CA1203667A - Process for hydrophobing pyrogenically produced silicon dioxide - Google Patents
Process for hydrophobing pyrogenically produced silicon dioxideInfo
- Publication number
- CA1203667A CA1203667A CA000424544A CA424544A CA1203667A CA 1203667 A CA1203667 A CA 1203667A CA 000424544 A CA000424544 A CA 000424544A CA 424544 A CA424544 A CA 424544A CA 1203667 A CA1203667 A CA 1203667A
- Authority
- CA
- Canada
- Prior art keywords
- silica
- process according
- waste gases
- fluidized bed
- 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
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
- C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
- C09C1/28—Compounds of silicon
- C09C1/30—Silicic acid
- C09C1/3081—Treatment with organo-silicon compounds
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
- C01P2004/82—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases
- C01P2004/84—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases one phase coated with the other
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Silicon Compounds (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
After separating the hydrogen halide pyrogenically produced silicon dioxide is mixed with nitrogen and fed into a cyclone. After separating the silicon dioxide from the gases, which are returned to the cooling zone of the production appar-atus, the silicone dioxide is mixed first with organo-halo silane and then with water vapour and nitrogen. The hydrophob-ing reaction is subsequently carried out in a conventional manner in a fluidized bed reactor. The waste gases from the reaction are returned to the cyclone.
After separating the hydrogen halide pyrogenically produced silicon dioxide is mixed with nitrogen and fed into a cyclone. After separating the silicon dioxide from the gases, which are returned to the cooling zone of the production appar-atus, the silicone dioxide is mixed first with organo-halo silane and then with water vapour and nitrogen. The hydrophob-ing reaction is subsequently carried out in a conventional manner in a fluidized bed reactor. The waste gases from the reaction are returned to the cyclone.
Description
L~
The present invention relates to process for hydro-phobin~ ~yro~enically produced silicoll dioxide which process is preferably directly combined with and following the process for producing t~e ~yrogenic silicone dioxide from a silicon halide compound.
German patent No. 1,163,748 discloses a process for the hydrophobing of pyrogenically produced silicon dioxide with dimethyl-dichloro silane in a fluidized bed. According to the process the individual components are so mixed wi-th one another that water vapour in mixture with nitrogen is mixed with the pyrogenically produced silicon dioxide. A gas mixture consist-ing of dimethyl-dichloro silane and nitrogen is then fed to this moist si]icon dioxide. The actual hydrophobing reaction is carried out subsequently in a fluidi~ed bed reactorD This process has -the disadvantage that because of the moisture con-tent of the pyrogenically produced silicon dioxide the pipe lines of the hydrophobing apparatus become clogged. Futhermore hi~h losses in yield and undesired by-products are obtained clue to the partial reaction oE the organo-halo silane with the ~0 water vapour on the pyrogenically produced silicon dioxide be~ore -the hydrophobing reaction can be carried out under con-trolled conditions in the fluid bed reactor. A further disad-vanta~e of the process of German Patent No. 1,163,784 results from the specific composition of the waste gas of the hydro-phobing reaction. This waste gas consists of hydrophobed pyrogenic silicon dioxide, excess organo-halo silane, hydrogen chloride and, when dimethyl-dichloro silane is reacted as or~ano-halo silane, nitrogen and water.
~y means of the recycling of waste gas described in -the drawin~ of German Patent No~ 1,163,784 hydrophobed si]icon~iio~ide is passed in-to the hydrogen chloride absorption device.
This results in undesired foaming. The waste gas pipes become ~,~
clogged by polymeriza-tion reac-tions of the organo-halo silane.
This causes problems in the plant, such as pressure loss and fire. :[n the attempt -to process this was-te gas by washing it with wa-ter in a cooling tower intense foaming occurs in the waste water. This foam is circulated in the cooling -tower, causing the forma-tion of "dry water" by the hydrophobic pyro-genically produced silicon dioxideO This foam cannot be fil--tered off since the filters would rapidly become clogged.
I() According to the present invention there is pro-vided:
In a process for the hydrophobiza-tion by means of organohalosilane, s-team and inert gas in a fluidized bed reactor oE a pyrogenically produced silica made from a silicon hallcl~ compound in a burner wherein the silica, hydrogen halide and waste gases produced in said pyrogenic produc-tion are cooled in a cooling zone and the hydrogen halide separa-ted therefrom, -the improvement comprising direc-tly aE-ter -the separa-tiOII of the hydrogen halide formed in the pyrogenic produc-tion of ~ l:he silica, adding an inert gas to the silica and entrained waste gases separa-ting -the silica from the en-trained was-te gases, leadirlg the separated gases :in-to said cooling zone, mixing the silica freed from said waste gases firs-t with a gaseous mixture consisting of said organohalosilane and an inert gas, introduc-ing the mixture of silica and said gaseous mi~-ture in-to the fluidized bed reactor and introducing a mixture of s-team and inert gas separately from said mix-ture of silica, organohalo-silane and iner-t gas, into the fluidized bed reactor and mixing -the mix-ture of steam and inert gas with the mixture of silica organohalosilane and iner-t gas therein and then carrying out the hydropllobiza-tion reactian in the fluidized bed reac-tor and re-turning the waste gases oE the hydrophobization reaction to -the separatory apparatus used to separate the silica ~rom the en--tr~ined waste yases.
The present inven-tion -thus provides a process fox hydrophobing silicon dioxide which has been pyrogenically pro-duced from silicon halide compounds, as for example, silicon chloride, with an organo-halo silane in a fluidized bed. In this process direc-tly aE-ter the separa-tion of the hydrogen halide ~ollowing the pyrogenic production the silicon dioxide, which under certain conditions still carries along reaction was-te gases, is mixed with inert gas, preferably nitrogen, the silicon dioxide is freed from the gases carried along by means of a separator, for example, a cyclone, these gases are fed into -the coo:ling zone oE the production apparatus, the silicon dioxide ~reed Erom the gases is mixed firs-t with the oryano-halo silane ancl iner-t gas, preferably nitrogen, the hydrophobing reaction is subsectuently carried out in a Eluidized bed reac-tor in a con-ventional manner arld the waste yases from the hydrophobing re-a~t:ion are returned -to the separator, for example, a cyclone.
The hydrophobing reaction can be carried out at tempera-tures from ~00 to 600C, preferably from 500 -~o 600C.
Particularly well deacidified silicon dioxide is obtained at temperatures from S50 -to 580C. Conventional organo-halo silanes can be used as hydrophobing agen-ts. Organo-halo com pounds, particularly dimethyl-dichloro silane, are preferably used.
In a preferred embodiment the process according to - 2a -:
~3~7 the present invention is carried out in a combined system with the process for producing the pyrogcnic silicon dioxide and silicon tetracfiloride can be used as the starting material.
In an embodiment o~ the present invention the flow o~ the quant~ty o~ waste gas of the hydrophobing reaction can be controlled by means of automatiC valves. The valves are used preferably in the form o~ throttle valves. Pressure surges are thus equalized and constant reaction conditions and smaller temperature variations are thus attained.
The hydrophobed silicon dioxide can be d~scharged from the fluidized bed by means of a sluice, preferably by means of a cell wheel sluice. Oxygen is thus prevented from getting into the hydrophobing cycle and from forming an explosive rnix-ture with the organo-halo silane.
The process according to the present invention has the advantage that it provides a substantially longer service life of the apparatus since clogging of the pipes is reduced.
Since side reactions are avoided, a substantially more homo-~3C?lleOUS ~roduct is obtained.
The was-te gas of the hyclrophobing reaction is return-ed to the hydrophobing process so that no losses in yield are obtained. On the contrary an increase in yield of approximate-ly 3~ is attained. Hydrogen chloride is the only by-product obtained when using, for example, silicon tetrachloride as the starting material for -the production of silicon dioxide and dimethyl-dichloro silane as the hydrophobing agent.
The consumption of organo-halo silane can be reduced since -the non-reacted organo-halo silane can be at least par-tially re-turned -to the hydrophobing process.
3~ By mixing -the pyrogenically produced silicon dioxide with inert ~as, for example, nitrogen, directly following the production process the danger of fire caused b~ the mixture i'7 of organo-halo silane and residual oxygen from the production process of the silicon dio~ide is removed. secause of this measure the costs for repairs are reduced.
The fact that the hydrophobed silicon dioxide is completely free from discoloring components is a special advan-tage.
The process according to the present invention will be explained hereafter in ~reate.r detail with reerence to the ~ accormpanying drawing, in which the single Figure is a flow sheet of a process according to one embodiment of the present invention.
In the burner 1 SiC14, hydrogen and air are converted to pyrogenic silicon dioxide~ The reaction products which also conta.in :residual oxygen are passed from the burner 1 into the coagulation zone 2 and then into the cooling zone 3, whereupon the reaction products pass into the cyclones 4, 5 and 6, where the separat.ion of the solid silicon dioxides from the gaseous ~eact.ion products is carri.ed out. The gaseous reaction produ~t MiXtU.~e, i~e., substantially hydrogen chloride, is drawn off
The present invention relates to process for hydro-phobin~ ~yro~enically produced silicoll dioxide which process is preferably directly combined with and following the process for producing t~e ~yrogenic silicone dioxide from a silicon halide compound.
German patent No. 1,163,748 discloses a process for the hydrophobing of pyrogenically produced silicon dioxide with dimethyl-dichloro silane in a fluidized bed. According to the process the individual components are so mixed wi-th one another that water vapour in mixture with nitrogen is mixed with the pyrogenically produced silicon dioxide. A gas mixture consist-ing of dimethyl-dichloro silane and nitrogen is then fed to this moist si]icon dioxide. The actual hydrophobing reaction is carried out subsequently in a fluidi~ed bed reactorD This process has -the disadvantage that because of the moisture con-tent of the pyrogenically produced silicon dioxide the pipe lines of the hydrophobing apparatus become clogged. Futhermore hi~h losses in yield and undesired by-products are obtained clue to the partial reaction oE the organo-halo silane with the ~0 water vapour on the pyrogenically produced silicon dioxide be~ore -the hydrophobing reaction can be carried out under con-trolled conditions in the fluid bed reactor. A further disad-vanta~e of the process of German Patent No. 1,163,784 results from the specific composition of the waste gas of the hydro-phobing reaction. This waste gas consists of hydrophobed pyrogenic silicon dioxide, excess organo-halo silane, hydrogen chloride and, when dimethyl-dichloro silane is reacted as or~ano-halo silane, nitrogen and water.
~y means of the recycling of waste gas described in -the drawin~ of German Patent No~ 1,163,784 hydrophobed si]icon~iio~ide is passed in-to the hydrogen chloride absorption device.
This results in undesired foaming. The waste gas pipes become ~,~
clogged by polymeriza-tion reac-tions of the organo-halo silane.
This causes problems in the plant, such as pressure loss and fire. :[n the attempt -to process this was-te gas by washing it with wa-ter in a cooling tower intense foaming occurs in the waste water. This foam is circulated in the cooling -tower, causing the forma-tion of "dry water" by the hydrophobic pyro-genically produced silicon dioxideO This foam cannot be fil--tered off since the filters would rapidly become clogged.
I() According to the present invention there is pro-vided:
In a process for the hydrophobiza-tion by means of organohalosilane, s-team and inert gas in a fluidized bed reactor oE a pyrogenically produced silica made from a silicon hallcl~ compound in a burner wherein the silica, hydrogen halide and waste gases produced in said pyrogenic produc-tion are cooled in a cooling zone and the hydrogen halide separa-ted therefrom, -the improvement comprising direc-tly aE-ter -the separa-tiOII of the hydrogen halide formed in the pyrogenic produc-tion of ~ l:he silica, adding an inert gas to the silica and entrained waste gases separa-ting -the silica from the en-trained was-te gases, leadirlg the separated gases :in-to said cooling zone, mixing the silica freed from said waste gases firs-t with a gaseous mixture consisting of said organohalosilane and an inert gas, introduc-ing the mixture of silica and said gaseous mi~-ture in-to the fluidized bed reactor and introducing a mixture of s-team and inert gas separately from said mix-ture of silica, organohalo-silane and iner-t gas, into the fluidized bed reactor and mixing -the mix-ture of steam and inert gas with the mixture of silica organohalosilane and iner-t gas therein and then carrying out the hydropllobiza-tion reactian in the fluidized bed reac-tor and re-turning the waste gases oE the hydrophobization reaction to -the separatory apparatus used to separate the silica ~rom the en--tr~ined waste yases.
The present inven-tion -thus provides a process fox hydrophobing silicon dioxide which has been pyrogenically pro-duced from silicon halide compounds, as for example, silicon chloride, with an organo-halo silane in a fluidized bed. In this process direc-tly aE-ter the separa-tion of the hydrogen halide ~ollowing the pyrogenic production the silicon dioxide, which under certain conditions still carries along reaction was-te gases, is mixed with inert gas, preferably nitrogen, the silicon dioxide is freed from the gases carried along by means of a separator, for example, a cyclone, these gases are fed into -the coo:ling zone oE the production apparatus, the silicon dioxide ~reed Erom the gases is mixed firs-t with the oryano-halo silane ancl iner-t gas, preferably nitrogen, the hydrophobing reaction is subsectuently carried out in a Eluidized bed reac-tor in a con-ventional manner arld the waste yases from the hydrophobing re-a~t:ion are returned -to the separator, for example, a cyclone.
The hydrophobing reaction can be carried out at tempera-tures from ~00 to 600C, preferably from 500 -~o 600C.
Particularly well deacidified silicon dioxide is obtained at temperatures from S50 -to 580C. Conventional organo-halo silanes can be used as hydrophobing agen-ts. Organo-halo com pounds, particularly dimethyl-dichloro silane, are preferably used.
In a preferred embodiment the process according to - 2a -:
~3~7 the present invention is carried out in a combined system with the process for producing the pyrogcnic silicon dioxide and silicon tetracfiloride can be used as the starting material.
In an embodiment o~ the present invention the flow o~ the quant~ty o~ waste gas of the hydrophobing reaction can be controlled by means of automatiC valves. The valves are used preferably in the form o~ throttle valves. Pressure surges are thus equalized and constant reaction conditions and smaller temperature variations are thus attained.
The hydrophobed silicon dioxide can be d~scharged from the fluidized bed by means of a sluice, preferably by means of a cell wheel sluice. Oxygen is thus prevented from getting into the hydrophobing cycle and from forming an explosive rnix-ture with the organo-halo silane.
The process according to the present invention has the advantage that it provides a substantially longer service life of the apparatus since clogging of the pipes is reduced.
Since side reactions are avoided, a substantially more homo-~3C?lleOUS ~roduct is obtained.
The was-te gas of the hyclrophobing reaction is return-ed to the hydrophobing process so that no losses in yield are obtained. On the contrary an increase in yield of approximate-ly 3~ is attained. Hydrogen chloride is the only by-product obtained when using, for example, silicon tetrachloride as the starting material for -the production of silicon dioxide and dimethyl-dichloro silane as the hydrophobing agent.
The consumption of organo-halo silane can be reduced since -the non-reacted organo-halo silane can be at least par-tially re-turned -to the hydrophobing process.
3~ By mixing -the pyrogenically produced silicon dioxide with inert ~as, for example, nitrogen, directly following the production process the danger of fire caused b~ the mixture i'7 of organo-halo silane and residual oxygen from the production process of the silicon dio~ide is removed. secause of this measure the costs for repairs are reduced.
The fact that the hydrophobed silicon dioxide is completely free from discoloring components is a special advan-tage.
The process according to the present invention will be explained hereafter in ~reate.r detail with reerence to the ~ accormpanying drawing, in which the single Figure is a flow sheet of a process according to one embodiment of the present invention.
In the burner 1 SiC14, hydrogen and air are converted to pyrogenic silicon dioxide~ The reaction products which also conta.in :residual oxygen are passed from the burner 1 into the coagulation zone 2 and then into the cooling zone 3, whereupon the reaction products pass into the cyclones 4, 5 and 6, where the separat.ion of the solid silicon dioxides from the gaseous ~eact.ion products is carri.ed out. The gaseous reaction produ~t MiXtU.~e, i~e., substantially hydrogen chloride, is drawn off
2~ ~rom the cyclone 6 for further processing.
The solid powdered silicon dioxide is mixed with ni-trogen and is fed from the cyclones 4, 5 and 6 into the cyclone 8 by means of a conveying device (blower) 7.
In the cyclone 8 the solid silicone dioxide is once more separated from the gases carried along. The gases are re-turned into the cooling zone 3 via the pipe 9.
The solid silicon dioxide is subsequently rnixed with dimethyl-dichloro silane and nitrogen in the injector 10 and Eed to the :~luidi~zed bed reactor 11.
~t the sar~e time a mixture of water vapour and nitro-gen is fed to the fluidized bed reactor 11 via the separate pipe 12. The hydrophobing reaction is carried out in the fluidized bed reactor l.l.
The react,ion waste ~ases consisting of hydrophobed silico.n dioxide, dimethyl-dichloro silane, hydrogen chloride, nitrogen and water ~apour are returned ~ia the pipe 13 and in-jected on the suction side pipe of the conveying device 7.
The hydrophobed silicon dioxide is discharged from the fluidized bed reactor via the pipe 14 and passed into the intermediate bin via the cell wheel sluice 15.
In order to reduce the danger of fire, nitrogen is passed via the pipe 16 into the discharge pipe 14.
The only product obtained in addition to hydrophobic silicon dioxide is hydrogen chloride at the cyclone 6.
'20 ~ 5
The solid powdered silicon dioxide is mixed with ni-trogen and is fed from the cyclones 4, 5 and 6 into the cyclone 8 by means of a conveying device (blower) 7.
In the cyclone 8 the solid silicone dioxide is once more separated from the gases carried along. The gases are re-turned into the cooling zone 3 via the pipe 9.
The solid silicon dioxide is subsequently rnixed with dimethyl-dichloro silane and nitrogen in the injector 10 and Eed to the :~luidi~zed bed reactor 11.
~t the sar~e time a mixture of water vapour and nitro-gen is fed to the fluidized bed reactor 11 via the separate pipe 12. The hydrophobing reaction is carried out in the fluidized bed reactor l.l.
The react,ion waste ~ases consisting of hydrophobed silico.n dioxide, dimethyl-dichloro silane, hydrogen chloride, nitrogen and water ~apour are returned ~ia the pipe 13 and in-jected on the suction side pipe of the conveying device 7.
The hydrophobed silicon dioxide is discharged from the fluidized bed reactor via the pipe 14 and passed into the intermediate bin via the cell wheel sluice 15.
In order to reduce the danger of fire, nitrogen is passed via the pipe 16 into the discharge pipe 14.
The only product obtained in addition to hydrophobic silicon dioxide is hydrogen chloride at the cyclone 6.
'20 ~ 5
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a process for the hydrophobization by means of organohalosilane, steam and inert gas in a fluidized bed reactor of a pyrogenically produced silica made from a silicon halide compound in a burner wherein the silica, hydrogen halide and waste gases produced in said pyrogenic production are cooled in a cooling zone and the hydrogen halide separated therefrom, the improvement comprising directly after the separation of the hydrogen halide formed in the pyrogenic production of the silica, adding an inert gas to the silica and entrained waste gases separating the silica from the entrained waste gases, leading the separated gases into said cooling zone, mixing the silica freed Eros said waste gases first with a gaseous mixture con-sisting of said organohalosilane and an inert gas, introducing the mixture of silica and said gaseous mixture into the fluidized bed reactor and introducing a mixture of steam and inert gas separately from said mixture of silica, organohalosilane and inert gas, into the fluidized bed reactor and mixing the mixture of steam and inert gas with the mixture of silica organohalosil-ane and inert gas therein and then carrying out the hydrophobiza-tion reaction in the fluidized bed reactor and returning the waste gases of the hydrophobization reaction to the separatory apparatus used -to separate the silica from the en-trained waste gases .
2. A process according to claim 1 wherein the organohalosilane is dimethyldichlorosilane.
3. A process according to claim 2 wherein the sili-con halide compound is a silicon chloride.
4. A process according to claim 3 wherein the silicon chloride is silicon tetrachloride.
5. A process according to claim 1, including the step of controlling the flow of the waste gases of the hydro-phobization reaction by passing the waste gases through an automatic valve.
6. A process according to claim 5 comprising carrying the hydrophobized silica out of the fluidized bed reactor through a locking device.
7. A process according to claim 1 comprising carrying the hydrophobized silica out of the fluidized bed reactor through a locking device.
8. A process according to claim 1 wherein the hydrophobization ls carried out at 400° to 600°C.
9. A process according to claim 8 wherein the hydrophobization is carried out at a temperature of 500°
to 600°C.
to 600°C.
10. A process according to claim 9 wherein the hydrophobization is carried out at 550° to 580°C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3211431.1 | 1982-03-27 | ||
| DE19823211431 DE3211431A1 (en) | 1982-03-27 | 1982-03-27 | METHOD FOR HYDROPHOBIZING PYROGEN-PRODUCED SILICON DIOXIDE |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1203667A true CA1203667A (en) | 1986-04-29 |
Family
ID=6159547
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000424544A Expired CA1203667A (en) | 1982-03-27 | 1983-03-25 | Process for hydrophobing pyrogenically produced silicon dioxide |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4503092A (en) |
| EP (1) | EP0090125B2 (en) |
| JP (1) | JPS58181715A (en) |
| CA (1) | CA1203667A (en) |
| DE (2) | DE3211431A1 (en) |
Families Citing this family (23)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4554147A (en) * | 1984-04-02 | 1985-11-19 | General Electric Company | Method for treating fumed silica |
| US4661056A (en) * | 1986-03-14 | 1987-04-28 | American Hoechst Corporation | Turbulent incineration of combustible materials supplied in low pressure laminar flow |
| JPS63103083U (en) * | 1986-12-23 | 1988-07-04 | ||
| DE3912504A1 (en) * | 1989-04-17 | 1990-10-18 | Degussa | PRESSLINGS BASED ON PYROGEN-PRODUCED SILICON DIOXIDE, PROCESS FOR THEIR PRODUCTION AND THEIR USE |
| US5183710A (en) * | 1990-08-30 | 1993-02-02 | U-Sus Distributors, Inc. | Hydrophobic inorganic materials and process for making same |
| DE4142897A1 (en) * | 1991-12-23 | 1993-06-24 | Sued Chemie Ag | CATALYST SHAPED BODY |
| DE4240741A1 (en) * | 1992-12-03 | 1994-06-09 | Wacker Chemie Gmbh | Process for the hydrophobization of fumed silica |
| DE4419234A1 (en) * | 1994-06-01 | 1995-12-07 | Wacker Chemie Gmbh | Process for the silylation of inorganic oxides |
| DE19620942A1 (en) * | 1995-06-05 | 1996-12-12 | Gen Electric | Efficient process for hydrophobicizing inorganic powder |
| JP3229174B2 (en) * | 1995-08-21 | 2001-11-12 | 日本アエロジル株式会社 | Surface modified metal oxide fine powder and method for producing the same |
| US6120596A (en) * | 1997-01-23 | 2000-09-19 | Marconi Data Systems Inc. | Method for treating pigment particles to improve dispersibility and particle size distribution |
| DE19756840A1 (en) * | 1997-01-23 | 1998-07-30 | Degussa | Pyrogenic oxide, especially silicon di:oxide production |
| DE19756831A1 (en) | 1997-12-19 | 1999-07-01 | Wacker Chemie Gmbh | Silicon dioxide, which carries partially or completely silylated polysilicic acid chains on its surface |
| US6030660A (en) * | 1997-12-19 | 2000-02-29 | General Electric Company | Method of steam stripping an inorganic powder |
| JP3767672B2 (en) * | 2000-04-21 | 2006-04-19 | 信越化学工業株式会社 | Method for producing hydrophobic silicon dioxide fine powder |
| WO2001083369A1 (en) | 2000-04-28 | 2001-11-08 | Mitsui Chemicals, Inc. | Water-repellent porous silica, method for preparation thereof and use thereof |
| JP3674683B2 (en) | 2000-08-31 | 2005-07-20 | 信越化学工業株式会社 | Method for producing hydrophobic silicon dioxide fine powder |
| JP3685250B2 (en) * | 2000-08-31 | 2005-08-17 | 信越化学工業株式会社 | Method and apparatus for producing hydrophobic silicon dioxide fine powder |
| EP1656324B1 (en) * | 2003-08-20 | 2013-07-31 | Evonik Degussa GmbH | Purification of finely divided, pyrogenically prepared metal oxide particles |
| CN100506921C (en) * | 2005-03-28 | 2009-07-01 | 广州吉必时科技实业有限公司 | Method for preparing hydrophobic type nano silicon dioxide thruogh continuous surface treatment |
| CN100575256C (en) * | 2008-03-07 | 2009-12-30 | 南京工业大学 | A kind of preparation method of super-hydrophobic silica |
| US20100061912A1 (en) * | 2008-09-08 | 2010-03-11 | Stephen Michael Lord | Apparatus for high temperature hydrolysis of water reactive halosilanes and halides and process for making same |
| ES2784739T3 (en) | 2008-10-01 | 2020-09-30 | Nippon Aerosil Co Ltd | Hydrophobic Silica Fine Particles and Electrophotographic Toner Composition |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1031764B (en) * | 1943-01-04 | 1958-06-12 | Erik Torvald Linderoth | Method and device for the wet separation of particles from gases |
| DE1163784C2 (en) * | 1962-03-30 | 1973-05-03 | Degussa | Process for the surface treatment of highly dispersed oxides |
| DE2609487C2 (en) * | 1976-03-08 | 1983-09-15 | Wacker-Chemie GmbH, 8000 München | Process for the production of highly dispersed silicon dioxide with an enhanced thickening effect |
-
1982
- 1982-03-27 DE DE19823211431 patent/DE3211431A1/en not_active Ceased
-
1983
- 1983-01-05 EP EP83100048A patent/EP0090125B2/en not_active Expired
- 1983-01-05 DE DE8383100048T patent/DE3360084D1/en not_active Expired
- 1983-03-23 US US06/477,875 patent/US4503092A/en not_active Expired - Lifetime
- 1983-03-25 CA CA000424544A patent/CA1203667A/en not_active Expired
- 1983-03-25 JP JP58049055A patent/JPS58181715A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| DE3360084D1 (en) | 1985-05-09 |
| EP0090125A1 (en) | 1983-10-05 |
| JPS58181715A (en) | 1983-10-24 |
| JPS6150882B2 (en) | 1986-11-06 |
| DE3211431A1 (en) | 1983-09-29 |
| EP0090125B2 (en) | 1988-07-06 |
| US4503092A (en) | 1985-03-05 |
| EP0090125B1 (en) | 1985-04-03 |
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