IE57642B1 - Production of silicon from raw quartz - Google Patents
Production of silicon from raw quartzInfo
- Publication number
- IE57642B1 IE57642B1 IE3012/84A IE301284A IE57642B1 IE 57642 B1 IE57642 B1 IE 57642B1 IE 3012/84 A IE3012/84 A IE 3012/84A IE 301284 A IE301284 A IE 301284A IE 57642 B1 IE57642 B1 IE 57642B1
- Authority
- IE
- Ireland
- Prior art keywords
- reducing agent
- furnace
- carbon
- quartz
- briquettes
- Prior art date
Links
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims abstract description 68
- 239000010453 quartz Substances 0.000 title claims abstract description 36
- 229910052710 silicon Inorganic materials 0.000 title claims description 16
- 239000010703 silicon Substances 0.000 title claims description 16
- 238000004519 manufacturing process Methods 0.000 title claims description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 44
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 34
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 31
- 238000006243 chemical reaction Methods 0.000 claims abstract description 16
- 229910052681 coesite Inorganic materials 0.000 claims abstract description 10
- 229910052906 cristobalite Inorganic materials 0.000 claims abstract description 10
- 229910052682 stishovite Inorganic materials 0.000 claims abstract description 10
- 229910052905 tridymite Inorganic materials 0.000 claims abstract description 10
- 238000000034 method Methods 0.000 claims description 26
- 239000003245 coal Substances 0.000 claims description 8
- 239000002006 petroleum coke Substances 0.000 claims description 5
- 229910000519 Ferrosilicon Inorganic materials 0.000 claims description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 4
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 3
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 claims description 2
- 239000003830 anthracite Substances 0.000 claims description 2
- 239000000969 carrier Substances 0.000 claims description 2
- 239000008187 granular material Substances 0.000 claims description 2
- 239000010439 graphite Substances 0.000 claims description 2
- 229910002804 graphite Inorganic materials 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 239000003077 lignite Substances 0.000 claims description 2
- 239000000126 substance Substances 0.000 claims description 2
- 229910004298 SiO 2 Inorganic materials 0.000 claims 1
- 235000012239 silicon dioxide Nutrition 0.000 abstract description 34
- 239000000377 silicon dioxide Substances 0.000 abstract description 13
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 16
- 229910010271 silicon carbide Inorganic materials 0.000 description 16
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 13
- 230000015572 biosynthetic process Effects 0.000 description 8
- 239000000203 mixture Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 239000000571 coke Substances 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 239000006004 Quartz sand Substances 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 239000003610 charcoal Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000003415 peat Substances 0.000 description 2
- 239000002023 wood Substances 0.000 description 2
- 206010024769 Local reaction Diseases 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000000875 corresponding effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 238000004441 surface measurement Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/02—Making non-ferrous alloys by melting
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Silicon Compounds (AREA)
- Carbon And Carbon Compounds (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
An electric low-shaft furnace is charged with the raw quartz in granular form together with briquettes of a quartz/carbon reducing agent having excess carbon (>50 wt %) in relation to the reaction SiO2 + 3C = SC + 2CO, the quartz in the briquetted reducing agent is first converted to SiC plus activated carbon at a temperature below 1600 DEG C in an upper section of the furnace, and the molten raw quartz is then reduced at a temperature above 1600 DEG C in a lower section of the furnace.
Description
This invention relates to the production of silicon from raw quartz.
Specifically, the invention relates generically to a process for the production of silicon from raw quartz in an electric low-shaft furnace,in which the furnace is charged with the raw quartz in granular form together with briquettes of a quartz/carbon reducing agent having excess carbon in relation to- the reaction Si02 + 3C s SiC + 2C0, the quartz in the briquetted reducing agent is first converted to SiC at a temperature below 1600°C, in an up,per section of the furnace, and the molten raw quartz is then reduced at a temperature above 1600°C, preferably between 1800 and 2000°C, in a lower section of the furnace. The briquettes of reducing agent are preferably prepared by briquetting. Raw quartz denotes any silica-bearing material used for the production of silicon, more particularly quartzites and quartz sands.
The briquettes of reducing agent are usually prepared from quartz sand. Hot briquetting , denotes a process using no binders, in which J the raw materials are heated to a temperature of 430 to 540 °C and compacted under pressure to form briquettes (cf.DE-PS 19 1 5 905).
However, it is within the scope of the invention to use briquettes of reducing agent made by other processes.
The briquettes of reducing agent 5 used in the known process (DE-PS 30 32 720) only have a small excess of carbon in relation to the reaction SiO2 + 3C s SiC + 2C0. The actual objective is to achieve as nearly complete conversion as possible of the reagents in the briquettes of reducing agent that undergo this reaction,i.e., to produce SiC and CO,and then to carry out the reduction of the molten raw quartz at the high temperatures quoted, in the lower section of the low-shaft furnace, with the SiC as reducing agent. The excess carbon is only present because the carbon also reacts with oxygen as it reduces the silica in the briquetted reducing agent, and to this extent is unavailable for silica reduction. In practical terms, when the silica has been reduced in the known process the briquetted reducing agent consists entirely of silicon carbide and no longer contains carbon. The known process has proved sound but is open to improvement in respect of the silicon yield and the associated energy demand.
The object of the invention is to modify the generic process so as to obtain a high silicon yield at a lower energy consumption.
According to the present invention,there is provided a process for the production of silicon from raw quartz, 1 as hereinbefore defined, in an electric lew—shaft furnace, in which the furnace is charged with the raw quartz in granular form together with briquettes of a quartz/cafbon reducing agent having excess carbon in relation to the reaction Si+ 3C = SiC +2CO, the quartz in the briquetted reducing agent is first converted to SiC at a temperature below 1600°C in an upper section of the and the molten raw quartz is then reduced at a tenperature above 160G°C in a lower section of the furnace, and use is made of briquetted reducing agent having an excess of more than 50 wt.% carbon in relation to the reaction SiO2 + 3C = SiC + 2CO, the briquetted reducing agent is converted to SiC plus activated carbon at a temperature below 1600°C in the upper section of the furnace, the briquettes of reducing agent assuming a coke—like structure, and the raw quartz is reduced partly by this activated carbon and partly by the SiC in the lower section of the furnace.
It is preferable to operate with an excess of carbon in the briquetted reducing agent amounting to less than 90 wt.%, preferably about 80 wt.%. Preferably, in order to approach optimum conditions more closely, the process as a whole is carried out in such a manner that the activated carbon reduces at least 50 wt.% of charged raw quartz in the lower section of the furnace. The burden as a whole is adjusted to give the corresponding material balance. Under these conditions, it is not essential to operate exclusively with briquetted reducing agent of the composition described. 0n the contrary, additions can be made within the limits of a classical mix (comprising for example 3 tons or 3050 kg of quartz / 0.4 tons or 407 kg of wood charcoal / 0.4 tons or 407 kg of peat coke / 0.3 tons or 305 kg of petroleum coke / 0.5 tons or 508 kg of low-ash coal), provided only that care is taken to make adequate amounts of activated carbon available from the briquetttes of reducing agent.
As already stated, the method and procedure for producing the briquetted reducing agent are fundamentally optional.
However, care must be taken to ensure that the briquettes of reducing agent are sufficiently durable to withstand charging into an electric low-shaft furnace in the manner described, as it were as a burden mixed with the raw quartz, and there to react in the manner described.
In this connection, use is preferably made of briquettes of reducing agent prepared by the hot briquetting method in the form of ovate or cushion-shaped briquettes in the size range 15 to 60 cm3. In conjunction therewith, it is also advantageous for use to be made of briquettes of reducing agent having a carbon content made up from sufficient caking coal for hot briquetting plus inert carbon carriers such as petroleum coke, anthracite, graphite, brown coal and hard coal.
It is self evident that the process of the invention can be used to make ferrosilicon as well as silicon metal, by charging suitable substances into the electric low-shaft furnace in addition to the raw quartz, including for example ferrous swarf or iron granules.
The invention arises from the discovery that during the carbon reduction of silica in the briquetted reducing agent the formation of silicon carbide is accompanied by the formation of active carbon, which becomes avilable as nascent carbon accompanying the silicon carbide for the reduction of silica in the lower section of the electric low-shaft furnace, and results in an improved yield and a lower energy consumption. This will now be discussed in more detail with reference to a number of embodiments.
Example 1 In order to produce about 600 tons or 5 about 600,000 kg of silicon, 1200 tons or about 1,200,000 kg of briquettes were prepared and charged into the electric low-shaft furnace together with an almost equal amount of lumpy quartz. in the first step of the process, the briquettes were prepared by the hot briquetting method from a mixture of, by weight: % caking coal 32% petroleum coke and 38% quartz sand (99.8 % SiO2), thus using the coal as a binder at temperatures around 500°C. The prepared briquettes were examined when cold and found to contain (42 +/_ 0.4,SiO2 and (52 +/_ 0.7) Cf ixed. Strength testing showed that point pressure strengths of 150 to 200 kg had been attained, the plasticised and re-cooled coal having bonded together the inert materials, petroleum coke and sand. An internal surface area measurement on the briquettes gave 0.5 to 2 1.0 m /g. This means that there are no surfaces available which could influence the ----------8 reaction kinetics and give rise to significant heterogeneous conversion reactions between gases such as SiO on the one hand and carbon on the other.
In the second step of the process, the briquettes were charged into an electric low-shaft furnace. At the furnace, the debris resulting from abrasion and crushing during transport was removed by sieving; the proportion of fines was less than *12. This is a very good result, since wood charcoal, peat coke and other coals undergo much .more comminution and losses of more than 102 are encountered.
The electric furnace was continually charged with a mixture of lumpy quartz and briquettes, which behave similarly in the burden and therefore heat up and react in a statistically uniform mixture.
If one takes the overall reaction of silicon formation: Si02 + 2C = Si + 2C0, it can be seen from the analysis of the briquettes that they contain an excess of carbon and the complete conversion can only take place by further reaction with the quartz lumps. However, silicon formation is preceded by the formation of silicon carbide according to the equation: SiO2 + 3C = SiC + 2C0 5 which raises the question as to whether the briquettes contain sufficient carbon for this reaction. The calculation shows that the briquettes contain about twice as much carbon as the reaction requires. The molar ratio is between 1 to 5 and 1 to 6. This ratio was aimed at, so that hot briquetting would preserve strong coke structures even if losses occurred by silicon carbide formation.
Evidence for this view was obtained by using thenrooouples to determine the termperature interval in which carbide formation takes place. Specimens were taken of material heated to 1500 - 16OO°C which clearly showed that the briquettes still retain their original form but reaction between carbon and silicon has already started and can reach completion.
Most of the briquettes had a white surface,demonstrating that local reactions had taken place. However, the internal surface measurements on the cooled briquettes were more significant. They showed an increase in internal surface area of 20 to 230 n2/g.
This leads to a major reduction in the SiO2 recovery from the gas cleaning system. The energy consumption and silicon yield are closely correlated with this effect. Measurements on the furnace showed that the current consumption was about 14% lower and the Si yield more than 20% higher. 0ne unexpected but important cost-reducing advantage was the halving of the electrode consumption. This fell from 128 kg/ton or 125 kg/1000 kg Si to 59 kg/ton or 58 kg/1000 kg si. The electrode movements were reduced to a minimum.
Example 2.
The conditions are more favourable when producing ferrosilicon. In this case the losses from SiO formation are lower.
If one modifies the procedure described in Example 1 so that the ratio of lumpy quartz to briquettes, by weight, remains at 50s50 and adds sufficient ferrous scrap to make a 75% alloy, by weight, the advantages of the briquettes are even more pronounced: The current consumption falls by 8% and the silicon yield increases by 12%.
Claims (5)
1. A process for the production of silicon from raw quartz, as hereinbefore defined, in an electric low-shaft furnace, in which the furnace is charged with the raw 5 quartz in granular form together with briquettes of a quartz/carbon reducing agent having excess carbon in relation to the reaction Si02 + 3C SiC + 2C0 » the <3 ua rtz in the briquetted reducing agent is first 10 converted to SiC at a temperature below 1600°C in an upper section of the furnace, and the molten raw quartz is then reduced at a temperature above 1600°C , in a lower section of the furnace, and use is made of briquetted 15 reducing agent having an excess of more than 50 wt.% carbon in relation to the reaction SiO 2 + 3C SiC + 200, the briquetted reducing agent is converted to SiC plus activated I ' carbon at a temperature below 1600°C in the 20 upper section of the furnace, the briquettes of reducing agent assuming a coke-like structure, and the raw quartz is reduced
2. A process as in Claim 1, wherein use is made of a briquetted reducing agent having a carbon excess of less than 90wt.%, preferably about 80wt.%.*
3. A process as claimed in Claim 1 or 2, wherein the activated carbon from the briquetted reducing agent reduces at least 50wt.% of the charged raw quartz in the lower section of the furnace.
4. A process as claimed in any one of Claims 1 to 3, wherein use is made of briquettes of reducing agent made by the hot briquetting method in the form of ovate or cushion-shaped briquettes. 5. A process as claimed in Claim 4, wherein use is made of briquettes of reducing agent having a carbon content made up from sufficient caking coal for hot briquetting plus inert carbon carriers such as petroleum coke, anthracite, graphite, brown coal and hard coal. 6. A process as claimed in any one of Claims 4 partly by this activated carbon and partly by the SiC in the lower section of the furnace.
5. 8. Silicon whenever produced by a process claimed in a preceding claim.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3342890 | 1983-11-26 | ||
| DE19843411731 DE3411731A1 (en) | 1983-11-26 | 1984-03-30 | METHOD FOR PRODUCING SILICON FROM RAW MATERIAL QUARTZ IN AN ELECTRONIC LOWER FURNACE AND METHOD FOR REDUCING OXIDIC RAW MATERIALS |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| IE843012L IE843012L (en) | 1985-05-26 |
| IE57642B1 true IE57642B1 (en) | 1993-02-10 |
Family
ID=25815937
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IE3012/84A IE57642B1 (en) | 1983-11-26 | 1984-11-23 | Production of silicon from raw quartz |
Country Status (27)
| Country | Link |
|---|---|
| AT (1) | AT396460B (en) |
| AU (1) | AU568166B2 (en) |
| BE (1) | BE901114A (en) |
| BR (1) | BR8405974A (en) |
| CA (1) | CA1217032A (en) |
| CH (1) | CH663610A5 (en) |
| DD (1) | DD229102A5 (en) |
| DE (1) | DE3411731A1 (en) |
| DK (1) | DK168003B1 (en) |
| ES (1) | ES8600702A1 (en) |
| FI (1) | FI76056C (en) |
| FR (1) | FR2555565B1 (en) |
| GB (1) | GB2150128B (en) |
| IE (1) | IE57642B1 (en) |
| IN (1) | IN162374B (en) |
| IT (1) | IT1177279B (en) |
| LU (1) | LU85649A1 (en) |
| MX (1) | MX162694A (en) |
| MY (1) | MY100749A (en) |
| NL (1) | NL8403572A (en) |
| NO (1) | NO163004B (en) |
| PH (1) | PH22408A (en) |
| PL (1) | PL148125B1 (en) |
| PT (1) | PT79544B (en) |
| SE (1) | SE461647B (en) |
| YU (1) | YU43676B (en) |
| ZW (1) | ZW19184A1 (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3356169A (en) * | 1966-04-01 | 1967-12-05 | Emery Co A H | Batch weigher with respective dials for successive loads and total weight |
| DE3541125A1 (en) * | 1985-05-21 | 1986-11-27 | International Minerals & Chemical Corp., Northbrook, Ill. | METHOD FOR THE PRODUCTION OF SILICON OR FERROSILICIUM IN AN ELECTRONIC SHELL OVEN AND FOR THE METHOD SUITABLE RAW MATERIALS |
| US4981668A (en) * | 1986-04-29 | 1991-01-01 | Dow Corning Corporation | Silicon carbide as a raw material for silicon production |
| DE3724541A1 (en) * | 1987-07-24 | 1989-02-02 | Applied Ind Materials | METHOD AND SYSTEM FOR THE PRODUCTION OF RAW MATERIAL BRIQUETTES FOR THE PRODUCTION OF SILICON OR SILICON CARBIDE OR FERROSILICIUM |
| SE461037B (en) * | 1987-10-09 | 1989-12-18 | Skf Plasma Tech | COATED BY COAL AND SILICON Dioxide CONTINUOUSLY MAKING LIQUID SILICONE IN A REACTOR |
| US4897852A (en) * | 1988-08-31 | 1990-01-30 | Dow Corning Corporation | Silicon smelting process |
| US4997474A (en) * | 1988-08-31 | 1991-03-05 | Dow Corning Corporation | Silicon smelting process |
| US4898712A (en) * | 1989-03-20 | 1990-02-06 | Dow Corning Corporation | Two-stage ferrosilicon smelting process |
| DE3923446C1 (en) * | 1989-07-15 | 1990-07-26 | Applied Industrial Materials Corp. Aimcor, Deerfield, Ill., Us | |
| WO2010037709A2 (en) * | 2008-09-30 | 2010-04-08 | Evonik Degussa Gmbh | Production of solar-grade silicon from silicon dioxide |
| EP2530050A1 (en) * | 2011-06-03 | 2012-12-05 | Evonik Solar Norge AS | Starting materials for production of solar grade silicon feedstock |
| WO2012163534A1 (en) * | 2011-06-03 | 2012-12-06 | Evonik Solar Norge As | Starting materials for production of solar grade silicon feedstock |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1530655A (en) * | 1967-05-19 | 1968-06-28 | Pechiney Prod Chimiques Sa | Manufacture of silicon and its alloys by carbothermal energy |
| DE1915905C3 (en) * | 1969-03-28 | 1974-07-11 | Eschweiler Bergwerks-Verein, 5122 Kohlscheid | Process for the production of hot briquettes |
| BE759122A (en) * | 1969-11-19 | 1971-05-18 | Union Carbide Corp | PROCESS AND CHARGE FOR THE PRODUCTION OF SILICON IN AN ELECTRIC ARC OVEN BY CARBOTHERMAL REDUCTION OF SILICA |
| GB2008559A (en) * | 1977-09-09 | 1979-06-06 | Goldblatt N Z | Production of silicon |
| DE3009808C2 (en) * | 1980-03-14 | 1982-02-18 | Coc-Luxembourg S.A., Luxembourg | Process for the production of raw material blanks containing silicon and carbon and the use of the raw material blanks |
| DE3032720C2 (en) * | 1980-08-30 | 1982-12-16 | International Minerals & Chemical Luxembourg S.A., 2010 Luxembourg | Process for the production of silicon from quartz and carbon in an electric furnace |
-
1984
- 1984-03-30 DE DE19843411731 patent/DE3411731A1/en active Granted
- 1984-11-13 IN IN781/CAL/84A patent/IN162374B/en unknown
- 1984-11-15 CH CH5468/84A patent/CH663610A5/en not_active IP Right Cessation
- 1984-11-15 GB GB08428898A patent/GB2150128B/en not_active Expired
- 1984-11-21 DD DD84269725A patent/DD229102A5/en not_active IP Right Cessation
- 1984-11-21 IT IT23680/84A patent/IT1177279B/en active
- 1984-11-22 PH PH31474A patent/PH22408A/en unknown
- 1984-11-23 FI FI844617A patent/FI76056C/en not_active IP Right Cessation
- 1984-11-23 DK DK557384A patent/DK168003B1/en not_active IP Right Cessation
- 1984-11-23 PT PT79544A patent/PT79544B/en not_active IP Right Cessation
- 1984-11-23 BR BR8405974A patent/BR8405974A/en not_active IP Right Cessation
- 1984-11-23 BE BE2/60552A patent/BE901114A/en not_active IP Right Cessation
- 1984-11-23 SE SE8405904A patent/SE461647B/en not_active Application Discontinuation
- 1984-11-23 IE IE3012/84A patent/IE57642B1/en not_active IP Right Cessation
- 1984-11-23 NO NO844668A patent/NO163004B/en unknown
- 1984-11-23 FR FR8417923A patent/FR2555565B1/en not_active Expired
- 1984-11-23 YU YU1987/84A patent/YU43676B/en unknown
- 1984-11-23 NL NL8403572A patent/NL8403572A/en active Search and Examination
- 1984-11-23 LU LU85649A patent/LU85649A1/en unknown
- 1984-11-26 PL PL1984250592A patent/PL148125B1/en unknown
- 1984-11-26 CA CA000468603A patent/CA1217032A/en not_active Expired
- 1984-11-26 AU AU35869/84A patent/AU568166B2/en not_active Ceased
- 1984-11-26 ZW ZW191/84A patent/ZW19184A1/en unknown
- 1984-11-26 AT AT0373684A patent/AT396460B/en not_active IP Right Cessation
- 1984-11-26 MX MX203487A patent/MX162694A/en unknown
- 1984-11-26 ES ES537973A patent/ES8600702A1/en not_active Expired
-
1986
- 1986-12-17 MY MYPI86000216A patent/MY100749A/en unknown
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MM4A | Patent lapsed |