WO1997027143A1 - Production of high purity silicon metal, aluminium, their alloys, silicon carbide and aluminium oxide from alkali alkaline earth alumino silicates - Google Patents

Production of high purity silicon metal, aluminium, their alloys, silicon carbide and aluminium oxide from alkali alkaline earth alumino silicates Download PDF

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Publication number
WO1997027143A1
WO1997027143A1 PCT/NO1997/000016 NO9700016W WO9727143A1 WO 1997027143 A1 WO1997027143 A1 WO 1997027143A1 NO 9700016 W NO9700016 W NO 9700016W WO 9727143 A1 WO9727143 A1 WO 9727143A1
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Prior art keywords
cryolite
high purity
alloys
aluminium
production
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PCT/NO1997/000016
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French (fr)
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Jan Reidar Stubergh
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Jan Reidar Stubergh
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Priority claimed from NO960249A external-priority patent/NO960249L/en
Priority claimed from NO960383A external-priority patent/NO960383L/en
Priority claimed from NO960422A external-priority patent/NO960422L/en
Priority claimed from NO961088A external-priority patent/NO961088D0/en
Application filed by Jan Reidar Stubergh filed Critical Jan Reidar Stubergh
Priority to AU15600/97A priority Critical patent/AU1560097A/en
Publication of WO1997027143A1 publication Critical patent/WO1997027143A1/en
Priority to NO19983324A priority patent/NO313750B1/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
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/02—Silicon
    • C01B33/021—Preparation
    • 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
    • C22B5/00—General methods of reducing to metals
    • 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
    • C22B61/00—Obtaining metals not elsewhere provided for in this subclass
    • 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
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/04—Working-up slag
    • 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
    • C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the present invention concerns a series of refining steps for producing high purity silicon (Si) metal, Al 2 O 3 , hydrogen gas and high purity aluminium (Al), AISi alloys of all compositions, and silicon carbide (SiC), after the required conditions in a electrolysis bath, preferably using feldspars ((Na,Ca,K)Al,. 2 Si 3 . 2 O g ) or feldspar containing rocks dissolved in fluorides, preferably cryolite (Na 3 AlF 6 ).
  • the high grade Si is produced, deposited together with Al 2 O 3 and Na 2 O dissolved in cryolite in a cathode layer in an electrolysis process (1) (Fig. 1).
  • the species in the cathode layer are refined by water (2) with formation of a sodium hydoxide (NaOH) solution, H 2 gas, and an aluminium hydroxide (AI(OH) 3 ) precipitate (Figs. 2 and 3).
  • the fines, containing Si and graphite (C) floats to the top, and are decanted with the NaOH solution and filtered (Fig. 3) and heated above 1410 °C to produce SiC (1-9) (Fig. 2).
  • the residual precipitate, containing Si, Al 2 O 3 and cryolite is milled, stirred washed and separated with water, all species are treated with HCl and/or H 2 SO 4 and at different temperatures (2-4), The fines, containing cryolite, are decanted, washed, filtered and separated from the Si/AI 2 O 3 deposits, which is then separated in a jig.
  • the enriched Si fraction is melted above 1410 °C, treated with CO 2 and crystallized when cooled (5-6).
  • the Al 2 O 3 enriched fraction (1-4) is treated with Al-metal to remove residual Si (11) (Figs. 2 and 3).
  • the high grade Si alloyed with high grade Al gives high purity AlSi-alloys (ll).
  • step I Fig. 1
  • step II Fig. 2
  • Fig. 1 Fig. 1
  • step I The cathode, containing Si deposited in a residual electrolyte is taken out of the bath and placed in water/HCl/H 2 SO 4 mixtures and separated from the crushed electrolyte with organic heavy liquids.
  • the AlSi-alloys are produced by alumino thermal reduction in step II (Fig. 1) at about 1000°C in WO 95/33870 and Al metal is produced in step III (Fig. 1 ).
  • SiAl-alloys are produced today by adding Si to AlSi-alloys or Al at 680 to 1410°C.
  • SiC is produced, today, from carbothermal reduction of quartz at high temperature.
  • Al 2 O 3 is produced from the well known Bayer process, using bauxite as an raw material.
  • Al(OH) 3 is an intermediate product formed in this process. NaOH and H 2 are produced from the well known alkali/Cl 2 electrolysis processes containing saturated NaCl in the cell.
  • Na 2 CO 3 and NaHCO 3 are produced by the well known Solvay process from CO 2 , NH 3 and saturated NaCl.
  • the present invention produces high purity Si and Al 2 O 3 .
  • Si and Al 2 O 3 are deposited with the compound Na 2 O dissolved in cryolite in a layer deposited at the cathode surface in an electrolysis bath (step I) (Fig. 1), which is the refinement step (1) (Figs. 1 and 2). (The equations are not balanced.)
  • the species in the cathode layer are then separated from the CO, flushed and refined graphite cathode (1) by picking, milling and grinding to a fine powder so that the largest parts of the Si grains with purity above 99.7 % Si are almost free from Al metal, Na metal, Al 2 O 3 crystals and of Na 2 O dissolved in cryolite.
  • High applied voltage or high current density favour formation of a separate layer at the cathode of Si metal in the inner part of the layer instead of deposited Al 2 O 3 .
  • the purity of the separated Si ( >99.7 % Si) grains deposited as solids is not influenced by the voltage applied and formation of Al and Na formed, because they do not form any alloy.
  • step (2) water is added to the powder, the mixture is kept at room temperature or tempered and NaOH, Al(OH) 3 and H 2 -gas starts to form.
  • Graphite containing small Si grains floats to the top and is removed by decanting.
  • Al(OH) 3 precipitates as a gel and is separated together with the NaOH solution from the solid precipitated cathode species (Si, cryolite and Al 2 O 3 ) by stirring, decanting and filtering operation.
  • the impurities as Na, K and Ca alloyed with Si reacts with water and dissolve (eq.2).
  • the NaOH which is formed has a concentration below 0.1 M.
  • Na 2 O forms partly from electrolysis, where Na metal formed, oxidate in air to form Na 2 O, and is formed by partly released alkali oxides (Na 2 O and K 2 O) from electrolysed and dissolved feldspars in cryolite (eq. l).
  • Ca or Ca 2+ forms CaF 2 in the electrolysis bath (step I) (Fig. 1).
  • Na 2 CO 3 and NaHCO 3 can be produced by adding self-produced CO 2 from the anodes (steps I and III) (Fig. 1 ) to the solution of NaOH (2).
  • Either the whole fraction containing Si, Al 2 O 3 and cryolite could be added HCl (3) or just any ofthe enriched fractions with HCl (3) in various concentrations (Figs. 2 and 3).
  • Either the whole fraction containing Si, Al 2 O 3 and cryolite could be added H 2 SO 4 (4) or just any of the enriched fractions with H 2 SO 4 (4) in various concentrations.
  • Especially high concentrated H 2 SO 4 reacts at high temperature with residual cryolite to produce fluoric acid (HF) (eq.5), which is very active to remove foreign elements in Si.
  • H 2 SO 4 should be added before (4) and after the melting/freezing process of Si and then be washed with water to remove the salt from the Si metal.
  • Either the whole fraction could be added a mixture of HCl and H 2 SO 4 (3-4) or just any of the enriched fractions with H 2 SO 4 (3-4) with various concentrations and temperature.
  • cryolite/Al 2 O 3 rich fractions By adding the pure Al metal (10) to the Si containing cryolite/Al 2 O 3 rich fractions by stirring and at the temperature about 1000 °C , the cryolite/Al 2 O 3 rich fractions are free from impurities as Fe and Si, which are removed .
  • the purified cryolite/ A1 2 0 3 mixture can be used for production of super pure Al metal by electrolysis (10).
  • the Si crystals deposited in the cathode layer is milled and treated with water at different temperature (2).
  • a high grade Si with a purity around 99.99 % Si is obtained.
  • the Si crystals mixed with a portion of cryolite are melted above 1410 °C (5).
  • a high grade Si crystallised with purity in the range 99.999 - 99.99999 % Si is obtained.
  • Example 3 The Si crystals mixed with cathode carbons in the fines are treated with water and in addition acids at different temperatures (2) and heated above 1410 °C (7). High grade SiC of purity in the range 99.99-99.999 % SiC is obtained.
  • Example 4 The milled and crushed cathode layer is added water. After a time NaOH, Al(OH) 3 and H 2 are formed (12). NaOH is dissolved in the water. Al(OH) 3 forms a gelatinous precipitate, which is decanted from the cathode layer compounds, containing Si, Al 2 O 3 and cryolite.
  • Example 5 High grade Al metal is produced by electrolysis (10) in a cryolite and Al 2 O 3 purified fraction, where iron is removed from the mixture by treating it with HCl and/or H 2 SO 4 . Silicon is removed after treating the cryolite/Al 2 O 3 mixture with Al at about 1000 °C .
  • Example 6 A mixture of high grade Si and of Al gives a high purity AlSi-alloys and SiAl-alloys (11) with low Fe content, when heated at about 580 to 1410°C and crystallised.
  • the dissolved NaOH is added CO 2 , produced at the anodes, to form Na 2 CO 3 and NaHCO 3 by addition of equivalent amounts of CO 2 .

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  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
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Abstract

The present invention concerns a procedure for production of high purity metals, their alloys and other species from feldspars and feldspar containing rocks. Silicon 'metal' (Si) and aluminium oxide (Al2O3) are produced by electrolysis. High purity Si produced from electrolysis is leached and refined by water which forms sodium hydroxide (NaOH), aluminium hydroxide (Al(OH)3) and hydrogen (H2). Si is then refined by using acids, and melted above 1410 °C. High purity silumin (AlSi alloys) is produced by alloying high purity Al and high purity Si from residual Si and Si(IV) in cryolite (Na3AlF6)/Al2O3 mixtures at about 970 °C. High purity silicon carbide (SiC) is produced by melting Si and adding cathodic and leached purified graphite (C) above 1410 °C.

Description

Production of high purity silicon metal, aluminium, their alloys, silicon carbide and aluminium oxide from alkali alkaline earth alumino silicates .
The present invention concerns a series of refining steps for producing high purity silicon (Si) metal, Al2O3, hydrogen gas and high purity aluminium (Al), AISi alloys of all compositions, and silicon carbide (SiC), after the required conditions in a electrolysis bath, preferably using feldspars ((Na,Ca,K)Al,.2Si3.2Og) or feldspar containing rocks dissolved in fluorides, preferably cryolite (Na3AlF6).
The high grade Si is produced, deposited together with Al2O3 and Na2O dissolved in cryolite in a cathode layer in an electrolysis process (1) (Fig. 1). The species in the cathode layer are refined by water (2) with formation of a sodium hydoxide (NaOH) solution, H2 gas, and an aluminium hydroxide (AI(OH)3 ) precipitate (Figs. 2 and 3). The fines, containing Si and graphite (C) floats to the top, and are decanted with the NaOH solution and filtered (Fig. 3) and heated above 1410 °C to produce SiC (1-9) (Fig. 2). The residual precipitate, containing Si, Al2O3 and cryolite is milled, stirred washed and separated with water, all species are treated with HCl and/or H2SO4 and at different temperatures (2-4), The fines, containing cryolite, are decanted, washed, filtered and separated from the Si/AI2O3 deposits, which is then separated in a jig. The enriched Si fraction is melted above 1410 °C, treated with CO2 and crystallized when cooled (5-6). The Al2O3 enriched fraction (1-4) is treated with Al-metal to remove residual Si (11) (Figs. 2 and 3). The enriched two fractions, one containing cryolite and the other containing Al2O3, are mixed and treated with Al-metal to remove the residual Si, for then to produce high grade Al-metal by coupling the graphite cathodes as anodes in an Al- electrolysis bath (10). The high grade Si alloyed with high grade Al gives high purity AlSi-alloys (ll).
Methods for production of silicon, silumin and aluminium by electrolysis in a continuous or a batch process from feldspar is described in WO 95/33870, which is the inventors' own application. The production step (step I) (Fig. 1) and refinement steps (1,3 and 4) (Fig. 2) of Si are approximately the same as in the application WO 95/33870. Feldspars dissolved in cryolite are electrolysed wάth a carbon anode placed at the bottom and the cathode placed at the top (Fig. 1 , step I). The cathode, containing Si deposited in a residual electrolyte is taken out of the bath and placed in water/HCl/H2SO4 mixtures and separated from the crushed electrolyte with organic heavy liquids.
The AlSi-alloys are produced by alumino thermal reduction in step II (Fig. 1) at about 1000°C in WO 95/33870 and Al metal is produced in step III (Fig. 1 ).
SiAl-alloys are produced today by adding Si to AlSi-alloys or Al at 680 to 1410°C.
SiC is produced, today, from carbothermal reduction of quartz at high temperature.
Al2O3 is produced from the well known Bayer process, using bauxite as an raw material.
Al(OH)3 is an intermediate product formed in this process. NaOH and H2 are produced from the well known alkali/Cl2 electrolysis processes containing saturated NaCl in the cell.
Na2CO3 and NaHCO3 are produced by the well known Solvay process from CO2, NH3 and saturated NaCl.
The present invention produces high purity Si and Al2O3. Si and Al2O3 are deposited with the compound Na2O dissolved in cryolite in a layer deposited at the cathode surface in an electrolysis bath (step I) (Fig. 1), which is the refinement step (1) (Figs. 1 and 2). (The equations are not balanced.)
2 NaAlSi3O8 + 24 e → 6 Si + Na2O + Al2O3 (+ Al + Na) (eq.l)
When the feldspar concentration is large in the silicate rock, Al2O3 is deposited in the cathode layer by electrolysis because of saturation. The cathode layer is separated from the electrolyte in the bath. The higher the voltage applied and therefore the current density, the larger the deposition of Al and Na.
The species in the cathode layer are then separated from the CO, flushed and refined graphite cathode (1) by picking, milling and grinding to a fine powder so that the largest parts of the Si grains with purity above 99.7 % Si are almost free from Al metal, Na metal, Al2O3 crystals and of Na2O dissolved in cryolite. High applied voltage or high current density favour formation of a separate layer at the cathode of Si metal in the inner part of the layer instead of deposited Al2O3. The purity of the separated Si ( >99.7 % Si) grains deposited as solids is not influenced by the voltage applied and formation of Al and Na formed, because they do not form any alloy.
In refinement step (2), water is added to the powder, the mixture is kept at room temperature or tempered and NaOH, Al(OH)3 and H2-gas starts to form. Graphite containing small Si grains floats to the top and is removed by decanting. Al(OH)3 precipitates as a gel and is separated together with the NaOH solution from the solid precipitated cathode species (Si, cryolite and Al2O3) by stirring, decanting and filtering operation. The impurities as Na, K and Ca alloyed with Si reacts with water and dissolve (eq.2).
Elemental P and Al metal alloyed with Si, and Al metal react with NaOH and purify the Si grains.
Na + H2O → NaOH + H2(g) (eq.2)
The NaOH which is formed, has a concentration below 0.1 M.
Al(Si) + NaOH → Al(OH)3(s) + Si + H2 (eq.3)
Na2O forms partly from electrolysis, where Na metal formed, oxidate in air to form Na2O, and is formed by partly released alkali oxides (Na2O and K2O) from electrolysed and dissolved feldspars in cryolite (eq. l). Ca or Ca2+ forms CaF2 in the electrolysis bath (step I) (Fig. 1).
Na2CO3 and NaHCO3 can be produced by adding self-produced CO2 from the anodes (steps I and III) (Fig. 1 ) to the solution of NaOH (2).
Then the brittle cryolite is crushed and milled and its suspension is removed by decantation after stirring. The Si and Al2O3 grains are settled in one fraction at the bottom after cryolite is removed (Fig. 3). Si and Al2O3 are then partly separated in a jig (Fig. 3). The milled C from the cathode can be mixed with the Si-rich portion and melted above 1410 °C to produce SiC (7) after various steps (1-4), and (5) (Fig. 2). It is possible in this invention to refine SiC further after steps (3-5), for a short and controlled time, by flushing with CO2 (8 and 9), to make it more pure (eq.4) (Figs. 2 and 3). SiC(Al) + CO2 → SiC + Al2O3 (eq.4)
Either the whole fraction containing Si, Al2O3 and cryolite could be added HCl (3) or just any ofthe enriched fractions with HCl (3) in various concentrations (Figs. 2 and 3). Either the the whole fraction containing Si, Al2O3 and cryolite could be added H2SO4 (4) or just any of the enriched fractions with H2SO4 (4) in various concentrations. Especially high concentrated H2SO4 reacts at high temperature with residual cryolite to produce fluoric acid (HF) (eq.5), which is very active to remove foreign elements in Si. H2SO4 should be added before (4) and after the melting/freezing process of Si and then be washed with water to remove the salt from the Si metal. Either the the whole fraction could be added a mixture of HCl and H2SO4 (3-4) or just any of the enriched fractions with H2SO4 (3-4) with various concentrations and temperature.
Na3AlF6 + H2SO4 → HF + sulfates (eq.5)
After washing the settled fraction of Si or/and the decanted graphite/silicon fraction they are dried and melted and crystallised above 1410 °C in an Ar atmosphere (5) or in a CO2 atmosphere (6) produced from the anodes (steps I and I1I)( Fig. 1). To get the molten Si in better contact with CO2 , CO2 is bubbled through the molten Si before crystallising it (6). The high grade Si produced in (5 and 6) are obtained because of the manner of cryolite (fluoride) to complex foreign elements (5) in the molten state in addition to that the CO2 has a purifying effect on Si.
By adding the pure Al metal (10) to the Si containing cryolite/Al2O3 rich fractions by stirring and at the temperature about 1000 °C , the cryolite/Al2O3 rich fractions are free from impurities as Fe and Si, which are removed . The purified cryolite/ A1203 mixture can be used for production of super pure Al metal by electrolysis (10).
Super pure AlSi-alloys or SiAl-alloys are produced by mixing super pure Si with super pure Al at 580 °C to 1410°C and then solidify the alloys (11) (Fig. 2). Example 1 :
The Si crystals deposited in the cathode layer is milled and treated with water at different temperature (2). A high grade Si with a purity around 99.99 % Si is obtained.
Example 2:
The Si crystals mixed with a portion of cryolite are melted above 1410 °C (5). A high grade Si crystallised with purity in the range 99.999 - 99.99999 % Si is obtained.
Example 3: The Si crystals mixed with cathode carbons in the fines are treated with water and in addition acids at different temperatures (2) and heated above 1410 °C (7). High grade SiC of purity in the range 99.99-99.999 % SiC is obtained.
Example 4: The milled and crushed cathode layer is added water. After a time NaOH, Al(OH)3 and H2 are formed (12). NaOH is dissolved in the water. Al(OH)3 forms a gelatinous precipitate, which is decanted from the cathode layer compounds, containing Si, Al2O3 and cryolite.
Example 5: High grade Al metal is produced by electrolysis (10) in a cryolite and Al2O3 purified fraction, where iron is removed from the mixture by treating it with HCl and/or H2SO4. Silicon is removed after treating the cryolite/Al2O3 mixture with Al at about 1000 °C .
Example 6: A mixture of high grade Si and of Al gives a high purity AlSi-alloys and SiAl-alloys (11) with low Fe content, when heated at about 580 to 1410°C and crystallised.
Example 7:
The dissolved NaOH is added CO2, produced at the anodes, to form Na2CO3 and NaHCO3 by addition of equivalent amounts of CO2.

Claims

Claims
1. Method for producing high purity silicon metal and A120„ and other valuable species formed in a cathode layer in an electrolysis bath, from alkali alkaline earth alumino silicates preferably feldspars or feldspar containing rocks, dissolved in fluoride, preferably cryolite, by a series of refining steps, having a cathode layer comprising high grade Si, Al2O3, Al, Na and Na2O dissolved in the fluoride, characterised in that said layer is removed from the cathode and treated with water, whereby graphite originating from the cathode layer with some Si float to the top and are decanted off - with formation of NaOH solution, H2 gas and a precipitate containing Si, Al2O3, Al(OH)3 and fluoride (cryolite), the precipitate is milled and washed with water, whereafter Al(OH)3 is decanted off with NaOH, the residue is then treated with acid, preferably HCl and/or H2SO4 whereafter the fines, containing cryolite, are decanted off from the Si/Al2O3 solids, which then are separated in a jig, the Si fractions are melted above 1410 °C, treated with CO2 and crystallised when cooled (5-9), the Al2O3 enriched fraction (1-4) is treated with Al-metal to remove residual Si (11), and can be used for production of pure aluminium, and AlSi-alloys of all compositions.
2. Method according to claim 1, characterised in that Si is refined by water and by the formed NaOH, which has a concentration below 0.1 M.
3. Method according to claims 1-2, characterised in that AI2O3 is freed from silicon by using the purified Al, and a mixture of purified cryolite and Al2O3 is electrolysed for production of pure Al.
4. Method according to claims 1-2, characteri sed in that a Si and graphite mixture is heated above 1410 CC to produce refined Si and/or SiC by bubbling a controlled amount of CO2 through the mixture.
PCT/NO1997/000016 1996-01-22 1997-01-21 Production of high purity silicon metal, aluminium, their alloys, silicon carbide and aluminium oxide from alkali alkaline earth alumino silicates WO1997027143A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU15600/97A AU1560097A (en) 1996-01-22 1997-01-21 Production of high purity silicon metal, aluminium, their alloys, silicon carbide and aluminium oxide from alkali alkaline earth alumino silicates
NO19983324A NO313750B1 (en) 1996-01-22 1998-07-17 Process for the preparation of highly pure silicon metal and Al2O3, and other valuable substances from a cathode layer formed in an electrolytic bath

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
NO960249 1996-01-22
NO960249A NO960249L (en) 1996-01-22 1996-01-22 Preparation of highly pure silicon metal from alkali aluminum-silicate minerals - separation of silicon from electrolyte
NO960383A NO960383L (en) 1996-01-30 1996-01-30 Formation of alumina by cathodic production of silicon - '' metal '' from alkali aluminum-silicate minerals.- Separation Methods
NO960383 1996-01-30
NO960422 1996-02-01
NO960422A NO960422L (en) 1996-02-01 1996-02-01 Formation of sodium oxide by cathodic production of silicon "metal" from alkali aluminum-silicate minerals. - Manufacture of products from sodium oxide
NO961088A NO961088D0 (en) 1996-03-18 1996-03-18 Preparation of highly pure silicon carbide from silicates. - Manufacture of products such as alumina and sodium hydroxide from alkali aluminum silicates
NO961088 1996-03-18

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002068719A1 (en) * 2001-02-26 2002-09-06 Norwegian Silicon Refinery As Process for preparing silicon by electrolysis and crystallization, and preparing low-alloyed and high-alloyed aluminum silicon alloys
WO2002072920A1 (en) * 2001-02-26 2002-09-19 Norwegian Silicon Refinery As Process for preparing silicon carbide and optionally aluminum and silumin (aluminum-silicon alloy)
WO2002099166A1 (en) * 2001-06-05 2002-12-12 Sintef Electrolyte and method for manufacturing and/or refining of silicon
US6974534B2 (en) 2001-02-26 2005-12-13 Norwegian Silicon Refinery As Process for preparing silicon and optionally aluminum and silumin (aluminum-silicon alloy)
WO2007139023A1 (en) * 2006-05-26 2007-12-06 Sumitomo Chemical Company, Limited Method for producing silicon
CN104593828A (en) * 2014-12-18 2015-05-06 东北大学 Preparation method of low-boron-phosphorus metallurgical grade silicon
EP3643680A1 (en) * 2018-10-23 2020-04-29 SiQAl UG (haftungsbeschränkt) Coupled production of high purity silicon and alumina

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US2866701A (en) * 1956-05-10 1958-12-30 Vanadium Corp Of America Method of purifying silicon and ferrosilicon
DE2933164A1 (en) * 1979-08-16 1981-02-26 Consortium Elektrochem Ind METHOD FOR CLEANING RAW SILICON
US4292145A (en) * 1980-05-14 1981-09-29 The Board Of Trustees Of Leland Stanford Junior University Electrodeposition of molten silicon
WO1995033870A1 (en) * 1994-06-07 1995-12-14 Jan Stubergh Method for the production of silicium metal, silumin and aluminium metal

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2866701A (en) * 1956-05-10 1958-12-30 Vanadium Corp Of America Method of purifying silicon and ferrosilicon
DE2933164A1 (en) * 1979-08-16 1981-02-26 Consortium Elektrochem Ind METHOD FOR CLEANING RAW SILICON
US4292145A (en) * 1980-05-14 1981-09-29 The Board Of Trustees Of Leland Stanford Junior University Electrodeposition of molten silicon
WO1995033870A1 (en) * 1994-06-07 1995-12-14 Jan Stubergh Method for the production of silicium metal, silumin and aluminium metal

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WO2002068719A1 (en) * 2001-02-26 2002-09-06 Norwegian Silicon Refinery As Process for preparing silicon by electrolysis and crystallization, and preparing low-alloyed and high-alloyed aluminum silicon alloys
WO2002072920A1 (en) * 2001-02-26 2002-09-19 Norwegian Silicon Refinery As Process for preparing silicon carbide and optionally aluminum and silumin (aluminum-silicon alloy)
US6974534B2 (en) 2001-02-26 2005-12-13 Norwegian Silicon Refinery As Process for preparing silicon and optionally aluminum and silumin (aluminum-silicon alloy)
AU2002236369B2 (en) * 2001-02-26 2006-08-10 Norwegian Silicon Refinery As Process for preparing silicon carbide and optionally aluminum and silumin (aluminum-silicon alloy)
US7101470B2 (en) 2001-02-26 2006-09-05 Norwegian Silicon Refinery As Process for preparing silicon by electrolysis and crystallization and preparing low-alloyed and high-alloyed aluminum silicon alloys
CN1320166C (en) * 2001-02-26 2007-06-06 挪威硅精炼厂股份有限公司 Process for preparing silicon carbide and optionally aluminum and silumin (Aluminum-silicon alloy )
WO2002099166A1 (en) * 2001-06-05 2002-12-12 Sintef Electrolyte and method for manufacturing and/or refining of silicon
WO2007139023A1 (en) * 2006-05-26 2007-12-06 Sumitomo Chemical Company, Limited Method for producing silicon
US8303796B2 (en) 2006-05-26 2012-11-06 Sumitomo Chemical Company, Limited Method for producing silicon
CN104593828A (en) * 2014-12-18 2015-05-06 东北大学 Preparation method of low-boron-phosphorus metallurgical grade silicon
EP3643680A1 (en) * 2018-10-23 2020-04-29 SiQAl UG (haftungsbeschränkt) Coupled production of high purity silicon and alumina
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