CN102863312B - Preparation process of carbon tetrafluoride and device implementing same - Google Patents
Preparation process of carbon tetrafluoride and device implementing same Download PDFInfo
- Publication number
- CN102863312B CN102863312B CN201210355457.5A CN201210355457A CN102863312B CN 102863312 B CN102863312 B CN 102863312B CN 201210355457 A CN201210355457 A CN 201210355457A CN 102863312 B CN102863312 B CN 102863312B
- Authority
- CN
- China
- Prior art keywords
- reactor
- stage
- reaction
- raw material
- fluorine 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.)
- Active
Links
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
The invention discloses a preparation process of carbon tetrafluoride and a device implementing the same. The preparation process includes directly reacting fluorine with solid carbonic raw material, performing two-stage reaction to prepare carbon tetrafluoride, filling fluorine from the upper portion of a first-stage reactor to contact with the solid carbonic raw material in the reactor for reaction, mixed gas produced by the first-stage reactor entering a second-stage reactor, and further reacting fluorine which is not reacted with the solid carbonic raw material in the second-stage reactor, wherein the first-stage reactor and the second stage reactor are both vertical reactor and are communicated with each other in a sealing manner. A temperature-decreasing water jacket is arranged outside the first-stage reactor, and temperature-decreasing water is 20-90 DEG C. A heating sleeve is arranged outside the second-stage reactor, and temperature of the inside of the reactor is 310-400 DEG C. Efficiency of fluorine after reaction in the first-stage reactor and the second-stage reactor reaches 100%. The fluorine used for reaction by the process need not be diluted, ignition agent is not required, the fluorine directly enters the reactors for reaction, fluorine utilization rate is high, reaction process is stable and controllable, and the process is suitable for industrial application.
Description
Technical field
The present invention relates to the method and apparatus preparing tetrafluoro-methane.
Background technology
Tetrafluoro-methane is plasma etching gas important in current microelectronics industry, be widely used in the etching of the thin-film materials such as silicon, silicon-dioxide, silicon nitride, phosphorosilicate glass and tungsten, in stain remover, lubricant and braking fluid etc. in the production of electron device surface cleaning, solar cell, laser technology, cryogenic refrigeration, gas-insulated, leak detectants, printed wiring are produced, also have extensive application.
Tetrafluoro-methane synthetic method is a lot, comprises hydrofluorocarbons and fluorine gas, cfc and prepares tetrafluoro-methane etc. with hydrogen fluoride and fluorine gas and the direct contact reacts of carbon source in the presence of a catalyst.Wherein, current maturation process adopts hydrofluorocarbons, cfc does carbon source and prepares tetrafluoro-methane, and the prices of raw and semifnished materials are expensive, easily blast, and have the impurity not easily removed in synthetic product; The direct contact reaction method of fluorine carbon prepares tetrafluoro-methane, and the method, through continuous development and perfection, can prepare tetrafluoro-methane.
Patent documentation CN101580452 discloses a kind of preparation technology and equipment thereof, utilizes fluorine gas and solid carbon raw material direct reaction, adopts two-stage reactor preparation.First step reactor is the horizontal reactor of interior tray, and second stage reactor is vertical reactor, is first laid in equably on pallet by solid carbon raw material, then pass into fluorine gas under the effect of the gas that ignites with carbon contact reacts.The F of non-complete reaction in first step reactor product
2enter second stage vertical reactor and solid carbon raw material reacts further, I and II reactor is connected by gas pipeline.Thick gas purity after ordinary method dedusting, washing, alkali cleaning can reach more than 95%.Through two-stage reaction, F
2utilization ratio reaches more than 98%.Solid carbon raw material is charcoal, activated carbon, retard petroleum coke or after-smithing petroleum coke; Pilot gas is low-carbon paraffin or its fluoric ether; First step reactor reaction temperature is at 300 ~ 500 DEG C, and second stage reactor reaction temperature is at 300 ~ 550 DEG C.Unreacted fluorine gas can not be removed by this technique second reactor completely, in industrial production, fluorine gas total reaction efficiency can not reach 100%, second reactor adopts heating, cooling two kinds of means replace control temperature, and pyroreaction wall frequently contacts low temperature temperature lowering water, there is potential safety hazard.In addition, fluorine gas needs dilution before entering reactor, increases subsequent fine and makes this.
Patent documentation CN101298318 discloses a kind of technique preparing high-pure carbon tetrafluoride, this technique fluorine used source is pure fluorine gas, employing storage tank stores, cost is higher, and there is potential safety hazard in industrial production link, the gac reacted with fluorine gas needs to be preheating to 150 ~ 300 DEG C before the reaction, structure of reactor is complicated, and in this Process Production tetrafluoro-methane, foreign matter content is high, is unsuitable for suitability for industrialized production.
The anode gas containing HF that Russ P document RU2181351 adopts electrolysis KF2HF to generate does fluorine source, reacts to prepare CF with charcoal
4.This reaction process Problems existing is that temperature of reaction is higher, and the temperature tube stretching into reactive center district very easily corrodes, and in resultant, impurity is more, and subsequent purification cost is higher.
Patent documentation CN201250097 discloses a kind of reactor preparing carbon tetrafluoride gas, this temperature of reactor detector is also at inside reactor, under high temperature and fluorine gas exist, temperature tube very easily corrodes, there is potential safety hazard, and in the industrial production, because being single-stage reactor, fluorine gas utilization ratio is low, product foreign matter content is high, and production cost is higher.
Summary of the invention
First technical problem that the present invention will solve is to provide a kind of easy, efficient, preparation process of carbon tetrafluoride of being suitable for industrial applications, the fluorine gas that electrolytic process produces directly introduces reactor without dilution, fluorine gas reaction efficiency is high, and overcomes a reactor reaction zone temperature monitoring difficult problem.
Second technical problem that the present invention will solve is to provide a kind of equipment being suitable for this technique.
Present invention process utilizes fluorine gas and solid carbon raw material direct reaction, adopts two-stage reaction to prepare tetrafluoro-methane.The first step, second stage reactor are vertical reactor.Fluorine gas passes into from first step reactor top, with the solid carbon raw material contact reacts in reactor, the gas mixture that first step reactor produces enters second stage reactor, and unreacted fluorine gas reacts further with solid carbon raw material in the reactor of the second stage, and between I and II reactor, sealing is communicated with.First step reactor outside is provided with cooling chuck, and temperature lowering water temperature out is generally at 20 ~ 90 DEG C; Reactor outside, the second stage is provided with heating jacket, and inside reactor temperature is generally at 310 ~ 400 DEG C.After two-stage reactor reaction, fluorine gas reaction efficiency reaches 100%.First, second stage reactor above-mentioned directly can be processed into one.
Because the reaction of fluorine carbon is strong exothermal reaction, first step reactor of the present invention utilizes temperature lowering water system to take away reaction liberated heat, and guard reactor is not corroded by fluorine gas.The fluorine gas amount entering second stage reactor is less, and fluorine and carbon exothermic heat of reaction are not enough to the temperature maintaining second stage reactor, and second stage reactor is by indirect heating Systematical control temperature of reactor.
The thick gas generated through above-mentioned reactor reaction introduces pyrolysis device, can remove part oxidizing substance in thick gas further.
Be suitable for fluorine gas of the present invention except high-purity fluorine gas, the fluorine gas containing impurity generated by electrolytic process electrolyzer Direct Electrolysis is also suitable for the present invention.The inventive method is by controlling the flow velocity of fluorine gas in reactor and the residence time controls level of response, and fluorine gas flow velocity is generally 0.01 ~ 0.1m/s, and the residence time is generally 30 ~ 120s.Fluorine gas flow velocity in reactor is too low, reaction zone fluorine gas quantity not sufficient, and fluorine gas reaction efficiency is low and foreign matter content is higher; Fluorine gas flow velocity is too fast, reacts insufficient.Preferred fluorine gas flow velocity is 0.03 ~ 0.06m/s.
Be suitable for solid carbon raw material of the present invention and comprise charcoal, gac, coconut husk Jiao, retard petroleum coke and after-smithing petroleum coke etc.Because in solid carbon raw material, carbon content is higher, in reaction product, foreign matter content is lower, and operate simpler in later separation purifying process, cost is lower.Therefore the preferably gac of carbon content 96% ~ 99% or after-smithing petroleum coke.Solid carbon raw material preferably particle diameter at 4.5 ~ 10cm.
Being suitable for first step reactor of the present invention is vertical tubular reactor, fluorine gas entrance and solid carbon raw material charging opening are arranged at reactor top, inside reactor lower end is provided with sieve plate, and reactor lower part pneumatic outlet is directly connected with second stage reactor, reactor peripheral hardware cooling chuck.
Being suitable for the second stage of the present invention reactor is vertical tubular reactor, second stage reactor head communicates with the bottom of first step reactor, solid carbon raw material charging opening is arranged at top, bottom has product gas to export, inside reactor lower end is provided with sieve plate, there is heating system outside, and there is temperature measuring equipment inside.The material being suitable for first, second stage reactor of the present invention can be soft steel, stainless steel, nickel or Monel metal etc.
The present invention adopts two-stage vertical reactor, and reaction fluorine gas does not need dilution, does not need detonator, directly enters reactor reaction, and reaction core area temperature is high, and fluorine gas utilization ratio is high, and foreign matter content is low; Regulate fluorine gas flow velocity and the residence time, control reaction process, can evade and be difficult to monitoring problem to the temperature of high-temperature zone, reaction process is more steady, controlled.First and second stage reactor is combined as a whole, and structure is compacter, is suitable for industrial applications.
Accompanying drawing explanation
Fig. 1 is structure of reactor schematic diagram of the present invention.
Embodiment
Below in conjunction with drawings and Examples, the invention will be further described.
As shown in Figure 1, this reactor is divided into upper and lower two-stage.First step reactor lower part has sieve plate 3, and solid carbon raw material adds in reactor from charging opening 2, and fluorine gas enters first step reactor from entrance 1, and fluorine gas and solid carbon raw material react, and hybrid reaction gas directly enters second stage reactor, and gas mixture consists of CF
4, C
2f
6, HF, F
2deng.Cooling protection is carried out by cooling chuck 4 pairs of A reactors.
Second stage reactor and A reactor directly seal and are communicated with, and solid carbon raw material adds in the reactor of the second stage from charging opening 6, and second stage reactor lower part has sieve plate 5, and temperature of reactor is controlled by heated for controlling temperature system 7.The gas mixture of being discharged by first step reactor enters second stage reactor, and contact with the solid carbon raw material after heating, in first step reactor, unreacted fluorine gas and solid carbon raw material react further, obtained CF
4thick gas is discharged from the second reactor outlet 8.Fluorine gas reaction efficiency reaches 100%.
From reactor thick gas out, enter Pintsch process device, controlling cracker temperature is 250 ~ 500 DEG C, remove portion oxidative impurities, then product purity reaches more than 95% after ordinary method dedusting, washing, alkali cleaning.
Embodiment 1
Reactor is low-carbon steel material, and reactor inside diameter is 100mm, and two-stage reactor length is 3000mm.
Employing calcined coke is solid carbon raw material, and its carbon content is greater than 98%, particle diameter 4.5 ~ 7cm.Calcined coke after drying joins in reactor, and fluorine gas is obtained by electrolysis, containing have an appointment 5% the impurity such as HF, with the empty tower gas velocity of 0.02m/s, fluorine gas is passed into first step reactor continuously, mean residence time 100s.The gas mixture generated enters second stage reactor, reacts further in the reactor of the second stage with carbon.By temperature lowering water system to first step reactor cooling protection, controlling temperature lowering water temperature out is 20 DEG C, and second stage reactor, by electric heating system, controls reactor temperature 340 ± 20 DEG C.The thick gas that reaction generates enters Pintsch process device, in-built nickel wire, cracking temperature 300 ± 20 DEG C, and after cracking, gas is again after washing, alkali cleaning, adopts stratographic analysis product composition.Plant running 72h, stopped reaction.Analytical results is in table 1.
Embodiment 2
Reactor is low-carbon steel material, and structure is identical with embodiment 1.
Employing calcined coke is solid carbon raw material, and its carbon content is greater than 98%, particle diameter 4.5 ~ 7cm.Calcined coke after drying joins in reactor, fluorine gas is obtained by electrolytic process, containing have an appointment 5% the impurity such as HF, with the empty tower gas velocity of 0.06m/s, fluorine gas is passed into first step reactor continuously, mean residence time 50s, the gas mixture generated enters second stage reactor, reacts further in the reactor of the second stage with carbon.By temperature lowering water system to first step reactor cooling protection, control temperature lowering water temperature out 70 DEG C, second stage reactor, by electric heating system, controls reactor temperature 360 ± 20 DEG C.The thick gas that reaction generates enters Pintsch process device, in-built nickel wire, cracking temperature 350 ± 20 DEG C, and after cracking, gas is again after washing, alkali cleaning, adopts stratographic analysis product composition.Plant running 72h, stopped reaction.Analytical results is in table 1.
Embodiment 3
Reactor is stainless steel, and structure is identical with embodiment 1.
Employing calcined coke is solid carbon raw material, and its carbon content is greater than 98%, particle diameter 6 ~ 9cm.Calcined coke after drying joins in reactor, fluorine gas is obtained by electrolysis, containing have an appointment 5% the impurity such as HF, with empty tower gas velocity 0.08m/s, fluorine gas is passed into first step reactor continuously, mean residence time 40s, the gas mixture generated enters second stage reactor, reacts further in the reactor of the second stage with carbon.By temperature lowering water system to first step reactor cooling protection, control temperature lowering water temperature out 90 DEG C, second stage reactor passes through electric heating system, control temperature 370 ± 20 DEG C.The thick gas that reaction generates enters Pintsch process device, in-built palladium metal loaded catalyst, cracking temperature 400 ± 20 DEG C, and after cracking, gas is again after washing, alkali cleaning, adopts stratographic analysis product composition.Plant running 72h, stopped reaction.Analytical results is in table 1.
Embodiment 4
Reactor is nickel material, and structure is identical with embodiment 1.
Employing gac is solid carbon raw material, its carbon content about 96%, particle diameter 4.5cm ~ 6cm.Gac after drying joins in reactor, fluorine gas is obtained by electrolysis, containing have an appointment 5% the impurity such as HF, first step reactor is passed into continuously with empty tower gas velocity 0.04m/s, mean residence time 60s, the gas mixture generated enters second stage reactor, reacts further in the reactor of the second stage.By temperature lowering water system to first step reactor cooling protection, control temperature lowering water temperature out 40 DEG C, second stage reactor passes through electric heating system, control temperature 380 ± 20 DEG C.The thick gas that reaction generates enters Pintsch process device, in-built metal platinum loaded catalyst, temperature 400 ± 20 DEG C, and thick gas, again after washing, alkali cleaning, adopts stratographic analysis product composition.Plant running 72h, stopped reaction.Analytical results is in table 1.
Embodiment 5
Reactor is Monel material, and structure is same as Example 1.
Employing gac is solid carbon raw material, its carbon content about 96%, particle diameter 4.5cm ~ 6cm.Gac after drying joins in reactor, fluorine gas is obtained by electrolysis, containing have an appointment 5% the impurity such as HF, first step reactor is passed into continuously with empty tower gas velocity 0.09m/s, mean residence time 30s, the gas mixture generated enters second stage reactor, reacts further in the reactor of the second stage.By temperature lowering water system to first step reactor cooling protection, control temperature lowering water temperature out 60 DEG C, second stage reactor passes through electric heating system, control temperature 350 ± 20 DEG C.The thick gas that reaction generates enters Pintsch process device, in-built metal platinum loaded catalyst, temperature 450 ± 20 DEG C, and thick gas, again after washing, alkali cleaning, adopts stratographic analysis product composition.Plant running 72h, stopped reaction.Analytical results is in table 1.
Table 1 experimental result
Claims (9)
1. a preparation process of carbon tetrafluoride, utilize fluorine gas and solid carbon raw material direct reaction, two-stage reaction is adopted to prepare tetrafluoro-methane, the first step, second stage reactor is vertical reactor, fluorine gas passes into from first step reactor top, with the solid carbon raw material contact reacts in reactor, the gas mixture that first step reactor produces enters second stage reactor, unreacted fluorine gas reacts further with solid carbon raw material in the reactor of the second stage, one, between second reactor, sealing is communicated with, first step reactor outside is provided with temperature lowering water chuck, temperature lowering water temperature out is at 20 ~ 90 DEG C, reactor outside, the second stage is provided with heating jacket, and inside reactor temperature is at 310 ~ 400 DEG C, the not interior tray of first step reactor, enter the fluorine gas of first step reactor without the need to dilution, fluorine gas and solid carbon raw material react without the need to the gas that ignites.
2. preparation process of carbon tetrafluoride according to claim 1, the flow velocity of fluorine gas in reactor is 0.01 ~ 0.1m/s, and the residence time is 30 ~ 120s.
3., according to the preparation process of carbon tetrafluoride one of claim 1 ~ 2 Suo Shu, described fluorine gas refers to the fluorine gas containing impurity generated by electrolytic process electrolyzer Direct Electrolysis.
4., according to the preparation process of carbon tetrafluoride one of claim 1 ~ 2 Suo Shu, solid carbon raw material refers to charcoal, gac, coconut husk Jiao, retard petroleum coke or after-smithing petroleum coke.
5. preparation process of carbon tetrafluoride according to claim 4, solid carbon raw material is gac or the after-smithing petroleum coke of carbon content 96% ~ 99%, and particle diameter is at 4.5 ~ 10cm.
6. preparation process of carbon tetrafluoride according to claim 5, is characterized in that fluorine gas reaction efficiency reaches 100%.
7. preparation process of carbon tetrafluoride according to claim 6, is characterized in that the thick gas that reactor reaction generates introduces pyrolysis device, further oxidizing substance in the thick gas of removing.
8. the equipment of the described preparation process of carbon tetrafluoride of one of claim 1 ~ 7, be made up of two-stage vertical reactor, inner temperature measuring equipment is not established in first step reactor, fluorine gas entrance (1) and solid carbon raw material charging opening (2) are arranged at first step reactor top, inside reactor lower end is provided with sieve plate (3), reactor lower part pneumatic outlet is directly connected with second stage reactor, reactor peripheral hardware cooling chuck (4); Second stage reactor head communicates with the bottom of first step reactor, solid carbon raw material charging opening (6) is arranged at top, bottom has product gas to export (8), inside reactor lower end is provided with sieve plate (5), there is heating system (7) outside, and there is temperature measuring equipment inside.
9. the equipment of preparation process of carbon tetrafluoride according to claim 8, is characterized in that material is soft steel, stainless steel, nickel or Monel metal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210355457.5A CN102863312B (en) | 2012-09-07 | 2012-09-07 | Preparation process of carbon tetrafluoride and device implementing same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210355457.5A CN102863312B (en) | 2012-09-07 | 2012-09-07 | Preparation process of carbon tetrafluoride and device implementing same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102863312A CN102863312A (en) | 2013-01-09 |
| CN102863312B true CN102863312B (en) | 2015-02-11 |
Family
ID=47442482
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210355457.5A Active CN102863312B (en) | 2012-09-07 | 2012-09-07 | Preparation process of carbon tetrafluoride and device implementing same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102863312B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107128896B (en) * | 2017-07-17 | 2023-03-10 | 洛阳森蓝化工材料科技有限公司 | Graphite fluoride tubular reaction furnace |
| CN109867586A (en) * | 2017-12-04 | 2019-06-11 | 浙江省化工研究院有限公司 | A kind of method of fluoroform resourcable transformation production carbon tetrafluoride |
| JP7140983B2 (en) * | 2017-12-19 | 2022-09-22 | セントラル硝子株式会社 | Manufacturing method of tungsten hexafluoride |
| CN108946816A (en) * | 2018-09-03 | 2018-12-07 | 黎明化工研究设计院有限责任公司 | A kind of tungsten hexafluoride preparation method and its reactor |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201250097Y (en) * | 2008-06-24 | 2009-06-03 | 核工业理化工程研究院华核新技术开发公司 | Reactor for preparing carbon tetrafluoride gas |
| CN101580452A (en) * | 2009-06-22 | 2009-11-18 | 黎明化工研究院 | Preparation process of carbon tetrafluoride and equipment thereof |
-
2012
- 2012-09-07 CN CN201210355457.5A patent/CN102863312B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201250097Y (en) * | 2008-06-24 | 2009-06-03 | 核工业理化工程研究院华核新技术开发公司 | Reactor for preparing carbon tetrafluoride gas |
| CN101580452A (en) * | 2009-06-22 | 2009-11-18 | 黎明化工研究院 | Preparation process of carbon tetrafluoride and equipment thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102863312A (en) | 2013-01-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102863312B (en) | Preparation process of carbon tetrafluoride and device implementing same | |
| CN101580452B (en) | Preparation process of carbon tetrafluoride and equipment thereof | |
| CN108147406A (en) | A kind of method for purifying Delanium | |
| CN102816045B (en) | Method for synthesizing chloromethane by tail gas generated during chloroacetic acid production | |
| CN106139890A (en) | Cold-rolled steel sheet heat treatment nitrogen hydrogen mixed tail gas reclaims the apparatus and method purifying | |
| CN202864909U (en) | Carbon tetrafluoride reactor | |
| CN102145251A (en) | Dechloridation device and process in chlorinated paraffin production process | |
| CN104030293B (en) | A kind of silicon tetrachloride purifying technique and system | |
| CN101798689A (en) | Process and device for preparing nitrogen trifluoride by continuous electrolytic process | |
| CN103497086A (en) | Preparation method of perfluoropropane | |
| CN106621757B (en) | Chlorosilane analysis waste gas recovery treatment device and treatment method | |
| CN106699497B (en) | Method for preparing cyclopentadiene by gas-phase depolymerization of dicyclopentadiene | |
| CN105367379B (en) | A kind of method that utilization circular response prepares perfluoroethane | |
| CN103172067B (en) | Cold wall fluidized bed and application thereof | |
| CN215540754U (en) | Reaction device for high-purity chlorine trifluoride | |
| CN106220491B (en) | Production of chloroacetic acid method | |
| CN104555925A (en) | Method for recycling tail gas in trichlorosilane production process | |
| CN104261413B (en) | Plasma deoxidization in low termprature producing trichlorosilane by using silicon tetrachloride method and device thereof | |
| CN220780272U (en) | Device for continuously preparing high-purity tungsten hexafluoride in green, efficient and low-energy consumption mode | |
| CN103408021A (en) | Method for synthesizing trichlorosilane by utilizing reverse-disproportionation device | |
| CN109956452A (en) | A kind of preparation method and its device of reagent hydrochloric acid | |
| CN116947598B (en) | Method for producing tetrafluoromethane by taking trifluoromethane as raw material | |
| CN103408020B (en) | For the preparation of the equipment of silane | |
| CN104016304B (en) | A kind of method utilizing the hydrogen chloride gas of tetrafluoroethylene by-product to prepare concentrated hydrochloric acid | |
| CN218909881U (en) | Tetrafluoro oxygen sulfur apparatus for producing |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20210521 Address after: 471012 No.12 Daonan Road, Jili District, Luoyang City, Henan Province Patentee after: Haohua Gas Co.,Ltd. Address before: 471000 No. 69 Wangcheng Avenue, Luoyang, Henan Patentee before: LIMING Research Institute OF CHEMICAL INDUSTRY |