WO1999028538A1 - Cellule electrolytique destinee a la production de fluor - Google Patents

Cellule electrolytique destinee a la production de fluor Download PDF

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Publication number
WO1999028538A1
WO1999028538A1 PCT/GB1998/003494 GB9803494W WO9928538A1 WO 1999028538 A1 WO1999028538 A1 WO 1999028538A1 GB 9803494 W GB9803494 W GB 9803494W WO 9928538 A1 WO9928538 A1 WO 9928538A1
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WO
WIPO (PCT)
Prior art keywords
fluorine
anode
cell according
cell
gas
Prior art date
Application number
PCT/GB1998/003494
Other languages
English (en)
Inventor
Graham Hogdson
Robert Dawson
Original Assignee
Fluorogas Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fluorogas Limited filed Critical Fluorogas Limited
Priority to AU12488/99A priority Critical patent/AU1248899A/en
Publication of WO1999028538A1 publication Critical patent/WO1999028538A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/24—Halogens or compounds thereof
    • C25B1/245—Fluorine; Compounds thereof

Definitions

  • the present invention relates to an electrolytic cell for the generation of fluorine.
  • Fluorine gas is presently available from three different sources: compressed fluorine supplied in cylinders; secondary electrolytic fluorine producing cells; and, chemical fluorine generators.
  • a significant disadvantage of compressed fluorine supplied in cylinders is that the fluorine is generally only available diluted with nitrogen or some other diluent gas such as, for example, 20% fluorine in nitrogen. This is due to fluorine being considered too hazardous to transport and/or use as a pressurised pure gas. Cylinder fluorine is convenient to use but safety considerations necessitate the use of expensive gas handling cabinets and piping systems to mitigate the risks involved. Therefore, pressurised fluorine gas cylinders are generally disliked in establishments such as research institutions, e.g., universities and the like. However, if fluorine is needed in such establishments, it is necessary to accept the high risks and costs involved. Many potential users do not proceed with pressurised fluorine once they understand the risks and expense which are entailed.
  • US patent number 3,989,808 describes a method for storing and regenerating pure fluorine by producing a potassium hexafluoronickelate salt which generates fluorine gas on heating.
  • fluorine sources are useful for storing very small quantities of fluorine such as about 20g and have the advantages of being safe, easy to use and produce high purity fluorine gas.
  • the chief disadvantage is the high cost and small quantities of fluorine available by this route.
  • the synthesis route for the salt requires several stages and fluorine gas per se is initially required as a raw material. This has to be provided by an electrolytic fluorine cell of some form.
  • chemical fluorine generators are necessarily expensive and commercial applications are limited to those where high gas purity and safe transportation can justify the high cost.
  • a further object of the present invention is to produce a fluorine gas source which is safe to transport. Further objects of the present invention will become apparent as set out hereinbelow.
  • an electrolytic fluorine producing cell comprising: a vessel having therein anode means and cathode means, the anode and cathode means being separated by gas separation skirt means extending into and below the surface of an electrolyte contained within the vessel; means for removing hydrogen gas and fluorine gas produced during electrolysis of said electrolyte; wherein the anode means are metal sacrificial anode means and the gas separation skirt means extends below the lowest extent of said anode means.
  • the cell according to the present invention is a "primary" cell, i.e. a so-called “one shot” device which when exhausted is safely disposed of.
  • the non-consumable parts of the cell may be recycled.
  • Such cells are generally not amenable to being recharged, for example, with fresh electrolyte or a new anode by the purchaser or user.
  • the cell is used until the electrolyte is exhausted and a new cell is purchased.
  • the preferred cell according to the present invention is a sealed device which has a vent to take hydrogen away to a fume cupboard for example and a valved fluorine outlet to deliver fluorine to the user's process or experimental apparatus at a rate which is directly proportional to the applied DC current.
  • the user has only to heat the cell to melt the electrolyte which is generally solid at ambient temperatures and apply a power supply to the electrode terminals .
  • the vessel of the cell according to the present invention is effectively divided into two compartments by the gas separation skirt, these are the fluorine compartment in which the anode means is situated and the hydrogen compartment which has cathode means.
  • the gas separation skirt may be a generally cylindrical tube which may be sealed into an upper vessel closure member and extends down into and below the surface of the contained electrolyte, surrounding the anode and extending below the lowest extent of the anode.
  • the fluorine outlet means conducts fluorine gas away from this region via valve means.
  • the skirt may be made of metal which is generally resistant to the effects of fluorine such as steel for example or from a suitable plastics material.
  • the skirt may be formed from metal and have an electrically insulating plastics material layer thereon which will be explained further herein below.
  • the cell of the present invention provides a simple, inexpensive but highly reliable device for providing pure fluorine gas on demand. If the user wishes to restrict or stop the flow of fluorine, all that is necessary is that the fluorine outlet valve is restricted or closed. The effect of this is that the fluorine gas generated at the anode exerts a slight pressure on the surface of the liquid electrolyte contained within the gas separation skirt and slowly depresses the level of electrolyte in the fluorine generating compartment where the anode is situated. There is a corresponding rise in the electrolyte level in the hydrogen compartment caused by the displacement of the electrolyte from the fluorine compartment.
  • the pressure at which gas production ceases within the anode compartment may be controlled to pressures in the range 1-lOOcm water gauge by virtue of adjusting the length of the anode and the height and diameter of skirt and cell body.
  • the anode is a sacrificial metal anode comprising any suitable metal such as nickel for example.
  • the precious metals such as platinum or palladium are technically feasible, they are practically too expensive.
  • Secondary fluorine cells incorporate a carbon anode to give reliable operation over a long period of time typically 3000-10000 hours.
  • the anode has to survive many hydrogen fluoride recharge cycles and carbon is the only known material which can survive such duty.
  • the carbon survives due to the formation of a protective carbon polyfluoride layer on the surface which has the unfortunate side effect of being an electrical resistor.
  • the potential drop across the polyfluoride layer is typically 3 volts at a current density of only 1500 Am- 2 .
  • the gap between the anode and cathode is large typically in the region of 30-40mm so as to obviate the possibility of explosive recombination of fluorine and hydrogen generated below the bottom of the gas separating skirt.
  • the sacrificial metal anode exhibits a negligible over potential, since no resistive surface layer is formed, and so can allow a useful amount of current to flow without operation at high cell potentials and consequently avoids the bipolar cell formation with the explosive recombination of generated gases.
  • the anode slowly corrodes away but nonetheless lasts until all of the available fluorine in the hydrogen fluoride electrolyte is depleted to a level whereby no further fluorine can be generated, i.e. about 38%W/V.
  • the cathode may be an annular metal ring attached adjacent the lower end portion of the gas separating skirt and insulated therefrom as mentioned above. Since the anode does not protrude below the lower end of the skirt, all fluorine is produced at a level above the lowest extent of the gas separating skirt an thus cannot physically reach and recombine with the hydrogen generated at the cathode which is preferably situated slightly above the lowermost end of the gas separation skirt.
  • the cathode has generally been formed by the inner wall of a steel or cast iron containment vessel.
  • the vessel of the cell according to the present invention may also be made of metal and form the cathode.
  • the vessel may alternatively be formed of a plastics material such as PVDF for example, thus further reducing weight and possible contamination of the electrolyte due to corrosion products from the metal and consequently of the fluorine produced.
  • the cathode may be formed of a metal ring fixed in the base of the vessel for example.
  • the cathode is mounted directly on the gas separating skirt and insulated therefrom, the shortest possible current path is provided between anode and cathode without the possibility of recombination of hydrogen and fluorine.
  • the cell vessel may be made of metal such as carbon steel, stainless steel or Monel metal (trade name) for example and the anode may be in the form of a disc having a plane normal to the axis of the cell.
  • the cell vessel inner wall forms the cathode. Due to the increased area of the anode adjacent the lower end of the gas separation skirt, substantially increased current flow at reduced or low voltages have been found. However, the lowest extremity of the anode in this second embodiment is still above the lower end of the gas separation skirt.
  • the purge tube preferably passes through the hydrogen compartment and has an outlet which is positioned below and directed towards the fluorine compartment. In this way, it is not possible for any fluorine to inadvertently leak to the outside through the purge tube as there is no direct access to the purge tube from the fluorine compartment.
  • Any suitable gas such as nitrogen, helium or argon for example may be used as the purge gas.
  • a very important advantage of a primary cell according to the present invention is that being sealed it may be shipped to customers by air. This is banned by International regulations for fluorine contained in pressurised cylinders and secondary devices are too massive for economic transportation by air. Thus, this a further benefit of the cell of the present invention since in a secondary cell, the user has to charge the cell with anhydrous hydrogen fluoride which is itself a very hazardous chemical.
  • a further important advantage of the cell according to the present invention due to the use of a sacrificial metal anode is related to the purity of the fluorine produced.
  • the fluorine gas is contaminated with carbon tetrafluoride (CF 4 ) and other fully or partially fluorinated carbon-fluorine compounds.
  • CF 4 carbon tetrafluoride
  • the use of a metal ' anode in the cell of the present invention allows the use of high purity electrolyte which can be used to prepare high purity fluorine directly by electrolysis. This is not a practical proposition in a conventional secondary fluorine cell, partly due to the CF 4 mentioned above, but also because high purity electrolyte is known to cause problems in the operation of secondary fluorine cells.
  • the cell of the present invention may be brought to full current in a period of only 1 to 2 seconds and may be switched on and off as frequently as may be desired within the life of the sacrificial anode without any adverse effect on operation or reliability.
  • the vessel is normally constructed from metal such as carbon steel or Monel (trade name) metal. This is made cathodic to reduce corrosion and also form the cathode of the cell.
  • metal ions which form volatile fluorides, e.g. molybdenum, chromium and tungsten, are slowly leached from the metal by the hydrogen fluoride electrolyte which then react with the fluorine gas in the anode compartment to introduce gaseous metal fluoride contaminants in the resulting fluorine product.
  • the use of the separate metal ring cathode and a plastics material vessel such as PTFE or PVDF obviates the problem of leached metal ions and the production of gaseous metal fluorides contaminating the fluorine product.
  • a yet further advantage of the cell of the present invention is that the available weight of fluorine from a given weight of electrolyte is significantly increased because the upper hydrogen fluoride concentration may be increased and the lower hydrogen fluoride concentration may be decreased when compared to conventional secondary fluorine cells.
  • Carbon anodes start to disintegrate when the hydrogen fluoride concentration is above approximately 43% W/V.
  • the sacrificial metal anode used in the primary fluorine cell of the present invention is able to operate satisfactorily at more than 46% W/V.
  • carbon anodes exhibit a phenomenon known as "polarisation" whereby the current decline sharply and fluorine generation is reduced or ceases completely.
  • the metal anode in the cell of the present invention operates satisfactorily at less than 37% W/V hydrogen fluoride.
  • the capacity of the cell of the present invention to generate fluorine is at least double that of a conventional secondary fluorine cell of comparable size and electrolyte inventory. This is a significant advantage and makes the fluorine cell of the present invention lighter and more compact for transportation benefits.
  • a still further advantage of the present invention is that complex carbon anode constructions are necessary in conventional secondary fluorine cells to connect the carbon anode to the metal cell electrodes. Such constructions are necessary to prevent corrosion at the junction between the carbon anode and metal connection portions.
  • the anode hanger and electrical connection is metal to metal welded, providing good electrical contact.
  • the anode is also hollow and simultaneously acts as the fluorine outlet conduit. This feature avoids the need for a separate fluorine outlet pipe which would otherwise increase the diameter and hence the size of the unit.
  • a still further advantage of the cell of the present invention is that the purity of the fluorine gas is substantially constant for the life the cell.
  • a conventional secondary fluorine cell there is a regular addition of hydrogen fluoride electrolyte which may introduce water and sulphur compounds which give rise to contaminants in the fluorine such as SF 4 , SF 6 , S0 2 F 2 and OF 2 .
  • the electrolyte may be purified before it is put into the cell and the cell is then sealed. Thus, contaminants cannot be introduced during operation or recharging and the fluorine purity is constant and can be guaranteed in the same way as a cylinder of fluorine.
  • the majority of the components of the cell according to the present invention may be manufactured from suitable plastics materials such as PVDF, for example, which are both economic and easily formed.
  • suitable plastics materials such as PVDF, for example, which are both economic and easily formed.
  • the cell according to the present invention may be supplied with a reusable heating jacket such as an electrically heated blanket or water bath for example.
  • Figure 1 shows a section in elevation of a cell according to the present invention
  • Figure 2 is a view in the direction of the arrow 2 shown in Figure 1;
  • FIG 3 which shows a section similar to Figure 1 of a second embodiment of a fluorine cell according to the present invention.
  • Figure 4 which shows a plan view of the top of the cell of Figure 3.
  • the cell comprises a vessel 12 made of a plastics material such as PVDF, a sacrificial metal anode 14 made of nickel, a fluorine outlet conduit 16 to which the anode 14 is connected, a cylindrical gas separation skirt 18, a cathode 20, hydrogen venting conduits 22 and an end closure arrangement 24 to seal the open end 26 of the vessel 12.
  • a plastics material such as PVDF
  • a sacrificial metal anode 14 made of nickel
  • a fluorine outlet conduit 16 to which the anode 14 is connected
  • a cylindrical gas separation skirt 18 to which the anode 14 is connected
  • a cathode to which the anode 14 is connected
  • hydrogen venting conduits 22 and an end closure arrangement 24 to seal the open end 26 of the vessel 12.
  • the overall height of the cell 10 is about 0.5m.
  • the anode 14 is connected to the fluorine outlet tube 16 by means of co-operating male and female screw threads 28 on a spigot 30 on the fluorine outlet tube and a recess 32 in the end of the nickel anode 14.
  • the gas separation skirt 18 comprises an inner cylindrical member 34 made of a suitable metal such as carbon steel or copper/nickel alloys, for example, and an outer insulating layer 36 of a suitable plastics material. As may be seen from Figure 1, the end 40 of the anode 14 terminates above the lowest extent 42 of the gas separation skirt 18.
  • the cathode 20 is a steel ring clamped on and adjacent the lower end 42 of the gas separation skirt 18.
  • An electrical conductor 44 extends between the cathode ring 20 and a terminal connector block 46 sealed into the vessel wall for the connection of a 5amp 10 volt DC power supply 50, the anode connection 52 being made to the Monel metal (trade mark) or stainless steel fluorine outlet conduit 16.
  • the outlet conduit 16 is provided with holes 54 to conduct fluorine gas away from the anode compartment 56 via a regulating valve 58 on the end of the fluorine conduit 16.
  • the vessel closure assembly 24 comprises a main plug member 60 fixed into the open end of the vessel 12 by means of screws 62 and sealed thereto by ⁇ 0' ring seals 6 .
  • the hydrogen venting conduits 22 are formed through the plug member 60 and provided with seal plugs 66 for use in transportation of the cell and which may be replaced by a valved conduit indicated by the dashed line 68 when in use.
  • the gas separation skirt 18 is received in a central bore 70 of the plug member 60.
  • a gland sealing arrangement 72 seals the bore of the gas separation skirt metal member 34 from the ambient atmosphere and also seals the fluorine take off conduit 16 from the ambient atmosphere.
  • a space 76 is filled with compressible gland sealing material such as expanded PTFE for example.
  • An olive 78 is fixed to the fluorine outlet conduit 16 so as to locate the lowest extent 40 of the anode 14 relative to the end 42 of the gas separation skirt 18.
  • the lowest extent 40 of the anode is above the lowest extent 42 of the gas separation sleeve 18.
  • the cathode 20 is fixed so that it is slightly above the lowest extent 42 of the gas separation skirt and is insulated from the metal member 34 by the plastics material layer 36.
  • a heating device indicated generally by the dashed line 90 and which may be a water or oil bath for example.
  • the temperature of the cell is brought to between 75 and 100°C (preferably 85°C) and allowed to come to temperature equilibrium with the heating device.
  • the cell is purged with nitrogen gas through the outlet valve 58 and pipe 16.
  • the 5 amp, 10 volt DC power supply 50 provided for the purpose is connected between the terminal block 36 and the connection 52 on the fluorine outlet pipe 16.
  • fluorine is generated at the anode and rises into the anode compartment 56 above the surface 92 of the electrolyte 94, hydrogen is generated at the cathode 20 and rises into the cathode compartment 96 where it may be vented away via the conduit and valve 68 and safely disposed of.
  • the fluorine is generated at a rate which is directly proportional to the applied DC current.
  • the fluorine in the fluorine compartment 56 exerts a slight pressure on the liquid electrolyte 94 in the anode/fluorine compartment and thus slowly depresses the level of electrolyte such that it eventually extends below the lowest extent 40 of the anode 14 to a position indicated by the dashed line 100.
  • the level of the electrolyte in the cathode compartment 96 rises to a level indicated by the dashed line 102.
  • electrolysis stops and consequently, generation of fluorine also stops.
  • the generation of fluorine may be started and stopped at will, i.e. "on demand" by the user.
  • FIGS 3 and 4 show a second embodiment 110 of a fluorine cell according to the present invention.
  • the vessel 112 is made of carbon steel, stainless steel or preferably Monel metal (trade name) and the inner wall 114 thereof forms the cathode of the cell.
  • the centrally disposed anode 116 comprises a nickel alloy tube 118 having fluorine tapping holes 120 into the central bore 122 for taking off fluorine and an active anode portion 126 in the shape of a horizontally disposed disc having holes 130 therethrough to allow fluorine gas to pass up into the fluorine compartment 132.
  • the gas separation skirt 136 comprises an insulated tube portion 138 and a lower bell-mouthed portion 140 surrounding the disc anode 126.
  • a spacer 142 is provided at the lower end of the skirt 136 to ensure that the skirt remains centrally disposed in the vessel 112 and cannot touch the inner wall 114.
  • a pressure release valve 150 is provided in the hydrogen compartment 152 to prevent any unwanted build-up of pressure within the compartment for any unforeseen reason.
  • a purge tube 156 is connected to a union 158 at the top and anchored to a block of plastics material 160 at the lower end thereof to form an upwardly directed gas stream 162 directed towards the fluorine compartment 132 for purging purposes the union 158 may be connected to a suitable gas supply such as nitrogen for example for purging before and after use if desired.
  • the base of the cell is fitted with a plastics material disc 164 to ensure that no hydrogen can be formed below the fluorine compartment.
  • Fluorine is extracted from a valve arrangement 166 at the top of the anode tube 118. Electrical connections are made to the anode tube 118 and to screwed post 168 for the cathode which, with other radially directed dowels 170 secure the top block 172 and gland assembly 174 to the vessel 112.
  • each embodiment may be interchanged as desired.
  • the gas purge tube of Figures 3 and 4 may be fitted to the embodiment of Figures 1 and 2.
  • the cathode of Figures 1 and 2 may also be employed with the separation skirt and anode arrangement of Figures 3 and .
  • the cell does not contain fluorine and may have an electrolyte inventory of 2kg it can be legally and safely transported by air, which is not possible with compressed fluorine in cylinders.
  • the fluorine gas produced contains about 5%v/v HF. However, this can be simply and easily removed by means such as absorption onto sodium fluoride. Thereafter, the purity of the fluorine gas produced is high and constant.
  • the quantity of fluorine produced from a given weight of electrolyte may be up to twice that available from conventional secondary cells.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Abstract

L'invention concerne une cellule électrolytique destinée à la production de fluor, ladite cellule comprenant: une cuve (12) dont laquelle se trouvent un élément anode (14) et un élément cathode (20), les éléments anode et cathode étant séparés par une jupe de séparation (18) des gaz s'étendant sous la surface d'un électrolyte contenu dans la cuve, un dispositif permettant l'évacuation de l'hydrogène et du fluor à l'état gazeux produits au cours de l'électrolyse dudit électrolyte. L'élément anode est une anode métallique soluble et la jupe de séparation des gaz se trouve au-dessous de l'extrémité inférieure dudit élément anode.
PCT/GB1998/003494 1997-11-28 1998-11-23 Cellule electrolytique destinee a la production de fluor WO1999028538A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU12488/99A AU1248899A (en) 1997-11-28 1998-11-23 Electrolytic cell for the production of fluorine

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9725067.4 1997-11-28
GBGB9725067.4A GB9725067D0 (en) 1997-11-28 1997-11-28 Fluorine cell

Publications (1)

Publication Number Publication Date
WO1999028538A1 true WO1999028538A1 (fr) 1999-06-10

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Application Number Title Priority Date Filing Date
PCT/GB1998/003494 WO1999028538A1 (fr) 1997-11-28 1998-11-23 Cellule electrolytique destinee a la production de fluor

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AU (1) AU1248899A (fr)
GB (1) GB9725067D0 (fr)
WO (1) WO1999028538A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004005584A1 (fr) * 2002-07-06 2004-01-15 The Boc Group Plc Cellule generatrice de fluor
EP1455918A2 (fr) * 2001-11-26 2004-09-15 Fluorine on Call, Ltd. Generation, distribution et utilisation du fluor moleculaire avec installation de production
US6843258B2 (en) 2000-12-19 2005-01-18 Applied Materials, Inc. On-site cleaning gas generation for process chamber cleaning

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB425979A (en) * 1932-10-31 1935-03-22 Du Pont Improvements in and relating to the electrolytic production of fluorine
WO1995006763A1 (fr) * 1993-09-03 1995-03-09 Minnesota Mining And Manufacturing Company Cellules utilisees dans la production de fluor

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB425979A (en) * 1932-10-31 1935-03-22 Du Pont Improvements in and relating to the electrolytic production of fluorine
WO1995006763A1 (fr) * 1993-09-03 1995-03-09 Minnesota Mining And Manufacturing Company Cellules utilisees dans la production de fluor

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6843258B2 (en) 2000-12-19 2005-01-18 Applied Materials, Inc. On-site cleaning gas generation for process chamber cleaning
US6981508B2 (en) 2000-12-19 2006-01-03 Applied Materials, Inc. On-site cleaning gas generation for process chamber cleaning
EP1455918A2 (fr) * 2001-11-26 2004-09-15 Fluorine on Call, Ltd. Generation, distribution et utilisation du fluor moleculaire avec installation de production
EP1455918A4 (fr) * 2001-11-26 2004-12-15 Fluorine On Call Ltd Generation, distribution et utilisation du fluor moleculaire avec installation de production
WO2004005584A1 (fr) * 2002-07-06 2004-01-15 The Boc Group Plc Cellule generatrice de fluor
CN100351432C (zh) * 2002-07-06 2007-11-28 波克股份有限公司 氟电解槽
US7481911B2 (en) 2002-07-06 2009-01-27 The Boc Group Plc Fluorine cell

Also Published As

Publication number Publication date
AU1248899A (en) 1999-06-16
GB9725067D0 (en) 1998-01-28

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