EP0546984A1 - Décomposition semi-continue d'amiante - Google Patents
Décomposition semi-continue d'amiante Download PDFInfo
- Publication number
- EP0546984A1 EP0546984A1 EP92710035A EP92710035A EP0546984A1 EP 0546984 A1 EP0546984 A1 EP 0546984A1 EP 92710035 A EP92710035 A EP 92710035A EP 92710035 A EP92710035 A EP 92710035A EP 0546984 A1 EP0546984 A1 EP 0546984A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- asbestos
- supernatant
- reactor
- acid
- reaction
- 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- Withdrawn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
- 239000010425 asbestos Substances 0.000 title claims abstract description 84
- 229910052895 riebeckite Inorganic materials 0.000 title claims abstract description 84
- 238000000354 decomposition reaction Methods 0.000 title claims abstract description 28
- 238000000034 method Methods 0.000 claims abstract description 26
- 239000002253 acid Substances 0.000 claims abstract description 19
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 19
- 239000007864 aqueous solution Substances 0.000 claims abstract description 15
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000011737 fluorine Substances 0.000 claims abstract description 12
- 229910052731 fluorine Inorganic materials 0.000 claims abstract description 12
- 239000006228 supernatant Substances 0.000 claims description 34
- 238000006243 chemical reaction Methods 0.000 claims description 32
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 28
- 239000011541 reaction mixture Substances 0.000 claims description 14
- 239000000835 fiber Substances 0.000 claims description 13
- 239000013049 sediment Substances 0.000 claims description 10
- 238000003756 stirring Methods 0.000 claims description 10
- -1 hexafluorosilicic acid Chemical compound 0.000 claims description 7
- 150000008043 acidic salts Chemical class 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 3
- 239000008394 flocculating agent Substances 0.000 claims description 2
- 239000004094 surface-active agent Substances 0.000 claims description 2
- 150000003839 salts Chemical class 0.000 abstract description 3
- 238000010924 continuous production Methods 0.000 abstract 1
- 239000004033 plastic Substances 0.000 description 7
- 229920003023 plastic Polymers 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 239000000920 calcium hydroxide Substances 0.000 description 4
- 235000011116 calcium hydroxide Nutrition 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- MIMUSZHMZBJBPO-UHFFFAOYSA-N 6-methoxy-8-nitroquinoline Chemical compound N1=CC=CC2=CC(OC)=CC([N+]([O-])=O)=C21 MIMUSZHMZBJBPO-UHFFFAOYSA-N 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 3
- 229920000573 polyethylene Polymers 0.000 description 3
- ULEFFCDROVNTRO-UHFFFAOYSA-N trimagnesium;disodium;dihydroxy(oxo)silane;iron(3+) Chemical compound [Na+].[Na+].[Mg+2].[Mg+2].[Mg+2].[Fe+3].[Fe+3].O[Si](O)=O.O[Si](O)=O.O[Si](O)=O.O[Si](O)=O.O[Si](O)=O.O[Si](O)=O.O[Si](O)=O.O[Si](O)=O ULEFFCDROVNTRO-UHFFFAOYSA-N 0.000 description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- 229910017665 NH4HF2 Inorganic materials 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 239000004566 building material Substances 0.000 description 2
- 239000007884 disintegrant Substances 0.000 description 2
- 229910000040 hydrogen fluoride Inorganic materials 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000008267 milk Substances 0.000 description 2
- 210000004080 milk Anatomy 0.000 description 2
- 235000013336 milk Nutrition 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- IRPGOXJVTQTAAN-UHFFFAOYSA-N 2,2,3,3,3-pentafluoropropanal Chemical compound FC(F)(F)C(F)(F)C=O IRPGOXJVTQTAAN-UHFFFAOYSA-N 0.000 description 1
- KLZUFWVZNOTSEM-UHFFFAOYSA-K Aluminum fluoride Inorganic materials F[Al](F)F KLZUFWVZNOTSEM-UHFFFAOYSA-K 0.000 description 1
- 241000047774 Amphibola Species 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- WYTGDNHDOZPMIW-RCBQFDQVSA-N alstonine Natural products C1=CC2=C3C=CC=CC3=NC2=C2N1C[C@H]1[C@H](C)OC=C(C(=O)OC)[C@H]1C2 WYTGDNHDOZPMIW-RCBQFDQVSA-N 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 229910001634 calcium fluoride Inorganic materials 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229910001610 cryolite Inorganic materials 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 230000009970 fire resistant effect Effects 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 231100000206 health hazard Toxicity 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- VBKNTGMWIPUCRF-UHFFFAOYSA-M potassium;fluoride;hydrofluoride Chemical compound F.[F-].[K+] VBKNTGMWIPUCRF-UHFFFAOYSA-M 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000000565 sealant Substances 0.000 description 1
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 150000003388 sodium compounds Chemical class 0.000 description 1
- BFXAWOHHDUIALU-UHFFFAOYSA-M sodium;hydron;difluoride Chemical compound F.[F-].[Na+] BFXAWOHHDUIALU-UHFFFAOYSA-M 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
- A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
- A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
- A62D3/36—Detoxification by using acid or alkaline reagents
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
- A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
- A62D2101/40—Inorganic substances
- A62D2101/41—Inorganic fibres, e.g. asbestos
Definitions
- the invention relates to a process for the decomposition of asbestos, the asbestos being contacted with an aqueous solution of an inorganic fluorine-containing acid or an acidic salt of such an acid.
- Asbestos is known to be ascribed a health hazard. Asbestos has been used for a variety of applications, for example as a sealing cord, as a flat gasket, in the form of plates or as a fire-resistant fabric. To make asbestos harmless, you can encapsulate it, for example. Of course, the only encapsulated asbestos remains latently hazardous to health.
- the object of the present invention is to provide an uncomplicated process for the decomposition of asbestos with which a high throughput is possible at the same time with high effectiveness. This object is achieved by the invention specified in the claims.
- the process according to the invention for the semi-continuous decomposition of asbestos provides that in a first reaction cycle, asbestos is contacted with an aqueous solution of an inorganic fluorine-containing acid or an acidic salt of an inorganic fluorine-containing acid as a decomposition agent in a reactor, up to at least 90% by weight.
- the acid or salt can be generated in situ, e.g. by a mixture of mineral acid, e.g. As sulfuric acid, and an alkaline earth or alkali fluoride.
- the decomposition according to the invention takes place even faster if the asbestos is used in a comminuted form.
- the particle size is expediently below 0.5 cm, for example between 0.1 and 0.4 cm.
- the reaction can be accelerated if the reaction mixture is stirred during the reaction. The stirring is then stopped when you want to let the asbestos settle.
- the mixture is preferably stirred for 2 to 10 minutes, in particular 2 to 5 minutes, and the stirring is then stopped. The supernatant can then be separated off, for example after 2 to 10 minutes.
- the supernatant is partially separated off. It is important to ensure that no asbestos is discharged from the reactor. It is therefore expedient to completely separate off the supernatant only if, as will be described later, the reaction mixture has been left for a long time after the end of the reaction cycles without separating off the supernatant. Usually at least 70% by volume of the supernatant is separated off, for example between 85 and 90% by volume.
- the advantages of the process according to the invention are already apparent when only two reaction cycles are carried out.
- the supernatant could be partially or completely separated from the reactor after the second reaction cycle, as will be described further below, or together with the solid that settles out, if necessary.
- time can be saved.
- the asbestos which has not yet decomposed is preferably allowed to settle and at least part, if desired the entire supernatant, is left in the reactor. The remaining undecomposed asbestos is then completely decomposed.
- the process according to the invention is particularly advantageous if a plurality, for example 5 to 30 reaction cycles are provided.
- the reaction cycles can be repeated as often as required; however, the addition of asbestos and decomposing agent should be stopped when the asbestos-containing sediment has taken up such a large part of the reactor volume that the throughput decreases disadvantageously or there is a risk that asbestos-containing sediment could be discharged from the reactor when the supernatant was separated off.
- the above statement that the process is terminated when the sediment has taken up 30% of the reactor volume gives an expedient Directive. In individual cases, the procedure can be terminated sooner or later.
- the asbestos-containing residue can be treated further in various ways. For example, it can be removed from the reactor when asbestos fibers are still present, neutralized, e.g. with milk of lime, and then deposit. The amount of asbestos to be deposited is reduced to a fraction in this variant of the method according to the invention.
- the procedure is preferably such that after the addition of asbestos and decomposing agent in the last reaction cycle, the supernatant is not removed, but the reaction mixture is left to stand, if desired with stirring, until the asbestos has completely decomposed. This happens overnight or for example in a period of 2 to 5 hours.
- the residue which is then free of asbestos, can be completely removed from the reactor together with the supernatant.
- the reaction mixture can be readily used to prepare fluorine-containing compounds, e.g. Aluminum fluoride or cryolite can be used. It is then mixed with aluminum compounds and possibly sodium compounds. After neutralization, e.g. with milk of lime, it can be used as an additive for building materials. With this variant there is no material at all that has to be deposited.
- fluorine-containing compounds e.g. Aluminum fluoride or cryolite can be used. It is then mixed with aluminum compounds and possibly sodium compounds. After neutralization, e.g. with milk of lime, it can be used as an additive for building materials. With this variant there is no material at all that has to be deposited.
- the separated supernatant can be recycled into the process, optionally with removal of the entrained solids or strengthening with fresh decomposition agent.
- the supernatant can also be neutralized and used as an additive in the production of building materials or the hydrogen fluoride content can be recovered by adding sulfuric acid.
- An advantage of the method according to the invention is the high flexibility.
- various types of asbestos or forms of asbestos processing can be introduced into the reactor while the successive decomposition cycles are being carried out.
- the ratio of asbestos to disintegrant can also vary. If necessary or sensible, only asbestos or only decomposing agents can be introduced into the reactor in individual cycles.
- the amount of disintegrant should be such that it is sufficient to completely decompose the asbestos.
- the decomposition agent is expediently used in excess. This excess can then be recycled if necessary.
- the necessary amount can be determined by experiments. When using 20% by weight HF containing hydrofluoric acid, for example, asbestos and aqueous solution are used in a weight ratio of about 1: 5.
- the concentration of the decomposing agent in the aqueous solution must be so high that the reaction starts. It is therefore preferable to use an aqueous solution which contains at least 10% by weight of decomposing agent.
- the concentration of decomposing agent in the aqueous solution is expediently between 10 and 40% by weight. Higher concentrations are possible, but the reaction then becomes very violent.
- Preferred decomposing agents are hydrofluoric acid, hexafluorosilicic acid and tetrafluoroboric acid or an aqueous solution of their acidic salts, for example NH4HF2, NaHF2 or KHF2.
- Hydrofluoric acid is particularly suitable, preferably in a concentration of 10 to 40% by weight. If desired, one can also introduce gaseous hydrogen fluoride into an aqueous slurry of asbestos or dilute a previously concentrated hydrofluoric acid to a low concentration.
- the decomposition can preferably be carried out at temperatures between ambient temperature and 85 ° C. If desired, the temperature can be increased by adding external thermal energy, for example in a heatable reactor.
- surfactants and / or flocculants can be added.
- the method according to the invention is very well suited for the decomposition of any asbestos modifications, in particular for the decomposition of serpentine and amphibola asbestos (fibers). Asbestos can be decomposed in various forms. E.g. in the form of sealing cords, flat gaskets, loose fibers, insulation boards, plastic sealants, asbestos cement boards and other material containing asbestos fibers, in particular sprayed asbestos. The previous shredding is recommended.
- the method according to the invention allows the complete decomposition of asbestos at a very high throughput.
- the following examples are intended to explain the example further, without restricting its scope.
Landscapes
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Processing Of Solid Wastes (AREA)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19914139928 DE4139928A1 (de) | 1991-12-04 | 1991-12-04 | Halbkontinuierliche asbestzersetzung |
| DE4139928 | 1991-12-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP0546984A1 true EP0546984A1 (fr) | 1993-06-16 |
Family
ID=6446219
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP92710035A Withdrawn EP0546984A1 (fr) | 1991-12-04 | 1992-11-28 | Décomposition semi-continue d'amiante |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0546984A1 (fr) |
| DE (1) | DE4139928A1 (fr) |
| NO (1) | NO924669L (fr) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5811360A (en) * | 1993-01-15 | 1998-09-22 | The Morgan Crucible Company Plc | Saline soluble inorganic fibres |
| US5928975A (en) * | 1995-09-21 | 1999-07-27 | The Morgan Crucible Company,Plc | Saline soluble inorganic fibers |
| US5955389A (en) * | 1993-01-15 | 1999-09-21 | The Morgan Crucible Company, P/C | Saline soluble inorganic fibres |
| US5994247A (en) * | 1992-01-17 | 1999-11-30 | The Morgan Crucible Company Plc | Saline soluble inorganic fibres |
| US6987076B1 (en) | 1998-09-15 | 2006-01-17 | The Morgan Crucible Company Plc | Bonded fibrous materials |
| WO2008093368A1 (fr) * | 2007-01-31 | 2008-08-07 | Irsai S.R.L. | Procédé d'élimination de l'amiante et usine destinée à mettre en œuvre ce procédé |
| US7651965B2 (en) | 2002-01-04 | 2010-01-26 | The Morgan Crucible Company Plc | Saline soluble inorganic fibres |
| US7875566B2 (en) | 2004-11-01 | 2011-01-25 | The Morgan Crucible Company Plc | Modification of alkaline earth silicate fibres |
| WO2017051117A1 (fr) * | 2015-09-22 | 2017-03-30 | Paul Poggi | Procédé et dispositif fixe ou mobile de neutralisation et valorisation de déchets d'amiante |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3708014A (en) * | 1971-06-23 | 1973-01-02 | Phillips Petroleum Co | Hydrochloric acid/hydrofluoric acid treatment to remove asbestos fibers from a well bore |
| CA1114533A (fr) * | 1979-01-12 | 1981-12-15 | Meguru Nagamori | Procede pour la neutralisation des acides nitriques-fluorhydriques uses |
| WO1988010234A1 (fr) * | 1987-06-26 | 1988-12-29 | Forskningscenter Risø | Procede de traitement de l'amiante |
| EP0372084A1 (fr) * | 1988-04-30 | 1990-06-13 | Solvay Umweltchemie GmbH | Agent et procede de traitement d'amiante |
| WO1990015642A1 (fr) * | 1989-06-15 | 1990-12-27 | Tony Nocito Inc. | Procede et produits ameliores de traitement d'amiante |
-
1991
- 1991-12-04 DE DE19914139928 patent/DE4139928A1/de not_active Withdrawn
-
1992
- 1992-11-28 EP EP92710035A patent/EP0546984A1/fr not_active Withdrawn
- 1992-12-03 NO NO92924669A patent/NO924669L/no unknown
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3708014A (en) * | 1971-06-23 | 1973-01-02 | Phillips Petroleum Co | Hydrochloric acid/hydrofluoric acid treatment to remove asbestos fibers from a well bore |
| CA1114533A (fr) * | 1979-01-12 | 1981-12-15 | Meguru Nagamori | Procede pour la neutralisation des acides nitriques-fluorhydriques uses |
| WO1988010234A1 (fr) * | 1987-06-26 | 1988-12-29 | Forskningscenter Risø | Procede de traitement de l'amiante |
| EP0372084A1 (fr) * | 1988-04-30 | 1990-06-13 | Solvay Umweltchemie GmbH | Agent et procede de traitement d'amiante |
| WO1990015642A1 (fr) * | 1989-06-15 | 1990-12-27 | Tony Nocito Inc. | Procede et produits ameliores de traitement d'amiante |
Non-Patent Citations (1)
| Title |
|---|
| PATENT ABSTRACTS OF JAPAN vol. 16, no. 304 (C-959)(5347) 6. Juli 1992 & JP-A-04 083574 ( NIPPON STEEL CHEM CO LTD ) 17. März 1992 * |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5994247A (en) * | 1992-01-17 | 1999-11-30 | The Morgan Crucible Company Plc | Saline soluble inorganic fibres |
| US6180546B1 (en) | 1992-01-17 | 2001-01-30 | The Morgan Crucible Company Plc | Saline soluble inorganic fibers |
| US5955389A (en) * | 1993-01-15 | 1999-09-21 | The Morgan Crucible Company, P/C | Saline soluble inorganic fibres |
| US5811360A (en) * | 1993-01-15 | 1998-09-22 | The Morgan Crucible Company Plc | Saline soluble inorganic fibres |
| US5928975A (en) * | 1995-09-21 | 1999-07-27 | The Morgan Crucible Company,Plc | Saline soluble inorganic fibers |
| US6987076B1 (en) | 1998-09-15 | 2006-01-17 | The Morgan Crucible Company Plc | Bonded fibrous materials |
| US7651965B2 (en) | 2002-01-04 | 2010-01-26 | The Morgan Crucible Company Plc | Saline soluble inorganic fibres |
| US7875566B2 (en) | 2004-11-01 | 2011-01-25 | The Morgan Crucible Company Plc | Modification of alkaline earth silicate fibres |
| WO2008093368A1 (fr) * | 2007-01-31 | 2008-08-07 | Irsai S.R.L. | Procédé d'élimination de l'amiante et usine destinée à mettre en œuvre ce procédé |
| WO2017051117A1 (fr) * | 2015-09-22 | 2017-03-30 | Paul Poggi | Procédé et dispositif fixe ou mobile de neutralisation et valorisation de déchets d'amiante |
| CN108290186A (zh) * | 2015-09-22 | 2018-07-17 | P·颇纪 | 中和与再利用石棉废料的移动或固定方法与设备 |
| CN108290186B (zh) * | 2015-09-22 | 2021-07-30 | P·颇纪 | 中和与再利用石棉废料的移动或固定方法与设备 |
| US11331526B2 (en) | 2015-09-22 | 2022-05-17 | Paul Poggi | Method and stationary or movable device for neutralizing and recycling asbestos waste |
Also Published As
| Publication number | Publication date |
|---|---|
| NO924669L (no) | 1993-06-07 |
| DE4139928A1 (de) | 1993-06-09 |
| NO924669D0 (no) | 1992-12-03 |
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| STAA | Information on the status of an ep patent application or granted ep patent |
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|
| 18D | Application deemed to be withdrawn |
Effective date: 19960603 |