KR20140052853A - Anodes for the electrolytic production of nitrogen trifluoride and fluorine - Google Patents

Abstract

The present invention relates to a process for producing nitrogen trifluoride or fluorine in which anodes in an electrolytic cell is produced mainly with anisotropic carbon which contains a needle coke and/or a meso-carbon microbead and is aligned in parallel; and the anodes. Anisotropic carbon anodes which are aligned in parallel minimize CF_4 and improve the purity of the produced nitrogen trifluoride or fluorine. In addition, the anodes are molded, instead of being extruded or machined, to provide an improved anode size and mechanical integrity.

Description

FIELD OF THE INVENTION [0001] The present invention relates to an anode for electrolytic production of nitrogen trifluoride and fluorine,

This application claims the benefit of US Provisional Application Serial No. 61 / 716,259 filed on October 19, 2012 and US Provisional Application Serial No. 61 / 790,810, filed March 15, 2013, This application is a continuation-in-part of U.S. Patent Application No. 13 / 859,263, filed April 9, 2013, claiming priority benefit under §119 (e). The contents of each priority application are incorporated herein by reference in their entirety.

The present invention relates to a process for the production of electrolytic decomposition of nitrogen trifluoride and fluorine, in particular to a process for the production of electrolytically produced paraffin-like carbon from acicular anisotropic carbon comprising mesophase carbon and acicular coke exhibiting certain physical properties for producing nitrogen trifluoride and fluorine RTI ID = 0.0 > anode. ≪ / RTI >

Nitrogen trifluoride (NF ₃ ) is a stable gas that has little reactivity at room temperature. On the other hand, fluorine (F ₂ ) is a reactive gas with most materials at ambient conditions. Both NF ₃ and F ₂ are increasingly used in semiconductor manufacturing. For example, NF ₃ is typically used as an etchant for a silicon or silicon oxide layer on a semiconductor substrate, or as a CVD chamber cleaning gas in which NF ₃ is activated in situ.

On an industrial scale, NF ₃ can be produced by a fluorination process. There are two main methods for fluorination, direct fluorination (DF) and electrochemical fluorination (ECF). In electrochemical fluorination, the electrolyte is electrolyzed in the electrolysis cell to produce NF ₃ . F ₂ is produced by an electrochemical process similar to the ECF process for producing NF ₃ . Conventional electrolysis cells use carbon steel cathodes and extruded and carbonated anodes made, for example, from carbon-coke particles and carbon pitch binders. Conventional anodes are made from isotropic coke and exhibit high macroporosity, often above 100 microns, as a result of the large particle size used. Typical extruded carbon anodes are carbonized at temperatures below 1000 ° C, typically not graphitized, and such graphitization requires temperatures above 1500 ° C. However, it is also possible to use the methods described in Ellis, J, F. and GF May, "Modern Fluorine Generation" in Fluorine, the First Hundred Years, RE Banks, DWA Sharp, and JC Tatlow, eds., Elsevier Sequoia, As noted, there are many disadvantages associated with conventional extruded carbon anodes.

One problem associated with electrochemical fluorination is the contamination of electrolytic decomposition-produced NF ₃ or F ₂ by CF ₄ (tetrafluoromethane or carbon tetrafluoride). Any kind of contamination is a concern because high purity NF ₃ or F ₂ is desired and required in many industries, such as the semiconductor industry. It is practically impossible to separate CF ₄ from NF ₃ . J. Massonne, CHEMIE INGENIEUR TECHNIK, v. 41, N 12, p. 695 (1969). Thus, any CF ₄ contamination reduces the purity of the resulting NF ₃ and can not be easily removed. With respect to F ₂ , CF ₄ can be removed, but it can be separated and removed, requiring additional and costly process steps to purify and recover the purified F ₂ .

Another problem associated with an anode made by carbon coke with a conventional carbon anode, such as a pitch binder, is that the anode needs to be extruded or machined, or both to be formed into an anode shape . However, the anode may not be accurate shape and design to function properly, and may not be reproducible. This results in poor dimensions and mechanical integrity of the anode.

Another problem is the polarization of the anode when the anode is immobilized or stops functioning. This state is indicated by the cell voltage above normal and is referred to as "polarization ". When the carbon-type anode is used to produce F ₂ or NF ₃ , polarization is a major cause of cell failure. The extreme situation is sometimes referred to as the "anode effect". [M. Jaccaud, M. Faron, D. Devilliers, and R. Romano, "Fluorine" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH Verlag, 2000). By preventing polarization, the cell is allowed to run longer between rebuilds, thereby reducing production costs.

Thus, NF ₃ or F ₂ to form a less by-product in the electrolytic production thereof higher NF ₃ or anode, better dimensional integrity (integrity) minimizes or reduces the anode and polarization having a to produce F ₂ with a purity by of There is still a demand for an anode.

SUMMARY OF THE INVENTION

The present invention relates to a process for the preparation of an anode comprising an electrolytic cell made of a parallel ordered anisotropic carbon or coke comprising an initial meso-phase carbon containing an acicular coke, a lens-like coke, a mesocarbon, and a mesocarbon microbead, , Fluorine, or both. These carbon and coke are all described in J. Med. Speight, Handbook of Petroleum Product Analysis, John Wiley & Sons, 2002.]. These types of carbon represent substantially parallel ordered or stratified domains of varying sizes, as opposed to random stratified or concentrically stratified (onion-shaped) carbon, or amorphous or free-like carbon. By using such anodes comprising anisotropic carbon arranged in parallel, it is possible to achieve a lower cell voltage and a lower voltage by using sponges, shots, concentrically stratified, amorphous or conventional anodes made from any isotropic coke It has been found that a high current density is achievable. In addition, it has been found that such anodes, which exhibit certain physical properties, provide reduced and minimized production of by-products such as CF ₄ , thereby significantly improving the purity of the produced nitrogen trifluoride or fluorine. The physical properties that provide this advantage include reduced particle size, low open porosity, high density and / or reduced porosity of carbon resulting from the use of microporous carbons, such as the carbonation of oxygen-containing carbon precursors or porous cokes-like sponge cokes Lt; / RTI > In addition, the anode is modeled to provide improved dimensional and mechanical integrity of the anode, instead of being extruded or machined. In other words, unlike conventional anodes, which require extrusion and / or machining, the shape of the anodized anode is set by the mold, which makes the anode more precise and reproducible, Enabling an anode of excellent function. This also makes the geometry of the cell more consistent, which makes the electrolyte circulation and gas bubble disengagement more reproducible. The anodes of the present invention also exhibit improved resistance to polarization with the other advantages described herein.

Carbon articles of the type described in this document are typically characterized using apparent density among other physical properties. Since these materials are composed of aggregated and bonded or sintered particles, they are porous. Features such as mean pore diameter, pore size distribution, and whether pores are interconnected (open) or isolated (closed), as well as the range of such porosity measured as a percentage of the total product volume are all functions of processing conditions and techniques . Pure crystalline graphite represents the highest density packing for sp ² -hybridized carbon, e. G., Carbon found in the carbon products described above. The presence of pores reduces the apparent density from this theoretical maximum of about 2.23 g / cm < ^{3 &} gt ;. Typical carbon anodes for the production of NF ₃ and F ₂ and most carbon and graphite products, including the disclosed carbon anodes, have an apparent density of about 1.5 g / cm ³ to 1.9 g / cm ³ .

There is currently no ASTM standard test for porosity of carbonaceous material, but several techniques known in the art are commonly applied. For example, mercury porosimetry and gas adsorption data can be analyzed by using the Washburn equation and the Brunauer-Emmett-Teller theory, respectively. Most synthetic carbon and graphite products made through bonded or sintered carbon powder exhibit an open porosity of about 8% to about 20% when measured using mercury porosimetry. The literature reports that higher densities for a given carbon material, which essentially represents reduced total porosity, also correspond to lower open porosity and fewer smaller pores [R. Sheppard, Dwayne Morgan , DM Mathes, DJ Bray, eds., POCO Graphite, Inc., 2002].

Without being limited to any particular theory, it is believed that the reduced porosity leads to a lower surface area achievable by the liquid electrolyte. Formation of CF ₄ is believed to be minimized by reducing this achievable surface area and eliminating trapping of the electrolyte in small pores.

In one embodiment, the present invention provides a method of performing electrolysis of an electrolyte by using an electrolytic anode comprising parallelly arranged anisotropic carbon (e.g., mesocomposite carbon, such as mesocarbon microbeads) To obtain fluorine, nitrogen trifluoride or fluorine, including obtaining fluorine. The anode may have an active geometric surface area of up to about 70,000 cm ² or greater, for example. In the case of mesocarbon microbeads, the mesocarbon microbeads may be isostatically compressed mesocarbon microbeads. In one embodiment, the anode is comprised of only modulated and self-sintered mesocarbon microbeads and does not include a binder or other additive for modifying or sintering the anode. The mesocarbon microbeads are also preferably not graphitized. In one embodiment, all of the anode made from the molding mesocarbon microbeads are less than about 20%, more preferably high density with a porosity of less than about 15%, e.g., 1.7 g / cm ³ or greater Lt; / RTI > In addition, the mesocarbon microbeads may have an average particle size ranging from about 1 to 5 microns in diameter.

In another embodiment, the present invention provides a method of producing nitrogen trifluoride or fluorine, comprising performing electrolysis of an electrolyte by using an electrolysis anode comprising needle coke. The needle coke may be combined with a suitable binder, such as a high aromatic pitch binder or a mesophase-forming pitch, which may contain a small amount of oxygen in the precursor. In addition, the anode may be less than 50 microns, and more preferably contains particles of less than 20 microns and 1.6 g / cm ³ greater than, more preferably 1.7 g / cm ³ greater than, and most preferably 1.8 g / cm It may have a density of greater than ^3. The anode is preferably baked to a temperature of about 1600 ° C or less. The needle coke in these embodiments may also be replaced by another parallel ordered coke, e.g., a lens shaped coke. In a further embodiment, the coke or binder may be replaced by a mesophase, an initial mesophase coke or pitch, or an amorphous but mesophase-forming pitch.

By using the carbon according to the present invention as the anode material, it is possible to produce nitrogen trifluoride and fluorine at a higher purity with little or substantially no CF ₄ compared to conventional extruded carbon anodes. For example, such a method will be less than 100ppm in the pure nitrogen trifluoride gas or fluorine product three CF _4, preferably less than 75ppm CF _4, and more preferably may produce a less than 50ppm of CF _4. The selectivity in the electrolytic process for producing nitrogen trifluoride or fluorine may be 70% or more, preferably 80% or more. Suitable electrolytes may be selected by one skilled in the art. In order to produce nitrogen trifluoride, the electrolyte may be, for example, a binary electrolyte or a ternary electrolyte. Binary electrolytes may include HF and NH ₄ F or other suitable binary electrolytes known in the art. Three won the electrolyte can include one, three won or other suitable electrolyte known in the art of such HF, NH ₄ F, and KF, LiF, CsF, and. For example, the ternary electrolyte composition may comprise about 35-45 wt% HF, about 15-25 wt% NH ₄ F, and about 40-45 wt% KF. In order to produce fluorine, the electrolyte may be a binary electrolyte including, for example, HF and KF.

The nitrogen trifluoride process and the fluorine process may be performed under appropriate conditions and operating process parameters, including temperature and current densities selected by those skilled in the art. For example, nitrogen trifluoride can be produced at a temperature of about 120 to 140 DEG C and a current density of up to about 250 mA / cm < ² >. The fluorine can be produced at a temperature of about 80 to 90 DEG C and a current density of about 350 mA / cm < ² >

In another embodiment, the present invention provides a process for the preparation of an electrolyte composition comprising an anode, a cathode, and an electrolyte composition comprising HF, optionally KF and optionally NH ₄ F, comprising anisotropic carbon arranged in parallel, Thereby providing an electrolytic cell to be produced. The electrolysis cell is operated to produce nitrogen trifluoride or fluorine at high purity with little or no impurities of CF ₄ . In an exemplary embodiment, the anode comprises self-sintered isostatically compressed mesocarbon microbeads. In another exemplary embodiment, the anode comprises isostress-modulated mesocarbon microbeads optionally bearing a phenolic resin sintering aid. In another exemplary embodiment, the anode comprises a needle coke formed by isobaric molding, which is associated with a high aromatic binder and exhibits a low porosity (e.g., porosity of less than 20%) and a density of greater than 1.7 g / cm < ³ >.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is best understood when the following detailed description is read in conjunction with the appended drawings. According to the general practice, it is emphasized that the various features of the drawings do not follow the scale. On the other hand, the dimensions of the various features are arbitrarily enlarged or reduced for clarity. The following figures are included in the drawings.
Figure 1 shows two views of a mesophase carbon spheres (a) and a cross section (b) through a mesophase spheres shown in a.
Figure 2 is a cross-sectional view of one embodiment of an electrolytic cell useful in the present invention.
Figure 3 is a cross-sectional view of another embodiment of an electrolytic cell useful in the present invention.
Figure 4 is an X-ray diffraction pattern for meso-phase carbon which may be suitable for forming the anode according to the present invention.

The present invention provides for the production of high purity nitrogen trifluoride and fluorine using anodes comprising parallelly ordered anisotropic carbon. In particular, the process for producing nitrogen trifluoride or fluorine can be carried out in the presence of high selectivity and mesophase carbon, mesocarbon microbeads, needle cokes or other parallelly arranged beads for obtaining nitrogen trifluoride or fluorine with a reduced or minimal amount of CF ₄ And performing electrolysis of the electrolyte by using an electrolysis anode containing isotropic carbon.

As used herein, the term "anode" refers to an electrochemically-active portion of an electrode, wherein nitrogen trifluoride or fluorine is produced in the cell as current is applied to the cell.

As used herein and in the claims, the terms "comprising" and "comprising" are inclusive or open terms and do not exclude additional non-recited elements, components, or method steps. Accordingly, the terms " comprises "and" comprising "encompass " consisting essentially of" and "consisting essentially of " Unless otherwise specified, all values provided herein include up to and including a given endpoint, and the constituent or component values of the composition are expressed as a weight percentage or weight percent of each component in the composition.

Parallel Anisotropy  carbon

The present invention provides for the production of high purity nitrogen trifluoride and fluorine using anodes comprising parallelly anisotropic carbon or coke. The anode for producing nitrogen trifluoride or fluorine comprises parallelly arranged anisotropic carbon, such as mesocarbon microbeads (or MCMB) or needle coke. As used herein, the term "parallel ordered anisotropic carbon" or "parallel ordered anisotropic coke" refers to a mixture of randomly stratified carbon, concentrically stratified (on-like) carbon, In contrast to free-like carbon, it is intended to encompass a class of carbon which exhibits a substantially parallel ordered or stratified domain. Parallel ordered anisotropic carbon or coke can be prepared, for example, in J. of J. Lenticular coke, meso-phase carbon, initial meso-phase carbon, and mesocarbon microbeads, as defined by Speight, Handbook of Petroleum Product Analysis, John Wiley & Sons,

As used herein, the term "meso-phase carbon" or "mesocarbon" is an optically anisotropic graphitizable carbon phase derived from fusible organic compounds. Acicular cokes and related parallel aligned anisotropic carbons are often thought of as "meso-forms" of carbon, although they often represent different physical forms of carbon representing similar microstructural properties. The meso-phase carbon can be separated from the optically isotropic material in the form of small particles, often referred to as mesocarbon microbeads. Thus, the meso-phase carbon is intended to encompass carbon having an optically isotropic phase. In other words, carbon exhibits optical anisotropy when observed under a polarizing microscope (e.g., an optical microscope with polarization).

As used herein, the term "acicular coke" refers to an ordered, parallel layer or carbon, or as described in "Recommended Terminology for the Description of Carbon as a Solid", IUPAC, Pure & Appl. Chern., Vol. 67, No. 3, pp. 473-506, 1995). ≪ RTI ID = 0.0 > [0050] < / RTI > It should be understood that the physical modification of the needle coke by grinding or size reduction does not remove it from this definition, even at particle sizes near 1 micron.

In an exemplary embodiment, the anode comprises mainly anisotropic carbon arranged in parallel. As used herein, the term "predominantly" indicates that the component is present in greater amounts than any other component of the related composition, e.g., the anode is mostly or exclusively anisotropic carbon aligned in parallel. In other words, the anisotropic carbon arranged in parallel becomes the main anode of any other component. In particular, the anode may comprise at least 40%, at least 50%, at least 60%, at least 75%, at least 90%, at least 95% or at least 99% parallelly arranged anisotropic carbon. In an exemplary embodiment, the anode is substantially pure, parallel ordered anisotropic carbon. In other words, the anode is an anisotropic carbon that is mostly or substantially all arranged in parallel, as opposed to a coke or carbonized pitch or anode that accidentally contains any small amount of parallel ordered anisotropic carbon. In addition, the anode is an anisotropic carbon, most of which is arranged in parallel, as opposed to binders, fillers or other auxiliaries known in the art.

In one embodiment, the anode primarily comprises a meso-phase carbon, such as mesocarbon microbeads. For example, the anode is mostly or exclusively mesocarbon. In other words, the meso-phase carbon forms more of the anode than any other component. In particular, the anode may comprise at least 40%, at least 50%, at least 60%, at least 75%, at least 90%, at least 95%, or at least 99% mesocosan. In an exemplary embodiment, the anode is substantially pure meso-phase carbon. In other words, the anode is most or substantially all mesocarbon, as opposed to a coke or carbonized pitch or anode that accidentally contains any small amount of mesocarbon. In addition, the anode is predominantly a mesocarbon, as opposed to binders, fillers or other adjuvants known in the art.

In one embodiment, the anode for producing nitrogen trifluoride or fluorine comprises mesocarbon microbeads. Figure 1 shows an example of a mesocarbon microbead including (a) a mesophase spheres 100 and (b) a cross-section depiction through a mesophase spheres 100a. The mesophase spherical body 100 may include two poles 110, a small amount of lamellae direction 120, and an edge of the disk 130 of the mesophase spheres 100. Although the mesocarbon microbeads shown in Fig. 1 have a layered structure, the mesocarbon microbeads prepared by different routes may have different shapes. The mesocarbon microbeads may be spherical in shape, or may have a waist or irregular shape, for example.

The microbeads may have a bead diameter of up to about 100 microns (e.g., about 1-100 microns in diameter). In an exemplary embodiment, the mesocarbon microbeads may have an average particle size ranging from about 1 to 5 microns in diameter. The mesocarbon microbeads can have a high specific surface area, for example, in the range of 1,000 to 4,000 m ² / g. Similarly, also the density of the In other embodiments, the nitrogen trifluoride or the anode for the production of fluorine up to particles of needle coke, and 20 microns in size, more preferably a particle size of less than 10 micron, 1.6 g / cm ³ greater than, More preferably a density of greater than 1.7 g / cm < ³ >, and a porosity of less than 15%, more preferably less than 10%. The needle coke and the binder may be molded into a desired shape.

Figure 4 shows an X-ray diffraction (RXD) pattern for a suitable type of meso-phase carbon. The sharp peaks with the mark at the top are peaks from ZnG that were added as an internal calibration standard during analysis and are not part of the carbon anode. As evidenced, there is no graphite peak in the XRD indicating that there is no well-crystallized grapid. XRD represents only one wide-band peak of 25 to 30 DEG representing a poorly-registered graphene-type plane of carbon. The meso-phase carbon does not have a peak at a low angle indicating that it does not contain any well-crystallized or well-formed graphite or other crystal structure.

In another embodiment, the anode mainly comprises a parallel ordered anisotropic coke, e.g., acicular coke, coupled with a suitable binder to produce the final product in a minimum amount of porosity. Aromatic pitch, mesophase pitch, and coar tar pitch are preferred binders, but oxygen-containing binders such as polyfurfural alcohol or phenolic resins are less preferred. In all cases, the anode is not graphitized.

Parallel ordered anisotropic cokes, including needle coke and meso-phase carbon or mesocarbon microbeads, can be used, for example, as bitumen precursors such as coir tar, coar tar pitch, petroleum heavy oil, decant oil, , Pyrolytic residues, petroleum pitch, emulsion-polymerized plastics, synthetic pitch, surfactants, or small molecules to convert the low molecular weight material into a polymeric material through repeated polycondensation. Parallel ordered anisotropic coke and meso-phase carbon can also be synthetically produced from aromatic molecules, such as naphthalene. For example, the precursor material can be heated at 200 to 600 占 폚 (depending on the precursor) to produce "meso-shaped" green carbon particles or a greenbody. Isotropic carbon may optionally be removed by solvent extraction to produce pure meso-phase carbon. The green carbon particles can then be molded or pressed into the desired shape, and then baked to sinter and remove volatiles. Various methods for producing meso-phase carbon are known, such as those taught and described in WO 2006/109497 and Korean Patent No. 10-2006-0138731.

Such as needle coke, mesophase carbon, mesocarbon microbeads, or other types of parallel stratified anisotropic cokes, to any suitable supplier or distributor, such as CR Tech with offices in Korea, MWI with offices in Rochester, New York, USA, Graftech International with offices in Parma, Ohio, USA; Y-Carbon with offices in Pan-Silva or Bristol, USA; Timcal Graphite and Carbon, Ltd. with offices in Bodio, Switzerland; Qinhuangdao Huarui Coal Chemicals Co. with offices in Tangshan, China; Asbury Carbons, Inc., with offices in Asbury, New Jersey, USA; MTI Corporation, with offices in Richmond, California; Linyi Gelon New Battery Materials Co., Ltd, with offices in Shandong, China; Osaka Gas Chemicals Co., Ltd., SGL Carbon SE with offices in Wiesbaden, Germany, and Kao-Shi, Taiwan. Production from China Steel Chemical Corporation, Japan probably another supplier to produce the ROC, SEC Carbon, Ltd., or amorphous carbon, which has offices in Amagasaki or may be obtained.

Parallel ordered anisotropic carbon is used to produce the anode. For example, the anode can be modeled from a combination of parallel aligned anisotropic cokes and suitable pitch binders or from mesocarbon microbeads. The anode can be modeled by using any suitable modulation and modulation technique known in the art. In one embodiment, the coke / pitch combination or mesocarbon microbeads are isostatically compressed (e.g., cold isostatically compressed) to form the anode. Cold isostatic pressing (CIP) involves applying pressure to the mold at room temperature (e.g., using a fluid as a means of applying pressure to the mold at a temperature of about 20 to 25 DEG C). Some may optionally be heated under pressure applied at or during the mold to soften the pitch or meso carbon during formation. Some may be heated or sintered or not after being released from the mold. In an exemplary embodiment, the molded shape is sintered. If a binder, e.g., pitch, is used, the binder will soften and then fill the gaps between the coke particles before they are melted and carbonized to secure the finished body together. On the other hand, due to the nature of the mesocarbon microbeads, the mesocarbon microbeads can self-sinter at low temperatures (e.g., about 400-600 DEG C). Self-sintering means that the microbeads are pressed and fused together, sintered or heated but do not require a binder, resin, filler, or the like to mold and sinter the anode portion. In one embodiment, the anode is composed of only modulated and self-sintered mesocarbon microbeads. The parallelly anisotropic carbon or mesocarbon can also be formed using other techniques known in the art, including, but not limited to, isostatic pressing, uniaxial pressing, or extrusion.

In another embodiment, at least one stabilizing aid or sintering aid, such as a phenolic resin, may be added for the purpose of stabilizing the parallel aligned anisotropic carbon formed without oxidation or in addition to oxidation. The stabilizing adjuvant may contain oxygen or sulfur. For example, a small amount of a stabilizing or sintering aid, such as a phenolic resin, may be added to introduce an oxygen which acts to bridge the parallelly anisotropic carbon and imparts resistance to deformation when the shape is heated during the carbonization process Can be provided. The anode may comprise stabilizing or sintering aids of 10% or less, 8% or less, 5% or less, 3% or less, or 1% or less.

In a preferred embodiment, the binder, porosity filler, or sintering aid comprises an aromatic pitch, an aromatic synthetic pitch, or other carbon precursor known to produce graphitized carbon when heated.

The green body formed may optionally be oxidized, for example, by exposure to air at elevated temperatures to stabilize the physical morphology and reduce or eliminate deformation during subsequent heating. In other words, the green body can be oxidized by heating in air or an oxygen-containing gas. Suitable conditions for oxidizing the mesocarbon are well known in the art. Various methods for oxidatively stabilizing a meso-phase carbon product are described in F. Fanjul, M. Granda, R. Santamaria, and R. Menendez, "On the chemistry of the oxidative stabilization and carbonization of carbonaceous mesophase." Fuel. 2002 Nov; 81 (16): 2061-70).

After the sintering treatment, densification heat treatment may also be carried out, for example, a heat treatment at a temperature of about 500 to 1500 ° C. The density or apparent density of the anodized anode may be a low density in the range of about 1.60 to 1.65 g / cm < ³ >. In one embodiment, the anode formed from parallel aligned anisotropic carbon (e.g., mesocarbon microbeads) preferably has a high density of about 1.7 g / cm ³ or more. It may also be desirable for an anode comprising parallel aligned anisotropic carbon to have low porosity (e.g., less than 20% porosity, preferably less than 15% porosity, more preferably less than 10% porosity) have.

The anode can be any suitable sized and shaped anode as is commonly used in electrolysis cells known in the art. For example, the anode blades can range in length from about 1.5 to 2.5 feet, from about 6 to 10 inches wide, and from about 1 to 3 inches thick. The anode blades may be flat and / or may be formed to improve the industry-known surface area or other characteristics for producing anode blades having an enlarged geometric surface area, for example, as described in U.S. Patent Nos. 5,290,413 and 4,511,440 , Grooves, ridges, recesses, and pyramids, and the like. The anode may have any suitable active surface area. The shape and physical characteristics of the anode can be formed during the molding process, or they can be machined at any point after forming the green body using conventional manufacturing techniques.

The anode of the present invention is preferably not graphitized. Graphitized carbon materials, including needle coke, mesocarbon microbeads, and conventional extruded carbon anodes, are typically molded, extruded, or otherwise baked after they have been formed to remove volatile materials and sinter or bulk carbonaceous materials Consolidate. This baking can occur at temperatures up to about 1300 ° C. At higher temperatures, typically above 1500 ° C, however, depending on the type of carbon material, the carbon starts to form larger graphitic domains and the electrical resistance decreases. This is called graphitization. Many types of carbon products are partially or completely graphitized. The anode for NF ₃ and F ₂ production is preferably not graphitized because the graphitization can lead to poor performance in the electrolysis cell (eg graphite is attacked by fluorine products, Disintegrating due to insertion by various components in the electrolyte).

Compared to conventional extruded anodes, the anodes of the present invention, including parallel ordered anisotropic cokes including needle coke and mesocarbon microbeads, offer many advantages, such as: (1) reduced formation of CF ₄ , resulting in a higher of NF ₃ and F ₂ with a purity of service, (2) a shorter manufacturing time (e.g., from F _2, without the need for additional separation step), and (3) less required to produce a finished anode (4) lower manufacturing costs for the anode leading to lower production costs for NF ₃ and F ₂ , (5) improved resistance to polarization, (6) ability to operate at higher current densities, and (7) provides a reduced operating cell voltage.

By using anisotropic carbons arranged in parallel to form the anode, it is possible to produce nitrogen NF ₃ and F ₂ at higher purity with substantially less or no CF ₄ compared to conventional extruded anodes. For example, the process may be carried out in pure NF ₃ or F ₂ at less than 100 ppm (volume), preferably less than 75 ppm (volume), more preferably less than 50 ppm (volume), most preferably less than 25 ppm It may produce a less than CF _4. Thus, 25 ppm is the same as that of 25 million molecules per molecule of NF ₃ or CF ₄ ml of 25 million per ml of CF ₄ NF _3. The selectivity in the process of producing NF ₃ or F ₂ is also preferably high and may be 70% or more, preferably 80% or more, more preferably 85% or more, or even 90% or more It may be a selection for NF ₃ or F ₂ in excess of that.

Carbon articles made from parallel ordered anisotropic cokes containing needle coke and mesocarbon microbead anodes can exhibit improved wetting properties without conventional wetting adjuvants. Conventional carbon anodes often develop low energy surfaces as a result of their interaction with electrolytes and electrochemically-produced species, such as fluorine, during the production of NF ₃ or F ₂ . The wetting of the anode surface by the electrolyte becomes poor, resulting in higher cell operating voltage and increased polarization tendency. For example, the electrolysis of a three-way KF-HF-NH ₄ F molten salt electrolyte having a composition of 40 wt% HF, 18 wt% NH ₄ F, and 42 wt% KF, Or nearby, to produce NF ₃ at a current density of 70 mA / cm ² , more preferably 180 mA / cm ² for more than 150 hours. Upon removal from the melt and cooling to about room temperature, the anode may be cleaned and dried with water without physically polishing the active surface. The surface energy of the active surface can then be measured using known surface tension inks or markers ("dyne pens").

It has been found that the anode of the present invention exhibits a high surface energy of 65 dyne / cm or more after more than 30% of the active surface after 150 hours. In other words, the anodes of the present invention comprising parallelly arranged anisotropic carbon exhibit wettability retained over an extended period of time without the need for wetting agents. On the other hand, conventional extruded carbon anodes exhibit surface energies below this value, for example, often less than 55 dyne / cm, and require a wetting agent to improve wettability. See, e.g., P. Fluorine and its Compounds, W. Childs and T. Fuchigami, eds., The Electrochemical Society, 1997) improve the wetting by incorporating the additive into the carbon, as described in Hough, "Fluorine Production and Use - An Overview" . Similarly, U.S. Patent No. 7,608,235 improves wetting by adding MgF ₂ or AlF ₃ to conventional carbon anodes. However, such additives may add to the cost of the anode and may contaminate the electrolyte and anode fabrication facility.

Surprisingly, unlike other carbon forms, the parallel ordered anisotropic carbon, such as mesocarbon microbeads, that form the anode is resistant to the formation of low-energy surfaces without the need for such wetting additives, The ability to operate at higher current densities and lower cell operating voltages. The lower cell voltage is NF ₃ Or a reduced power consumption rate during the fabrication of F ₂ , but increased current density causes more NF ₃ or F ₂ to be generated from a given cell. In addition, removal of conventional wetting aids from the anode composition reduces cost and contamination in the manufacturing process.

Other attempts have been made to improve conventional extruded carbon anode materials. U.S. Publication No. 2010/0193371 describes the use of a conductive diamond film on glassy carbon. U.S. Publication No. 2010/0252425 proposes the use of mesocarban carbon as a filler or binder for more desirable carbonaceous components with a specialized X-ray diffraction pattern. It also suggests that a high degree of porosity is desirable and that a specialized carbonaceous material requires a conductive diamond coating that performs well as an anode. The present invention does not require an expensive diamond film. Instead, the present invention establishes that a suitably fabricated parallel ordered anisotropic carbon material is advantageous as an anode material. Anisotropic carbons arranged in parallel may exhibit low porosity, e.g., less than 15%, or less than 10% porosity. Additionally, the parallel ordered anisotropic carbon material of the present invention does not exhibit the diffraction pattern specified in U.S. Publication No. 2010/0252425, which requires crystallized well-formed graphite or other crystalline phases. As discussed above, the parallel-ordered anisotropic carbon material of the present invention does not contain a pronounced diffraction peak that is not a wide-band peak of 25 to 30 degrees, so that the parallel aligned anisotropic carbon is any well-formed graphite or other And does not contain a crystal structure.

Electrolysis cell

In one embodiment, the present invention provides an electrolytic cell that produces nitrogen trifluoride or fluorine, comprising an anode, a cathode, and an electrolyte composition comprising an aligned anisotropic carbon (e.g., a mesocarbon microbead) to provide. The electrolysis cell is operated to produce nitrogen trifluoride or fluorine. The process of forming nitrogen trifluoride or fluorine includes, for example, electrolysis of the electrolyte using an electrolysis cell. Any suitable electrolysis cell known in the art may be selected by one skilled in the art.

For example, the electrolytic cell may comprise an inert wall and a container or housing for containing the electrolyte. The anode and the cathode may be connected to a source of direct current. For example, an electrode can be placed in a container for immersion into an electrolyte, so that the electrode can form an electrochemical anode and cathode when an electric current is applied. A partition or a separating skirt may be disposed to prevent fluorine or nitrogen trifluoride from mixing with hydrogen during electrolysis when fluorine or nitrogen trifluoride is produced at the anode and hydrogen is produced at the cathode. Typically, such partition walls are positioned vertically.

As long as any material is durable when exposed to the corrosive conditions of the cell, such material can be used to constitute a part of the cell. Materials useful for cell bodies and separating skirts include iron, stainless steel, carbon steel, nickel, or nickel alloys known to those skilled in the art, such as MONEL®, and TEFLON®. The constituent material (s) for the cathode is not particularly limited as long as the cathode is made of materials useful for the purpose known to those skilled in the art, such as nickel, carbon steel, and iron.

Figure 2 shows a schematic representation of an example of an electrolytic cell device which may be suitable for the production of nitrogen trifluoride or fluorine according to the present invention. The electrolytic cell arrangement may include an electrolytic cell 25 having an electrolytic body 26, sides 51 and 52 and an upper lead or lid 28. The cell 25 is divided into an anode chamber 17 and a cathode chamber 18 by a vertically disposed gas separation skirt 19 and a diaphragm 22. The anode 20 is disposed in the anode chamber 17 and the cathode 21 is disposed in the cathode chamber 18. The electrolyte 23 is disposed in the electrolytic cell 25 and the level 27 of the electrolyte 23 is the height of the electrolyte 23 on the bottom surface 53 of the electrolytic cell 25. [ The level of the electrolyte 23 can be measured by a level indicator 31 and such level 27 can be adjusted, for example, between a high level set point 32 and a low level set point 33 have. In addition, the composition of the electrolyte 23 can be sampled by the electrolyte sample port 41.

The electrolytic cell 25 may include supply tubes 12 and 16 for supplying raw materials or components forming the electrolyte 23. Generally, feed tubes 12 and 16 are provided in the cathode chamber 18. The anode chamber 17 may have an anode product outlet pipe 11 for discharging the product gas mixture (e.g., NF ₃ or F ₂ ) from the electrolytic cell 25. The cathode chamber 18 may have a cathode product outlet pipe 13 for discharging gas from the electrolytic cell 25. The electrolytic cell 25 may include a temperature detector 30, and temperature regulating means 29, etc., for adjusting the appropriate process parameters during electrolysis.

If desired, the electrolytic apparatus of the present invention may further comprise additional components, for example a purge gas pipe connection in the anode and cathode chambers 17,18. For example, in order to provide a purge gas source, e.g., nitrogen, to provide purging of the electrolysis cell 25 for safety reasons, to provide a blow-out means for the clogged pipe, (Not shown) to the anode chamber 17 and / or the cathode chamber 18 of the electrolysis cell 25 to provide proper functionalization of the tubes, pipes and other instruments.

When the cell 25 is in operation, nitrogen trifluoride or a fluorine-containing gas is produced in the anode 20 and hydrogen is generated in the cathode 21. The gas produced in the anode chamber 17 when used to produce nitrogen trifluoride may include, for example, nitrogen trifluoride (NF ₃ ), nitrogen (N ₂ ) and fluorine (F ₂ ) . When used to produce fluorine, the gas produced in the anode chamber 17 may contain, for example, fluorine (F ₂ ). In addition, HF may optionally be present in the gas leaving both the anode chamber 17 and the cathode chamber 18.

Figure 3 shows a cross-sectional view of an electrolysis cell similar to the cell shown in Figure 2 except that the cell 25 shown in Figure 3 includes only one anode chamber 17 and one cathode chamber 18 Respectively. The anode chamber 17 has one anode 20 and the cathode chamber 18 has one cathode 21. 2 and 3, like parts are numbered identically.

The cell 25 shown in Figure 3 is connected to the anode 20 via the anode current connection 14 to a level that can be increased or decreased within the target range specified by the control process or operator for the electrolysis cell 25. [ And a current controller 39 for supplying current to the cathode 21 through the cathode current connection 15.

Although a particular electrolysis cell 25 is described and illustrated herein, the cell 25 may include a known or later developed cell design. For example, cell types are described in Fluorine, The First Hundred Years, R.E. Banks, D.W.A. Sharp, and J.C. Tatlows, eds. Elsevier Sequoia, Netherlands, 1986].

NF ₃  Or F ₂ Production of

The electrolysis cell can produce NF ₃ , F _2, or both, and the process is substantially similar. The small difference between the production of NF ₃ or F ₂ involves the use of different electrolyte solutions and different operating conditions. Otherwise, the two processes are substantially the same. The cells are nearly interchangeable and the anode used in both processes is the same parallel-ordered anisotropic carbon-based anode material described herein. As noted above, undesired by-product CF ₄ is produced in both processes. The only difference is that CF ₄ and F ₂ can be separated by distillation while CF ₄ and NF ₃ can not be separated in practice. In either case, it is preferable not to generate CF ₄ , since the separation requires additional processing steps.

(a) NF ₃ Production of

Nitrogen trifluoride can be produced by using the electrolytic apparatus of the present invention together with electrolytes containing any known electrolytes useful for producing nitrogen trifluoride. For example, suitable electrolytes may include ternary electrolytes (e.g., HF-containing molten salts of ammonium fluoride (NH ₄ F), potassium fluoride (KF), and hydrogen fluoride (HF)). In addition, the molten salt electrolyte may also contain other additives such as cesium fluoride, lithium fluoride, and the like. In an exemplary embodiment, the ternary electrolyte composition may comprise about 35-45 wt% HF, about 15-25 wt% NH ₄ F, and about 40-45 wt% KF. The concentration can be expressed in terms of mol% NF ₄ F and HF ratio. HF is defined by the following equation:

HF = ratio (mol of titratable HF to neutral _{pH) / (NH 4 F (} mol) + KF (mol)).

The HF ratio represents the ratio of the solvent to the salt in the electrolyte. In some embodiments with a ternary electrolyte, an NH ₄ F concentration in the range of 14 wt% to 24 wt%, more preferably 16 wt% to 21 wt%, and most preferably 17.5 wt% to 19.5 wt%; It may be desirable to operate the electrolysis cell at a HF ratio of preferably 1.3 to 1.7, more preferably 1.45 to 1.6, and most preferably 1.5 to 1.55. In other embodiments, the preferred concentration range may vary depending on operating conditions, such as applied current and electrolyte temperature. It is desirable to select a concentration range based on a balance between high efficiency and safe operation of the electrolysis cell.

The present invention is not limited to any particular electrolyte composition and any description referred to herein, for example, the ternary electrolyte is for convenience only. It should be understood that any electrolyte useful in making NF ₃ may be substituted for the description and included in the present invention.

The nitrogen trifluoride electrolysis process may be performed under suitable conditions known in the art including temperature and current density. For example, nitrogen trifluoride can be produced at a temperature of about 100 to 140 DEG C, preferably about 120 to 130 DEG C and a current density of up to 250 mA / cm < ² >.

(b) F ₂ Production of

 In the case of fluorine, the fluorine-producing electrolyte may comprise a binary electrolyte. For example, the binary electrolyte may include a hydrogen fluoride (HF) -containing molten salt of HF and KF. In addition, the HF-containing molten salt electrolyte may also contain other additives such as ammonium fluoride, cesium fluoride, and lithium fluoride.

The HF ratio can be similar to that described above to achieve a balance between high efficiency and safe operation of the electrolysis cell and can be defined as:

HF ratio = (mol of HF titratable to neutral pH) / (KF (mol)).

The present invention is not limited to any particular electrolyte composition and any description referred to herein, for example, the binary electrolyte is for convenience only. It should be understood that any electrolyte useful for making F ₂ may be substituted for the description and included in the present invention.

The fluorine electrolysis process may be performed under suitable conditions known in the art, including temperature and current density. For example, fluorine can be produced at a temperature of about 80 to 90 DEG C and a current density of up to 250 mA / cm < ² >.

Example

Example  One- Mesocarbon On the anode  by NF ₃ Production of

The composition A ternary electrolyte having 40 wt% HF, 19.5 wt% NH ₄ F, and 40.5 wt% KF was electrolyzed in a 250 mL laboratory cell to produce NF ₃ . The cathode was carbon steel and the cell was equipped with a Cu / CuF ₂ reference electrode. The anode was isobaric-compressed mesocarbon microbeads with an active area of 2.25 cm ² . The anode and cathode product gases were kept separated by a TEFLON® skirt extending below the liquid line. The cell was operated at 130 < 0 > C. The electrolysis was carried out in a constant current manner by an applied current density of 70 mA / cm < ² >. The anode gas was analyzed by gas chromatography after the cell reached a stable state.

The anode gas contained 71 ppm CF ₄ on a pure NF ₃ basis. The selectivity for NF ³ was 70.7% and is defined as:

NF ₃ selectivity = (mol of produced NF ₃ ) / (mol of produced NF ₃ + mol of produced N ₂ ).

After an operation of more than 150 hours as the anode at 70 mA / cm ² , the anode is removed from the electrolyte, cooled to room temperature, washed with water without abrading the active surface, It was well wetted by 70 dyne / cm ink (high surface energy ink), representing surface energy. The remaining surface was wetted by 58 dyne / cm ink.

Comparative Example  1- Typical Anode

The electrolysis described in Example 1 was repeated except that the anode was replaced with a conventional extruded carbon anode. The active anode area was maintained at 2.25 cm < ^{2 &} gt ;. The anode gas contained 341 ppm CF ₄ (on a pure NF ₃ basis) and the selectivity to NF ₃ was 89.9%. The anode was removed after more than 150 hours of operation and given the same test as in Example 1, during which the anode was only wetted by 50 dyne / cm, but not by any higher surface energy ink I did.

Example  2- Mesocarbon On the anode  by NF ₃ Production of

Composition A ternary electrolyte having 37.5 wt% HF, 18.3 wt% NH ₄ F, and 44.2 wt% KF was electrolyzed in a 250 mL laboratory cell to produce NF ₃ . The cathode was carbon steel and the cell was equipped with a Cu / CuF ₂ reference electrode. The anode was an isobaric-compressed mesocarbon microbead with an active area of 2,25 cm ² . The anode and cathode product gases were separated by a TEFLON? Skirt extending below the liquid line. The cell was operated at 139 占 폚. The electrolysis was carried out in a constant current manner by an applied current density of 100 mA / cm < ² >. The anode gas was analyzed by gas chromatography after the cell reached a stable state. The anode contained 20 ppm CF ₄ on a pure NF ₃ basis. The selectivity for NF ₃ was 77.6%.

Comparative Example  2- Typical Anode

The electrolysis described in Example 2 was repeated except that the anode was replaced with a conventional extruded carbon anode. The active anode area was maintained at 2.25 cm < ^{2 &} gt ;. The anode gas contained 70 ppm CF ₄ (on a pure NF ₃ basis) and the selectivity for NF ₃ was 87.0%.

Example  3A-low density Mesocarbon On the anode  by NF ₃ Production of

The ternary electrolyte containing HF, NH ₄ F, and KF was electrolyzed in a 250 ml laboratory cell to produce NF ₃ . The cathode was carbon steel and the cell was equipped with a Cu / CuF ₂ reference electrode. The anode of the constant pressure low-density (1.60 g / cm ³⁾ having an active area of 2.25cm ² - was compressed mesocarbon microbeads. The anode and cathode product gases were separated by a TEFLON? Skirt extending below the liquid line. The cell was operated at 130 < 0 > C. The electrolysis was carried out in a constant current manner by an applied current density of 70 mA / cm < ² >. The anode gas was analyzed by gas chromatography after the cell reached a stable state. The anode gas contained 61 ppm CF ₄ on a pure NF ₃ basis. The selectivity for NF ₃ was 82.3%. The anode was evaluated for surface energy as described in Example 1, wetted by 70 dyne / cm of ink over a surface of about 40%, and the remaining area was wetted by 58 dyne / cm of ink.

Example  3B - High density Mesocarbon On the anode  by NF ₃ Production of

The electrolysis described in Example 3A was repeated except that the anode was replaced by high density (≥1.70 g / cm ³ ) isostatic-compressed mesocarbon microbeads. The anode contained <25 ppm CF ₄ (on a pure NF ₃ basis) and the selectivity to NF ₃ was 84.7%. The anode was evaluated for surface energy as described in Example 1, wetted by 70 dyne / cm of ink over a surface of about 40%, and the remaining area was wetted by 58 dyne / cm of ink.

Comparative Example  3A-Typical Anode

The electrolysis described in Example 3A was repeated except that the anode was replaced with a conventional extruded carbon anode. The anode gas contained 341 ppm CF ₄ (based on pure NF ₃ ) and the selectivity to NF ₃ was 89.9%. The anode was evaluated for surface energy as described in Example 1 and wetted by 50 dyne / cm ink, but not by any higher surface energy ink.

Comparative Example  3B- Back pressure  Compressed conventional Anode

The electrolysis described in Example 3A was repeated except that the anode was replaced by an isobar-compressed non-meso carbon anode. The composition of this anode is similar to conventional extruded carbon (i.e., based on carbonized coke and pitch rather than mesocarbon). The anode gas contained 212 ppm CF ₄ (on a pure NF ₃ basis) and the selectivity for NF ₃ was 88.3%. The anode was evaluated for surface energy as described in Example 1 and wetted by 48 dyne / cm ink, but not by any higher surface energy ink.

Example  4A-needle coke-based The anode  Used NF ₃ Production of

The electrolysis described in Example 1 was repeated using an anode containing mainly needle-shaped coke together with a pitch-based binder. The anode had an apparent density of 1.75 g / cm &lt; ³ &gt; and a total porosity of 15%. The anode was not graphitized. The cell was operated at a current density of 70 mA / cm &lt; ² &gt;. The cell temperature was 130 캜. The anode potential during the test was 5.15 V versus Cu / CuF ₂ , the selectivity to NF ₃ was 88%, and the CF ₄ content of the NF ₃ product was 30 ppm.

Example  4B - Needle coke-based at high current density The anode  Used NF ₃ Production of

The electrolysis described in Example 4 was repeated at a current density of 178 mA / cm &lt; ^{2 &} gt ;. The cell temperature was 140 캜. The anode potential during the test was 5.47 V versus Cu / CuF ₂ , the selectivity to NF ₃ was 88%, and the CF ₄ content of the NF ₃ product was 20 ppm.

These results are summarized in the following table, where IP = isostatically compressed, MCMB = mesocarbon microbead, LD = low density, and HD = high density.

Table 1

Table 2

Table 3

Comparative Example  4- Graphitized  Needle coke-based The anode  Used NF ₃ Production of

The electrolysis of Example 4B was repeated using the graphitized anode by heating to a temperature above 2000 ° C, although the same composition as in Example 4B. The selectivity and CF ₄ level were the same, but the anode worked unstably and the anode potential varied between 6 and 7 V.

Example  5- Mesocarbon On the anode  By F ₂ Production of

Composition A binary electrolyte with 40 wt% HF and 60 wt% KF was electrolyzed in a 250 mL laboratory cell to produce F ₂ . The cathode was carbon steel and the cell was equipped with a Cu / CuF ₂ reference electrode. The anode was an isobaric-compressed mesocarbon microbead with an active area of 2,25 cm ² . The anode and cathode product gases were separated by a TEFLON? Skirt extending below the liquid line. The cell was operated at 88 [deg.] C. The electrolysis was carried out in a constant current manner by an applied current density of 80 mA / cm &lt; ² &gt;. The cell operated stably to release the fluorine gas, and the cell voltage was 6.4 volts.

Comparative Example  5- Typical On the anode  By F ₂ Production of

The electrolysis described in Example 5 was repeated except that the anode was replaced with a conventional extruded carbon anode. The cell operated stably to release fluorine gas, but the cell voltage was higher at 7.0 volts.

Example  6- Mesocarbon On the anode  F at high current density due to ₂ Production of

The electrolysis described in Example 5 was repeated, except that a smaller cell was used which contained 25 ml of electrolyte. The isobaric-compressed mesocarbon anode has an active area of 0.5 cm ² . The cell operated at a current density of 225 mA / cm &lt; ^{2 &} gt ;. The anode emitted F ₂ gas with stable operation at a cell voltage of 6.8 volts.

Comparative Example  6- Typical On the anode  F at high current density ₂ Production of

The electrolysis described in Example 6 was repeated except that the anode was a conventional extruded carbon anode. The cell also operated at a current density of 225 mA / cm &lt; ^{2 &} gt ;. The cell emitted F ₂ gas, but the cell voltage was unstable at 7.7 to 8.5 volts.

Although illustrated and described above with reference to certain specific embodiments and examples, it is nevertheless not intended that the invention be limited to the details shown. Rather, various modifications may be made within the scope of equivalents of the claims and without departing from the spirit of the invention. Obviously, all ranges broadly recited in this document, for example, are intended to include all narrower ranges that are within a broader range within that range. Further, features of one embodiment may be incorporated into another embodiment. All publications, patents, and other documents referred to in this document are incorporated herein by reference in their entirety for all purposes, as if individually incorporated by reference.

Claims (32)

A method of producing electrolytic electrolysis by using an electrolysis anode comprising mainly anisotropic carbon arranged in parallel to produce nitrogen trifluoride or fluorine, including obtaining nitrogen trifluoride or fluorine. The method of claim 1, wherein the parallelly arranged anisotropic carbon comprises needle-like coke. 3. The process of claim 2, wherein the anode comprises at least 60% needle coke and optionally from 0 to 40% binder. 4. The method of claim 3, wherein the anode comprises a binder and the binder is a pitch. 3. The method of claim 2 wherein the anode comprises a binder and the needle coke and binder are isostatically compressed into a uniform form. 3. The method of claim 2, wherein the anode comprises a binder and the needle coke and binder have an average particle size of less than 25 microns. 3. The method of claim 2 wherein the needle coke is graphitized. 2. The method of claim 1, wherein the parallelly arranged anisotropic carbon comprises mesocarbon microbeads. 9. The method of claim 8 wherein the mesocarbon microbeads are isobaric compressed mesocarbon microbeads. 9. The method of claim 8, wherein the mesocarbon microbeads have an average particle size of about 1 to 5 microns. The method of claim 8, wherein the mesocarbon microbeads are not graphitized. The process according to claim 1, wherein the parallelly arranged anisotropic carbon comprises meso-phase carbon and the anode comprises at least 40% meso-phase carbon and optionally up to 10% stabilization adjuvant. The method of claim 1, wherein the anode has a density of 1.7 g / cm ³ or greater. The method of claim 1, wherein the anode is modeled and self-sintered mesocarbon microbeads and optional sintering aids. The method of claim 1, wherein the anode has an active area of up to about 70,000 cm ² . The method of claim 1, wherein the process produces less than 100 ppm CF ₄ in pure nitrogen trifluoride or fluorine. The method of claim 1, wherein the process produces less than 25 ppm CF ₄ in pure nitrogen trifluoride or fluorine. The method according to claim 1, wherein the process produces nitrogen trifluoride or fluorine at a selectivity of 70% or more. The method of claim 1 wherein the process produces nitrogen trifluoride or fluorine at a selectivity of 80% or greater. The process of claim 1 wherein the nitrogen trifluoride is produced and the electrolyte is a ternary electrolyte composition comprising HF, NH ₄ F, and KF. The method of claim 20, wherein the ternary electrolyte composition comprises 35-45 wt% HF, 15-25 wt% NH ₄ F, and 40-45 wt% KF. The method of claim 1 wherein the fluorine is produced and the electrolyte is a binary electrolyte composition comprising HF and KF. The method of claim 1 wherein nitrogen trifluoride is produced and the electrolyte is electrolyzed at a temperature of about 120 to 140 占 폚. The method of claim 1, wherein fluorine is produced and the electrolyte is electrolyzed at a temperature of about 80 to 90 占 폚. The method of claim 1, wherein the method is operated at a current density of about 70 to 250 mA / cm ² . The method of claim 1 wherein nitrogen trifluoride is produced and the process is operated at a current density of about 100 to 250 mA / cm ² . The method of claim 1, wherein fluorine is produced and the method is operated at a current density of about 120 to 250 mA / cm ² . An anode comprising anisotropic carbon arranged in parallel; Cathode; And an electrolytic cell for producing nitrogen trifluoride or fluorine comprising an electrolyte composition comprising HF, optional KF, and optionally NH ₄ F,
An electrolytic cell in which an electrolytic cell operates to produce nitrogen trifluoride or fluorine. 29. The electrolytic cell of claim 28, wherein the anode comprises self-sintered isostatically compressed mesocarbon microbeads and optional sintering aid. The electrolytic cell of claim 28, wherein the anode comprises needle-shaped coke and a pitch binder. 31. The electrolytic cell of claim 30, wherein the pitch binder and needle coke are blended first and then ground prior to compression. 29. The electrolytic cell of claim 28, wherein the anode exhibits retained wettability without the addition of a wetting agent.

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