Abstract: A fluidized bed reactor and a Siemens reactor are used to produce polycrystalline silicon. The process includes feeding the vent gas from the Siemens reactor as a feed gas to the fluidized bed reactor.

Abstract: In the batch production of high purity polycrystalline silicon, in which a U-shaped silicon carrier body is fastened in an open deposition reactor, the deposition reactor is hermetically sealed, the U-shaped carrier body is heated electrical current, a silicon-containing reaction gas and hydrogen are introduced into the reactor through a supply line so that silicon from the reaction gas is deposited on the carrier body, the diameter of the carrier body increases and a waste gas formed is removed from the deposition reactor through a discharge line, and, after a desired diameter of the polysilicon rod is reached, deposition is terminated, the carrier body is cooled to room temperature, the reactor is opened, the carrier body is removed from the reactor and a second U-shaped silicon carrier body made of silicon is fastened in the deposition reactor, an inert gas is fed through the supply and discharge lines into the open reactor from at least the time when the reactor is opened to extract the first carrier body

Abstract: An aggregated crystalline silicon powder with a BET surface area of 20 to 150 m2/g is provided. The aggregated crystalline silicon may be doped with a doping component and can be used to produce electronic components.

Abstract: A method for preparation of high purity silicon suitable for photovoltaic cells using reduction of silica, which is pre-purified in an aqueous solution, in presence of a reducing agent, preferably carbonaceous agent, where the pre-purified silica has a low amount of boron suitable for photovoltaic cells is described.

Abstract: A process to the production of silicon from amorphous silica is disclosed. The amorphous silica is formed from a material rich in silica, especially rice husk ash or silica fume. The process comprises subjecting the amorphous silica to leaching with a lixiviant of aqueous mineral acid, especially hydrochloric acid. Preferably, material rich in silica is roasted at a temperature of not more than 850° C., subjected to leaching and then subjected to a second roasting at a temperature of less than 750° C. The process provides for the production of high purity silicon, especially to the production of solar grade silicon (SoG-Si).

Abstract: A process for producing silicon comprises the steps of a reduction step [1] of depositing silicon by reacting chlorosilanes and hydrogen in a reactor under heat and discharging an exhaust gas that contains hydrogen, oligomers of silanes, and a silicon powder; a carring step [2] of carrying the exhaust gas that has been exhausted in the step [1] while keeping a temperature of the exhaust gas at not less than 105° C.; a removal step [3] of supplying the exhaust gas that has been carried in the step [2] to a filter at a temperature of not less than 105° C. and discharging the exhaust gas from the filter at a temperature of not less than 105° C. to remove the silicon powder from the exhaust gas and give a mixed gas that contains the hydrogen and the oligomers of silanes; and a separation step [4] of cooling the mixed gas that has been obtained in the step [3] to separate the hydrogen as a gas phase from the mixed gas.

Abstract: The present invention relates to a method of purifying a material using a metallic solvent. The present invention includes a method of purifying silicon utilizing a cascade process. In a cascade process, as the silicon moves through the purification process, it contacts increasingly pure solvent metal that is moving through the process in an opposite direction.

Abstract: The present invention provides for methods of purifying silicon, methods for obtaining purified silicon, as well as methods for obtaining purified silicon crystals, purified granulized silicon and/or purified silicon ingots.

Abstract: A solidified mass for a high-purity multicrystal silicon material that is preferably applicable to producing crystal type silicon ingots for photo voltaics, and a process for producing the solidified mass are provided. The mass of silicon solidified from molten state is a solidified mass produced by dropping molten silicon into a receiving vessel and allowing the vessel to receive the molten silicon, said solidified mass containing bubbles and having (i) an apparent density of not less than 1.5 g/cm3 and not more than 2.2 g/cm3 and (ii) a compressive strength of not less than 5 MPa and not more than 50 MPa. The process for producing a mass of silicon solidified from molten state includes the steps of dropping molten silicon into a receiving vessel and allowing the vessel to receive the molten silicon, wherein the surface temperature of the vessel for receiving the molten silicon is not lower than 0° C. and not higher than 1000° C.

Abstract: The invention concerns a silicon designed in particular for making solar cells containing a total of impurities ranging between 100 and 400 ppm, a boron content ranging between 0.5 and 3 ppm, a phosphorus/boron content ratio ranging between 1 and 3, and a content of metal elements ranging between 30 and 300 ppm. The invention also concerns a method for making such a silicon from an oxygen- or chorine-refined metallurgical silicon containing at least 500 ppm of metal elements, and comprising: refusion under neutral atmosphere of the refined silicon, in an electric furnace equipped with a hot crucible; transferring the molten silicon, to provide a plasma refining, in an electric furnace equipped with a hot crucible; plasma refining with as plasma-forming gas a mixture of argon and of at least a gas belonging the group consisting of chlorine, fluorine, HCI and HF; casting under controlled atmosphere in an ingot mold wherein is produced segregated solidification.

Abstract: A method for producing silicon by the thermal reduction of a starting material based on silicon dioxide using a reducing agent in a microwave oven.

Abstract: Methods and systems for continuous multistage processing of particulate solids that can control the distribution of residence times of processed particles. One disclosed method includes admitting fluidizing gas into transfer tunnels between fluidized bed vessel stages, using gas inlets located in or outputting directly into the transfer tunnel to promote flow of the fluidized solids through the transfer tunnel. A common gas distributor plate can supply gas to the stage vessels and to any transfer tunnels having gas inlets. The distributor plate can be separable from the system or openable to provide access for removal of obstructions and for maintenance. A common base plate can incorporate lower portions of the stage vessels and the sides and roofs of the transfer tunnels, the bottoms of the vessels and tunnels optionally being provided by the gas distributor plate. Some multistage systems and processing methods have from 15 to 200 or more stages.

Abstract: To provide a method for producing polycrystalline silicon at relatively low cost, wherein the amount of waste generated is reduced by decreasing the amount of waste generated in producing polycrystalline silicon from silicon chloride by a method of reduction and increasing the amount of reused auxiliary raw materials. In the production of polycrystalline silicon using a gas phase reaction of a silicon chloride gas and a reducing agent gas, a chlorine gas is blown into an exhaust gas discharged from a reaction device to initiate a reaction, an unreacted reducing agent and silicon particles contained in the exhaust gas are chlorinated, and then a reducing agent chloride contained in the exhaust gas is separated from the other impurities and recovered.

Abstract: A silicon manufacturing apparatus is disclosed as having a reactor tube (10) in which reaction occurs between zinc and silicon compound, zinc supply pipes (30, 30?) having heating portions to heat zinc for generating zinc gas and zinc ejecting portions ejecting and supplying zinc gas to the reactor tube, a zinc feeding section (40A, 40B) feeding zinc into the zinc supply pipes, a silicon compound supply pipe (50, 50A, 50B, 50C, 50c, 54, 57, 90) having a silicon compound ejecting portion to eject and supply silicon compound gas to the reactor tube so as to allow silicon compound gas to flow from a lower side to an upper side in the reactor tube, and a heating furnace (20) disposed outside the reactor tube to define a heating region (a) accommodating therein a part of the reactor tube, the heating portion and the zinc ejecting section for heating the same so as to allow the reactor tube, through which zinc gas and silicon compound gas flow, to have the temperature distribution such that a temperature closer to

Abstract: The crude oil reserves have a calculable time limit. Starting materials containing silicon dioxide are preferably used as raw materials.

Abstract: The method enables metallurgical silicon to be purified by directional solidification to obtain solar or photovoltaic grade silicon. A crystallization step uses at least one silicon seed, preference of solar grade or even microelectronic grade, having for example a purity substantially equal to or greater than a predetermined purity of the solar-grade silicon. The silicon seed which covers the bottom of the crucible can come from a previous crystallization or be formed by a silicon wafer. The use of a single-crystal or textured multi-crystal seed enables crystallographic orientation of the solar-grade silicon. An intermediate layer of solid metallurgical silicon can be arranged on the silicon seed and a metallurgical silicon feedstock is arranged on the intermediate layer.

Abstract: The present invention provides for methods of purifying silicon, methods for obtaining purified silicon, as well as methods for obtaining purified silicon crystals, purified granulized silicon and/or purified silicon ingots.

Abstract: The present invention discloses a method for manufacturing a silicon material with high purity, and the method comprises the following steps of: selecting high purity quartz as a raw material; cleaning and comminuting the quartz; choosing the particle size of the quartz between 20 mm and 80 mm by an optical analyzer; purifying the quartz; melting the quartz in a metallurgical furnace; proceeding carbothermal reduction and post-refining to the quartz so as to obtain liquid silicon; draining the liquid silicon into a ladle through a tap hole of the metallurgical furnace; removing impurities of the liquid silicon in the ladle by Moist reduction Gas Blowing and Slag Treating; pouring the liquid silicon into a casting area of a crystal growth furnace; proceeding Directional Solidification to the liquid silicon in the casting area so as to obtain a solid silicon material.

Abstract: This invention relates generally to the area of metallurgy and/or chemistry and, more particularly, to the technologies and facilities for production of gaseous silicon tetrafluoride and polycrystalline silicon from gaseous silicon tetrafluoride. The method for production of silicon tetrafluoride from fluorosilicic acid solution includes: generation of acid extract, extract washing, extract drying, extract decompounding, bubbling of unseparated gaseous silicon tetrafluoride and hydrogen fluoride flow through silicon dioxide. The method of silicon production includes interreaction between gaseous silicon tetrafluoride and magnesium vapour with subsequent separation of the final product. Technical results is as follows: production of silicon with high purity level, increased output of the final product, improvement of environmental friendliness of production process, simplification of the technological process of silicon production, decreased prime cost of the final product.

Abstract: An apparatus for manufacturing high purity polycrystalline silicon comprises a vertical reactor, a vaporizer and a fusing evaporator for supplying gaseous silicon chloride and zinc, respectively. The fusing evaporator further comprises a zinc evaporator, a main vertical cylinder part connected to the upper part of the zinc evaporator, a solid trapping pipe inserted in the main vertical cylinder part, a zinc introducing pipe connected to the solid trapping pipe at an angle, a seal pot surrounding the lower portion of the solid trapping pipe, an induction heater surrounding the main vertical cylinder part, and a gas vent pipe connected to the side wall of the zinc evaporator.

Abstract: A simple and direct methodology for synthesis of polycrystalline silicon sheets is demonstrated in our invention, where silica (SiO2) and elemental carbon (C) are reacted under RF or MW excitation. These polycrystalline silicon sheets can be directly used as feedstock/substrates for low cost photovoltaic solar cell fabrication. Other techniques, such as textured polycrystalline silicon substrate formation, in situ doping, and in situ formation of p-n junctions, are described, which make use of processing equipments and scheme setups of various embodiments of the invention.

Abstract: The invention provides a method for producing silicon. The method for producing silicon is a method wherein a halogenated silane represented by the following formula (1) is reduced with a metal, the method comprising a first step of bringing metal particles into contact with a halogenated silane at a temperature T1 below the melting point of the metal to obtain silicon, and a second step following the first step, of bringing the metal residue into contact with a halogenated silane at a temperature T2 at or above the melting point of the metal to obtain additional silicon. SiHnX4-n??(1) In the formula, n represents an integer of 0-3 and X represents an atom selected from the group consisting of F, Cl, Br and I. When n is 0-2, X may be the same or different.

Abstract: The inventive method of producing silicon comprises reacting gaseous trichlorosilane with hydrogen to deposit silicon onto a substrate and to produce silicon tetrachloride by-product, vaporizing the silicon tetrachloride by-product to form gaseous silicon tetrachloride, converting the gaseous silicon tetrachloride to finely divided silicon, forming a silicon melt by melting the finely divided silicon, and forming solid silicon from the silicon melt.

Abstract: Aggregated crystalline silicon powder with a BET surface area of 20 to 150 m2/g. It is prepared by subjecting at least one vaporous or gaseous silane and optionally at least one vaporous or gaseous doping material, an inert gas and hydrogen to heat in a hot wall reactor, cooling the reaction mixture or allowing the reaction mixture to cool and separating the product from gaseous substances in the form of a powder, wherein the proportion of silane is between 0.1 and 90 wt. %, with respect to the sum of silane, doping material, hydrogen and inert gases, and wherein the proportion of hydrogen, with respect to the sum of hydrogen, silane, inert gas and doping material, is in the range 1 mol. % to 96 mol. %. It can be used to produce electronic components.

Abstract: A process for preparing trichlorosilane by reacting silicon with hydrogen chloride, or silicon tetrachloride with hydrogen in the presence of silicon, and catalysts where the silicon and catalysts are laminated together and reduced in particle size prior to reaction.

Abstract: Method and equipment for production of high purity silicon (Si) metal from reduction of silicon tetrachloride (SiCl4) by liquid zinc metal. The Zn reduction of SiCl4 and the production of Zn by electrolysis of ZnCl2 take place in a common, combined reactor and electrolysis cell using a molten salt as electrolyte. The reactor and electrolysis cell may preferably be provided in a common housing which is divided into two or more communicating compartments (13, 1, 2) by a first or more partition walls (15, 8, 7). Further, the electrolysis of ZnCl2, performed by means of suitable electrodes, is taking place in at least one compartment (1, 2) and the Zn reduction of SiCl4 takes place in at least one other compartment (13), where Zn metal flows between the chamber/s (1,2) of the ZnCl2 electrolysis to the chamber/s (13) of SiCl4 reduction, and where the electrolyte circulates between the chamber/s of ZnCl2 electrolysis to the chamber/s of SiCl4 reduction.

Abstract: This invention relates to a process for the production of high purity elemental silicon by reacting silicon tetrachloride with a liquid metal reducing agent in a two reactor vessel configuration. The first reactor vessel is used for reducing the silicon tetrachloride to elemental silicon, resulting in a mixture of elemental silicon and reducing metal chloride salt while the second reactor vessel is used for separating the elemental silicon from the reducing metal chloride salt. The elemental silicon produced using this invention is of sufficient purity for the production of silicon photovoltaic devices or other semiconductor devices.

Abstract: Provided is a method for the preparation of polycrystalline silicon in which, in conducting preparation of polycrystalline silicon by the Siemens method or by the monosilane method, no outer heating means is necessitated for the core member (seed rod), onto which polycrystalline silicon is deposited, from the initial stage of heating, the deposition rate is high and the core member seed rod can be used repeatedly. The method for deposition of high-purity polycrystalline silicon, at a high temperature, onto a white-heated seed rod in a closed reaction furnace by pyrolysis or hydrogen reduction of a starting silane gas supplied thereto, is characterized in that the seed rod is a member made from an alloy having a recrystallization temperature of 1200° C. or higher. It is preferable that the alloy member is of an alloy of Re—W, W—Ta, Zr—Nb, titanium-zirconium, or a carbon-added molybdenum (TZM) in the form of a wire member having a diameter of at least 0.

Abstract: The present invention provides for methods of purifying silicon, methods for obtaining purified silicon, as well as methods for obtaining purified silicon crystals, purified granulized silicon and/or purified silicon ingots.

Abstract: A self-propagating combustion cyclone reactor includes a reaction chamber delimited by a circumferential wall in which at least one reductant inlet and a plurality of oxidizer inlets are formed in a tangential manner. Reductant and oxidizer are fed, together with inert gas, through the inlets into the chamber in a cyclonic manner to induce self-propagating combustion reaction to generate a product of high purity metal, such as titanium, zirconium, hafnium, or silicon, semiconductor substance. The reactor serves as a continuous reactor for generation of metal or semiconductor substances of high purity.

Abstract: A method and apparatus for refining silicon which can remove impurity elements such as phosphorus and antimony as well as impurity elements such as boron and carbon using an electron beam in the same vacuum chamber are provided. Silicon is irradiated and melted with an electron beam in a low vacuum inside a vacuum vessel, a compound-forming substance such as H2O which reacts with boron or the like in the molten silicon and forms a vaporizable oxide is introduced into the vacuum chamber, and impurity elements such as boron having a low vapor pressure in a vacuum are evaporated from the molten silicon as part of the vaporizable compound. Silicon in the vacuum vessel is then irradiated with an electron beam in a high vacuum in the vacuum vessel, and impurity elements contained in the silicon having a high vapor pressure in a vacuum such as phosphorus are removed.

Abstract: Nitrogen and aluminum and fluxing agents (Al2O3, SiO2, CaO and MgO) are added to molten silicon to create an oxy-nitride slag that acts as a sink for dissolved boron and phosphorus. The nitrogen can be added by bubbling nitrogen gas through the molten silicon; the aluminum can be added as aluminum metal or as Al2O3. Normally, the silicon must initially be deoxidized to allow the boron and phosphorus refining reactions to occur. The process may be followed by oxidative refining, SiC settling, the Silgrain process and directional solidification to remove other impurities and produce silicon suitable for use in solar cells. In an alternative version of the process, the molten silicon is passed through a particulate bed formed of a nitrogen-containing compound and an aluminum-containing compound.

Abstract: A method for the production of a robust, chemically stable, crystalline, passivated nanoparticle and composition containing the same, that emit light with high efficiencies and size-tunable and excitation energy tunable color. The methods include the thermal degradation of a precursor molecule in the presence of a capping agent at high temperature and elevated pressure. A particular composition prepared by the methods is a passivated silicon nanoparticle composition displaying discrete optical transitions.

Abstract: The present invention provides a method of refining low purity Si by a slag, in particular removing B, which suppresses wear of the reaction vessel due to the slag and produces high purity Si used for solar battery materials etc. at a low cost, comprising adding SiO2 and an alkali oxide or alkali carbonate as a slag material into molten Si to form a slag during which adding one or more types of materials among materials the same as the reaction vessel material used or ingredients included in the reaction vessel material into the slag so as to remove the impurities in the molten Si.

Abstract: In a reactor for the decomposition of a silicon-containing gas, provision is made, to avoid silicon deposition on an inner wall of a reactor vessel, for at least one catalytically active mesh to be provided within a reaction chamber between at least one gas feed line and the inner wall (4). The mesh accelerates the thermal decomposition of the gas and reduces the deposition of silicon on the inner wall. Also described is a process for the preparation of silicon using the reactor according to the invention and the use in photovoltaics of the silicon prepared.

Abstract: A production method of nano-sized silicon crystal particles comprising the step of allowing monosilane to be oxidized in a bulk liquid phase to form the nano-sized silicon crystal particles within the bulk liquid phase, wherein a liquid of the bulk liquid phase is an unsaturated hydrocarbon free from an oxidizing gas; and isolating the nano-sized silicon crystal particles from the bulk liquid phase.

Abstract: The invention relates to the manufacture of high purity silicon as a base material for the production of e.g. crystalline silicon solar cells. SiHCl3 is converted to Si metal by contacting gaseous SiHCl3 with liquid Zn, thereby obtaining a Si-bearing alloy, H2 and ZnCl2, which are separated. The Si-bearing alloy is then purified at a temperature above the boiling point of Zn. This process does not require complicated technologies and preserves the high purity of the SiHCl3 towards the end product. The only other reactant is Zn, which can be obtained in very high purity grades, and which can be recycled after electrolysis of the Zn-chloride.

Abstract: The invention concerns a method for the manufacture of silicon tetrachloride by conversion of a mixture of finely divided and/or amorphous silicon dioxide, carbon and an energy donator with chlorine. Energy donators are metallic or silicon alloys such as silicon, ferrosilicon or calcium suicide. The addition of the donors effects a self-sustaining, exothermic reaction on one hand and a significant lowering of the reaction starting temperature on the other hand. As finely divided and/or amorphous silicon dioxide ashes containing silicon dioxide are primarily used. These are produced by the incineration of silicon-containing plant skeletal structures such as rice husks or straw. Other sources include silicas from the digestion of alkaline earth silicates with hydrochloric acid and filtered particulate from the electrochemical manufacture of silicon, as well as naturally occurring products containing silicon dioxide, such as diatomaceous earth kieselguhr).

Abstract: Gas distribution units of fluidized bed reactors are configured to direct thermally decomposable compounds to the center portion of the reactor and away from the reactor wall to prevent deposition of material on the reactor wall and process for producing polycrystalline silicon product in a reactor that reduce the amount of silicon which deposits on the reactor wall.

Abstract: The present invention relates to a process for producing silicon by thermal decomposition of a gaseous mixture comprising monosilane, monochlorosilane and, if desired, further chlorosilanes, e.g. dichlorosilane.

Abstract: A method of recovering carbon dioxide from a synthesis gas stream generated within a synthesis gas facility. After the synthesis gas stream is passed through at least one process heat exchanger of the steam generation system located downstream of the water-gas shift reactor, the temperature of the synthesis gas stream is increased while simultaneously adding steam to the synthesis gas stream. Thereafter, the synthesis gas stream is added to an absorption system having an absorption zone utilizing a solvent to absorb the carbon dioxide and a regeneration zone to disengage the carbon dioxide from the solvent and thereby regenerate the solvent. Heat is transferred from the synthesis gas stream to the regeneration zone to promote disengagement of the carbon dioxide from the steam and such that between about 40 percent and about 90 percent of the carbon dioxide originally present in the synthesis gas stream is recovered.

Abstract: The invention provides a method for purifying silicon which comprises a step of blowing a treating gas generated by reacting carbon with an oxidized gas into a molten silicon, as well as silicon produced by the method. Carbon can be held in a container, the oxidized gas can be passed through the container, and the oxidized gas can contain at least one of water vapor and hydrogen.

Abstract: A method for making solar grade silicon from metallurgical grade silicon is disclosed, which including, treating a calcium-silicate based slag by molten calcium-silicate based slag in a first vessel, whereby phosphorous in the calcium-silicate based slag is transferred to the ferrosilicon alloy producing a calcium-silicate based containing less than 3 ppmw phosphorous; obtaining the calcium-silicate based slag containing less than 3 ppmw phosphorous from the first vessel; treating a molten metallurgical grade silicon in a second vessel with the calcium-silicate based slag containing less than 3 ppmw phosphorous to reduce the content of phosphorous, boron and iron in the metallurgical grade silicon; and removing solar grade silicon with low content of phosphorous, boron and iron from the second vessel.

Abstract: An improved process for producing high purity silicon results from the reaction of sodium with pure silicon tetrafluoride gas, which produces sodium fluoride as a by-product. The silicon tetrafluoride gas is formed by decomposing sodium fluorosilicate. The sodium fluorosilicate is produced by precipitation when fluorosilicic acid (FSA) is reacted with the by-product sodium fluoride in closed loop process. Likewise, the fluorosilicic acid is preferably formed at high purity using a source material that consists essentially of silica by reacting the by-product sodium fluoride with an acid to create reactive fluoride ions.

Abstract: A method for producing silicon is provided. The silicon production method comprises the step (i) of reducing a halosilane represented by the formula (1) with a metal SiHnX4-n??(1) wherein n is an integer of 0 to 3, X is at least one selected from F, Cl, Br and I, with the proviso that plural Xs may be the same or different from each other, wherein said metal has a melting point of not higher than 1300° C. and takes a liquid phase of spherical or thin film shape in the reduction of the halosilane, with the proviso that when the liquid phase is in the shape of sphere, the relationships (A), (B) and (C) are satisfied wherein r is radius (?m) of the sphere, t is reduction time (min) and x is reduction temperature (° C.), while when the liquid phase is in the shape of thin film, the relationships (A?), (B?) and (C) are satisfied wherein r? is thickness (?m) of the thin film, t is reduction time (min) and x is reduction temperature (° C.): ln (r/?t)?(10.5?7000/(x+273))??(A) ln (r?/?t)?(10.

Abstract: Provided is a process for producing a boron added silicon (purified silicon) in an energy saving mode from a reduced silicon obtained by reducing a silicon halide with a metal aluminium. The production process of the invention comprises reducing a silicon halide with a metal aluminium to give a reduces silicon, heating and melting the resulting reduced silicon, and adding boron thereto followed by solidification for purification under the condition of a temperature gradient provided in one direction in a mold. Preferably, after washed with an acid, the reduced silicon is heated and molten, and boron is added thereto. After the reduced silicon is heated and molten under reduced pressure, boron is added thereto. After heated and molten, the reduced silicon is purified by solidification in one direction, then heated and molten, and thereafter boron is added thereto.

Abstract: When high purity silicon is produced through a gas-phase reaction between silicon tetra-chloride and zinc in a reaction furnace, the produce silicon is obtained as block or molten state. after the reaction in which the silicon is not in contact with air and reaction temperature is maintained at melting point of the silicon or less.

Abstract: A starting material including silica and carbon is heated to form an intermediate material. The intermediate material includes silica and silicon carbide. The intermediate material is reacted to form silicon. At least some of the emissions that are generated by heating the starting material and reacting the intermediate material are collected and used to generate electric power.

Abstract: Silicon nanosponge particles prepared from a metallurgical grade silicon powder having an initial particle size ranging from about 1 micron to about 4 microns is presented. Each silicon nanosponge particle has a structure comprising a plurality of nanocrystals with pores disposed between the nanocrystals and throughout the entire nanosponge particle.

Abstract: Porous silicon particles are prepared from a metallurgical grade silicon powder having an initial particle size greater than about 1 micron is presented. Each porous silicon particle comprises a solid core surrounded by a porous silicon layer having a thickness greater than about 0.5 microns.