EP0463049A1 - Apparatus - Google Patents
ApparatusInfo
- Publication number
- EP0463049A1 EP0463049A1 EP19900904883 EP90904883A EP0463049A1 EP 0463049 A1 EP0463049 A1 EP 0463049A1 EP 19900904883 EP19900904883 EP 19900904883 EP 90904883 A EP90904883 A EP 90904883A EP 0463049 A1 EP0463049 A1 EP 0463049A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- reactor
- gas
- temperature
- gaseous
- insert
- 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- Withdrawn
Links
Classifications
-
- 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
-
- 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
- B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
- B01J8/1845—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles with particles moving upwards while fluidised
- B01J8/1854—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles with particles moving upwards while fluidised followed by a downward movement inside the reactor to form a loop
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/90—Carbides
- C01B32/914—Carbides of single elements
- C01B32/956—Silicon carbide
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/90—Carbides
- C01B32/914—Carbides of single elements
- C01B32/956—Silicon carbide
- C01B32/963—Preparation from compounds containing silicon
- C01B32/97—Preparation from SiO or SiO2
-
- 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
- C01B33/181—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof by a dry process
-
- 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
- C01F7/302—Hydrolysis or oxidation of gaseous aluminium compounds in the gaseous phase
-
- 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
- B01J2219/0894—Processes carried out in the presence of a plasma
Definitions
- This invention relates to an apparatus for effecting high temperature reactions between reactants, such as between a gaseous reactant and a solid reactant.
- reactants such as between a gaseous reactant and a solid reactant.
- apparatus for such purposes which uses a plasma gas discharge to produce the requisite ' high temperatures.
- the present invention seeks to provide an improved form of apparatus for effecting high temperature reactions utilising a plasma arc to generate the necessary high temperatures.
- an apparatus for effecting high temperature reactions between reactants comprising a reactor means, an open ended insert means disposed within the reactor means and spaced from the walls thereof, gas inlet means at one end of the reactor means for discharging into one end of the inlet means a jet of a gaseous mixture comprising at least one reactant and a plasma forming gas, outlet means for the reaction product or products from the reactor means, and plasma discharge means for heating the gaseous medium by plasma discharge to an elevated temperature, the insert means being so disposed in relation to the gas inlet means that an extended path for gas is formed between the gas inlet means and the gas outlet means.
- the insert means is so disposed that recycle of gas from the other end of the insert means to the said one end of the inlet means is induced in the space between the insert means and the walls of the reactor by the incoming jet o.f said gaseous medium.
- the reactants may be introduced into the reactor in gaseous, liquid or solid form, or in any combination of two or more thereof.
- the reactants may include a gas and a solid.
- the gaseous mixture introduced into the reactor may comprise a mixture containing, besides a plasma-forming gas, at least one gaseous, liquid or solid reactant or any combination of two or more thereof, such as a mixture of two solids dispersed in the plasma forming gas.
- the plasma arc Upon heating by the plasma arc at least one of the reactants may be wholly or partially vaporised.
- the apparatus of the invention is of particular applicability in the manufacture of ceramic powders.
- Such powders are finding increasing usage in the manufacture of engineering components as a replacement for metal.
- an internal combustion engine has been produced in which such items as the cylinder block and pistons have been produced from ceramic materials, thereby obviating the need for lubrication.
- a typical specification for a silicon carbide powder for this purpose requires that it should be in the form of ⁇ -silicon carbide, that it should have a low level, e.g. less than about 2% by weight, of by-product impurities, such as silicon dioxide, carbon and silicon, and that it should have a small range of size distribution.
- a low level e.g. less than about 2% by weight
- by-product impurities such as silicon dioxide, carbon and silicon
- 90% or more of the particles should lie in the range 0.1 to lOum, whilst it is preferred that over 95% of particles should lie in the range 0.1 to 5um.
- Particles of regular shape, e.g. spherical particles are preferred.
- Silicon carbide can be produced in lump form by reactions of quartz and coke in an electric furnace. The resulting lumps of silicon carbide can then be milled and the appropriate fraction of the required particle size can be selected for use as the powder for production of ceramic components.
- the resulting powder is relatively impure and its particles are of a very irregular shape.
- an appreciable proportion of the powder has to be rejected as being of unsuitable size for compaction.
- milling is a process requiring high cost equipment and consumes much energy.
- An alternative method of producing silicon carbide powder involves production of metallurgical grade silicon as a first step. This is then reacted, in a second step, with chlorine to produce silicon tetrachloride, which is then purified in a third step. Next the purified silicon tetrachloride is reacted with a gaseous source of carbon, e.g. methane, to produce silicon carbide. In a fifth and final step the chlorine released is recovered and recycled for production of further silicon tetrachloride.
- a gaseous source of carbon e.g. methane
- the apparatus of the invention can be used for the production of ceramic powders and enables powders of defined morphology to be obtained by a continuous process in one stage or in at most a few stages, e.g. 2 or 3 stages, with acceptable energy requirements and with low production of by product waste. It can be used, for example, for the production of silicon carbide powders suitable for compaction, as well as for the production of silica or alumina powders of defined morphology.
- silicon carbide of the required size and morphology The key to producing silicon carbide of the required size and morphology is to react silica or silicon monoxide with particulate carbon produced in a specific particle size range under controlled conditions of temperature and residence time. It is therefore very important to provide a reactor design to produce both particulate carbon and silicon carbide.
- the simplest form of process for producing silicon carbide uses particulate carbon with a controlled particle size produced in a separate reactor. Finely divided silica and the particulate carbon are intimately mixed and reacted at high temperature under controlled conditions of temperature and residence time.
- An example of a process for production of silicon carbide involves reaction under the high temperature conditions generated by the plasma arc of gaseous silicon monoxide with a dispersion in a carrier gas of finely divided carbon particles.
- the gaseous silicon monoxide can be produced by reacting silicon dioxide of suitable purity with a carbonaceous reducing agent to produce a gaseous stream comprising silicon monoxide in admixture with carbon monoxide.
- a carbonaceous reducing agent Preferably an approximately stoichiometric mixture of silicon dioxide and the carbonaceous reducing agent is used.
- silicon dioxide used as feed material should contain at least 99% Si ⁇ 2 and minimum amounts of Fe and/or Al.
- the carbonaceous reducing agent may be a particulate carbon source well mixed with the silicon dioxide or it may comprise a gaseous or vaporous hydrocarbon such as an alkane of the general formula ⁇ *n H 2n+2' an lkene of the general formula C n H2 n , or an alkyne of the general formula C n H n , where n is an integer from 1 to about 20, or a mixture of two or more thereof.
- hydrocarbons examples include methane, ethane, propane, n- and iso-butane, pentane, hexane, octane, nonane, decane, ethylene, propylene, butene-1, butene-2, acetylene, and the like, as well as mixtures thereof.
- cyclic hydrocarbons such as benzene, cyclohexane, cyclopentane, cyclohexene, naphthalene, tetralin and decalin, as well as mixtures thereof is not excluded.
- an apparatus in accordance with the invention is used to heat a mixture of particulate carbon or a hydrocarbon and silica to a temperature of at least about 1700°K to produce a gaseous stream containing gaseous silicon monoxide and carbon monoxide which is then reacted in a second reactor with a dispersion of finely divided carbon particles in the gaseous medium, preferably at a temperature below about 2350°K.
- a hydrocarbon the dispersion of finely divided carbon particles in the gaseous medium can be formed in situ by thermal cracking of a hydrocarbon supplied to the second reactor.
- Such a second reactor may also use a plasma arc to generate the high temperature needed to crack the hydrocarbon.
- it comprises an apparatus according to the invention.
- a dispersion of finely divided carbon particles in a gaseous medium is formed by thermally cracking a gaseous or vaporous hydrocarbon in a third reactor so as to form a gaseous dispersion of carbon particles in a gaseous medium comprising hydrogen which is introduced into the second reactor.
- the third reactor is operated at a temperature of at least about 1000°K. Again plasma arc heating can be used; thus the third reactor may also be an apparatus according to the invention.
- the finely divided carbon may be produced by thermal cracking using the heat generated by burning part of the hydrocarbon.
- a second reactor When a second reactor is used this is preferably operated at a temperature below that used in the first reactor, for example at a temperature of in the range of from about 1300°K to about 2350°K. If the second reactor is operated at temperature below about 2350°K, and preferably below about 2000°K, then the possibility of producing alpha-silicon carbide is reduced.
- silicon carbide particles produced in the process of the invention can be sieved or classified to produce a fraction or fractions of suitable morphology for use in production of engineering components.
- the apparatus of the invention may further be used in the production of silica or alumina powder for compaction.
- the plasma arc is used to produce the suboxide of either silica or alumina from impure or coarse feeds which is then passed to a second reactor, which may also be an apparatus according to the invention, for reaction with air or oxygen to produce oxide powder with controlled particle size under controlled conditions.
- the important features of the reactor are the provision of a high intensity source of heat to supply the energy required in a small volume and the predictability and control of both residence time and the temperature of the reactor.
- the high intensity source of heat is conveniently a plasma arc, whilst the residence time is controlled by control of the length of path which the reactants must travel and the degree of mixing in the reactor.
- the temperature in the reactor is controlled by the degree of mixing in the reactor and by the temperature and position of the heat source and by the rate of throughput of the reactants.
- the reactor means is preferably circular in section, e.g. cylindrical.
- the insert means is also preferably of circular section, e.g. cylindrical.
- the insert is coaxially positioned within the reactor.
- the gas inlet means is conveniently coaxially arranged with respect to the reactor means and/or to the insert means.
- an apparatus for effecting high temperature reactions between reactants comprises a generally cylindrical reactor 1 with an open ended cylindrical insert 2 positioned coaxially therein.
- Appropriate supports (not shown) are provided to hold insert 2 in spaced relationship to the walls of reactor 1.
- a gas inlet duct 3 is connected to reactor 1 coaxially with insert 2.
- Reactor 1 also has a gas outlet duct 4 radially connected thereto.
- Upstream from reactor 1 gas inlet duct 3 has a pair of electrodes 5 and 6, between which a plasma arc 7 may be struck upon application of a suitable high current dc or ac voltage between electrodes 5 and 6.
- a plasma-forming gas such as argon, is fed, as indicated by arrows 8, at a pressure of just above atmospheric pressure through the narrow gap 9 between electrodes 5 and 6 to assist in sustaining the plasma arc 7.
- a reactant mixture comprising methane or particulate carbon and finely divided silica in approximately stoichiometric proportions, possibly in admixture with a non-oxidising gas, such as hydrogen, carbon monoxide, argon or helium, is supplied along gas inlet duct 3 as indicated by arrow 13.
- a gas such as hydrogen, carbon monoxide, argon or helium, is supplied as indicated by arrow 10 and passes through the plasma arc 7.
- the gas of arrow 10 is heated rapidly to a high temperature, typically at least about 3000°K.
- reactor 1 operates essentially as an isothermal and adiabati ⁇ reactor and the reactions to form silicon carbide occur, typically at at least 2000°K up to about 2350°K, according to the following equations : CH 4 > C + 2H 2 (A)
- Reaction (A) can be carried out at about 1000°K or above, while reaction (B) begins at about 1675°K. Reaction (C) becomes significant at about 2100°K.
- the gas introduced into reactor 1, as indicated by arrow 13, also induces circulation and serves to control the reaction conditions.
- the gaseous mixture can be introduced to a second reactor of similar design, which is also fed with further particulate carbon, so as to form silicon carbide according to equation (C) above.
- Such a second reactor can be supplied with the gaseous mixture along the path indicated by arrow 10 or along the path indicated by arrow 13.
- Reaction temperature control within reactor 1 can be achieved by controlling the energy input to the plasma arc 7 and the feed rate of the reactants. Isothermal conditions are maintained by the very rapid circulation of gases 12 around insert 2, induced by the jet 11 of plasma gas.
- Mean residence time in reactor 1 is governed by the ratio of the volume of reactor 1 to the total input gas flow rate plus product gas production rate. For a specified feed rate the required residence time may therefore be selected by selecting the volume of reactor 1.
- the distribution of residence times may be predicted by controlling the ratio of recycle gas flow to input gas flow so as to ensure that the percentage of reactants with the residence time below the minimum to achieve the desired product does not exceed the feed impurity specification of the desired product.
- reactor 1 and insert 2 should be constructed of materials which will withstand the temperature and chemistry of the reaction system. It may be convenient to construct both from the same ceramic material as the required final product, e.g. silicon carbide. Graphite is another material that can be used as it is relatively cheap and is easy to fabricate and install and as it can, in some cases, aid the process to be carried out in the reactor by helping to create a reducing atmosphere.
- the size of the silicon carbide particles is determined largely by the size of the carbon particles. Hence by appropriate control or the conditions it is possible to influence the size of the silicon carbide particles by providing hydrocarbon cracking conditions to produce particulate carbon of the appropriate size or providing particulate carbon of the required size from an external source.
- the product gas stream from reactor 1, or from the final reactor, if more than one such reactor is used contains silicon carbide particles dispersed in a gaseous medium comprising a mixture of carbon monoxide, hydrogen, and the plasma forming gas. This gas stream can be passed to a quenching zone in which recovery and separation of the silicon carbide particles is effected.
- Quenching can be achieved by addition of a solid or liquid with a high latent heat of vaporisation which will remain in the vapour phase at the quenching temperature.
- Water and liquid sodium are examples of suitable quenching media.
- quenching can be achieved by admixture with a large volume of gas, such as methane, hydrogen, cooled process recycle gas, or nitrogen.
- a third possibility involves rapid separation of the solid from the gas at reaction temperature, for example by use of cold wall cyclones, electrostatic precipitation, diffusion of the gas through a porous medium, or by high temperature diffusion.
- Another use for the apparatus of Figure 1 is in the production of silica or alumina powders for compaction.
- the feed mixture of arrow 10 comprises a mixture of a gas, such as nitrogen, a hydrocarbon and a coarse or impure sand, whilst air or oxygen is injected as indicated by arrows 13.
- a gas such as nitrogen, a hydrocarbon and a coarse or impure sand
- air or oxygen is injected as indicated by arrows 13.
- the gaseous silicon monoxide produced by reaction (B) above is oxidised by the air or oxygen to silica, according to the following equation :
- a coarse or impure alumina is used in place of silica in the feed mixture of arrow 10. Again air or oxygen is supplied as indicated by arrows 13. These reactions are :
- Electrodes 5 and 6 are replaced by cathode 15 and anode 16 between which is struck a long radiating plasma arc 17 that provides the heat energy required by the reactions occurring in the reactor 1. Additional arc stability may be induced by injecting feeds or other gases tangentially through the top of the walls of reactor 1, as indicated by arrows 18 or 19, to produce a vortex effect in the space within insert 2.
- Figure 3 shows an alternative embodiment in which a hollow electrode 20 and the insert 2 itself form the electrodes between which a plasma arc 21 is struck. In this case an electrical contact with insert 2 will be required; this contact may be part of the support structure for the insert 2.
- Arc 21 may be operated either as an ac arc or as a dc arc. Normally it will be preferred to operate using dc power, with the insert 2 acting as anode, in order to maximise heat efficiency.
- FIG. 4 A similar arrangement is shown in Figure 4 in which an axial electrode 22 is used in conjunction with insert 2 to provide an ac or dc plasma arc 23. Again d.c operation is preferred, in which case it is preferable to use the insert 2 as an anode.
- FIG. 5 A further embodiment of the reactor concept is shown in Figure 5 which is particularly suitable for reacting particulate carbon and finely divided silica.
- the apparatus comprises a cylindrical reactor 1 with a cylindrical insert 24 positioned coaxially and connected to the inlet means 3 and the furnace roof 25 to form an extended path between the inlet means 3 and the exit means 4.
- the reactant mixture comprising an approximately stoichiometric mixture of methane or particulate carbon and finely divided silica, possibly in admixture with a non oxidising gas such as hydrogen, carbon monoxide, argon or helium is supplied along a duct 3 as indicated by arrow 13.
- a non oxidising gas such as hydrogen, carbon monoxide, argon or helium
- a source of heat such as a plasma arc or a hot gas is also supplied to the reactor as indicated by arrow 26 using any of the means illustrated in Figures 1 to 4.
- the apparatus is operated in the manner illustrated above so that reactions (A), (B) and (C) take place to produce particulate carbon, silicon monoxide and silicon carbide in the manner described above.
- the extended path for reactants and the control of residence time and temperature is provided by the cylindrical insert means connected to the furnace roof and is assisted by the feed injected tangentially into the inlet means 3 so that it forms a spiral path down the inner wall of the insert means.
- Reaction heat is provided by the plasma heat source. On reaching the bottom of the insert means the reactants and reaction products are picked up in the gas stream and pass to the reactor exit 4.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Thermal Sciences (AREA)
- Physics & Mathematics (AREA)
- Combustion & Propulsion (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
On décrit un appareil permettant d'effectuer des réactions à températures élevées entre des réactants, qui comprend un réacteur (1), un élément d'insertion à extrémités ouvertes (2) placé dans ledit réacteur (2) mais à une certaine distance des parois de ce dernier, une entrée pour le gaz (3) disposée à l'une des extrémités du réacteur et permettant d'introduire par l'une des extrémités de l'entrée pour le gaz un jet de mélange gazeux comprenant au moins un réactant et un gaz de formation de plasma, une sortie (4) pour le(s) produit(s) de réaction du réacteur, ainsi qu'un dispositif d'évacuation du plasma (5, 6) permettant de chauffer le milieu gazeux par décharge de plasma à une température plus élevée, l'élément d'insertion étant monté de telle manière par rapport à l'entrée pour le gaz qu'il se forme un chemin étendu pour le gaz entre l'entrée de gaz et la sortie de gaz. Grâce audit appareil on peut, par exemple, produire du carbure de silicium par la réaction de dioxyde de silicium ou de monoxyde de silicium avec des carbones particulaires, que l'on produit par exemple par craquage d'un hydrocarbone, à une température comprise entre environ 2000°K et environ 2350°K.An apparatus for carrying out reactions at high temperatures between reactants is described, which comprises a reactor (1), an insert with open ends (2) placed in said reactor (2) but at a certain distance from the walls. from the latter, an inlet for the gas (3) disposed at one end of the reactor and making it possible to introduce via one of the ends of the inlet for the gas a jet of gaseous mixture comprising at least one reactant and a plasma-forming gas, an outlet (4) for the reaction product (s) from the reactor, as well as a plasma discharge device (5, 6) enabling the gaseous medium to be heated by discharging plasma at a higher temperature, the insertion member being mounted in such a manner with respect to the gas inlet that an extended path for gas is formed between the gas inlet and the gas outlet. Thanks to said apparatus it is possible, for example, to produce silicon carbide by the reaction of silicon dioxide or of silicon monoxide with particulate carbons, which is produced for example by cracking of a hydrocarbon, at a temperature between about 2000 ° K and about 2350 ° K.
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB898906045A GB8906045D0 (en) | 1989-03-16 | 1989-03-16 | Apparatus |
GB8906045 | 1989-03-16 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0463049A1 true EP0463049A1 (en) | 1992-01-02 |
Family
ID=10653437
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19900904883 Withdrawn EP0463049A1 (en) | 1989-03-16 | 1990-03-16 | Apparatus |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0463049A1 (en) |
AU (1) | AU5277590A (en) |
GB (1) | GB8906045D0 (en) |
WO (1) | WO1990010496A1 (en) |
ZA (1) | ZA902046B (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4997476A (en) * | 1988-12-08 | 1991-03-05 | Plasma Energy Corporation | Recovery of free aluminum from aluminum dross using plasma energy without use of a salt flux |
DE102009005053A1 (en) * | 2009-01-19 | 2010-07-22 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Apparatus and process for the surface treatment of particulate and powdery substrates in a fluidized bed |
EP3565782A1 (en) * | 2017-01-05 | 2019-11-13 | Plassein Technologies Ltd. LLC | Refining process for producing solar silicon, silicon carbide, high-purity graphite and hollow silica microspheres |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL132104C (en) * | 1965-02-15 | |||
FI75968C (en) * | 1986-06-30 | 1988-08-08 | Imatran Voima Oy | PLASMAPROCESSENHET MED CELLSTRUKTUR. |
JPS63221842A (en) * | 1987-03-11 | 1988-09-14 | Nippon Steel Corp | Manufacturing method of metallic powder, metallic compound powder and ceramic powder and device thereof |
-
1989
- 1989-03-16 GB GB898906045A patent/GB8906045D0/en active Pending
-
1990
- 1990-03-16 WO PCT/GB1990/000394 patent/WO1990010496A1/en not_active Application Discontinuation
- 1990-03-16 ZA ZA902046A patent/ZA902046B/en unknown
- 1990-03-16 AU AU52775/90A patent/AU5277590A/en not_active Abandoned
- 1990-03-16 EP EP19900904883 patent/EP0463049A1/en not_active Withdrawn
Non-Patent Citations (1)
Title |
---|
See references of WO9010496A1 * |
Also Published As
Publication number | Publication date |
---|---|
GB8906045D0 (en) | 1989-04-26 |
ZA902046B (en) | 1991-02-27 |
AU5277590A (en) | 1990-10-09 |
WO1990010496A1 (en) | 1990-09-20 |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
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17P | Request for examination filed |
Effective date: 19910909 |
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AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK ES FR GB IT LI LU NL SE |
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RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: NADEN, DAVID 47 SCALBY GROVE Inventor name: BAGHA, SHAHIN |
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17Q | First examination report despatched |
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