CA2163221C - Process and apparatus for the purification of graphite - Google Patents
Process and apparatus for the purification of graphite Download PDFInfo
- Publication number
- CA2163221C CA2163221C CA002163221A CA2163221A CA2163221C CA 2163221 C CA2163221 C CA 2163221C CA 002163221 A CA002163221 A CA 002163221A CA 2163221 A CA2163221 A CA 2163221A CA 2163221 C CA2163221 C CA 2163221C
- Authority
- CA
- Canada
- Prior art keywords
- chlorine
- core
- pressure
- wall
- inert gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
- B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/14—Production of inert gas mixtures; Use of inert gases in general
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/20—Graphite
- C01B32/21—After-treatment
- C01B32/215—Purification; Recovery or purification of graphite formed in iron making, e.g. kish graphite
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
- B01J2208/00008—Controlling the process
- B01J2208/00017—Controlling the temperature
- B01J2208/00106—Controlling the temperature by indirect heat exchange
- B01J2208/00168—Controlling the temperature by indirect heat exchange with heat exchange elements outside the bed of solid particles
- B01J2208/00176—Controlling the temperature by indirect heat exchange with heat exchange elements outside the bed of solid particles outside the reactor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
- B01J2208/00008—Controlling the process
- B01J2208/00539—Pressure
Abstract
A process for the use of elemental chlorine, as a gas, in high temperature processes consists in circulating chlorine in a graphite reactor which has a double wall chamber. In the space defined by the double wall, a pressure of either nitrogen, argon or helium is maintained at a value higher than the pressure inside the reactor. In so doing, a radial diffusion of the gas within the wall towards the lower pressure zone inside the reactor is maintained through the graphite wall, thus sweeping to the inside of the reactor any chlorine that would otherwise diffuse radially outward and corrode rapidly the outer metallic shell of the reactor.
Description
TITLE OF THE INVENTION
Process and apparatus for the purification of graphite FIELD OF THE INVENTION
The present invention relates to an apparatus and a process for the confinement of chlorine gas at high temperature in the course of chlorination operations on various substrates.
BACKGROUND OF THE INVENTION
The use of chlorine gas at high temperature is quite common in many processes. For Example, treatment of impure graphite is reported as a technique for the purification of graphite.
In all these operations, chlorine at temperatures from 800 to more than 1600°C must be contained inside a reaction vessel and it has been found that the material showing the ideal resistance to the otherwise extremely corrosive action of C12 at high temperature is graphite.
But graphite has a very serious drawback as a material for handling hot chlorine: chlorine diffuses very readily through this substance.
Therefore, if a reactor or a reacting chamber is made of graphite inside a steel shell, chlorine, especially at high temperature, will diffuse outwards very readily and attack the external metallic wall, thus destroying the apparatus.
It would be highly desirable to use graphite reactors or reaction vessels in chlorination apparatus because of the very high stability of this form of carbon at high temperature if it were possible to prevent the adverse diffusion of chlorine outside of these graphite reactors or vessels.
Numerous attempts have been made in the past to provide moderate to high temperature treatments of substrates with chlorine.
Process and apparatus for the purification of graphite FIELD OF THE INVENTION
The present invention relates to an apparatus and a process for the confinement of chlorine gas at high temperature in the course of chlorination operations on various substrates.
BACKGROUND OF THE INVENTION
The use of chlorine gas at high temperature is quite common in many processes. For Example, treatment of impure graphite is reported as a technique for the purification of graphite.
In all these operations, chlorine at temperatures from 800 to more than 1600°C must be contained inside a reaction vessel and it has been found that the material showing the ideal resistance to the otherwise extremely corrosive action of C12 at high temperature is graphite.
But graphite has a very serious drawback as a material for handling hot chlorine: chlorine diffuses very readily through this substance.
Therefore, if a reactor or a reacting chamber is made of graphite inside a steel shell, chlorine, especially at high temperature, will diffuse outwards very readily and attack the external metallic wall, thus destroying the apparatus.
It would be highly desirable to use graphite reactors or reaction vessels in chlorination apparatus because of the very high stability of this form of carbon at high temperature if it were possible to prevent the adverse diffusion of chlorine outside of these graphite reactors or vessels.
Numerous attempts have been made in the past to provide moderate to high temperature treatments of substrates with chlorine.
2 However, it has been found that such operation was destructive for the equipment and therefore this approach did not receive the industrial applications which it deserved. This was due mainly to the great permeability of graphite toward chlorine, and it was noted that, for lack of material that can contain chlorine at an operating temperature between 800 and 1600°C, the gas would not discriminate between the substrate under treatment and the heating system, thus resulting in severe attack on both. Therefore, extreme corrosion prevented the use of a technique that would otherwise have allowed high performances.
OBJECTS AND STATEMENT OF THE INVENTION
It is an object of the present invention to define a process allowing reactions inside a reactor chamber made of graphite, with appropriate substrates, while preventing diffusion of chlorine through the walls of the reaction chamber.
Thus, the present invention is first concerned with a method whereby the permeability of graphite is put to use in order to avoid leakage of aggressive chlorine outside of the graphite reactor used for the reaction.
The implementation of reactions with chlorine calls for temperatures in the range of 800 to more than 1600°C. At these temperatures, a graphite reactor must be protected from atmospheric oxidation. Therefore, the present invention uses an atmosphere of an inert gas which does not react with carbon and an outside metallic shell for the containment of the inert atmosphere.
It has been found that, if a blanket of inert gas is circulated within the graphite walls of the reaction vessel and if the pressure inside the reactor is kept slightly below the pressure of the inert gas within the wall of ~a
OBJECTS AND STATEMENT OF THE INVENTION
It is an object of the present invention to define a process allowing reactions inside a reactor chamber made of graphite, with appropriate substrates, while preventing diffusion of chlorine through the walls of the reaction chamber.
Thus, the present invention is first concerned with a method whereby the permeability of graphite is put to use in order to avoid leakage of aggressive chlorine outside of the graphite reactor used for the reaction.
The implementation of reactions with chlorine calls for temperatures in the range of 800 to more than 1600°C. At these temperatures, a graphite reactor must be protected from atmospheric oxidation. Therefore, the present invention uses an atmosphere of an inert gas which does not react with carbon and an outside metallic shell for the containment of the inert atmosphere.
It has been found that, if a blanket of inert gas is circulated within the graphite walls of the reaction vessel and if the pressure inside the reactor is kept slightly below the pressure of the inert gas within the wall of ~a
3 the vessel which contains the atmosphere of chlorine, the chlorine is retained completely inside the reaction vessel.
The present invention therefore relates to a process for reacting a substrate with hot chlorine, the substrate being contained in the core of a reactor defined by enclosing walls made of graphite, the walls including a passageway therein; the process comprising the steps of:
- circulating an inert gas under pressure in the passageway within the graphite wall of the reactor;
- circulating chlorine under pressure in the core to react with the substrate;
- maintaining the pressure of the inert gas within the wall at a value higher than the pressure of the chlorine inside the reacting chamber so that chlorine permeating from the chamber through the wall is swept inside the core by the inert gas in the passageway and prevented from permeating completely through the wall; and - maintaining a temperature in the core at a value sufficient to obtain the desired reaction.
The present invention is further concerned to provide a geometry of construction of graphite reactors so as to allow reactions, inside the reactor chamber made of graphite, with appropriate substrates while preventing diffusion of chlorine through the walls of the reaction chamber.
The invention therefore further relates to an apparatus for implementing the above process, which comprises:
- a reactor having a core to receive therein substrate and walls around the core, the walls being made of graphite and defining a passageway therein;
g
The present invention therefore relates to a process for reacting a substrate with hot chlorine, the substrate being contained in the core of a reactor defined by enclosing walls made of graphite, the walls including a passageway therein; the process comprising the steps of:
- circulating an inert gas under pressure in the passageway within the graphite wall of the reactor;
- circulating chlorine under pressure in the core to react with the substrate;
- maintaining the pressure of the inert gas within the wall at a value higher than the pressure of the chlorine inside the reacting chamber so that chlorine permeating from the chamber through the wall is swept inside the core by the inert gas in the passageway and prevented from permeating completely through the wall; and - maintaining a temperature in the core at a value sufficient to obtain the desired reaction.
The present invention is further concerned to provide a geometry of construction of graphite reactors so as to allow reactions, inside the reactor chamber made of graphite, with appropriate substrates while preventing diffusion of chlorine through the walls of the reaction chamber.
The invention therefore further relates to an apparatus for implementing the above process, which comprises:
- a reactor having a core to receive therein substrate and walls around the core, the walls being made of graphite and defining a passageway therein;
g
4 - first inlet means to the core for allowing ingress of chlorine to react with the substrate in said core;
- second inlet means to the passageway for allowing ingress of an inert gas under pressure in the passageway;
- heating means surrounding the walls to maintain a temperature at a value sufficient to react chlorine with the substrate; and - outlet means from the core for allowing egress of said chlorine inert gas and volatile components.
In one preferred form of the invention, the inert gas is selected from a group comprising nitrogen, argon and helium, nitrogen being preferred.
In another form of the invention, the ratio of the pressure of the inert gas to the pressure of the chlorine is from 1.2 to 5, preferably 3.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that this detailed description, while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.
IN THE DRAWINGS
Fig. 1 is a cross-sectional view schematically representing an apparatus for carrying out the present invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
The annexed figure 1 illustrates an apparatus, generally designated 10, having a main body 12 provided with a central reaction chamber 14 in which is received a substrate 16 to be treated. The body 12 has an outlet port 18 with a passage 19 in communication with the upper part of the chamber 14 and an inlet port 20 having a central passage 22 in communication with the lower part of the chamber 14. Surrounding the inlet
- second inlet means to the passageway for allowing ingress of an inert gas under pressure in the passageway;
- heating means surrounding the walls to maintain a temperature at a value sufficient to react chlorine with the substrate; and - outlet means from the core for allowing egress of said chlorine inert gas and volatile components.
In one preferred form of the invention, the inert gas is selected from a group comprising nitrogen, argon and helium, nitrogen being preferred.
In another form of the invention, the ratio of the pressure of the inert gas to the pressure of the chlorine is from 1.2 to 5, preferably 3.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that this detailed description, while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.
IN THE DRAWINGS
Fig. 1 is a cross-sectional view schematically representing an apparatus for carrying out the present invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
The annexed figure 1 illustrates an apparatus, generally designated 10, having a main body 12 provided with a central reaction chamber 14 in which is received a substrate 16 to be treated. The body 12 has an outlet port 18 with a passage 19 in communication with the upper part of the chamber 14 and an inlet port 20 having a central passage 22 in communication with the lower part of the chamber 14. Surrounding the inlet
5 port is a second body 24 having a pair of inlets 26 and 28 to receive an inert gas, such as nitrogen. Body 24 is enclosed within a third body 30 having an inlet port 32 and an outlet port 34 for the circulation of water inside the body.
The water serves as a refrigerant for the walls of body 24.
A coil 50 is schematically represented to indicate that heat is required and provided in order to treat the content 16 in the reactor. A
metallic envelope to the apparatus has not been shown.
Body 24 has an inlet 36 for chlorine to be received within the chamber via passage 22. The inert gas introduced at inlets 26 and 28 circulates in the space between port 20 and body 24 and then through the surrounding area 38 defined between the inner wall 40 and the outer wall 42 of the body 12.
As illustrated by the various arrows 52 in figure 1, it can be seen that the chlorine introduced within the central chamber and attempting to diffuse outwardly through the wall 40 is returned inwardly as it reaches the passageway 38; it is swept inward by the high pressure of the inert gas in the passageway 38 which may also permeate through the walls 40 and 42 as indicated by arrows 54 and 56, respectively.
The implementation of the present invention calls for the adjustment of three variables; namely, the relative pressure within the reactor, the pressure ratio existing between chlorine and nitrogen and the ratio of thickness of the inner wall 40 and the outer wall 42 of the reactor.
The water serves as a refrigerant for the walls of body 24.
A coil 50 is schematically represented to indicate that heat is required and provided in order to treat the content 16 in the reactor. A
metallic envelope to the apparatus has not been shown.
Body 24 has an inlet 36 for chlorine to be received within the chamber via passage 22. The inert gas introduced at inlets 26 and 28 circulates in the space between port 20 and body 24 and then through the surrounding area 38 defined between the inner wall 40 and the outer wall 42 of the body 12.
As illustrated by the various arrows 52 in figure 1, it can be seen that the chlorine introduced within the central chamber and attempting to diffuse outwardly through the wall 40 is returned inwardly as it reaches the passageway 38; it is swept inward by the high pressure of the inert gas in the passageway 38 which may also permeate through the walls 40 and 42 as indicated by arrows 54 and 56, respectively.
The implementation of the present invention calls for the adjustment of three variables; namely, the relative pressure within the reactor, the pressure ratio existing between chlorine and nitrogen and the ratio of thickness of the inner wall 40 and the outer wall 42 of the reactor.
6 The relative pressure within the reactor as related to atmosphere must be kept negative so as to insure that the excess chlorine and other products are evacuated through the intended port 18 and do not tend to diffuse through the top cover. A negative pressure from 100 to 1000 Pascal proved to be appropriate.
The ratio of pressure of nitrogen to chlorine is a critical parameter. Chlorine, as it flows through the substrate layer 16 to be reacted, must have a positive pressure to insure an appropriate flow through the reacting bed. This positive pressure existing at the chlorine inlet at the bottom of the reactor is the main site of potential leaks. To correct this situation, the absolute pressure of nitrogen within the wall must be kept at values from two to five times the absolute pressure of chlorine. Under those conditions, no leakage of chlorine is observed.
The ratio of the thickness of the inner and outer walls determines the distribution of nitrogen leakage. This ratio may also be influenced by the density of the graphite walls, such density being related to porosity. Mechanical constraints may also enter into consideration. An inner chamber with high density material and with a 1:1 to 1:2 inner-to-outer wall width ratio gave excellent performances.
Examples 1. Determination of chlorine leakage A demonstration reactor has been built, having an inner diameter of 7.62 cm, the thickness of the inner wall being 2.54 cm (ratio 1:4).
A layer of 25 cm of impure graphite (85% C content) having an average particle size of 75 micron was loaded in the reactor. A vacuum of 1100 Pa was applied at the outlet of the reactor which was placed inside a steel envelope and was heated by arc on the bottom of the graphite cell.
The ratio of pressure of nitrogen to chlorine is a critical parameter. Chlorine, as it flows through the substrate layer 16 to be reacted, must have a positive pressure to insure an appropriate flow through the reacting bed. This positive pressure existing at the chlorine inlet at the bottom of the reactor is the main site of potential leaks. To correct this situation, the absolute pressure of nitrogen within the wall must be kept at values from two to five times the absolute pressure of chlorine. Under those conditions, no leakage of chlorine is observed.
The ratio of the thickness of the inner and outer walls determines the distribution of nitrogen leakage. This ratio may also be influenced by the density of the graphite walls, such density being related to porosity. Mechanical constraints may also enter into consideration. An inner chamber with high density material and with a 1:1 to 1:2 inner-to-outer wall width ratio gave excellent performances.
Examples 1. Determination of chlorine leakage A demonstration reactor has been built, having an inner diameter of 7.62 cm, the thickness of the inner wall being 2.54 cm (ratio 1:4).
A layer of 25 cm of impure graphite (85% C content) having an average particle size of 75 micron was loaded in the reactor. A vacuum of 1100 Pa was applied at the outlet of the reactor which was placed inside a steel envelope and was heated by arc on the bottom of the graphite cell.
7 A positive pressure of chlorine was admitted at the bottom of the reactor (1400 Pa) while the nitrogen pressure in the wall was kept at 4200 Pa. The system operated for eight hours and the outside surface probed for chlorine leak using a silver nitrate detector. No detectable chlorine could be measured either by chemical test or by olfaction. Copious production of volatile chlorides was noted at the outlet of the reactor.
2. Purification of graphite Using a reactor as described in Example 1, a sample of natural graphite was treated with chlorine in excess at 1750°C for 30 minutes.
The starting material, StratminT"" grade +5094, contained 94% of elemental carbon. After the operation, the carbon content was 99.99% t 0.01 %. No chlorine leakage was noted during this very high temperature operation.
Although the invention has been described above with respect with one specific form, it will be evident to a person skilled in the art that it may be modified and refined in various ways. It is therefore wished to have it understood that the present invention should not be limited in scope, except by the terms of the following claims.
i
2. Purification of graphite Using a reactor as described in Example 1, a sample of natural graphite was treated with chlorine in excess at 1750°C for 30 minutes.
The starting material, StratminT"" grade +5094, contained 94% of elemental carbon. After the operation, the carbon content was 99.99% t 0.01 %. No chlorine leakage was noted during this very high temperature operation.
Although the invention has been described above with respect with one specific form, it will be evident to a person skilled in the art that it may be modified and refined in various ways. It is therefore wished to have it understood that the present invention should not be limited in scope, except by the terms of the following claims.
i
Claims (10)
1. A process for reacting a substrate with hot chlorine, said substrate being contained in the core of a reactor defined by an enclosing wall made of graphite, said wall including a surrounding passageway therein;
said process comprising the steps of:
- circulating an inert gas in said passageway;
- circulating chlorine under a pressure in said core to react with said substrate;
- maintaining said inert gas at a pressure higher than said pressure of said chlorine in said core so that chlorine permeating from said core partially through said wall is swept inside said core by said inert gas in said passageway and prevented from permeating completely through said wall; and - maintaining a temperature in said core at a value sufficient to react chlorine with said substrate.
said process comprising the steps of:
- circulating an inert gas in said passageway;
- circulating chlorine under a pressure in said core to react with said substrate;
- maintaining said inert gas at a pressure higher than said pressure of said chlorine in said core so that chlorine permeating from said core partially through said wall is swept inside said core by said inert gas in said passageway and prevented from permeating completely through said wall; and - maintaining a temperature in said core at a value sufficient to react chlorine with said substrate.
2. A process as defined in Claim 1, wherein said inert gas is a gas selected from the group consisting of nitrogen, argon and helium.
3. A process as defined in Claim 1, wherein the ratio of the pressure of the inert gas to the pressure of chlorine is from 1.2 to 5.
4. A process as defined in Claim 3, wherein said ratio is about 3.
5. A process as defined in Claim 1, wherein the pressure above said substrate in the core of the reactor is maintained negative with respect to atmosphere pressure.
6. Apparatus for reacting a substrate with hot chlorine, which comprises:
- a reactor having a wall defining a core to receive therein said substrate, said wall being made of graphite and defining therein a passageway surrounding said core;
- first inlet means to said core allowing ingress of chlorine at a pressure to react with said substrate in said core;
- second inlet means to said passageway allowing ingress of an inert gas at a pressure higher than said pressure in said core so that chlorine partially permeating from said core through said wall is swept inside said core by said inert gas at said higher pressure and thereby prevented from permeating through said wall;
- means for heating said substrate in said core at a temperature sufficient to react chlorine with said substrate; and - outlet means from said core allowing egress of said chlorine, inert gas and volatile products.
- a reactor having a wall defining a core to receive therein said substrate, said wall being made of graphite and defining therein a passageway surrounding said core;
- first inlet means to said core allowing ingress of chlorine at a pressure to react with said substrate in said core;
- second inlet means to said passageway allowing ingress of an inert gas at a pressure higher than said pressure in said core so that chlorine partially permeating from said core through said wall is swept inside said core by said inert gas at said higher pressure and thereby prevented from permeating through said wall;
- means for heating said substrate in said core at a temperature sufficient to react chlorine with said substrate; and - outlet means from said core allowing egress of said chlorine, inert gas and volatile products.
7. Apparatus as defined in Claim 6, wherein said inert gas is a gas selected from the group consisting of nitrogen, argon and helium.
8. Apparatus as defined in Claim 6, wherein the ratio of the pressure of the inert gas to the pressure of chlorine is from 1.2 to 5.
9. Apparatus as defined in Claim 8, wherein said ratio is about 3.
10. Apparatus as defined in Claim 6, wherein said passageway defines an inner wall and an outer wall, each having a width, and wherein the width ratio of the inner wall to the outer wall is between 1:1 to 1:2.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/CA1993/000219 WO1994027909A1 (en) | 1993-05-21 | 1993-05-21 | Process and apparatus for the purification of graphite |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2163221A1 CA2163221A1 (en) | 1994-12-08 |
| CA2163221C true CA2163221C (en) | 2001-10-30 |
Family
ID=4172973
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002163221A Expired - Fee Related CA2163221C (en) | 1993-05-21 | 1993-05-21 | Process and apparatus for the purification of graphite |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU4057593A (en) |
| CA (1) | CA2163221C (en) |
| WO (1) | WO1994027909A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109437186A (en) * | 2018-11-23 | 2019-03-08 | 湖南顶立科技有限公司 | A kind of graphite powder and its denitrification process |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101817523B (en) * | 2009-03-19 | 2011-09-28 | 株洲弗拉德科技有限公司 | Graphite purification and graphitizable high temperature vertical continuous induction heating furnace |
| CN102745681B (en) * | 2012-07-19 | 2014-07-09 | 武汉工程大学 | Method and device for purifying graphite |
| CN106145104A (en) * | 2016-08-31 | 2016-11-23 | 无锡东恒新能源科技有限公司 | A kind of integration graphite purification equipment |
| TWI607966B (en) * | 2016-12-22 | 2017-12-11 | 國家中山科學研究院 | Method for making graphite structure of different phases |
| CN107539982A (en) * | 2017-10-31 | 2018-01-05 | 湖南国盛石墨科技有限公司 | A kind of high-purity micro crystal graphite production system and its production technology |
| EP3514128A1 (en) | 2018-01-18 | 2019-07-24 | Heraeus GMSI LLC | Process for manufacturing a silicon carbide coated body |
| EP3514130A1 (en) | 2018-01-18 | 2019-07-24 | Heraeus GMSI LLC | Process for manufacturing a silicon carbide coated body |
| EP3514259A1 (en) | 2018-01-18 | 2019-07-24 | Heraeus GMSI LLC | Process for manufacturing a silicon carbide coated body |
| EP3514257A1 (en) | 2018-01-18 | 2019-07-24 | Heraeus GMSI LLC | Process for manufacturing a silicon carbide coated body |
| EP3514127A1 (en) | 2018-01-18 | 2019-07-24 | Heraeus GMSI LLC | Process for manufacturing a silicon carbide coated body |
| EP3514129A1 (en) | 2018-01-18 | 2019-07-24 | Heraeus GMSI LLC | Process for manufacturing a silicon carbide coated body |
| EP3626865A1 (en) | 2018-09-20 | 2020-03-25 | Heraeus GMSI LLC | Susceptor and method for manufacturing the same |
| CN109336104A (en) * | 2018-11-23 | 2019-02-15 | 北京航空航天大学 | A kind of low temperature graphite purification method |
| CN111362263A (en) * | 2020-04-07 | 2020-07-03 | 佛山瑞之进智汇科技有限公司 | Preparation method of high-purity graphite material |
| CN111841286A (en) * | 2020-08-28 | 2020-10-30 | 上海岚玥新材料科技有限公司 | Novel graphite purification residual waste gas treatment device and process |
| CN112320793B (en) * | 2020-10-22 | 2022-04-05 | 中钢新型材料股份有限公司 | Preparation process of high-purity graphite powder for synthesizing semiconductor-grade SiC powder |
| CN112340726A (en) * | 2020-11-18 | 2021-02-09 | 湖南顶立科技有限公司 | Preparation method of high-purity graphite crucible |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2914383A (en) * | 1951-11-16 | 1959-11-24 | Graphitwerk Kropfmuhl Ag | Process of purifying graphite |
| JPS61101408A (en) * | 1984-10-19 | 1986-05-20 | Hitachi Chem Co Ltd | Purification of graphite and apparatus therefor |
| JPH0645446B2 (en) * | 1988-09-19 | 1994-06-15 | 東海カーボン株式会社 | Method for producing high-purity graphite fine powder |
-
1993
- 1993-05-21 CA CA002163221A patent/CA2163221C/en not_active Expired - Fee Related
- 1993-05-21 AU AU40575/93A patent/AU4057593A/en not_active Abandoned
- 1993-05-21 WO PCT/CA1993/000219 patent/WO1994027909A1/en active Application Filing
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109437186A (en) * | 2018-11-23 | 2019-03-08 | 湖南顶立科技有限公司 | A kind of graphite powder and its denitrification process |
Also Published As
| Publication number | Publication date |
|---|---|
| AU4057593A (en) | 1994-12-20 |
| WO1994027909A1 (en) | 1994-12-08 |
| CA2163221A1 (en) | 1994-12-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2163221C (en) | Process and apparatus for the purification of graphite | |
| US6548113B1 (en) | Vacuum/gas phase reactor for dehydroxylation and alkylation of porous silica | |
| EP0194373A2 (en) | Improvements in or relating to the deposition of a coating on a porous substrate | |
| JPS6256232B2 (en) | ||
| US4484954A (en) | Halogenation treatment | |
| US3222212A (en) | Process for chromizing | |
| JP4327410B2 (en) | Batch type hydrothermal reactor and hydrothermal reactor | |
| CA2095646A1 (en) | Method for Co-Processing Organic Wastes and Spent Nitric Acid Wash Water | |
| EP0063555B1 (en) | Chlorinator furnace and method for producing tetrachloride of such metals as titanium and zirconium | |
| US9901890B2 (en) | Dual vessel reactor | |
| US4153480A (en) | Method for forming an anticorrosive oxide layer on steels | |
| US4314880A (en) | Hydrogen permeation resistant barrier | |
| US5580397A (en) | Carbide and carbonitride surface treatment method for refractory metals | |
| JPS56161841A (en) | Manufacture of composite oxide catalyst | |
| GB1551340A (en) | Method of electroplating | |
| US20040089238A1 (en) | Vacuum/gas phase reactor for dehydroxylation and alkylation of porous silica | |
| JP5260012B2 (en) | Method for forming surface oxide film on stainless steel | |
| US3353936A (en) | Chromized ferrous article | |
| EP0533380B1 (en) | Catalytic reactor | |
| US20140086809A1 (en) | Dual vessel reactor | |
| JP3683572B2 (en) | CVD reactor | |
| US4298495A (en) | Processes for reducing the oxygen content of metal oxides | |
| Barański et al. | The concept of mixed-control mechanisms and its applicability to paper degradation studies | |
| Savić et al. | In-house-prepared carbon-based Fe-doped catalysts for electro-Fenton degradation of azo dyes | |
| FI82716B (en) | FOERFARANDE FOER AVLAEGSNANDE AV VAETE FRAON ETT METALLFOEREMAOL GENOM VAERMEBEHANDLING I ROTERUGN. |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |