CN103774171A

CN103774171A - Anodes for the electrolytic production of nitrogen trifluoride and fluorine

Info

Publication number: CN103774171A
Application number: CN201310495849.6A
Authority: CN
Inventors: J·P·内尔森; K·R·伯格; R·M·玛查多; 崔暻浩
Original assignee: Air Products and Chemicals Inc
Current assignee: Air Products and Chemicals Inc
Priority date: 2012-10-19
Filing date: 2013-10-21
Publication date: 2014-05-07
Also published as: JP2014084529A; US20140110269A1; TW201416492A; ZA201307805B; US20140110267A1

Abstract

A process and an anode for the production of nitrogen trifluoride or fluorine where the anode in the electrolytic cell is made primarily from mesocarbon microbeads. The mesocarbon microbead anodes minimize the production of CF4 and improve the purity of the nitrogen trifluoride or fluorine gas produced. Additionally, the anodes may be molded, instead of extruded or machined, providing for improved dimensional and mechanical integrity of the anode.

Description

For the anode of electrolysis production nitrogen trifluoride and fluorine

the cross reference of related application

The application is the U.S. Patent application No.13/859 submitting on April 9th, 2013,263 part continuation application, described U.S. Patent application is according to 35U.S.C. § 119(e) to require the sequence number that submit to 19 days October in 2012 be early 61/716, the benefit of priority of the U.S. Patent application that the sequence number of submitting in 259 U.S. Patent application and on March 15th, 2013 is 61/790,810.The content of each priority application is all incorporated to herein by reference with it.

Technical field

The present invention relates generally to electrolysis production nitrogen trifluoride and fluorine, specifically, relates to and using by parallel orderly anisotropic carbon, comprises needle coke and mesocarbon, the anode of making, and described anode shows some physical properties for generation of nitrogen trifluoride and fluorine.

Background technology

Nitrogen trifluoride (NF ₃) be at room temperature reactive very little stabilizing gas.On the other hand, fluorine (F ₂) be under envrionment conditions with the gas of most responding property of material.Have been found that NF ₃and F ₂the two purposes in semi-conductor is manufactured is growing.For example, NF ₃be typically used as the etching reagent of silicon in semiconducter substrate or silicon oxide layer or in the time that it activates in position as the purge gas in CVD chamber.

In technical scale, NF ₃can manufacture by fluorination method.There are two kinds of main fluorination process: directly fluoridize (DF) and electrochemical fluorination (ECF).In electrochemical fluorination, ionogen can be by electrolysis in electrolyzer, to produce NF ₃.F ₂in electrochemical process, produce NF to be similar to ₃eCF method produce.For instance, traditional electrolyzer uses the carbonized plate of carbon steel negative electrode and extrusion molding, and described anode is made up of carbon coke particle and anthraxolite tackiness agent.Traditional anode is made up of isotropic cokes, and is conventionally greater than the volume particle size of 100 microns owing to using, so show height macroporosity.Described traditional extrusion molding carbon anode carbonization at the temperature lower than 1000 ℃, and greying not conventionally, greying need to exceed the temperature of 1500 ℃.But, as described in document, there is many to traditional relevant shortcoming of extrusion molding carbon anode, for example, as reference Ellis, J.F. and G.F.May, described in " Modern Fluorine Generation ", the Fluorine that described document is write at R.E.Banks, D.W.A.Sharp and J.C.Tatlow, in the First Hundred Years, Elsevier Sequoia, 1986.

A problem relevant with electrochemical fluorination is the NF that electrolysis produces ₃or F ₂by CF ₄(tetrafluoromethane or tetrafluoro-methane) pollutes.Because expect in a lot of industry, for example semi-conductor industry and the highly purified NF of needs ₃or F ₂, the pollution of any kind is all misgivings.CF ₄hardly may with NF ₃separate.J.Massonne,CHEMIE?INGENIEUR?TECHNIK,v.41,N12,p.695（1969）。Therefore, any CF ₄pollute and all reduce generated NF ₃purity and be not easy to remove.For F ₂although, may form CF ₄, but it can separate and remove, but this that need to add and expensive procedure of processing are with purifying and reclaim the F of purifying ₂.

Another problem relevant to traditional carbon anode, for example to by the relevant problem of the carbon coke of bituminous cement, be that described anode needs extrusion molding, mechanical workout or these two kinds to be formed as anode shape.But described anode may not have accurate shape and pattern is suitably brought into play function and may not be reproducible.This causes size and the poor mechanical integrity of described anode.

Another problem is in the time that anode becomes passivation and stops bringing into play function, the polarization of described anode.This state is by indicating higher than standard cell voltage (normal cell voltage), and is called as " polarization ".When carbon type anode is used for manufacturing F ₂or NF ₃time, polarization is the major cause of groove fault.Extreme case is to be sometimes called as " anode effect ".M.Jaccaud, R.Faron, D.Devilliers and R.Romano, " Fluorine ", Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH Verlag, 2000.Polarize by prevention, allow electrolyzer to move the long period between rebuilding, thereby cut down production cost.

Therefore, at electrolysis production NF ₃or F ₂thereby middle formation is by product the more highly purified NF of generation still less ₃or F ₂anode, there is the anode of better dimensional integrity and minimize or reduce the anode of polarization, still have needs.

Summary of the invention

Provide the present invention for using electrolyzer to produce nitrogen trifluoride, fluorine or these two kinds, its Anodic is made up of parallel orderly anisotropic carbon or coke, described parallel orderly anisotropic carbon or coke comprise needle coke, pod shape coke (lenticular coke), mesocarbon (mesophase carbon) and initial stage mesocarbon (incipient mesophase carbon), comprise carbonaceous mesophase spherules, all as J.Speight, Handbook of Petroleum Product Analysis, John Wiley & Sons, 2002 institutes define.Contrary with random layering or concentric layering (onion sample) carbon or decolorizing carbon or hyaloid carbon, such carbon shows all size substantially parallel in order or the territory of layering.Have been found that, by using this anode being formed by parallel orderly anisotropic carbon, compared with using the conventional anode of being made by sponge coke, bullet coke, concentric layering coke, amorphous coke or any isotropic cokes, can reach the current density of lower bath voltage and Geng Gao.In addition, have been found that this anode that shows some physical property provides minimizing and minimized such as CF of by product ₄generation; Therefore the nitrogen trifluoride that, greatly improvement is produced or the purity of fluorine.The microporous carbon that provides the physical properties of this advantage to comprise small grain size, low percentage of open area, high-density and/or reduction, for example, because containing the carbonization of oxygen carbon precursor or using the microporous carbon producing as the porous coke of sponge coke.In addition, described anode can molded rather than extrusion molding or mechanical workout, and improved size and the mechanical integrity of described anode is provided.In other words, the conventional anode of extrusion molding and/or mechanical workout is different from needing, and the shape of molded anode is set by mould, makes it more accurately with reproducible, and more high quality and the better anode of function are provided.This also allows the geometrical shape of described groove more consistent, and this more can repeat circulation of elecrolyte and bubble effusion.Anode of the present invention also shows the anti-polarizability of improvement and other benefit as described herein.

In the middle of other physical properties, the carbon product type of describing in the literature utilizes apparent density to characterize conventionally.Because these materials are made up of the particle of assembling with bonding or sintering, they are porous.This degree of porosity of measuring with total product volume per-cent, and whether feature for example mean pore size, pore size distribution and hole interconnect (open) or isolation (sealing), are all the functions of processing conditions and technology.Pure kish represents sp ²the high-bulk-density of-hydridization carbon, example is found in carbon goods as described in this article.The existence in hole by apparent density from the about 2.23g/cm of this theoretical maximum ³reduce.Most of carbon and graphite product, comprise for the production of NF ₃and F ₂routine and disclosed carbon anode, there is about 1.5g/cm ³to 1.9g/cm ³apparent density.

Although the not ASTM standard test of the porosity to carbon material at present, several technology known in the art are to be conventionally suitable for.For example, can use respectively the data of Washburn equation and Brunauer-Emmett-Teller theoretical analysis mercury porosimetry and gas adsorption.Use mercury porosimetry, by conjunction with or the synthetic carbon of the major part of sintering carbon dust manufacture and graphite product to show percentage of open area be approximately 8% to approximately 20%.Report in the literature, for given carbon material, must show that the higher density of the overall porosity reducing is also corresponding to lower percentage of open area and less aperture (Properties and Characteristics of Graphite, R.G.Sheppard, Dwayne Morgan, D.M.Mathes, D.J.Bray write, POCO Graphite, Inc., 2002).

Be not subject to concrete theoretical constraint, porosity reduces long-pending reduction of accessible surface that is considered to cause liquid electrolyte.Believe by reducing this accessible surface and amass and eliminate ionogen holding back in aperture, will minimize CF ₄formation.

In one embodiment, the invention provides the method for producing nitrogen trifluoride or fluorine, described method comprises: use the electrolytic anode that comprises parallel orderly anisotropic carbon (for example mesocarbon, for example carbonaceous mesophase spherules) to carry out electrolytical electrolysis, to obtain nitrogen trifluoride or fluorine.For example, described anode can have up to approximately 70,000cm ²or larger effective (active) geometrical surface.The in the situation that of carbonaceous mesophase spherules, described carbonaceous mesophase spherules can be the carbonaceous mesophase spherules that waits static pressure compacting.In one embodiment, described anode is only by molded and form and do not comprise tackiness agent or other additive from the carbonaceous mesophase spherules of sintering and carry out anode described in molded or sintering.Described carbonaceous mesophase spherules is not also preferably by greying.In one embodiment, the anode of being made up of molded carbonaceous mesophase spherules is highdensity, for example density 1.7g/cm ³or higher, and porosity is less than approximately 20%, or be more preferably less than approximately 15%.In addition, described carbonaceous mesophase spherules can have the mean particle size of diameter from about 1-5 micron.

In another embodiment, the invention provides the method for producing nitrogen trifluoride or fluorine, described method comprises that the electrolytic anode that use comprises needle coke carries out electrolytical electrolysis.Described needle coke can combine with suitable tackiness agent, and described tackiness agent can contain a small amount of oxygen in precursor, and for example bituminous cement or the centre of height aromatics form shape pitch mutually.In addition, described anode can, by being less than 50 microns or be more preferably less than the particle of 20 microns and form, can have the 1.6g/cm of being greater than ³, or more preferably greater than 1.7g/cm ³and be most preferably greater than 1.8g/cm ³density.Described anode is preferably baked to the not temperature higher than approximately 1600 ℃.Needle coke in this embodiment can also be replaced by for example pod shape coke of other parallel orderly coke.In another embodiment, but described coke or tackiness agent can be replaced by phase coke in the middle of middle phase, initial stage or pitch or the amorphous middle shape pitch that forms mutually.

By using carbon according to the invention as anode material, compared with traditional extrusion molding carbon anode, may produce more highly purified nitrogen trifluoride and fluorine, wherein CF ₄seldom or significantly reduce.For example, described method can be created in the CF in pure nitrogen trifluoride or fluorine product gas ₄be less than 100ppm, be preferably less than the CF of 75ppm ₄, even more preferably less than the CF of 50ppm ₄.Selectivity in the electrolytic process of described production nitrogen trifluoride or fluorine can be 70% or higher, preferably 80% or higher.Suitable ionogen can be selected by those of ordinary skill in the art.In order to produce nitrogen trifluoride, described ionogen can be for example binary electrolyte or ternary electrolyte.Binary electrolyte can comprise HF and NH ₄f, or other suitable binary electrolyte known in the art.Ternary electrolyte can comprise HF, NH ₄f and one of following: KF, LiF, CsF etc., or other suitable ternary electrolyte known in the art.For example, ternary electrolyte composition can comprise about 35-45wt%HF, about 15-25wt%NH ₄f and about 40-45wt%KF.In order to produce fluorine, described ionogen can be binary electrolyte, for example, comprise HF and KF.

Described nitrogen trifluoride method and fluorine method can be carried out under suitable condition and Operating parameters, and described processing parameter comprises temperature and current density, is selected by those of ordinary skills.For example, nitrogen trifluoride can be at temperature and the highest about 250mA/cm of about 120-140 ℃ ²current density under produce.Fluorine can be at temperature and the highest about 350mA/cm of about 80-90 ℃ ²current density under produce.

In another embodiment, the invention provides the electrolyzer of producing nitrogen trifluoride or fluorine, described electrolyzer comprises the anode, negative electrode and the electrolyte composition that contain parallel orderly anisotropic carbon, and described electrolyte composition comprises HF, optional KF and optional NH ₄f.Move described electrolyzer and there is seldom or do not have CF to produce ₄the high-purity nitrogen trifluoride or the fluorine that pollute.In exemplary embodiment, described anode is by forming from the carbonaceous mesophase spherules of the static pressure compactings such as sintering.In the exemplary embodiment of another kind, described anode is made up of the carbonaceous mesophase spherules of isostatic mold system and optional resol sintering aid.In the exemplary embodiment of another kind, described anode for example, by forming by the needle coke of height aromatics tackiness agent combination and showing low porosity (being less than 20% porosity) and density exceedes 1.7g/cm ³, form by isostatic mold system.

Accompanying drawing explanation

The present invention gets the best understanding by reference to the accompanying drawings in the time reading from following detailed description.Emphasize, according to convention, the various features of accompanying drawing are not pro rata.On the contrary, for the sake of clarity, the size of various features zooms in or out arbitrarily.Described accompanying drawing comprises following figure:

Fig. 1 has shown two figure: (a) mesocarbon ball and the cross section that (b) penetrates the middle phase ball showing in (a);

Fig. 2 is the cross-sectional view that can be used for a kind of electrolyzer embodiment of the present invention;

Fig. 3 is the cross-sectional view that can be used for another kind of electrolyzer embodiment of the present invention; With

Fig. 4 is the X-ray diffracting spectrum that can be suitable for the mesocarbon that forms anode of the present invention.

Embodiment

Provide the present invention for using anode production of high purity in the next life nitrogen trifluoride and the fluorine that comprise parallel orderly anisotropic carbon.Particularly, the method of producing nitrogen trifluoride or fluorine comprises that the electrolytic anode that comprises mesocarbon, carbonaceous mesophase spherules, needle coke or other parallel orderly anisotropic carbon by use carries out electrolytical electrolysis, obtains nitrogen trifluoride or fluorine and CF with highly selective ₄amount reduce or very little.

While use in this article, " anode " refers to the electrochemical activity part of electrode, in the time applying electric current to described groove, generates nitrogen trifluoride or fluorine in described groove.

While use in this paper and claims, term " comprises " and " comprising " is comprising property or open, does not get rid of other element of not enumerating, composition component or method steps.Therefore, term " comprise " and " comprising " forgive more restrictive term " substantially by ... composition " and " by ... form ".Unless otherwise indicated, otherwise all values providing is in this article including until the end points providing comprising described end points, and the integral part of composition or the value of component represent by weight percent or the % by weight of every kind of composition in described composition.

parallel orderly anisotropic carbon

Provide the present invention for using anode production of high purity in the next life nitrogen trifluoride and the fluorine that comprise parallel orderly anisotropic carbon or coke.Anode for the production of nitrogen trifluoride or fluorine is made up of parallel orderly anisotropic carbon, for example carbonaceous mesophase spherules (or MCMB) or needle coke.While use in this article, " parallel orderly anisotropic carbon " or " parallel orderly anisotropy coke " is intended to comprise a class carbon, it is contrary with random layering carbon, concentric layering (onion sample) carbon, decolorizing carbon or unordered hyaloid carbon, shows the territory of substantially parallel orderly or layering.Parallel orderly anisotropic carbon or coke can comprise needle coke, pod shape coke, mesocarbon, initial stage mesocarbon and carbonaceous mesophase spherules, for example, as J.Speight, Handbook of Petroleum Product Analysis, John Wiley & Sons, 2002 define.

While use in this article, " mesocarbon (mesophase carbon) " or " mesocarbon (mesocarbon) " be derive from the optically anisotropic of meltability organic compound can graphitized carbon phase.Needle coke and relevant parallel orderly anisotropic carbon are considered to " the middle phase " of carbon sometimes, although these two terms often refer to the carbon of the different physical form that show similar microstructure character.Mesocarbon can be taked small-particle, the form that is often called carbonaceous mesophase spherules and optical isotropy material separation.Therefore, mesocarbon is intended to comprise the carbon with optical anisotropy phase.In other words,, when for example, in the lower observation of polarizing microscope (using the opticmicroscope of polarized light), described carbon shows optical anisotropy.

While use in this article, " needle coke " is coke optically anisotropic, needle-like, its comprise orderly, parallel layer or carbon or meet " Recommended Terminology for the Description of Carbon as a Solid; " IUPAC, Pure & Appl.Chem., Vol.67, No.3,473-506 page, any carbon of the needle coke proposing in 1995 definition.Be appreciated that by grind or size reduce come physics change needle coke it can not be got rid of from this definition, even if granularity approaches 1 micron.

In exemplary embodiment, described anode is mainly made up of parallel orderly anisotropic carbon.While use in this article, " mainly " shows that the amount of this component is higher than compositions related any other component, and for example, described anode is parallel orderly anisotropic carbon to a great extent or only.In other words, any other component of described parallel orderly anisotropy carbon ratio forms the major part of described anode more.Particularly, described anode can comprise at least 40%, at least 50%, at least 60%, at least 75%, at least 90%, at least 95% or at least 99% parallel orderly anisotropic carbon.In exemplary embodiment, described anode is substantially pure parallel orderly anisotropic carbon.In other words, the coke of the parallel orderly anisotropic carbon a small amount of with containing by chance some or carbonization pitch or anode are contrary, and described anode is most of or be all parallel orderly anisotropic carbon substantially.In addition, contrary with tackiness agent known in the art, filler or other auxiliary agent, described anode major part is parallel orderly anisotropic carbon.

In one embodiment, described anode is mainly made up of mesocarbon, for example carbonaceous mesophase spherules.For example, described anode is mesocarbon to a great extent or only.In other words, mesocarbon forms the major part of described anode more than any other component.Particularly, described anode can comprise at least 40%, at least 50%, at least 60%, at least 75%, at least 90%, at least 95% or at least 99% mesocarbon.In exemplary embodiment, described anode is substantially pure mesocarbon.In other words, the coke of some a small amount of mesocarbons or carbonization pitch or anode are contrary with containing by chance, and described anode is most of or be all mesocarbon substantially.In addition, contrary with tackiness agent known in the art, filler or other auxiliary agent, described anode major part is mesocarbon.

In one embodiment, formed by carbonaceous mesophase spherules for the production of the anode of nitrogen trifluoride or fluorine.Fig. 1 has described the example of carbonaceous mesophase spherules, comprises phase ball 100 and the drawing of (b) passing the cross section 100a of middle phase ball in the middle of (a).Middle phase ball 100 can comprise two utmost points 110, the trace 120 of lamella direction and the disc edge 130 of middle phase ball 100.Although the carbonaceous mesophase spherules that Fig. 1 shows has laminated structure, the carbonaceous mesophase spherules of manufacturing by other approach can have other shape.For example, described carbonaceous mesophase spherules can be spherical form, maybe can have elongated or irregular shape.

Described microballoon can have for example diameter 1-100 μ spherical diameter m) up to approximately 100 μ m(.In exemplary embodiment, described carbonaceous mesophase spherules can have the mean particle size of diameter from about 1-5 micron.For example, described carbonaceous mesophase spherules can have from 1,000 to 4,000m ²the high-specific surface area of/g.Similarly, in another embodiment, formed by needle coke and tackiness agent for the production of the anode of nitrogen trifluoride or fluorine, 20 microns of described needle coke and tackiness agent maximum particle sizes, or more preferably granularity is less than 10 microns, and density is greater than 1.6g/cm ³or more preferably greater than 1.7g/cm ³, and be less than 15% porosity or be more preferably less than 10% porosity.Described needle coke and tackiness agent can be molded as required shape.

Fig. 4 has described X-ray diffraction (XRD) spectrum of the mesocarbon of suitable type.There is the spike of cue mark at top from ZnO, and it adds as internal calibration standard during analyzing, and is not the part of carbon anode.Obviously, in XRD, there is no graphite peaks, show not exist the graphite of well-crystallized.Described XRD has only shown a broad peak between 25-30 °, shows the Graphene type carbon plane that record is poor.There is no peak at lower angle place, show that described mesocarbon is not containing any well-crystallized or good graphite or other crystalline structure being shaped.

In another embodiment, described anode is mainly made up of with suitable tackiness agent combination parallel orderly anisotropy coke, for example needle coke, produces the porosity of minimum in end article.Aromatics pitch, mesophase pitch, coal coke oily bitumen etc. are preferred tackiness agents, and more not preferred containing for example poly-furfural alcohol of oxygen tackiness agent or resol.In all cases, described anode does not have greying.

For instance, by heated asphalt matter precursor for example plastics, synthetic asphalts, tensio-active agent or the small molecule material of coal tar, coal-tar pitch, black petroleum products, clarified oil (decant oil), pyrolysis residual oil, petroleum pitch, letex polymerization, cause that low molecular material is transformed into macromolecular material by polycondensation repeatedly, parallel orderly anisotropy coke be can produce, needle coke and mesocarbon or carbonaceous mesophase spherules comprised.Parallel orderly anisotropy coke and mesocarbon can also be from synthetic generations of for example naphthalene of aromatic molecules.For example, described precursor material can be in 200-600 ℃ (depending on precursor) lower heating, to generate " middle phase " raw (green) carbon particles or green compact (greenbody).Isotropy carbon can optionally be removed by solvent extraction, to produce pure mesocarbon.Described raw carbon particles is then molded or be pressed into the shape of wanting, and then can toast with sintering and remove volatile matter.It is known producing the whole bag of tricks of mesocarbon, for example in world patent WO2006/109497 and Korean Patent 10-2006-0138731 instruction and describe those.

Needle coke, mesocarbon, the parallel layering anisotropy coke of carbonaceous mesophase spherules or other form can be produced or be obtained from any suitable supplier or dealer, and for example office is at the CR of Korea S Tech, office is at the MWI of New York Rochester, office is at the Graftech of Ohio Parma International, office is at the Y-carbon of Pennsylvania Bristol, office is at the Timcal of Switzerland Bodio Graphite and carbon, Ltd., office is at the Qinhuangdao of Chinese Tangshan Huarui Coal Chemicals Co., Ltd., office is at the Asbury of New Jersey Asbury Carbons, Inc., office is at the MTI of California Richmond Corporation, office is at the Linyi of Shandong Province of China Gelon New Battery Materials Co., Ltd, office is at the Osaka of Osaka, Japan Gas Chemicals Co., Ltd, office is at the SGL of German Wiesbaden Carbon SE, office is at the China of Kao-hsiung Steel Chemical Corporation, office is at the ROC of Japanese Amagasaki, SEC Carbon, Ltd., or other supplier who produces anisotropic carbon.

Described parallel orderly anisotropic carbon is used for manufacturing described anode.For example, described anode can be from the adulterant of parallel orderly anisotropy coke and suitable bituminous cement or molded from carbonaceous mesophase spherules.Described anode can use any suitable mould known in the art and molding technique to carry out molded.In one embodiment, described coke/pitch adulterant or carbonaceous mesophase spherules by etc. static pressure compacting (for example isostatic cool pressing compacting), to form anode.Isostatic cool pressing compacting (CIP) is for example included in substantially under room temperature, to mould exert pressure (, using fluid as the instrument of exerting pressure to mould at the temperature of about 20-25 ℃).Shaping, described parts can be optionally in mould or heat under impressed pressure, to soften described pitch or mesocarbon simultaneously.After mould discharges, described parts can or can not experience heating or sintering.In exemplary embodiment, molded shape is sintering.If use such as pitch of tackiness agent, described tackiness agent will soften, and then fusing was filled the gap between coke particle, so that perfect aspect is kept together before carbonization.By contrast, due to the character of carbonaceous mesophase spherules, carbonaceous mesophase spherules can for example, from sintering under low temperature (about 400-600 ℃).Refer to that from sintering described microballoon is pressed and merges and sintering or heating, but described in molded and sintering, anode component does not need tackiness agent, resin, filler etc.In one embodiment, described anode is only by molded and form from the carbonaceous mesophase spherules of sintering.Described parallel orderly anisotropic carbon or mesocarbon can also use other technology known in the art to be shaped, and described technology includes but not limited to wait static pressure compacting, single shaft compacting or extrusion molding.

In another embodiment, without oxidation or except oxidation, can add at least one stabilization aid or sintering aid, for example resol is stablized the parallel orderly anisotropic carbon of described shaping.Described stabilization aid can contain aerobic or sulphur.For example, can provide a small amount of stabilization or sintering aid, for example resol, to introduce oxygen, when described oxygen heats described shape during carbonization process, the effect of playing crosslinked described parallel orderly anisotropic carbon and giving deformation resistance.Described anode can comprise 10% or still less, 8% or still less, 5% or still less, 3% or still less or 1% or described stabilization or sintering aid still less.

One preferred embodiment in, described tackiness agent, hole filler or sintering aid comprise aromatics pitch, aromatics synthetic asphalts or in the time of heating, produce other known carbon precursor of graphitized carbon.

The green compact that are shaped can optionally for example be oxidized by being exposed at elevated temperatures air, to stablize physical form and to reduce or eliminate the distortion between follow-up heating period.In other words, described green compact can be by heating and be oxidized in air or oxygen-containing gas.Known in the art for the conditions suitable that is oxidized mesocarbon shape.The whole bag of tricks of oxidation-stabilized mesocarbon goods has been described in document; for example F.Fanjul, M.Granda, R.Santamaria and R.Menendez, " On the chemistry of the oxidative stabilization and carbonization of carbonaceous mesophase. " Fuel.2002Nov; 81(16): 2061-70.

Sintering processes also can then be carried out fine and close thermal treatment, for example, at the temperature of about 500-1500 ℃.The density of molded anode or apparent density can be from about 1.60-1.65g/cm ³low density.In one embodiment, the anode for example, being formed by parallel orderly anisotropic carbon (carbonaceous mesophase spherules) preferably has about 1.7g/cm ³or higher high-density.The anode that comprises parallel orderly anisotropic carbon described in can also be preferably has low porosity (for example, be less than 20% porosity, be preferably less than 15% porosity, and be more preferably less than 10% porosity).

Described anode can have and will be generally used for any suitable sizes and shape of electrolyzer known in the art.For example, described anode blade can be for being about 1.5 to 2.5 feet, wide about 6-10 inch and thick about 1-3 inch.Described anode blade can be plane and/or can comprise other surface characteristic, comprise groove, protuberance, recessed, pyramid etc., to improve in surface-area or industry for generation of other known features with the anode blade that geometrical surface expands, for example, as U.S. Patent No. 5,290,413 and 4,511, described in 440.Described anode can have any suitable effective surface area.The shape of described anode and physical features can form during molding process, or whenever they can being machined after using conventional manufacturing technology formation green compact.

Anode of the present invention is not preferably by greying.Graphited carbon material, comprises needle coke, carbonaceous mesophase spherules and conventional extrusion molding carbon anode, conventionally toasts at molded, extrusion molding or after being otherwise shaped, to remove volatile materials and sintering or fixed described main body carbonaceous material.This baking can occur at the temperature up to approximately 1300 ℃.At higher temperature, be conventionally greater than 1500 ℃ of types that still depend on carbon material, described carbon starts to form larger graphite territory, and resistance reduces.This is known as greying.It is all partially or completely graphited being permitted eurypalynous carbon goods.For the production of NF ₃and F ₂anode preferably not by greying, for example, because this can cause poor performance in electrolyzer (, graphite corroded by fluorine product and owing to being embedded and disintegration by various components in ionogen).

Compared with conventional extrusion molding anode, the anode of the present invention that comprises parallel orderly anisotropy coke (comprising needle coke and carbonaceous mesophase spherules) provides many benefits, for example: (1) reduces CF ₄form, thereby more highly purified NF is provided ₃and F ₂; (2) manufacturing time is shorter (for example,, at F ₂in production, do not need other separating step); (3) manufacture the required mechanical workout of final anode less; (4) manufacturing cost of anode reduces, and this is converted into NF ₃and F ₂production cost reduce; (5) anti-polarizability is improved; (6) can under higher current density, move; (7) work nest loss of voltage.

By forming anode with parallel orderly anisotropic carbon, compared with traditional extrusion molding anode, may produce more highly purified NF ₃and F ₂, and CF ₄seldom or significantly reduce.For example, described method can be created in pure NF ₃or F ₂in CF ₄be less than 100ppm(by volume), be preferably less than 75ppm(by volume), even more preferably less than 50ppm(by volume) and be most preferably less than 25ppm(by volume).Therefore, 25ppm equals 25 CF ₄molecule/1,000,000 NF ₃molecule or 25ml CF ₄/ hundred ten thousand ml NF ₃.Also preferably producing NF ₃or F ₂method in high selectivity, and for NF ₃or F ₂, can be about 70% or higher, preferably 80% or higher, even more preferably 85% or higher, or even 90% or the selectivity of high-magnitude more.

The carbon goods of being made up of parallel orderly anisotropy coke, comprise needle coke and carbonaceous mesophase spherules anode, can also not mix the wetting property that shows improvement under traditional wetting aid.Producing NF ₃or F ₂during this time, traditional carbon anode, because for example fluorine of material that they and ionogen and electrochemistry produce interacts, often produces low-energy surface.Anode surface is by electrolytical wetting variation, causes the higher and polarization tendency of groove operating voltage to increase.For example, the anode that geometrical surface is known is used in 70mA/cm ², or more preferably 180mA/cm ²current density under, at 130 ℃ or approach at 130 ℃ by consisting of 40wt%HF, 18wt%NH ₄the ternary KF-HF-NH of F and 42wt%KF ₄f molten salt electrolyte electrolysis at least 150 hours, produces NF ₃.Shifting out and be cooled to from described melt after about room temperature, described anode can wash with water and without the physics described effective surface of polishing, and dry.Then can use known surface tension ink or marker (" dyne pen ") to measure the surface energy of described effective surface.

Find that anode of the present invention is at 70mA/cm ²after lower operation exceedes 150 hours, at least 30% effective surface, demonstrate 65 dynes per centimeter or higher high surface energy.In other words the anode of the present invention that, comprises parallel orderly anisotropic carbon does not need wetting agent just can within the time length extending, show the wettability of maintenance.By contrast, conventional extrusion molding carbon anode show lower than the surface of this value can, for example, often lower than 55 dynes per centimeter and need wetting agent to improve wettability.For example, P.Hough, " Fluorine Production and Use-An Overview ", the Electrochemistry in the Preparation of Fluorine and its Compounds writing at W.Childs and T.Fuchigami, The Electrochemical Society, in 1997, be proposed in blast blending in described carbon and improve wetting.Similarly, U.S. Patent No. 7,608,235 utilize to traditional carbon anode interpolation MgF ₂or AIF ₃improve wetting.But, increase cost to described anode such as these additive, and may pollute ionogen and anode producing apparatus.

Be surprised to find that, different from other carbon form, form the parallel orderly anisotropic carbon of described anode, for example carbonaceous mesophase spherules, do not need so wetting additive just can resist the formation of low-energy surface, cause groove operating voltage compared with conventional carbon anode to reduce and can under higher current density, move.Lower bath voltage causes manufacturing NF ₃or F ₂current consumption reduces during this time, and simultaneously current density increase is allowed from given groove and produced more NF ₃or F ₂.In addition, from anode composition, remove traditional wetting aid and reduced the pollution in cost and manufacturing processed.

Having carried out other trial is improved conventional extrusion molding carbon anode material.U.S. announcement No.2010/0193371 has described and on vitreous carbon, has used conductivity diamond film having.The U.S. announces No.2010/0252425 and proposes to use mesocarbon as filler or tackiness agent for having the better carbonaceous component of specifying X-ray diffracting spectrum.Also propose that height porosity is desirable, and specified carbonaceous material needs conductivity diamond coating using good as anode performance.The present invention does not need expensive diamond film having.On the contrary, the present invention has determined that the parallel orderly anisotropy carbon material of appropriate preparation is favourable as anode material.Described parallel orderly anisotropic carbon can show low porosity, and for example, porosity is less than 15% or be less than 10%.In addition, parallel orderly anisotropy carbon material of the present invention do not show the U.S. announce specify in No.2010/0252425, need crystallization, the good graphite being shaped or the diffracting spectrum of other crystallization phases.As mentioned above, the broad peak of parallel orderly anisotropy carbon material of the present invention between 25-30 °, not containing definite diffraction peak, show that described parallel orderly anisotropic carbon does not contain graphite or other crystalline structure of any good shaping.

electrolyzer

In one embodiment, the invention provides the electrolyzer of producing nitrogen trifluoride or fluorine, described electrolyzer comprises: the anode, negative electrode and the electrolyte composition that comprise parallel orderly anisotropic carbon (for example carbonaceous mesophase spherules).Move described electrolyzer to produce nitrogen trifluoride or fluorine.The method that forms nitrogen trifluoride or fluorine comprises and for example uses electrolyzer to carry out electrolysis to ionogen.Those of ordinary skills can select any suitable electrolyzer known in the art.

For example, described electrolyzer can comprise by the wall of ionogen inertia being formed and for holding electrolytical container or shell.Described anode can be connected with direct supply with negative electrode.For example, described electrode can be placed in described container to immerse in ionogen, makes in the time applying electric current, and described electrode becomes Anodic and negative electrode.During electrolysis, in the time generating fluorine or nitrogen trifluoride at anode place and generate hydrogen at negative electrode place, can arrange that partition wall or separation baffles mix with hydrogen to prevent fluorine or nitrogen trifluoride.Conventionally, described partition wall can vertically be arranged.

Any material can be for constructing the assembly of described groove, as long as described material is durable in the time being exposed to the etching condition of groove.For the useful materials of cell body and separation baffles be iron, stainless steel, carbon steel, nickel or nickelalloy for example deng, this is well known by persons skilled in the art.The building material of negative electrode has no particular limits, as long as described negative electrode is made up this object useful material for example nickel, carbon steel and iron of well known by persons skilled in the art.

Fig. 2 has shown the schematic diagram of an example of electrolytic cell equipment, and described equipment can be suitable for producing nitrogen trifluoride of the present invention or fluorine.Described electrolytic cell equipment can comprise electrolyzer 25, and it has cell body 26,

side

51,52 and upper cover or upper covering 28.Described groove 25 is separated into anolyte compartment 17 and cathode compartment 18 by the gas partitions baffle plate 19 of vertically arranging and dividing plate 22.Anode 20 is arranged in anolyte compartment 17, and negative electrode 21 is arranged in cathode compartment 18.Ionogen 23 is arranged in electrolyzer 25, and the level 27 of ionogen 23 is more than 53 ionogen 23 height of the basal surface of described electrolyzer 25.The level of ionogen 23 can be determined by level indicator 31, and described level 27 can be controlled between for example high-level setting point 32 and low level set point 33.In addition, the composition of ionogen 23 can sample by electrolyte sample port 41.

Electrolyzer 25 can comprise feed-

pipe

12 and 16, for raw material or the component of feeding composition ionogen 23.Conventionally, feed-

pipe

12 and 16 provides in cathode compartment 18.Anolyte compartment 17 can have anodic product outlet pipe 11, for example, for extract product gas mixture (NF out from electrolyzer 25 ₃or F ₂).Cathode compartment 18 can have cathode product outlet pipe 13, for from electrolyzer 25 withdrawing gass.Electrolyzer 25 can comprise Temperature Detector 30, temperature control equipment 29 etc., to control suitable processing parameter during electrolysis.

If needed, electrolyzer of the present invention can also comprise other parts, for example, sweeping gas tube stub in anode and cathode compartment 17,18.Purge gas source, for example nitrogen, can not show with the anolyte compartment of electrolyzer 25 17 and/or cathode compartment 18() be connected, so that the purging of electrolyzer 25 to be provided for security reason, thereby be provided for the means that blow off of choked pipe, or be provided in other respects described entrance and exit pipe and pipeline and other instruments and suitably bring into play function.

In the time that described groove 25 moves, at anode, 20 places generate containing nitrogen trifluoride or fluoro-gas, and generate hydrogen at negative electrode 21 places.For example, when for the production of nitrogen trifluoride, the gas generating in anolyte compartment 17 can comprise nitrogen trifluoride (NF ₃), nitrogen (N ₂) and fluorine (F ₂).For example, when for the production of fluorine, the gas generating in anolyte compartment 17 can comprise fluorine (F ₂).In addition, HF can optionally all exist in the gas that leaves anolyte compartment 17 and cathode compartment 18.

Fig. 3 has shown the cross sectional view of the electrolyzer 25 similar to the electrolyzer of Fig. 2 demonstration, and the groove 25 that just Fig. 3 shows comprises only an anolyte compartment 17 and a cathode compartment 18.Anolyte compartment 17 has an anode 20 and cathode compartment 18 has a negative electrode 21.Fig. 2 is with in 3, similarly unit number is identical.

The groove 25 that Fig. 3 shows comprises current controller 39, it supplies induced current by anodic current joint 14 anode 20 with by cathodic current joint 15 to negative electrode 21, and the level of described electric current can increase or reduce in the target zone of the control process regulation of operator or electrolyzer 25.

Although describe herein and show that concrete electrolyzer 25, described groove 25 can comprise any groove design known or Future Development.For example described groove type can be included in Fluorine, The First Hundred Years, and R.E.Banks, D.W.A.Sharp and J.C.Tatlows write, Elsevier Sequoia, Netherlands, the ICI fluouine cell of describing in 1986. design.

nF ₃ or F ₂ production

Described electrolyzer may can be produced NF ₃, F ₂or the two, and method is substantially similar.Produce NF ₃or F ₂between little difference comprise and use different electrolyte solution and different operational conditionss.In other respects, these two kinds of methods are substantially consistent.Described groove is almost interchangeable, and the anode using in the two is identical parallel orderly anisotropy carbon back anode material as described herein.As mentioned above, in these two kinds of methods, all produce undesired by product CF ₄.Unique difference is CF ₄and F ₂can pass through fractionation by distillation, and CF ₄and NF ₃almost can not separate.In both situations, preferably do not produce CF ₄, because separation subsequently needs extra procedure of processing.

(a) NF ₃ production

Nitrogen trifluoride can the application of the invention electrolyzer and the ionogen being formed by any known electrolyte that can be used for manufacturing nitrogen trifluoride produce.For example, suitable ionogen can comprise ternary electrolyte (for example Neutral ammonium fluoride (NH ₄f), Potassium monofluoride (KF) and hydrogen fluoride (HF) containing HF fused salt).In addition, described molten salt electrolyte can also contain other additive, for example cesium fluoride, lithium fluoride etc.In exemplary embodiment, described ternary electrolyte composition can comprise about 35-45wt%HF, about 15-25wt%NH ₄f and about 40-45wt%KF.Described concentration can be by NF ₄fmol% and HF ratio represent.HF ratio is defined by equation below:

HF ratio=(the titratable HF mole number to neutral pH)/(NH ₄f (mole number)+KF (mole number)).

Described HF ratio represents the ratio of solvent and salt in ionogen.In use some embodiments of ternary electrolyte, can be preferably with NH ₄f concentration is within the scope of 14wt% and 24wt%, more preferably between 16wt% and 21wt%, most preferably between 17.5wt% and 19.5wt%, preferably between 1.3 and 1.7, more preferably between 1.45 and 1.6, most preferably between 1.5 and 1.55, move described electrolyzer with HF ratio.In other embodiments, described preferred concentration range can change according to for example impressed current of operational conditions and electrolyte temperature.Expect to select concentration range according to the balance between the high-level efficiency of electrolyzer and safety operation.

The invention is not restricted to any specific electrolyte composition, herein reference example as described in ternary electrolyte any description just for convenience's sake.Be appreciated that for the manufacture of NF ₃any ionogen replaceable in described description, and comprise in the present invention.

Described nitrogen trifluoride electrolytic process can be at conditions suitable known in the art, comprise under temperature and current density and carrying out.For example, nitrogen trifluoride can be in the temperature of about 100-140 ℃, preferred about 120-130 ℃ with up to about 250mA/cm ²current density under produce.

(b) F ₂ production

The in the situation that of fluorine, fluorine is produced ionogen can comprise binary electrolyte.For example, described binary electrolyte can comprise fluorinated hydrogen (HF) fused salt of HF and KF.In addition, the described HF molten salt electrolyte that contains can also contain other additive, for example Neutral ammonium fluoride, cesium fluoride, lithium fluoride etc.

In order to reach the balance between high-level efficiency and the safe operation of electrolyzer, HF ratio can be to above-described similar, and can be defined as:

HF ratio=(the titratable HF mole number to neutral pH)/(KF (mole number)).

The invention is not restricted to any specific electrolyte composition, this reference example as described in binary electrolyte any description just for convenience's sake.Be appreciated that and can be used for manufacturing F ₂any ionogen replaceable in described description, and comprise in the present invention.

Described fluorine electrolytic process can be at conditions suitable known in the art, comprise under temperature and current density and carrying out.For example, fluorine can be the temperature of about 80-90 ℃ with up to 250mA/cm ²current density under produce.

embodiment

mesocarbon anode production NF for embodiment 1- ₃

Consist of 40wt%HF, 19.5wt%NH ₄the electrolysis in the groove of 250ml laboratory of the ternary electrolyte of F and 40.5w%KF, to produce NF ₃.Negative electrode is carbon steel, and described groove is equipped with Cu/CuF ₂reference electrode.Anode is the carbonaceous mesophase spherules that waits static pressure compacting, and useful area is 2.25cm ².Anode and the utilization of cathode product gas extend to below liquidus baffle plate keeps separating.Described groove is 130 ℃ of operations.It is 70mA/cm that described electrolysis adds current density outside ²constant current mode under carry out.Make described groove reach stable state and utilize gas chromatographic analysis anodic gas afterwards.

Based on pure NF ₃, described anodic gas contains 71ppm CF ₄.To NF ₃selectivity be 70.7%, be defined as:

NF ₃selectivity=(NF of generation ₃mole number)/(NF of generation ₃the N of mole number+generation ₂mole number).

At 70mA/cm ²lower exceed 150 hours as anode operation after, described anode takes out from ionogen, and cool to room temperature washes with water and the effective surface that need not wear and tear, and fully wetting by 70 dynes per centimeter inks (high surface energy ink) on approximately 50% described surface, show that surface can exceed this value.Residual surface is wetting by 58 dynes per centimeter inks.

comparative example 1-conventional anode

Repeating the electrolysis of describing in embodiment 1, is that the conventional extrusion molding carbon anode of described anode replaces.Efficient anode area remains on 2.25cm ².Anodic gas contains 341ppm CF ₄(based on pure NF ₃) and to NF ₃selectivity be 89.9%.Described anode takes out after operation exceedes 150 hours, and carries out the test identical with embodiment 1, and described anode is only had 50 dynes per centimeter inks and do not soaked by the ink of any more high surface energy during this period.

mesocarbon anode production NF for embodiment 2- ₃

Consist of 37.5wt%HF, 18.3wt%NH ₄the electrolysis in the groove of 250ml laboratory of the ternary electrolyte of F and 44.2wt%KF, to produce NF ₃.Negative electrode is carbon steel, and described groove is equipped with Cu/CuF ₂reference electrode.Anode is the carbonaceous mesophase spherules that waits static pressure compacting, and useful area is 2.25cm ².The TEFLON baffle plate that anode and the utilization of cathode product gas extend to below liquidus keeps separating.Described groove moves at 139 ℃.It is 100mA/cm that described electrolysis adds current density outside ²constant current mode under carry out.Make described groove reach stable state and utilize gas chromatographic analysis anodic gas afterwards.Based on pure NF ₃, described anodic gas contains 20ppm CF ₄.To NF ₃selectivity be 77.6%.

comparative example 2-conventional anode

Repeating the electrolysis of describing in embodiment 2, is that the conventional extrusion molding carbon anode of described anode replaces.Efficient anode area remains on 2.25cm ².Anodic gas contains 70ppm CF ₄(based on pure NF ₃) and to NF ₃selectivity be 87.0%.

low density mesocarbon anode production NF for embodiment 3A- ₃

There is HF, NH ₄the electrolysis in the groove of 250ml laboratory of the ternary electrolyte of F and KF, to produce NF ₃.Negative electrode is carbon steel, and described groove is equipped with Cu/CuF ₂reference electrode.Anode is low density (1.60g/cm ³) etc. the carbonaceous mesophase spherules of static pressure compacting, useful area is 2.25cm ².The Teflon baffle plate that anode and the utilization of cathode product gas extend to below liquidus keeps separating.Described groove moves at 130 ℃.It is 70mA/cm that described electrolysis adds current density outside ²constant current mode under carry out.Make described groove reach stable state and utilize gas chromatographic analysis anodic gas afterwards.Based on NF ³, described anodic gas contains 61ppm CF ₄.To NF ₃selectivity be 82.3%.The surface energy of evaluating as described in Example 1 described anode, described anode is wetting by 70 dynes per centimeter inks on about 40% surface, and remaining area is wetting by 58 dynes per centimeter inks.

high-density mesocarbon anode production NF for embodiment 3B- ₃

Repeating the electrolysis of describing in embodiment 3A, is described anode high-density (≤1.70g/cm ³) etc. the carbonaceous mesophase spherules of static pressure compacting replace.Described anodic gas contains <25ppm CF ₄(based on pure NF ₃).To NF ₃selectivity be 84.7%.The surface energy of evaluating as described in Example 1 described anode, described anode is wetting by 70 dynes per centimeter inks on about 40% surface, and remaining area is wetting by 58 dynes per centimeter inks.

comparative example 3A-conventional anode

Repeating the electrolysis of describing in embodiment 3A, is that the conventional extrusion molding carbon anode of described anode replaces.Described anodic gas contains 341ppm CF ₄(based on pure NF ₃).To NF ₃selectivity be 89.9%.Evaluate as described in Example 1 the surface energy of described anode, described anode is still wetting by the ink of any more high surface energy by 50 dynes per centimeter inks.

the conventional anode of the static pressure compactings such as comparative example 3B-

Repeating the electrolysis of describing in embodiment 3A, is that described anode use waits the non-mesocarbon anode of static pressure compacting to replace.The extrusion molding carbon (, based on carbonization coke and pitch rather than mesocarbon) of the similar routine of composition of this anode.Anodic gas contains 212ppm CF ₄(based on pure NF ₃) and to NF ₃selectivity be 88.3%.Evaluate as described in Example 1 the surface energy of described anode, described anode is still wetting by the ink of any more high surface energy by 48 dynes per centimeter inks.

embodiment 4A-uses the anode production NF based on needle coke ₃

Use the anode mainly being formed by needle coke and asphaltic base tackiness agent to repeat the electrolysis of describing in embodiment 1.Described anode has 1.75g/cm ³apparent density and 15% overall porosity.Described anode is not by greying.Described groove is at 70mA/cm ²current density under move.Groove temperature is 130 ℃.The anode potential of duration of test is with respect to Cu/CuF ₂reference is 5.15V, to NF ₃selectivity be 88%, and NF ₃the CF of product ₄content is 30ppm.

embodiment 4B-uses the anode based on needle coke to produce NF under high current density ₃

At 178mA/cm ²current density under repeat in embodiment 4 electrolysis described.Groove temperature is 140 ℃.The anode potential of duration of test is with respect to Cu/CuF ₂reference is 5.47V, to NF ₃selectivity be 88%, and NF ₃the CF of product ₄content is 20ppm.

These results are summarised in following table, the wherein static pressure such as IP=compacting, MCMB=carbonaceous mesophase spherules, LD=low density, and HD=high-density.

Table 1

Table 2

Table 3

comparative example 4-uses the anode production NF based on greying needle coke ₃

Use and form identical anode with embodiment 4B, repeat the electrolysis of embodiment 4B, still described anode by be heated to exceed 2000 ℃ temperature and by greying.Selectivity and CF ₄level is consistent, but described anode fluctuation of service, anode potential 6 and 7V between change.

mesocarbon anode production F for embodiment 5- ₂

In the groove of 250ml laboratory, electrolysis consists of the binary electrolyte of 40wt%HF and 60wt%KF, to produce F ₂.Negative electrode is carbon steel, and described groove is equipped with Cu/CuF ₂reference electrode.Anode is the carbonaceous mesophase spherules that waits static pressure compacting, and useful area is 2.25cm ².Anode and the utilization of cathode product gas extend to below liquidus

baffle plate keeps separating.Described groove moves at 88 ℃.It is 80mA/cm that described electrolysis adds current density outside ²constant current mode under carry out.Described groove steady running, discharges fluorine gas, and bath voltage is 6.4 volts.

comparative example 5-produces F by conventional anode ₂

Repeating the electrolysis of describing in embodiment 5, is that the conventional extrusion molding carbon anode of described anode replaces.Described groove steady running, discharge fluorine gas, but bath voltage is higher, is 7.0 volts.

embodiment 6-produces F with mesocarbon anode under high current density ₂

Repeat the electrolysis of describing in embodiment 5, just use that to hold 25ml electrolytical compared with sulculus.The described mesocarbon anode that waits static pressure compacting has 0.5cm ²useful area.Described groove is at 225mA/cm ²current density under move.Described anode is discharged F ₂gas, steady running under the bath voltage of 6.8 volts.

comparative example 6-produces F under high current density on conventional anode ₂

Repeat the electrolysis of describing in embodiment 6, just anode is conventional extrusion molding carbon anode.Described groove is again at 225mA/cm ²current density under move.Described groove is discharged F ₂gas, but bath voltage is unstable, is 7.7-8.5 volt.

Describe and describe with reference to some concrete embodiment and embodiment although above, the present invention is not intended to be limited to shown details.On the contrary, in the equivalent category of claims and scope and do not deviate from spirit of the present invention, can in described details, make various modifications.For example clearly illustrate that, in the literature, wide in range all scopes of enumerating are included in and in their scope, fall into all compared with close limit in relative broad range.In addition, a kind of feature of embodiment can be included in another kind of embodiment.All publications, patent and other documents of mentioning in the literature is incorporated to herein by reference, just like being individually incorporated to by reference the same herein with their full content for all objects.

Claims

1. the method for producing nitrogen trifluoride or fluorine, described method comprises:

The electrolytic anode that mainly comprises parallel orderly anisotropic carbon by using carries out electrolytical electrolysis, to obtain nitrogen trifluoride or fluorine.

2. method claimed in claim 1, wherein said parallel orderly anisotropic carbon comprises needle coke.

3. the method described in claim 1 or 2, wherein said anode comprises:

At least 60% needle coke; With

Optionally, 0 to 40% tackiness agent.

4. method claimed in claim 3, wherein said anode comprises tackiness agent and described tackiness agent is pitch.

5. the method described in any one in claim 2-4, wherein said anode comprises tackiness agent, and described needle coke and tackiness agent by etc. static pressure be pressed into definite shape.

6. the method described in any one in claim 2-5, wherein said anode comprises tackiness agent, and described needle coke and tackiness agent have the mean particle size that is less than 25 microns.

7. the method described in any one in claim 2-6, wherein said needle coke is not by greying.

8. method claimed in claim 1, wherein said parallel orderly anisotropic carbon comprises carbonaceous mesophase spherules.

9. method claimed in claim 8, wherein said carbonaceous mesophase spherules is the carbonaceous mesophase spherules that waits static pressure compacting.

10. the method described in claim 8 or 9, wherein said carbonaceous mesophase spherules has the mean particle size of about 1-5 micron.

Method in 11. claim 8-10 described in any one, wherein said carbonaceous mesophase spherules is not by greying.

12. methods claimed in claim 1, wherein said parallel orderly anisotropic carbon comprises mesocarbon, and described anode comprises:

At least 40% mesocarbon; With

Optionally, the highest 10% stabilization aid.

Method in 13. claim 1-12 described in any one, wherein said anode has 1.7g/cm ³or higher density.

Method in 14. claim 1-13 described in any one, wherein said anode is by molded and form from the carbonaceous mesophase spherules of sintering and optional sintering aid.

Method in 15. claim 1-14 described in any one, wherein said anode has the highest by approximately 70,000cm ²useful area.

Method in 16. claim 1-15 described in any one, wherein said method is created in pure nitrogen trifluoride or fluorine and is less than 100ppm, is preferably less than the CF of 25ppm ₄.

Method in 17. claim 1-16 described in any one, wherein said method produces nitrogen trifluoride or fluorine, and selectivity is 70% or higher, preferably 80% or higher.

Method in 18. claim 1-17 described in any one, wherein producing nitrogen trifluoride and described ionogen is to comprise HF, NH ₄the ternary electrolyte composition of F and KF, preferably comprises 35-45wt%HF, 15-25wt%NH ₄f and 40-45wt%KF.

Method in 19. claim 1-17 described in any one, wherein producing fluorine and described ionogen is the binary electrolyte composition that comprises HF and KF.

Method in 20. claim 1-18 described in any one, wherein produces the electrolysis at the temperature of about 120-140 ℃ of nitrogen trifluoride and described ionogen.

Method in 21. claim 1-17 and 19 described in any one, wherein produces the electrolysis at the temperature of about 80-90 ℃ of fluorine and described ionogen.

Method in 22. claim 1-21 described in any one, wherein said method is at about 70-250mA/cm ²current density under move.

Method in 23. claim 1-18,20 and 22 described in any one, wherein produces nitrogen trifluoride and described method at about 100-250mA/cm ²current density under move.

24. claim 1-17,19 and 21-22 in method described in any one, wherein produce fluorine and described method at about 120-250mA/cm ²current density under move.

25. electrolyzers for the production of nitrogen trifluoride or fluorine, it comprises:

The anode that comprises parallel orderly anisotropic carbon;

Negative electrode; With

Electrolyte composition, it comprises HF, optional KF and optional NH ₄f,

Wherein move described electrolyzer to produce nitrogen trifluoride or fluorine.

Electrolyzer described in 26. claims 25, wherein said anode is made up of the carbonaceous mesophase spherules from static pressure compactings such as sintering and optional sintering aid.

Electrolyzer described in 27. claims 25, wherein said anode is made up of needle coke and bituminous cement.

Electrolyzer described in 28. claims 27, wherein said bituminous cement and needle coke are being pressed

Before system, first then fusion also grinds.

Electrolyzer in 29. claim 25-28 described in any one, wherein said anode shows maintenance wettability not adding under wetting agent.