US2004238372A1PendingUtilityA1

Electrolyte and method for manufacturing and/or refining of silicon

40
Priority: Jun 5, 2001Filed: Jun 3, 2002Published: Dec 2, 2004
Est. expiryJun 5, 2021(expired)· nominal 20-yr term from priority
Inventors:Espen A. Olsen
C25B 1/33
40
PatentIndex Score
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Cited by
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References
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Claims

Abstract

Electrolyte for the manufacture or refining of silicon at high temperatures, particularly suited for the manufacture of high grade silicon. The electrolyte is mainly formed from a salt melt of CaCl 2 and CaO. The invention further concerns a method for the manufacture of silicon in a salt melt at a high temperature, in which quartz with a low content of phosphorus and boron is subjected to electrolysis in such a melt, and a method for the refining of silicon where the silicon to be refined is used as an alloy element for the anode used in an electrolytic cell including the melt defined above.

Claims

exact text as granted — not AI-modified
1 . Electrolyte for the manufacture of or refining of silicon at high temperatures, characterized in that it mainly comprises a salt melt of CaCl 2  and CaO.  
     
     
         2 . Electrolyte as claimed in  claim 1 , characterized in that the CaO constitutes 0.5-15% calculated on the basis of the entire melt, while the rest of the melt is preferably CaCl 2 .  
     
     
         3 . Electrolyte as claimed in  claim 1 , characterized in that the CaO constitutes 2-5% calculated on the basis of the entire melt, while the rest of the melt is preferably CaCl 2 .  
     
     
         4 . Method for the manufacture of silicon in a salt melt at high temperatures, characterized in that quartz with a low content of phosphorous and boron is subjected to electrolysis in a melt ofCaCl 2  and CaO.  
     
     
         5 . Method as claimed in  claim 4 , characterized in that the electrodes used in the process are substantially inert.  
     
     
         6 . Method as claimed in  claim 4 , characterized in that silicon or silicon-containing alloys are used as cathode material.  
     
     
         7 . Method as claimed in  claim 6 , characterized in that an alloy of silicon with some amounts of calcium is used as cathode material.  
     
     
         8 . Method as claimed in  claim 6 , characterized in that iron and/or tungsten or alloys of these materials are used as cathode material.  
     
     
         9 . Method as claimed in  claim 4 , characterized in that nickel ferrite, doped tin oxide, carbon or an oxidation resistant alloy of metals chosen from tungsten, silver or the noble metals platinum and palladium is used as anode material.  
     
     
         10 . Method as claimed in  claim 9 , characterized in that nickel ferrite cermet containing copper and nickel or antimony doped tin oxide is used as anode material.  
     
     
         11 . Method for the refining of silicon at a high temperature, characterized in that the silicon to be refined is used as an alloy element in the anode in an electrolytic cell comprising a melt of CaCl 2  and CaO.  
     
     
         12 . Method as claimed in  claim 11 , characterized in that a substantially inert material is used for the cathode.  
     
     
         13 . Method as claimed in  claim 12 , characterized in that silicon or silicon-containing alloys are used as cathode.  
     
     
         14 . Method as claimed in  claim 12 , characterized in that an alloy of silicon with some calcium is used as cathode.  
     
     
         15 . Method as claimed in  claim 13 , characterized in that an alloy of silicon with some calcium is used as cathode.

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