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US 4,378,306 AGranted
Surface heat treatment of silica-containing catalyst base
AssigneePhillips Petroleum Company
InventorsMax P. McDaniel, M. Bruce Welch
Life of this patent
Estimating the term…
Abstract
A silica base for a chromium olefin polymerization catalyst is subjected to a high temperature treatment as for instance by passing the silica through a flame in order to alter the surface characteristics. The chromium can be present during the flame treatment or added later. The result is a catalyst capable of giving a broader molecular weight distribution polymer which is of particular value with the silica-titania coprecipitated catalyst used in slurry olefin polymerization.
Claims12
A method comprising:
- subjecting a particulate silica-containing material to a heat treatment for a time and at a temperature sufficient to sinter the outside of the particles of said silica-containing material without significantly affecting the inside of the particles, said silica-containing material either having chromium contained therein during said heat treatment or having chromium thereafter added thereto.
A method comprising:
- passing a particulate silica-containing material through a zone at a temperature within the range of 1200.degree. to 4000.degree. C. for a residence time within the range of 0.1 to 3 seconds, said silica-containing material either containing chromium during said passing or having chromium thereafter added thereto.
Dependencies are inferred from the claim text.