NO317073B1 - Electrolyte and process for the manufacture or refining of silicon - Google Patents
Electrolyte and process for the manufacture or refining of silicon Download PDFInfo
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- NO317073B1 NO317073B1 NO20012749A NO20012749A NO317073B1 NO 317073 B1 NO317073 B1 NO 317073B1 NO 20012749 A NO20012749 A NO 20012749A NO 20012749 A NO20012749 A NO 20012749A NO 317073 B1 NO317073 B1 NO 317073B1
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- 239000010703 silicon Substances 0.000 title claims description 43
- 229910052710 silicon Inorganic materials 0.000 title claims description 42
- 238000000034 method Methods 0.000 title claims description 27
- 238000004519 manufacturing process Methods 0.000 title claims description 15
- 239000003792 electrolyte Substances 0.000 title claims description 13
- 238000007670 refining Methods 0.000 title claims description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 41
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims description 11
- 239000001110 calcium chloride Substances 0.000 claims description 11
- 229910001628 calcium chloride Inorganic materials 0.000 claims description 11
- 235000011148 calcium chloride Nutrition 0.000 claims description 11
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 11
- 229910052796 boron Inorganic materials 0.000 claims description 8
- 229910052698 phosphorus Inorganic materials 0.000 claims description 8
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 7
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 7
- 239000011574 phosphorus Substances 0.000 claims description 7
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 6
- 238000003723 Smelting Methods 0.000 claims description 6
- 229910045601 alloy Inorganic materials 0.000 claims description 6
- 239000000956 alloy Substances 0.000 claims description 6
- 239000010405 anode material Substances 0.000 claims description 6
- 239000011575 calcium Substances 0.000 claims description 6
- 229910052791 calcium Inorganic materials 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 5
- 229910052799 carbon Inorganic materials 0.000 claims description 5
- 239000010406 cathode material Substances 0.000 claims description 5
- 239000000155 melt Substances 0.000 claims description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 4
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 4
- 229910000676 Si alloy Inorganic materials 0.000 claims description 4
- 238000005868 electrolysis reaction Methods 0.000 claims description 4
- 150000003839 salts Chemical class 0.000 claims description 4
- 150000002739 metals Chemical class 0.000 claims description 3
- NQNBVCBUOCNRFZ-UHFFFAOYSA-N nickel ferrite Chemical class [Ni]=O.O=[Fe]O[Fe]=O NQNBVCBUOCNRFZ-UHFFFAOYSA-N 0.000 claims description 3
- 229910052697 platinum Inorganic materials 0.000 claims description 3
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 claims description 3
- 229910001887 tin oxide Inorganic materials 0.000 claims description 3
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 3
- 229910052721 tungsten Inorganic materials 0.000 claims description 3
- 239000010937 tungsten Substances 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 230000003647 oxidation Effects 0.000 claims description 2
- 238000007254 oxidation reaction Methods 0.000 claims description 2
- 229910052763 palladium Inorganic materials 0.000 claims description 2
- 239000010453 quartz Substances 0.000 claims description 2
- 229910052709 silver Inorganic materials 0.000 claims description 2
- 239000004332 silver Substances 0.000 claims description 2
- 241001062472 Stokellia anisodon Species 0.000 claims 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims 1
- 238000005275 alloying Methods 0.000 claims 1
- 239000011195 cermet Substances 0.000 claims 1
- 229910052802 copper Inorganic materials 0.000 claims 1
- 239000010949 copper Substances 0.000 claims 1
- 229910000510 noble metal Inorganic materials 0.000 claims 1
- 239000000047 product Substances 0.000 description 6
- 235000012239 silicon dioxide Nutrition 0.000 description 5
- 229910052681 coesite Inorganic materials 0.000 description 4
- 229910052906 cristobalite Inorganic materials 0.000 description 4
- 229910001610 cryolite Inorganic materials 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 239000000377 silicon dioxide Substances 0.000 description 4
- 229910052682 stishovite Inorganic materials 0.000 description 4
- 229910052905 tridymite Inorganic materials 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 238000010587 phase diagram Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 229910000882 Ca alloy Inorganic materials 0.000 description 1
- 229910014458 Ca-Si Inorganic materials 0.000 description 1
- 229910004709 CaSi Inorganic materials 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 229910000881 Cu alloy Inorganic materials 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229940043430 calcium compound Drugs 0.000 description 1
- 150000001674 calcium compounds Chemical class 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000006735 deficit Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000004070 electrodeposition Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- -1 silicon ion Chemical class 0.000 description 1
- 239000011573 trace mineral Substances 0.000 description 1
- 235000013619 trace mineral Nutrition 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
Description
Foreliggende oppfinnelse angår en elektrolytt. Oppfinnelsen angår videre en fremgangsmåte ved fremstilling av silisium og en fremgangsmåte ved raffinering av silisium, ved hvilke elektrolytten benyttes. The present invention relates to an electrolyte. The invention further relates to a method for the production of silicon and a method for refining silicon, in which the electrolyte is used.
Bakgrunn Background
Silisium kan kvalitetsmessig inndeles i minst tre kategorier, silisium for metallurgiske formål, høyren silisium for solceller (SoG-Si), og ekstremt ren silisium for elektronikkformål. Silicon can be divided into at least three categories in terms of quality, silicon for metallurgical purposes, high-purity silicon for solar cells (SoG-Si), and extremely pure silicon for electronic purposes.
De ulike kvalitetsgrader av silisium fremstilles ved forskjellige metoder og med varierende betingelser. Når det gjelder SoG-Si for solceller, er denne til nå i all hovedsak fremstilt av skrap som oppstår under fremstilling av den enda renere silisium for elektronikkformål. Så lenge denne kilden til solcellepanel har vært tilstrekkelig stor til å dekke markedets behov, har prisen kunnet holdes på et akseptabelt nivå. Dette har sammenheng med at pristoleransen for silisium til elektronikkformål er svært høy sammenlignet med tilsvarende for bruk i solceller. The different quality grades of silicon are produced by different methods and with varying conditions. As far as SoG-Si for solar cells is concerned, this has so far mainly been produced from scrap that occurs during the production of the even purer silicon for electronics purposes. As long as this source of solar panels has been sufficiently large to cover the market's needs, the price has been able to be kept at an acceptable level. This is related to the fact that the price tolerance for silicon for electronic purposes is very high compared to the equivalent for use in solar cells.
Etterspørselen etter solcelle-silisium er imidlertid i vekst, og allerede i løpet av år 2001 kan tilgangen på råmateriale i form av skrap fra elektronikkindustrien bli for liten til å dekke etterspørselen. However, the demand for solar cell silicon is growing, and already during the year 2001 the supply of raw material in the form of scrap from the electronics industry may become too small to cover the demand.
Elektrokjemisk fremstilling av Si fra kvarts oppløst i kryolittsmelte er beskrevet bl.a. i PCT patentpublikasjon nr. WO 95/33870. Kryolittsmelten har den gode egenskap at den løser silisiumdioksyd godt og den er rimelig. Den er derfor velegnet til fremstilling av metallurgisk kvalitet silisium med renhet typisk 99,5 - 99,7 % og hvor det ikke er krav til fravær av spesielle typer forurensninger. Den har imidlertid vesentlige ulemper i tilknytning til fremstilling av svært rent silisium. Kryolittsmelten er ekstremt korrosiv, spesielt ved høye temperaturer som følge av dens fluorid-innhold. Derfor er utvalget av elektrodemateriater som kan benyttes i en slik smelte, svært begrenset. 1 praksis har man hittil utelukkende vært i stand til å benytte karbon-elektroder. Karbonelektroder er beheftet med visse ulemper ved produksjon av svært ren silisium fordi de ofte forurenser smeiten, og derved det produserte silisium, med små mengder av bor og fosfor. Disse elementene, som finnes som sporstoffer i karbon, lar seg ikke rense fra produktet med noen kjent renseteknologi, og gjør bruk av slikt silisium til solcelleformål svært vanskelig. I tillegg fås utfelling av betydelige deler av selve kryolittsmelten sammen med produktet, og dette er også svært vanskelig å fjerne fra silisiumet med noen kjent rensemetode. Electrochemical preparation of Si from quartz dissolved in cryolite melt is described, among other things. in PCT Patent Publication No. WO 95/33870. The cryolite melt has the good property that it dissolves silicon dioxide well and it is affordable. It is therefore suitable for the production of metallurgical quality silicon with purity typically 99.5 - 99.7% and where there is no requirement for the absence of special types of contamination. However, it has significant disadvantages in connection with the production of very pure silicon. The cryolite melt is extremely corrosive, especially at high temperatures due to its fluoride content. Therefore, the range of electrode materials that can be used in such a melt is very limited. 1 practice has so far only been able to use carbon electrodes. Carbon electrodes are subject to certain disadvantages in the production of very pure silicon because they often contaminate the smelting, and thereby the silicon produced, with small amounts of boron and phosphorus. These elements, which are found as trace elements in carbon, cannot be cleaned from the product with any known cleaning technology, and make the use of such silicon for solar cell purposes very difficult. In addition, significant parts of the cryolite melt itself are precipitated together with the product, and this is also very difficult to remove from the silicon with any known cleaning method.
Fra US patent nr. 4,738,759 er det kjent fremstilling av høyren kalsium ved katodisk utfelling fra kalsiumforbindelser oppløst i en CaCl2-basert smelte, sekundært elektrokjemisk raffinering av en Ca-legering. Dette patent er relevant også til fremstilling av silisium, ved at det nevnes som en mulighet å tilsette CaSi og få oppkonsentrert kalsium katodisk mens silisium utfelles på anoden. Imidlertid er det neppe mulig å gjøre dette i praksis idet Si ikke vil utfelles på en anode. Si vil forefinnes som Si <4+->ioner løst komplekst i en saltsmelte. Dette er et kation som trenger tilførsel av elektroner for å avlades til metallisk Si, det vil si det motsatte av hva som skjer ved en positivt polarisert anode med underskudd av elektroner. Under enhver omstendighet vedrører ikke US patent nr. 4,738,759 elektrokjemisk utfelling av silisium på en negativt polarisert katode der elektroner tilføres et positivt ladet silisiumion. From US patent no. 4,738,759 it is known the production of high purity calcium by cathodic precipitation from calcium compounds dissolved in a CaCl2-based melt, secondary electrochemical refining of a Ca alloy. This patent is also relevant to the production of silicon, in that it is mentioned as a possibility to add CaSi and get concentrated calcium cathodically while silicon is precipitated on the anode. However, it is hardly possible to do this in practice as Si will not precipitate on an anode. Si will be found as Si <4+->ions dissolved complex in a salt melt. This is a cation that needs a supply of electrons to be discharged to metallic Si, that is, the opposite of what happens at a positively polarized anode with a deficit of electrons. In any event, US Patent No. 4,738,759 does not relate to the electrochemical deposition of silicon on a negatively polarized cathode where electrons are supplied to a positively charged silicon ion.
Formål Purpose
Det er således et formål for foreliggende oppfinnelse å komme frem til en fremstillingsmetode for silisium av solcellekvalitet (SoG-Si), det vil si med et maksimalt innhold av B og P i størrelsesorden 1 ppm. It is thus an aim of the present invention to arrive at a production method for silicon of solar cell quality (SoG-Si), that is to say with a maximum content of B and P in the order of 1 ppm.
Det er videre et formål å komme frem til en slik fremstillingsmetode basert på elektrolyse, hvor de forurensninger som følger produktet er av en slik art at de med forholdsvis enkle midler kan fjernes fra produktet i et etterbehandlingstrinn. It is also an aim to arrive at such a manufacturing method based on electrolysis, where the contaminants accompanying the product are of such a nature that they can be removed from the product in a post-treatment step by relatively simple means.
Det er videre et formål å komme frem til en slik metode som er enkel og rimelig, slik at sluttproduktet ikke blir for kostbart. It is also an aim to arrive at such a method which is simple and reasonable, so that the end product is not too expensive.
Disse og andre formål er oppnådd ved elektrolytten og fremgangsmåtene ifølge oppfinnelsen. These and other purposes have been achieved by the electrolyte and the methods according to the invention.
Oppfinnelsen The invention
Oppfinnelsen består således i en elektrolytt som angitt i patentkrav 1. The invention thus consists of an electrolyte as stated in patent claim 1.
Oppfinnelsen angår videre en fremgangsmåte for fremstilling av silisium som angitt i patentkrav 4. The invention further relates to a method for the production of silicon as stated in patent claim 4.
Oppfinnelsen angår dessuten en fremgangsmåte for raffinering av silisium som angitt i patentkrav 10. The invention also relates to a method for refining silicon as stated in patent claim 10.
Foretrukne utførelsesformer av oppfinnelsen fremgår av de uselvstendige kravene. Preferred embodiments of the invention appear from the independent claims.
Ifølge fasediagrammer av CaCl2 skal en smelte av dette saltet være i stand til å løse Si02 i en According to phase diagrams of CaCl2, a melt of this salt should be able to dissolve Si02 in a
mengde fullt tilstrekkelig til å kunne benyttes som elektrolytt i en prosess av den ovenfor nevnte art, nemlig av størrelsesorden 5%. Det er imidlertid funnet i forbindelse med arbeidet som ledet frem til foreliggende oppfinnelse, at dette ikke stemmer. Rent CaCl2 løser Si02 bare i helt ubetydelig grad, i området 0,1%. CaCl2 er sterkt hygroskopisk, og en feilkilde for de(t) kjente fasediagram(mer) kan være at de målinger som fasediagrammet er basert på, er gjort med ikke helt renset CaCl2, hvilket betyr at oksygen i form av vann er blitt opptatt i smeiten. amount fully sufficient to be used as an electrolyte in a process of the above-mentioned kind, namely of the order of 5%. However, it has been found in connection with the work that led to the present invention, that this is not true. Pure CaCl2 dissolves SiO2 only to a negligible extent, in the range of 0.1%. CaCl2 is strongly hygroscopic, and a source of error for the known phase diagram(s) may be that the measurements on which the phase diagram is based were made with incompletely purified CaCl2, which means that oxygen in the form of water has been taken up in the smelting .
Det er nå funnet som et element av foreliggende oppfinnelse, at tilsetning av forholdsvis små mengder CaO til CaCl2 gir en resultantsmelte som løser Si02 i fullt tilstrekkelig grad. Allerede ved 5% CaO var løseligheten i størrelsesorden 3-4%, hvilket er mer enn tilstrekkelig for formålet. Akseptable løseligheter ble funnet allerede ved konsentrasjoner lavere enn dette. Den underliggende kjemi er ikke kjent i detalj for denne smeiten mer enn i andre smelter, men det er grunn til å anta at Si02 kombineres med CaO i en ukjent støkiometri. Slike forbindelser kompliserer utfelling av metall fra en slik smelte. Ved prosessen ifølge oppfinnelsen har imidlertid dette vist seg ikke å være et problem i praksis. It has now been found, as an element of the present invention, that the addition of relatively small amounts of CaO to CaCl2 gives a resulting melt which dissolves SiO2 to a fully sufficient extent. Already at 5% CaO, the solubility was in the order of 3-4%, which is more than sufficient for the purpose. Acceptable solubilities were already found at concentrations lower than this. The underlying chemistry is not known in detail for this smelting any more than in other smeltings, but there is reason to assume that SiO2 combines with CaO in an unknown stoichiometry. Such compounds complicate the precipitation of metal from such a melt. With the process according to the invention, however, this has not proven to be a problem in practice.
En potensiell ulempe ved kloridbasert smelte for elektrolyse av oppløste oksider er at man som anodeprodukt får dannet betydelige mengder klorgass. Termodynamisk skal riktignok oksygen dannes før klor, men kinetiske forhold vil i praksis være bestemmende for hva man får dannet mest av. Det vil derfor være hensiktsmessig å benytte et anodemateriale som fremmer oksygenutvikling og undertrykker dannelse av klorgass. Karbon er et eksempel på et egnet anodemateriale ut ifra disse forutsetningene, men har den tidligere nevnte ulempe at det (ofte) inneholder fosfor og bor, som lett overføres til produktet. Enkelte karbonkilder kan imidlertid være egnet som anodemateriale for prosessen ifølge oppfinnelsen. A potential disadvantage of chloride-based melt for electrolysis of dissolved oxides is that significant amounts of chlorine gas are formed as an anode product. Thermodynamically, it is true that oxygen must be formed before chlorine, but kinetic conditions will in practice determine what is formed the most. It would therefore be appropriate to use an anode material that promotes oxygen development and suppresses the formation of chlorine gas. Carbon is an example of a suitable anode material based on these assumptions, but has the previously mentioned disadvantage that it (often) contains phosphorus and boron, which are easily transferred to the product. Certain carbon sources may, however, be suitable as anode material for the process according to the invention.
I tillegg til karbon med særlig lavt innhold av fosfor og bor, kan modifisert nikkelferrit, dopet tinnoksid eller en oksidasjonsbestandig metallegering f. eks. valgt blant metallene wolfram, sølv, platina og palladium, benyttes som anodemateriale. Generelt er det gunstig med inerte, det vil si ikke-konsumerbare, anoder. In addition to carbon with a particularly low content of phosphorus and boron, modified nickel ferrite, doped tin oxide or an oxidation-resistant metal alloy, e.g. chosen from among the metals tungsten, silver, platinum and palladium, is used as anode material. In general, inert, i.e. non-consumable, anodes are beneficial.
Som katodemateriale er for eksempel silisium eller legeringer av silisium velegnet. Silisium alene har imidlertid uhensiktsmessig lav elektrisk ledningsevne, og bør derfor tilsettes noe metall, hvorav kalsium utgjør et foretrukket eksempel. Mengden kalsium i en slik legering er typisk fra noen få prosent til for eksempel 30%. trenger bare være noen få prosent, typisk 5% eller mindre. Andre metaller som erfaringsmessig kan inngå i slike legeringer er wolfram, nikkel og jern. For example, silicon or alloys of silicon are suitable as cathode material. However, silicon alone has inappropriately low electrical conductivity, and some metal should therefore be added, of which calcium is a preferred example. The amount of calcium in such an alloy is typically from a few percent to, for example, 30%. need only be a few percent, typically 5% or less. Other metals which, based on experience, can be included in such alloys are tungsten, nickel and iron.
Det er viktig at de forurensninger som finnes i det direkte avsatte silisium på katoden, med enkle midler lar seg rense til forholdsvis høy grad av renhet. Prosessen kan med mindre krav til rensing være en konkurrent til produksjonsmetoder for silisium av lavere kvalitet enn solcelle-kvalitet. It is important that the impurities found in the directly deposited silicon on the cathode can be cleaned to a relatively high degree of purity with simple means. With less requirements for purification, the process can be a competitor to production methods for silicon of a lower quality than solar cell quality.
[følge ett aspekt ved oppfinnelsen kan den benyttes til å raffinere silisium med en eller annen grad av renhet. Ved denne variant av oppfinnelsen anvendes en legering av det "urene" silisium og et annet metall som anode i en elektrolytt av ovenfor beskrevne type. Spesielt foretrukket er en legering av kobber og silisium. Når en slik prosess kjøres, vil tilnærmet rent silisium vandre i elektrolytten fra anoden til katoden, og avsettes på denne som under produksjonsprosessen. Urenhetene vil i all hovedsak bli tilbake i anoden. [According to one aspect of the invention, it can be used to refine silicon of some degree of purity. In this variant of the invention, an alloy of "impure" silicon and another metal is used as anode in an electrolyte of the type described above. Particularly preferred is an alloy of copper and silicon. When such a process is run, almost pure silicon will migrate in the electrolyte from the anode to the cathode, and be deposited on this as during the production process. The impurities will mainly remain in the anode.
Eksempler Examples
Det ble gjennomført to enkle forsøk uten spesiell optimalisering av elektroder etc. for å få en indikasjon på elektrolyttens og fremgangsmåtens egnethet. Forsøksbetingelsene er listet i tabell 1. Two simple experiments were carried out without special optimization of electrodes etc. to get an indication of the suitability of the electrolyte and the method. The test conditions are listed in table 1.
Silisium fremstilt ved forsøkene ble analysert mht. fosfor og bor etter analysemetode (Ar-ICP-AE). Målingene ble kontrollert mot ren "elektronikk"-silisium. Resultatene er vist i tabell 2. Silicon produced in the experiments was analyzed with respect to phosphorus and boron by analytical method (Ar-ICP-AE). The measurements were checked against pure "electronics" silicon. The results are shown in table 2.
Resultatene av test la og lb viser et visst innhold av fosfor, hvilket hovedsakelig kommer fra råvarene. Typisk vil CaO kunne inneholde en del fosfor. Når det gjelder bor, viser det meget lave nivået i forsøkene la og lb, at fremgangsmåten virker etter hensikten med platina-anode og Ca-Si katode. The results of tests la and lb show a certain content of phosphorus, which mainly comes from the raw materials. Typically, CaO will contain some phosphorus. As far as boron is concerned, the very low level in experiments la and lb shows that the method works as intended with a platinum anode and Ca-Si cathode.
Forsøk 2 viser et uønsket høyt innhold av bor når det gjelder bruk av det fremstilte silisium til elektronikkformål. Dette stammer hovedsakelig fra elektrodene. Test 2 shows an undesirably high content of boron when it comes to using the manufactured silicon for electronics purposes. This mainly stems from the electrodes.
Generelt viser forsøkene at elektrolytten og fremgangsmåten som sådan fungerer etter hensikten, men at valg av elektroder må tilpasses og optimaliseres etter hvilken renhet som ønskes på sluttproduktet. In general, the experiments show that the electrolyte and the method as such work as intended, but that the choice of electrodes must be adapted and optimized according to the desired purity of the final product.
Claims (13)
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO20012749A NO317073B1 (en) | 2001-06-05 | 2001-06-05 | Electrolyte and process for the manufacture or refining of silicon |
| JP2003502269A JP2004532933A (en) | 2001-06-05 | 2002-06-03 | Electrolyte and method for producing and / or purifying silicon |
| CA002449659A CA2449659A1 (en) | 2001-06-05 | 2002-06-03 | Electrolyte and method for manufacturing and/or refining of silicon |
| EP02731017A EP1402086A1 (en) | 2001-06-05 | 2002-06-03 | Electrolyte and method for manufacturing and/or refining of silicon |
| US10/477,747 US20040238372A1 (en) | 2001-06-05 | 2002-06-03 | Electrolyte and method for manufacturing and/or refining of silicon |
| PCT/NO2002/000195 WO2002099166A1 (en) | 2001-06-05 | 2002-06-03 | Electrolyte and method for manufacturing and/or refining of silicon |
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| NO20012749A NO317073B1 (en) | 2001-06-05 | 2001-06-05 | Electrolyte and process for the manufacture or refining of silicon |
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| EP (1) | EP1402086A1 (en) |
| JP (1) | JP2004532933A (en) |
| CA (1) | CA2449659A1 (en) |
| NO (1) | NO317073B1 (en) |
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| NO333319B1 (en) * | 2003-12-29 | 2013-05-06 | Elkem As | Silicon material for the production of solar cells |
| JP4765066B2 (en) * | 2005-05-19 | 2011-09-07 | 国立大学法人京都大学 | Method for producing silicon |
| AU2007226754B2 (en) * | 2006-03-10 | 2011-01-20 | Elkem As | Method for electrolytic production and refining of metals |
| NL1031734C2 (en) * | 2006-05-03 | 2007-11-06 | Girasolar B V | Process for purifying a semiconductor material using an oxidation-reduction reaction. |
| WO2008122621A1 (en) * | 2007-04-05 | 2008-10-16 | Solvay (Société Anonyme) | High-purity calcium compounds |
| CN101743342A (en) * | 2007-06-18 | 2010-06-16 | Rec斯坎沃佛股份有限公司 | Method for recovering elemental silicon from cutting remains |
| US7872676B2 (en) * | 2007-07-13 | 2011-01-18 | Micron Technology, Inc. | Methods, systems, and devices for offset compensation in CMOC imagers |
| CN101736354B (en) * | 2008-11-06 | 2011-11-16 | 北京有色金属研究总院 | Method for preparing one or more of silicon nano power, silicon nanowires and silicon nanotubes by electrochemical method |
| CN101967649A (en) * | 2010-09-09 | 2011-02-09 | 昆明理工大学 | Method for preparing silicon from composite molten salt electrolyte |
| CN101979712A (en) * | 2010-12-01 | 2011-02-23 | 武汉大学 | Method for preparing elemental silicon |
| CN104704149A (en) | 2012-05-31 | 2015-06-10 | 德克萨斯大学系统董事会 | Production of thin film solar grade silicon on metals by electrodeposition from silicon dioxide in a molten salt |
| CN103173780B (en) * | 2013-03-01 | 2015-06-03 | 中南大学 | Method and device for preparing solar polycrystalline silicon material by semi-continuous molten salt electrolysis |
| US20180291513A1 (en) * | 2017-04-11 | 2018-10-11 | Wisconsin Alumni Research Foundation | Low temperature electrochemical production of silicon |
| CN110629241B (en) * | 2019-09-16 | 2021-06-22 | 上海大学 | Silicon material manufacturing method |
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| GB833767A (en) * | 1956-10-19 | 1960-04-27 | Timax Corp | Continuous electrolytic production of titanium |
| US3003934A (en) * | 1959-01-08 | 1961-10-10 | Timax Associates | Process for the electrolytic production of metals |
| IT1063201B (en) * | 1975-05-27 | 1985-02-11 | Univ Bruxelles | PROCEDURE FOR THE PREPARATION OF MANGANESE CHLORIDE AS PURE OF MANGANESE FOR ELECTROLYSIS IN MELT SALTS OF MANGANESE CHLORIDE OBTAINED |
| FR2480796A1 (en) * | 1980-04-21 | 1981-10-23 | Extramet Sarl | High purity silicon deposit formation - by electrolytic deposition from alkali (ne earth) metal halide melt contg. dissolved silicon |
| BR8507254A (en) * | 1984-10-05 | 1987-10-27 | Extramet Sa | PROCESS OF PRODUCTION OF CALCIUM OR HIGH PURITY CALCIUM ALLOYS |
| JPS61186489A (en) * | 1985-02-13 | 1986-08-20 | Hiroshi Ishizuka | Device for electrolyzing molten chloride of alkali metal or alkaline earth metal |
| AU1560097A (en) * | 1996-01-22 | 1997-08-20 | Jan Reidar Stubergh | Production of high purity silicon metal, aluminium, their alloys, silicon carbide and aluminium oxide from alkali alkaline earth alumino silicates |
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- 2002-06-03 WO PCT/NO2002/000195 patent/WO2002099166A1/en active Application Filing
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| US20040238372A1 (en) | 2004-12-02 |
| EP1402086A1 (en) | 2004-03-31 |
| NO20012749D0 (en) | 2001-06-05 |
| NO20012749L (en) | 2002-12-06 |
| WO2002099166A1 (en) | 2002-12-12 |
| JP2004532933A (en) | 2004-10-28 |
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