EP1991500A2 - Préparation de silicium de qualité solaire et éléctronique à partir de matériaux contenant des aluminosilicates - Google Patents

Préparation de silicium de qualité solaire et éléctronique à partir de matériaux contenant des aluminosilicates

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Publication number
EP1991500A2
EP1991500A2 EP07705914A EP07705914A EP1991500A2 EP 1991500 A2 EP1991500 A2 EP 1991500A2 EP 07705914 A EP07705914 A EP 07705914A EP 07705914 A EP07705914 A EP 07705914A EP 1991500 A2 EP1991500 A2 EP 1991500A2
Authority
EP
European Patent Office
Prior art keywords
silica
plasma
silicon
process according
subjecting
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.)
Withdrawn
Application number
EP07705914A
Other languages
German (de)
English (en)
Inventor
Tsvi Kaufman
Evgeny Meyerovich
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.)
Hyattville Co Ltd
Original Assignee
Hyattville Co Ltd
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
Application filed by Hyattville Co Ltd filed Critical Hyattville Co Ltd
Priority to EP07705914A priority Critical patent/EP1991500A2/fr
Publication of EP1991500A2 publication Critical patent/EP1991500A2/fr
Withdrawn legal-status Critical Current

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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
    • C01B33/20—Silicates
    • C01B33/26—Aluminium-containing silicates, i.e. silico-aluminates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
    • B01J19/087—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy
    • B01J19/088—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy giving rise to electric discharges
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/005—Separating solid material from the gas/liquid stream
    • B01J8/0055—Separating solid material from the gas/liquid stream using cyclones
    • 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
    • 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
    • C01B33/023—Preparation by reduction of silica or free silica-containing material
    • C01B33/025—Preparation by reduction of silica or free silica-containing material with carbon or a solid carbonaceous material, i.e. carbo-thermal process
    • 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
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • 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
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/126—Preparation of silica of undetermined type
    • 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
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/18—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof
    • C01B33/187—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof by acidic treatment of silicates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F11/00—Compounds of calcium, strontium, or barium
    • C01F11/20—Halides
    • C01F11/24—Chlorides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
    • C01F7/20—Preparation of aluminium oxide or hydroxide from aluminous ores using acids or salts
    • C01F7/22—Preparation of aluminium oxide or hydroxide from aluminous ores using acids or salts with halides or halogen acids
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
    • C01F7/30—Preparation of aluminium oxide or hydroxide by thermal decomposition or by hydrolysis or oxidation of aluminium compounds
    • C01F7/306—Thermal decomposition of hydrated chlorides, e.g. of aluminium trichloride hexahydrate
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
    • B01J2219/00087—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor
    • B01J2219/00094—Jackets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
    • B01J2219/0873—Materials to be treated
    • B01J2219/0881—Two or more materials
    • B01J2219/0883—Gas-gas

Definitions

  • the present invention relates to the recovery of silica from aluminosilicate-containing material and the production of solar grade silicon there from.
  • the present invention also relates to a device suitable for silicon production.
  • the majority of today' s solar cells are based on silicon.
  • the life cycle of a multicrystalline silicon solar cell module starts with the mining and refining of silica (quartz). Silica is reduced with carbon and the reduction step is followed by a lengthy purification process. The resulting highly pure silicon is melted and cast into blocks of multicrystalline silicon. The blocks are portioned into ingots, which are subsequently sliced into wafers. The wafers are processed into solar cells by etching, texturing, formation of the emitter layer, application of back surface layer and contacts and passivation and antireflective coating. The solar cells are tested, interconnected and subsequently encapsulated and framed into modules.
  • EP 0 866 769 discloses a process for the recovery of alumina and silica from aluminosilicate-containing material, comprising the steps of mixing the aluminosilicate-containing material with calcium chloride, heating the mixture at a temperature of 900-1300 0 C, leaching the obtained heated mixture with mineral acid to obtain a solution of aluminium and calcium salts and insoluble silica, separating insoluble silica from the solution, and further processing the salt solution.
  • the silica coming out of this process is not suitable for use in the preparation of solar grade silicon by in-flight plasma carbothermic reduction.
  • the present invention discloses that provision of the mixture of a metal chloride and the aluminosilicate-containing material in the form of granules combined with subsequent burning of the granules advantageously provides silica with characteristics suitable for use in the production of solar grade silicon by in-flight plasma carbothermic reduction.
  • the present invention provides a process for manufacturing of silica from an aluminosilicate- containing material comprising: mixing the material with a metal chloride being in the form of a solution or slurry, subjecting the wet mixture to a granulation step, burning the obtained granules at a temperature of 900-
  • the aluminosilicate-containing material may be any material suitable for the recovery of silica, for instance may contain industrial residues like coal ash or fly ash.
  • the aluminosilicate- containing material is substantially free from boron. More preferably, the boron level of the aluminosilicate-containing material is maximally 5 ppmw, most preferably maximally 1 ppmw.
  • the aluminosilicate-containing material may be composed of several different aluminosilicate raw materials, for example coal ash, fly ash and/or dross tailings (metal oxide values extracted from the salt cake residue produced during the melting of aluminum scrap in a secondary aluminum recycling process) that are appropriately mixed to obtain a suitable aluminosilicate-containing starting material, for instance fulfilling the requirements for boron level.
  • the aluminosilicate-containing material is mixed with a metal chloride.
  • the metal chloride preferably is calcium chloride, sodium chloride, potassium chloride and/or ammonium chloride, more preferably is calcium chloride.
  • the mixing with the metal chloride, e.g. calcium chloride may occur simultaneously with mixing of the different raw materials as described above.
  • the metal, e.g. calcium, chloride is added to the aluminosilicate-containing material at a weight ratio of 0.5-3:1 depending on the phase composition of the material and its relative alumina and silica content. More preferably, the weight ratio is in the range of 0.5-2:1, most preferably is 1.5:1.
  • metal, e.g. calcium, chloride is added to the aluminosilicate-containing material in the form of a solution or slurry. When dry metal chloride is used, sufficient water may be added to the mixture to enable granulation .
  • Mixing may preferably be done by proceeding the aluminosilicate-containing material (or the different raw materials making up the aluminosilicate-containing material), preferably in the form of a slurry, into a wet ball mill together with a metal chloride solution or slurry.
  • the aluminosilicate material as well as the metal chloride preferably have a concentration in the slurry or solution of about 30-50% (w/w) , preferably of about 40% (w/w) .
  • Sedimentation in the resulting slurry is avoided, preferably by constant stirring at room temperature.
  • the slurry of aluminosilicate-containing material and metal chloride is subsequently transferred to a granulation unit, preferably by spraying the slurry into the granulation unit. More preferably, the slurry is sprayed into the granulator at the bottom of the granulator.
  • the slurry Prior to spraying the slurry into the granulator, the slurry may be filtered over a membrane with a pore size ⁇ 500 ⁇ m to avoid clogging of the spraying nozzle (s).
  • the nozzle may be a one- or a two- or more-component nozzle.
  • granulation is performed by fluidized bed granulation.
  • a fluidized bed for production of about 1.7 ton/hour has a distribution plate with an area of 1.5-2.5 m 2 , preferably 1.8-2.3 m 2 .
  • a temperature is applied of 550-650 0 C under the distribution plate and 130-180 0 C in the bed. Dust from the drying bed is preferably recycled into the wet ball mill.
  • Granulation conveniently is accompanied by drying.
  • the bulk weight of the dry granules is about 0.8-1 kg/m 3 with a water content of about 1%.
  • the average granule size is 2-10 mm, preferably 3-8 mm.
  • the dry granules are transferred to a heating unit, for instance a rotary kiln, or any other appropriate industrial furnace.
  • Heating typically called burning
  • burning occurs at a temperature just below the melting temperature of the granulate.
  • burning occurs at a temperature of 900-1300 0 C, preferably 1150-1250 0 C, more preferably 1150-1200 0 C, for a time period of at least 2 hours.
  • HCL is sublimated.
  • the components of the aluminosilicate-containing material as well as the calcium chloride react in the burning step. This reaction implies breaking down the acid-resistant Mullite (Al 2 O 3 ⁇ SiO 2 ) phase and forming a calcium aluminium silicate phase, preferable Gehlenite (2CaO*Al 2 O 3 *SiO 2 ) .
  • the material from the heating unit may then be cooled in an air cooling unit.
  • the burnt material is pneumatically pushed by the cooling air into a cyclone for separation of the solids that go to the leaching reactor from gases and dust.
  • the hot air (at a temperature of about 600 0 C) may be recycled by returning it into the heating kiln.
  • the temperature is reduced to about 300 0 C and the cooled gases enter the quencher (preliminary scrubber) to separate the remaining dust.
  • the gases then flow to a scrubber to absorb HCl for the production of concentrated hydrochloric acid.
  • a fan is used to blow the clean gases into the ecological scrubber.
  • the clinker is fed into a leaching reactor, along with a mineral acid, preferably HCl, H 2 SO 4 and/or HNO 3 , more preferably concentrated HCl. Leaching typically occurs at 95-100 °C for a period of about 1 hour and results in a salt solution and insoluble silica.
  • the resulting salt solution may contain a number of salts in addition to AICI3 and CaCl2, such as FeCl 3 , MgCl 2 and heavy metal salts.
  • the solid silica residue may be separated from the salt solution by known methods such as filtration and/or decantation.
  • the slurry of the insoluble material in the acidic salt solution is delivered to a filtration unit.
  • Silica recovery comprises washing the silica cake on the filter and drying the silica.
  • the recovered silica may be subjected to quality control prior to its transfer to a storage unit.
  • the silica may be subjected to a fine milling process .
  • the process of the invention provides amorphous silica with a combination of characteristics hitherto unknown in the art. These characteristics advantageously allow the silica to be used in an in-flight plasma carbothermic reduction process for the preparation of solar-grade silicon.
  • the amorphous silica obtainable by the process of the first aspect forms a second aspect of this invention and preferably has the following characteristics. It has a purity (silica content) of at least 99.7%, preferably at least 99.9%; a boron content of at the most 1 ppm; a phosphorous content of at the most 5 ppm, preferably at the most 1 ppm; a surface area (BET) of 150-350 m 2 /g, preferably 175-325 m 2 /g, more preferably 200-300 m 2 /g; an average particle size of 5-80 ⁇ m, preferably 5- 20 ⁇ m, more preferable 5-10 ⁇ m; a LOI (1050 0 C) of 6-8%, preferably of 7-7.5% ; a tapped density of 200-500 g/1, preferably of 250-300 g/1; a pH of at least 4.
  • a purity (silica content) of at least 99.7%, preferably at least 99.9%
  • the amorphous silica preferably has a particle size distribution as follows: D(90): 10-80 ⁇ m, D(50): 5-40 ⁇ m, D(25): 1-25 ⁇ m, D(IO): ⁇ 10 ⁇ m, preferably as follows: D(90): 12-50 ⁇ m, D(50): 6-15 ⁇ m, D(25): 2-5 ⁇ m, D(IO): ⁇ 1 ⁇ m, more preferably as follows: D(90): 13-20 ⁇ m, D(50): 6-9 ⁇ m, D(25): 3-5 m, D(IO): ⁇ 1 ⁇ m;
  • Especially preferred silica' s have specifications as follows :
  • the above features are measured using techniques commonly known in the art.
  • the surface area is measured by nitrogen absorption (BET) , the particle size distribution by laser diffraction.
  • the pH of Silica is measured using a suspension of 10 gr of dry silica in 100 ml of water at 25°C.
  • the impurity content is analyzed with atomic-absorption spectroscopy and the silica content is calculated as a residual value .
  • the present invention provides a process for manufacturing silicon from silica comprising subjecting highly pure and particulate silica in amorphous form to an in-flight plasma carbothermic reduction using a plasma reactor comprising a plasma torch and a vessel for chemical reaction and collection of liquid silicon.
  • the process of the third aspect advantageously provides silicon with a purity of > 99.99%, preferably > 99.999%, more preferably > 99.9999%.
  • highly pure and particulate silica in amorphous form is preferably used.
  • "highly pure and particulate silica” means that the silica has a purity of at least 99%, preferably at least 99,5%, more preferably at least 99,7%, most preferably at least 99.9% and consists of particles with a average particle size of:
  • D(50) 6-9 ⁇ m D(25) : 3-5 ⁇ m D(IO) : ⁇ 1 ⁇ m, and with an average surface area (BET) of 150-350 m 2 /g, preferable of 175-325 m 2 /g and more preferable of 200-300 m 2 /g.
  • BET average surface area
  • silica is used that is obtainable by the process of the first aspect of this invention.
  • This silica conveniently is stored in silos having a capacity of a one month production, protected from dust and dirt.
  • a plasma reactor is depicted suitable for use in the carbothermic reduction of silica according to the invention .
  • the plasma reactor 1 contains one or more plasma torches 2, also called plasmatron, suitable for an in-flight process, and a vessel 3 suitable for plasma-associated chemical reaction and collection of liquid silicon, and containing an outlet 4 for further processing of liquid silicon.
  • plasma torches 2 also called plasmatron
  • the plasma flame for the in-flight carbothermic reduction process may be generated by all available plasma torch systems, for example a DC arc plasma torch or an RF electromagnetic field torch or others.
  • the plasma torch is a DC arc plasma torch charged with an electric capacity suitable to perform the thermodynamic reactions with consideration of energy losses (about 50%), and more preferably is an 8-10 MWh DC arc plasma torch.
  • the system is suitable for production of about 260-320 kg silicon/hour.
  • the flow in the nozzle and in the jet is axial (no swirl component), steady state, and rotationally symmetric.
  • Pressure is constant and equal to atmospheric pressure around the plasma plume.
  • the electric discharge is stationary. Since the anode is water cooled, the torch wall temperature is about 700 0 C for the entire column.
  • the vessel 3 of the plasma reactor is a vessel suitable for plasma-associated chemical reactions and liquid silicon collection and contains an outlet 4 for further processing of liquid silicon. Further processing may include gas blowing refining, electromagnetic casting, directional solidification and/or subjecting silicon to a Czochralski process.
  • the plasma torch 2 is positioned in such a way that the hot plasma stream that is generated in the plasma torch is directed into vessel 3.
  • the highly pure and particulate silica is fed into the plasma stream, preferably in the area where the temperature is highest, i.e. immediately downstream of the plasma torch. Feeding may be done by, for instance, use of a screw-feeder for feeding through a pneumatic transporter, with the aid of a transport gas.
  • the transport gas comprises nitrogen and/or a burning gas that helps to control the reducing medium.
  • the high temperature of the plasma sublimates the silica into gaseous form, together with small quantities of volatile impurities.
  • the impurities may be selectively reduced and separated by controlling the equilibrium phase.
  • reaction gas is sparged into the centre of the plasma stream, as close as possible to the silica evaporation point.
  • the reaction gas enters the reaction vessel via the plasma torch.
  • the reaction gas comprises air and a burning gas like methane or a propane/butane mixture.
  • the hot, ionized reaction gas reacts to form carbon monoxide that reduces the silica in gaseous form within less then 10 ⁇ s.
  • the resulting silicon is then cooled into liquid form on the walls of the reaction/collection vessel and collected into the collection area of the vessel.
  • the production of pure polycrystalline silicon is achieved by reduction and purification of amorphous silica.
  • burning gas e.g. CH 4
  • air are supplied in a proportion that provides for the reactions :
  • Reaction (1) occurs at the lower part of the plasma at a temperature of about 3000 °-5000 0 C .
  • burning gas is supplied in excess as compared to the stoichiometric amount of reaction (1) .
  • Reaction (2) and (3) occur in the upper plasma area, where the burning gas and air are supplied to produce the reducing CO stream that flows to the lower part of the plasma area, to react with the silica.
  • a plasma reactor is used as is provided by a further aspect of this invention.
  • the walls of the reaction/collection vessel are made of an inert material, such as stainless steel, and are cooled, for instance water-cooled.
  • the silicon will deposit on the walls as a solid thin layer until reliable heat-isolation of the walls is achieved that would allow maintaining 1700 - 2000 0 C inside the vessel. At that temperature the silicon in liquid form will flow down the walls to a collection area and accumulate there.
  • the impurities like metals, will transfer into the gas phase. This allows their discharge, along with other off-gases, to a water-cooled cyclone 5, where the impurities are collected in the form of solid particles. At the cyclone outlet, gases will pass through a flame igniter for securing burning of highly flammable off-gases.
  • the collected liquid silicon may reach at this stage the high purity level, e.g. ⁇ 99.999% or the preferred purity level > 99.9999%.
  • the obtained silicon may be further purified by subjecting the silicon in liquid form online to a multistage gas blowing refining process that performs additional chemical reactions and allows evaporation of impurities to form volatile molecular species to be separated from the liquid silicon.
  • the gas is delivered through a water cooled tube connected vertically and submerged in the melt.
  • the gas may be any gas that will cause an exothermic reaction with the molten silicon, which provides heat to keep the silicon in the molten stage and evaporates the metal impurities.
  • the used gas may be oxygen, HCl, chlorine, steam; preferably oxygen. This process may be performed together with liquid stirring by gas or with electromagnetic stirring, allowing further refining.
  • the refining process is preferably performed in a device comprising multiple water cooled metallurgical vessels (two or more but maximally five) connected online and equipped with gas blowing pipes to obtain continuous exothermic reactions .
  • the process may take an hour to achieve super pure silicon >99.999999 (8N) preferable >99.9999999 (9N).
  • Further purification may include directional solidification and/or ingot casting and/or electromagnetic casting.
  • liquid silicon may be subjected to an electromagnetic casting process (EMC) .
  • EMC electromagnetic casting process
  • liquid silicon is added on a vertical moveable substrate base shaped in the required ingot form and protected from dropping by an electromagnetic field.
  • a flow of inert gas cools the substrate and the ingot surface starting ingot solidification.
  • Down movement of the solid (cooled) ingot with a controlled speed creates multicrystalline solidification.
  • monocrystalline silicon may be produced by subjecting the silicon melt to a Czochralski process .
  • a combination of one or two or three embodiments will provide silicon with a purity level of ⁇ 99.9999%, preferably > 99.999999% and most preferable > 99.9999999%.
  • the present invention provides a device comprising a plasma reactor suitable for in-flight plasma carbothermic reduction and, optionally, a secondary vessel for further purification.
  • the plasma reactor 1 contains one or more plasma torches 2, also called plasmatron, suitable for an in-flight process, and a vessel 3 suitable for plasma-associated chemical reaction and collection of liquid silicon.
  • the plasma torch is a DC arc plasma torch.
  • the vessel is suitable for plasma- associated chemical reactions and liquid silicon collection implicates that the vessel should be capable to withstand the high temperature of the plasma reactions and the liquid silicon.
  • the walls of the reaction/collection vessel are made of an inert material, such as stainless steel.
  • the vessel should contain an outlet 4 for further processing of liquid silicon.
  • the outlet is positioned in the bottom part of the vessel, where liquid silicon is collected.
  • the outlet preferably comprised a siphon configuration.
  • a secondary vessel for additional silicon purification may comprise a water cooled vessel suitable for a multistage gas blowing refining process and/or a water cooled ladle suitable for pouring liquid silicon to an electromagnetic casting process for directional solidification equipped with a melt discharge system and/or a melt discharge for ingot casting suitable for further processing, for example a Czochralski process.
  • the present invention provides a process for manufacturing alumina from an aluminosilicate- containing material comprising: mixing the material with metal chloride, preferably calcium chloride, being in the form of a solution or slurry, subjecting the wet mixture to a granulation step, burning the granules at a temperature of 900-1300 0 C, leaching the obtained heated mixture with a mineral acid, preferably hydrochloric acid, to obtain a salt solution and insoluble silica, separating insoluble silica from the solution, crystallizing aluminium chloride hexahydrate from the solution, heating the aluminium chloride hexahydrate crystals to produce alumina .
  • metal chloride preferably calcium chloride
  • the alumina preferably is recovered from the process of the first aspect for silica production.
  • the salt solution obtained according to the process of the first aspect after separation of solid silica is subjected to aluminium chloride hexahydrate (A1C1 3 *6H 2 O) crystallization.
  • Crystallization of aluminium chloride hexahydrate is carried out in a strongly acidic environment (HCl) . Due to differences in solubility in the presence of a high chloride ion concentration, the aluminium chloride hexahydrate crystallizes from solution selectively.
  • the crystallization is carried out in a sparging HCl gas crystallization unit, more preferably at a temperature of 45 0 C. HCl gas is sparged through an injector.
  • aluminium chloride hexahydrate crystals then are separated from the acidic solution, preferably by filtration.
  • the slurry of aluminium chloride crystals in concentrated HCl is transferred to a filtration unit.
  • the crystals on the filter are washed with concentrated HCl and the pure crystals proceed to the alumina conversion stage.
  • the filtrate is heated in a heat exchanger and enters into the stripping and distillation stage.
  • the distilled HCl gas is recycled into the crystallizer, the surplus water from the vaporization is used as process water and the calcium chloride solution is recycled back into the raw material mixing stage.
  • Conversion of aluminium chloride hexahydrate to alumina is performed by heating at 400-600 0 C (thermal decomposition) and heating at 1000-1200°C (calcination), for instance in a rotary kiln, such that calcined alumina is produced.
  • Some secondary materials may be recovered as follows.
  • the solids from the rotary kiln dust chamber are subjected to a recovery step during the heating of the granular aluminosilicate material.
  • the solids are washed with water to separate the soluble salts from the insoluble ones.
  • the solids are returned to the mixing and granulation stage while the solution containing mainly KCl (-24%) and NaCl (-6.5%) and a small amount of MgCl 2 , is processed to extract and dry the KCl for selling as potash.
  • Ti- phosphate salt is crystallized. This salt is used in the paint industry without requiring additional processing.
  • the CaCl 2 solution resulting after the crystallization of the AICI 3 is forwarded to a metal precipitation stage where Al(OH) 3 and Fe(OH) 3 are precipitated with limestone and separated from the solution by a thickener.
  • the solution is then treated with Ca(OH) 2 to precipitate Mg(OH) 2 .
  • the CaCl 2 solution is recycled to the mixing and drying stage where overcapacities are heated to increase the CaCl 2 concentration (about 77%) and sold as CaCl 2 *2H 2 O flakes.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
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  • Geology (AREA)
  • Physics & Mathematics (AREA)
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  • Chemical Kinetics & Catalysis (AREA)
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  • Toxicology (AREA)
  • Silicon Compounds (AREA)

Abstract

La présente invention concerne la récupération de silice à partir d'une matière contenant un aluminosilicate et la production de silicium de qualité solaire et/ou électronique à partir de celle-ci. En particulier, l'invention concerne un procédé servant à fabriquer du silicium consistant à soumettre de la silice particulaire et extrêmement pure sous forme amorphe à une réduction carbothermique par plasma en vol dans un réacteur à plasma comprenant une torche à plasma et un récipient convenant pour une réaction chimique associée au plasma sur la silice et pour le recueil de silicium liquide. On produit de préférence la silice particulaire et extrêmement pure en utilisant un procédé servant à fabriquer de la silice et/ou de l'alumine à partir d'une matière contenant un aluminosilicate, lequel procédé consiste à mélanger la matière avec un chlorure de métal, de préférence du chlorure de calcium, lequel est sous la forme d'une solution ou d'une suspension épaisse, soumettre le mélange humide à une étape de granulation, brûler les granulés à une température de 900-1300°C, dissoudre le mélange chauffé obtenu avec de l'acide chlorhydrique pour obtenir une solution de sel et de la silice insoluble, séparer la silice insoluble de la solution de sel et récupérer de la silice sèche. On peut produire de l'alumine en faisant cristalliser AlCl3 dans la solution de sel et en chauffant les cristaux de AlCl3*6H2O pour produire de l'alumine.
EP07705914A 2006-02-20 2007-02-20 Préparation de silicium de qualité solaire et éléctronique à partir de matériaux contenant des aluminosilicates Withdrawn EP1991500A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP07705914A EP1991500A2 (fr) 2006-02-20 2007-02-20 Préparation de silicium de qualité solaire et éléctronique à partir de matériaux contenant des aluminosilicates

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP06110176 2006-02-20
PCT/IB2007/050535 WO2007116326A2 (fr) 2006-02-20 2007-02-20 Production de silicium de qualité solaire et électronique à partir d'une matière contenant un aluminosilicate
EP07705914A EP1991500A2 (fr) 2006-02-20 2007-02-20 Préparation de silicium de qualité solaire et éléctronique à partir de matériaux contenant des aluminosilicates

Publications (1)

Publication Number Publication Date
EP1991500A2 true EP1991500A2 (fr) 2008-11-19

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EP07705914A Withdrawn EP1991500A2 (fr) 2006-02-20 2007-02-20 Préparation de silicium de qualité solaire et éléctronique à partir de matériaux contenant des aluminosilicates

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EP (1) EP1991500A2 (fr)
WO (1) WO2007116326A2 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2647596A3 (fr) 2008-12-18 2014-08-27 Silicon Fire AG Procédé et appareil pour fournir une source d'énergie en utilisant du dioxyde de carbone comme source de carbone et de l'énergie électrique
CA2747083A1 (fr) * 2008-12-18 2010-06-24 Silicon Fire Ag Procede de preparation d'un vecteur d'energie
EP2367752A1 (fr) * 2008-12-18 2011-09-28 Silicon Fire AG Silicium ou métaux élémentaires comme sources d'énergie
US7964172B2 (en) 2009-10-13 2011-06-21 Alexander Mukasyan Method of manufacturing high-surface-area silicon
US8790584B2 (en) 2009-11-06 2014-07-29 Korea Institute Of Industrial Technology System for refining UMG Si using steam plasma torch
CA3231096A1 (fr) * 2021-09-21 2023-03-30 Yafeng GUO Procede de production d'alumine

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3116973A (en) * 1959-03-06 1964-01-07 Minerals & Chem Philipp Corp Method for producing high purity silica from kaolin clay
DE1667815C2 (de) * 1967-11-23 1974-02-28 Eleusis Bauxite Mines Inc., Athen Verfahren zur Gewinnung von Aluminiumoxid aus Alunit und Aluminosilikat-Materialien. Ausscheidung aus: 1592091
CA1321706C (fr) * 1986-04-29 1993-08-31 Alvin William Rauchholz Carbure de silicium utilisee comme matiere premiere dans la production de silicium
US4897852A (en) * 1988-08-31 1990-01-30 Dow Corning Corporation Silicon smelting process
IL116409A (en) * 1995-12-15 1999-11-30 Mashal Alumina Ind Ltd Process for the recovery of alumina and silica
US6409978B1 (en) * 1998-04-01 2002-06-25 Svedala Industries, Inc. Method of removing impurities from mineral concentrates
GB0130907D0 (en) * 2001-12-22 2002-02-13 Ineos Silicas Ltd Amorphous silica

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2007116326A3 *

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WO2007116326A3 (fr) 2008-01-31

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