal cryolite alone or a mixture of different alkali metal cryolites with or without an alkali metal or alkaline earth metal fluoride or a mixture of the same; (2) alkaline earth or alkaline metal fluorides alone or in admixture; (3) the same as in (l) and (2) with oxides of the metal or element being refined, and (4) alkali metal and/or alkaline earth metal chlorides in admixture with alkali metal or alkaline earth fluorides or fluosilicates.
  • the chlorides alone are not satisfactory for the reason that they form volatile compounds with silicon, for example, which evolve at bath temperature.
  • the same or different electrolyte can be used in the two compartments of the cell. Working with the latter conditions is very advantageous.
  • an electrolyte can be used which is capable of dissolving a certain quantity of the oxide of the metal to be deposited, such as a bath based on cryolites.
  • any of the above mentioned electrolytes can be used.
  • An electrolyte containing alkaline fluosilicates and chlorides without cryolites is particularly useful because the deposited metal is easily recovered from the bath carried over with it.
  • the cell in which a reduction and refining takes place may be formed of material capable of withstanding bath temperatures on the order of 500 to 1100 C., the temperature at which the electrolyte is molten, and is characterized by the presence of a dividing partition therein which extends toward the bottom of the cell and forms an anode compartment and a cathode compartment which communicate with each other through a passage between the bottom of the cell and the lower edge of the partition.
  • a pool of molten alloy of the metal being produced fills the cell to a level above the lower edge of the partition and thereby separates an overlying molten bath of the electrolyte in the anode compartment from a molten bath of electrolyte in the cathode compartment.
  • An anode and a cathode are immersed in the electrolytic baths in the respective compartments but are out of direct contact with the molten metal alloy in the bottom of the cell.
  • An oxide of silicon or germanium is introduced into 3,219,551 Patented Nov. 23, 1965 or present in the electrolyte in the anode compartment and when a direct current of a current density of a proper value, e.g. 5 to amperes per square decimeter, is applied across the anode-cathode circuit, the metal of the oxide is deposited into molten alloy at the bottom of the cell.
  • silicon or germanium in the alloy by the eflect of current, goes into the solution, migrates therefrom and is deposited on the cathode in a highly refined state.
  • the cathode By mounting the cathode in such a manner that it can be removed or replaced readily, the deposit of refined and highly purified metal thereon can be removed and separated from any electrolyte clinging to the deposit and to the cathode.
  • the metal recovered from the cathode has a sufiiciently high purity, e.g. 99.99+% that it can be used directly for many purposes requiring high purity silicon or germanium, particularly, it is very suitable to be purified by zone-refining.
  • the cell 9 comprises a steel casing or jacket 10, in which the refractory bricks are laid in such a way as to form a lining which is coated with material resistant to corrosion under operating conditions, e. g. carbon or graphite but preferably a poor electrically conductive material such as SiC bonded with silicon nitride.
  • Any suitable means may be used for heating the cell, such as electric resistance heaters, but preferably the cell is heated only by the current flowing between the anode 11 and the cathode 12.
  • a partition 13 Extending across about the middle of the cell 10 is a partition 13 having a lower edge spaced from the bottom of the cell to provide a passage 14 permitting circulation of a molten alloy 15 between the anode compartment 16 and the cathode compartment 17.
  • the partition wall 13 may be composed of carbon, graphite or refractory bricks covered with silicon carbide bonded with silicon nitride of the type of Crystolon.
  • the partition 13 must be made of a material which does not conduct electricity and is resistant to the corrosion by the electrolytes with which it is in contact.
  • a typical agitator includes a shaft 18 extending downwardly through the partition 13 and rotated at slow speed by means of a motor and interposed reduction gearing 19.
  • a rod-like stirrer 20 is mounted transversely on the lower end of the shaft 18 below the partition 13.
  • the stirrer may be composed of graphite, carbon or the like and may be reenforced internally, if required. That portion of the stirred shaft 18 which is not immersed in the molten bath may be protected from oxidation by means of a silicon carbide tube or the like, not shown.
  • a graphite or carbon anode 11 and a graphite or carbon cathode 12 are mounted for movement into and out of their respective compartments 16 and 17 in order to permit removal and replacement.
  • the cathode 12 should be removable to enable the deposit to be separated therefrom.
  • Example 1 The anode and cathode 11 and 12 of the cell have an area of 50 square decimeters each. Each of the anode 16 and cathode 17 compartments has a bottom area of 100 square decimeters.
  • Into the cell is poured a molten alloy of copper and silicon containing 16% silicon. Enough of the molten alloy is charged into the cell to fill it above the level of the lower end or edge of the partition 13. Compartments 16 and 17 are charged with a molten electrolyte composed of sodium cryolite containing 4% silica.
  • a direct current of an intensity of about 2000 amperes, i.e., a current density of 40 amperes per decimeter is passed between the electrodes.
  • the stirrer 18, 20 is rotated slowly.
  • a temperature of about 1000 C. is maintained in the cell by regulating the distance between the anode and the cathode or by regulating the intensity of the current.
  • Pure quartz powder is supplied to the anode compartment 16 to maintain the silica content of the electrolyte therein at between 1% and 4%.
  • Example 2 In a similar manner, the cell was charged with molten silver-germanium alloy containing 20% germanium to form the anode-cathode layer at the bottom of the cell. A mixture of 70% sodium cryolite, 28% sodium fluoride and 2% germanium oxide was poured into the anode compartment. A molten mixture of sodium fluoride and potassium fluoride in substantially equal proportions by weight was poured into the cathode compartment. The cell temperature was maintained at about 930 C. by passing an electric current of a density of 2000 amperes between the anode and the cathode, that is, a current density of 40 amperes per square decimeter. Germanium oxide was supplied to the anode compartment to maintain a concentration thereof between about 1% land 2% in the electrolyte.
  • Germanium deposited on the cathode, after removal of soluble components by pulverizing the deposit and Washing with boiling dilute hydrochloric acid, and filtering was 99.99% pure.
  • the cell operated at a current efiiciency of 60%.
  • the proportions of the components of the anode-cathode molten alloy can be varied so long as the alloy is molten at cell operating temperatures.
  • germanium alloys with nobler metals than germanium for example Ag or Cu may contain up to 50% germanium and are molten at temperatures less than 1000 C.
  • the structure of the cell, the current density and the electrolytes are susceptible to variation as indicated.
  • Refined metals obtained in accordance with the invention may be used for purposes commensurate with their purity. For example, 99.99% pure silicon or germanium obtained in the manner disclosed in the examples can be used in many different fields, and if higher purity than 99.99% is required, they can be purified further, for example, by zone-refining.
  • a method of producing refined silicon and germanium comprising passing a direct current between an anode in contact with a molten salt bath containing a fluoride and an oxide of a metal of the class consisting of germanium and silicon and a cathode in contact with another molten salt bath containing a fluoride, said baths being separated by a molten alloy of the metal corresponding to said oxide and a nobler metal to reduce said oxide to metal and deposit it on said cathode.
  • a method of producing refined silicon comprising passing a direct current between an anode and a cathode, each being in contact with separate molten salt baths containing a fluoride, said salt baths being separated by and in contact with a molten alloy of silicon and a metal nobler than silicon, said alloy containing less than 50% silicon, maintaining at least 1% silica in the salt bath in contact with said anode for reduction to silicon and deposit thereof on said cathode.
  • a method of producing refined germanium comprising passing a direct current between an anode and a cathode, each being in contact with separate molten salt baths containing a fluoride, said salt baths being separated by and in contact with a molten metal containing germanium, maintaining at least 1% of germanium oxide in said salt bath in contact with said anode for reduction to germanium and deposit thereof on said cathode.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Silicon Compounds (AREA)
US179726A 1962-03-14 1962-03-14 Dual cell refining of silicon and germanium Expired - Lifetime US3219561A (en)

Priority Applications (13)

Application Number Priority Date Filing Date Title
NL290208D NL290208A (enrdf_load_stackoverflow) 1962-03-14
NL290209D NL290209A (enrdf_load_stackoverflow) 1962-03-14
US179726A US3219561A (en) 1962-03-14 1962-03-14 Dual cell refining of silicon and germanium
US179725A US3254010A (en) 1962-03-14 1962-03-14 Refining of silicon and germanium
GB9362/63A GB989452A (en) 1962-03-14 1963-03-08 Electrolytic refining of silicon and germanium
GB9363/63A GB993192A (en) 1962-03-14 1963-03-08 Electrolytic refining of silicon and germanium
CH314563A CH410441A (fr) 1962-03-14 1963-03-12 Procédé d'affinage du silicium et du germanium
CH319963A CH409416A (fr) 1962-03-14 1963-03-13 Procédé de fabrication de silicium et de germanium affinés et cellule électrolytique pour la mise en oeuvre de ce procédé
AT199163A AT245273B (de) 1962-03-14 1963-03-13 Verfahren zur Herstellung reinen Siliziums bzw. Germaniums durch Schmelzflußelektrolyse und Zelle zur Durchführung des Verfahrens
FR927910A FR1351123A (fr) 1962-03-14 1963-03-14 Raffinage de silicium et de germanium par élément double
DEG37275A DE1217077B (de) 1962-03-14 1963-03-14 Verfahren und Vorrichtung zur Herstellung von Silicium oder Germanium hoher Reinheit durch Schmelzflusselektrolyse
DEG37274A DE1213627B (de) 1962-03-14 1963-03-14 Verfahren zur Raffination von unreinem Silicium und Germanium durch Schmelzflusselektrolyse
FR927909A FR1351122A (fr) 1962-03-14 1963-03-14 Raffinage de silicium et de germanium

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US179726A US3219561A (en) 1962-03-14 1962-03-14 Dual cell refining of silicon and germanium
US179725A US3254010A (en) 1962-03-14 1962-03-14 Refining of silicon and germanium

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US3219561A true US3219561A (en) 1965-11-23

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US179726A Expired - Lifetime US3219561A (en) 1962-03-14 1962-03-14 Dual cell refining of silicon and germanium
US179725A Expired - Lifetime US3254010A (en) 1962-03-14 1962-03-14 Refining of silicon and germanium

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US179725A Expired - Lifetime US3254010A (en) 1962-03-14 1962-03-14 Refining of silicon and germanium

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US (2) US3219561A (enrdf_load_stackoverflow)
CH (2) CH410441A (enrdf_load_stackoverflow)
DE (2) DE1213627B (enrdf_load_stackoverflow)
GB (2) GB989452A (enrdf_load_stackoverflow)
NL (2) NL290208A (enrdf_load_stackoverflow)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3983012A (en) * 1975-10-08 1976-09-28 The Board Of Trustees Of Leland Stanford Junior University Epitaxial growth of silicon or germanium by electrodeposition from molten salts
US4142947A (en) * 1977-05-12 1979-03-06 Uri Cohen Electrodeposition of polycrystalline silicon from a molten fluoride bath and product
US4448651A (en) * 1982-06-10 1984-05-15 The United States Of America As Represented By The United States Department Of Energy Process for producing silicon
US20070215483A1 (en) * 2006-03-10 2007-09-20 Elkem As Method for electrolytic production and refining of metals
WO2007106709A2 (en) 2006-03-10 2007-09-20 Elkem As Method for electrolytic production and refining of metals
US20100276297A1 (en) * 2009-04-30 2010-11-04 Metal Oxygen Separation Technologies, Inc. Primary production of elements
CN101400811B (zh) * 2006-03-10 2012-03-07 埃尔凯姆有限公司 电解生产和精炼金属的方法
WO2012083480A1 (en) * 2010-12-20 2012-06-28 Epro Development Limited Method and apparatus for producing pure silicon
DE112010004425T5 (de) 2009-05-26 2012-11-29 Sumitomo Chemical Co., Ltd. Verfahren zur Herstellung von gereinigtem Metall oder Halbmetall
CN110482556A (zh) * 2019-09-10 2019-11-22 中国科学院合肥物质科学研究院 一种用于硅材料低温精炼除硼的造渣剂及其使用方法
CN115305507A (zh) * 2021-05-08 2022-11-08 中南大学 熔盐电解氧化铝生产金属铝的方法
CN115305568A (zh) * 2021-05-08 2022-11-08 中南大学 一种多晶硅的冶炼方法

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH426279A (fr) * 1965-06-15 1966-12-15 Fiduciaire Generale S A Cellule électrolytique pour la fabrication de silicium
FR2480796A1 (fr) * 1980-04-21 1981-10-23 Extramet Sarl Procede de production de silicium de haute purete par voie electrochimique
NO156172C (no) * 1984-02-13 1987-08-12 Ila Lilleby Smelteverker Fremgangsmaate til fremstilling av renset silisium ved elektrolytisk raffinering.
CN101743342A (zh) 2007-06-18 2010-06-16 Rec斯坎沃佛股份有限公司 从切割剩余物回收元素硅的方法
CN103243385B (zh) * 2013-05-13 2016-04-27 北京科技大学 电解精炼-液态阴极原位定向凝固制备高纯单晶硅的方法
CN112708764A (zh) * 2020-12-15 2021-04-27 湖南腾驰环保科技有限公司 一种从铜锗合金物料中综合回收二氧化锗和铜的方法

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BE533780A (enrdf_load_stackoverflow) *
US800984A (en) * 1905-06-02 1905-10-03 Henry M Chance Process of purifying metals.
US2861030A (en) * 1956-10-19 1958-11-18 Timax Corp Electrolytic production of multivalent metals from refractory oxides
US2892763A (en) * 1957-04-12 1959-06-30 American Potash & Chem Corp Production of pure elemental silicon
US2952605A (en) * 1956-12-29 1960-09-13 Montedison Spa Refractories resistant to aggressive melts and treatment for obtaining them
US3009870A (en) * 1954-05-25 1961-11-21 Ver Aluminum Werke Electrolytic cell
US3030284A (en) * 1960-11-03 1962-04-17 American Potash & Chem Corp Electrolytic production of elemental boron

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US2755240A (en) * 1953-11-02 1956-07-17 Shawinigan Water And Power Com Electrolysis of titanium tetrachloride to produce titanium
US2940911A (en) * 1959-01-02 1960-06-14 American Potash & Chem Corp Electrorefining of elemental boron

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE533780A (enrdf_load_stackoverflow) *
US800984A (en) * 1905-06-02 1905-10-03 Henry M Chance Process of purifying metals.
US3009870A (en) * 1954-05-25 1961-11-21 Ver Aluminum Werke Electrolytic cell
US2861030A (en) * 1956-10-19 1958-11-18 Timax Corp Electrolytic production of multivalent metals from refractory oxides
US2952605A (en) * 1956-12-29 1960-09-13 Montedison Spa Refractories resistant to aggressive melts and treatment for obtaining them
US2892763A (en) * 1957-04-12 1959-06-30 American Potash & Chem Corp Production of pure elemental silicon
US3030284A (en) * 1960-11-03 1962-04-17 American Potash & Chem Corp Electrolytic production of elemental boron

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3983012A (en) * 1975-10-08 1976-09-28 The Board Of Trustees Of Leland Stanford Junior University Epitaxial growth of silicon or germanium by electrodeposition from molten salts
US4142947A (en) * 1977-05-12 1979-03-06 Uri Cohen Electrodeposition of polycrystalline silicon from a molten fluoride bath and product
US4448651A (en) * 1982-06-10 1984-05-15 The United States Of America As Represented By The United States Department Of Energy Process for producing silicon
AU2007226754B2 (en) * 2006-03-10 2011-01-20 Elkem As Method for electrolytic production and refining of metals
CN101400811B (zh) * 2006-03-10 2012-03-07 埃尔凯姆有限公司 电解生产和精炼金属的方法
WO2007106709A3 (en) * 2006-03-10 2007-11-29 Elkem As Method for electrolytic production and refining of metals
JP2009529607A (ja) * 2006-03-10 2009-08-20 エルケム アクシエセルスカプ 金属の電解製造及び精練方法
WO2007106709A2 (en) 2006-03-10 2007-09-20 Elkem As Method for electrolytic production and refining of metals
US20070215483A1 (en) * 2006-03-10 2007-09-20 Elkem As Method for electrolytic production and refining of metals
US7901561B2 (en) 2006-03-10 2011-03-08 Elkem As Method for electrolytic production and refining of metals
US20100276297A1 (en) * 2009-04-30 2010-11-04 Metal Oxygen Separation Technologies, Inc. Primary production of elements
US8460535B2 (en) 2009-04-30 2013-06-11 Infinium, Inc. Primary production of elements
US8795506B2 (en) 2009-04-30 2014-08-05 Infinium, Inc. Primary production of elements
DE112010004425T5 (de) 2009-05-26 2012-11-29 Sumitomo Chemical Co., Ltd. Verfahren zur Herstellung von gereinigtem Metall oder Halbmetall
WO2012083480A1 (en) * 2010-12-20 2012-06-28 Epro Development Limited Method and apparatus for producing pure silicon
CN110482556A (zh) * 2019-09-10 2019-11-22 中国科学院合肥物质科学研究院 一种用于硅材料低温精炼除硼的造渣剂及其使用方法
CN110482556B (zh) * 2019-09-10 2020-12-08 中国科学院合肥物质科学研究院 一种用于硅材料低温精炼除硼的造渣剂及其使用方法
CN115305507A (zh) * 2021-05-08 2022-11-08 中南大学 熔盐电解氧化铝生产金属铝的方法
CN115305568A (zh) * 2021-05-08 2022-11-08 中南大学 一种多晶硅的冶炼方法

Also Published As

Publication number Publication date
CH410441A (fr) 1966-03-31
GB989452A (en) 1965-04-22
US3254010A (en) 1966-05-31
GB993192A (en) 1965-05-26
CH409416A (fr) 1966-03-15
DE1217077B (de) 1966-05-18
DE1213627B (de) 1966-03-31
NL290208A (enrdf_load_stackoverflow)
NL290209A (enrdf_load_stackoverflow)

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