EP0117755A2
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EP
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Process and apparatus for preparing metal oxide particles
Assignee: Montedison SpA
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Filing: 1984-02-27
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Granted: —
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Expires: 2004-02-27
Abstract
Abstract A process and an apparatus for preparing spherical submicronic, mono-dispersed and non-agglomerated particles of metal oxides by reacting with steam a gaseous stream containing an aerosol of liquid particles of a hydrolyzable metal compound. The process is characterized in that into a duct (1), in which an inert gas stream containing vapour of a hydrolyzable metal compound flows, there is fed, through a nozzle (2), a cold inert gas stream, the temperatures and flows of the two gaseous stream being such as to establish in the duct a temperature lower than the condensation temperature of the metal compound; the mixed gaseous streams have a turbulent flow in the duct, with a Reynolds number equal to or higher than 1800; at the duct outlet, the aerosol of the metal compound liquid particles, which has formed in the duct, is reacted with steam, whereby there form solid particles of hydrated metal oxide, which are then calcined to oxide.
Inventors
- 👤 Paolo Cortesi
- 👤 Gianni Donati
- 👤 Giuseppe Saggese
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 02:28
CPC Classifications
C; C01; C01G; C01G23/00; C01G23/04; C01G23/047; C01G23/07; B; B01; B01F; B01F25/00; B01F25/30; B01F25/31; B01F25/312; B01J; B01J19/00; B01J19/26; C01B; C01B13/00; C01B13/14; C01B13/20; C01F; C01F7/00; C01F7/02; C01F7/30; C01F7/302; C01F7/304; C01G25/00; C01G25/02; B01J2208/00; B01J2208/00008; B01J2208/00017; B01J2208/00327; B01J2208/00336; B01J2208/00353; B01J2208/00371; B01J2219/00; B01J2219/00049; B01J2219/00051; B01J2219/00121; B01J2219/00123; C01P; C01P2002/00; C01P2002/50; C01P2004/00; C01P2004/30; C01P2004/32; C01P2004/51; C01P2004/60; C01P2004/62; C01P2006/00; C01P2006/22; Y; Y10; Y10S; Y10S261/00; Y10S261/75
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
154 words
A process for preparing spherical, submicronic, mono-dispersed and non-agglomerated particles of metal oxides by reacting with steam a gaseous stream containing an aerosol of liquid particles of a hydrolyzable metal compound, characterized in that into a duct (1), in which an inert gas stream containing vapour of a hydrolyzable metal compound flows, there is fed, through a nozzle (2); a cold inert gas stream, the temperatures and flow-rates of the two gaseous streams being such as to establish in the duct a temperature lower than the condensation temperature of the metal compound, the mixed gaseous streams having a turbulent flow in the duct, with a Reynolds number equal to or higher than 1800; and in that at the duct outlet the aerosol of the metal compound liquid particles, which has formed in the duct, is reacted with steam, whereby there form solid particles of hydrated metal oxide, which are subsequently calcined to oxide .
Claim 2
Dependent Claim
154 words
A process for preparing spherical, submicronic, mono-dispersed and non-agglomerated particles of metal oxides by reacting with steam a gaseous stream containing an aerosol of liquid particles of a hydrolyzable metal compound, characterized in that into a duct (1), in which an inert gas stream containing vapour of a hydrolyzable metal compound flows, there is fed, through a nozzle (2); a cold inert gas stream, the temperatures and flow-rates of the two gaseous streams being such as to establish in the duct a temperature lower than the condensation temperature of the metal compound, the mixed gaseous streams having a turbulent flow in the duct, with a Reynolds number equal to or higher than 1800; and in that at the duct outlet the aerosol of the metal compound liquid particles, which has formed in the duct, is reacted with steam, whereby there form solid particles of hydrated metal oxide, which are subsequently calcined to oxide .
Claim 3
Dependent Claim
46 words
A process as claimed in claim 1, characterized in that the inert gas stream containing vapour of a hydrolyzable metal compound is prepared by causing an aerosol of liquid particles of the metal compound to, form in an inert gas stream, and then evaporating the aerosol.
Claim 4
Dependent Claim
28 words
A process as claimed in claim 1 or 2, characterized in that the hydrolyzable metal compound is a compound of titanium, aluminium, zirconium, chromium, vanadium, gallium or iron.
Claim 5
Dependent Claim
33 words
A process as claimed in claim 3, characterized in that the hydrolyzable metal compound is selected from isopropyltitanate, titanium ethoxide, titanium tetrachloride, aluminium sec.butoxide, aluminium ter.butoxide, aluminium n-butoxide, aluminium isobutoxide, isopropylzirconate and zirconium-n-propoxide.
Claim 6
Dependent Claim
48 words
A process as claimed in any of claims 1 to 4, characterized in that they inert gas stream containing vapour of a hydrolyzable metal compound is fed into the chamber (3) of an ejector (1), while the cold inert gas stream is fed into the ejector nozzle (2).
Claim 7
Dependent Claim
40 words
A process as claimed in any of claims 1 to 5, characterized in that, in the hydrolysis reaction, steam is used in an amount corresponding to 1.5 - 12 times the stoichiometric ratio with respect to the hydrolyzable metal compound.
Claim 8
Dependent Claim
30 words
A process as claimed in any of claims 1 to 6, characterized in that the hydrated metal oxide solid particles are separated from the gas stream prior to their calcination.
Claim 9
Dependent Claim
28 words
A process as claimed in any of claims 1 to 6, characterized in that the metal oxide solid particles are separated from the gas stream after their calcination.
Claim 10
Dependent Claim
191 words
Apparatus for preparing spherical, submicronic, mono-dispersed and non-aggregated particles of metal oxides, according to the process claimed in any of claims 1 to 8, characterized by comprising a convergent-divergent ejector (1) terminating in a cylindrical portion (8) which coaxially penetrates into the curved bottom portion (6) of a cylindrical chamber (5). the diameter of which is at least twice the diameter of the said cylindrical portion (8) of the ejector, the said curved bottom portion (6) of the cylindrical chamber being surmounted with an apertured plate (7), through which the end of the said cylindrical portion (8) of the ejector coaxially passes, an ejector nozzle (2) for receiving a cold inert gas stream feed, an ejector chamber (3) for receiving a feed of an inert gas stream (4) containing vapour of a hydrolyzable metal compound, and the said curved bottom portion (6) of the said cylindrical chamber being provided with one or more openings (9) for the inflow of steam, and down-stream of the said cylindrical chamber the apparatus including,a device for separating the hydrated metal oxide from the gaseous stream and a furnace for calcining the hydrated oxide to oxide.
Claim 11
Dependent Claim
37 words
Apparatus as claimed in claim 9, characterized in that the ratio between the diameter of the said cylindrical chamber (5) and the diameter of the said cylindrical portion (8) of the ejector is from 2 to 15.
Claim 12
Dependent Claim
32 words
Apparatus as claimed in claim 10, characterized in that the furnace for calcining the hydrated oxide to oxide is arranged before the device for separating the metal oxide from the gaseous stream.
Claim 13
Dependent Claim
25 words
Metal oxides in the form of spherical, submicronic, mono-dispersed and non-aggregated particles, obtained according to the process claimed in any of claims 1 to 8.
References Cited (Backward Citations)
No citation records indexed.
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