Producing a support for olefin polymerisation catalysts, involves making a co-hydrogel of silicon and titanium oxides, removing water by batch extraction followed by continuous extraction, and then drying

摘要

A method for making a spherical support for olefin polymerisation catalysts by (a) making a co-hydrogel of silicon oxide and other metal oxide(s), (b) optionally washing, (c) extracting water to a water content of less than 5 wt% based on total liquid and (d) drying, in which stage (c) involves (1) batch-wise extraction with water-miscible organic solvent to a water content of less than 50 wt% followed by (2) continuous extraction with water-miscible organic solvent. A method for the production of an essentially spherical support for olefin polymerisation catalysts by (a) making a hydrogel containing a co-gel of silicon oxide and other metal oxide(s), (b) optionally washing the hydrogel to an alkali metal ion content of less than 0.1 wt% (based on solid), (c) extracting water to a content of less than 5 wt% (based on total liquid) and (d) drying to form a xerogel, in which stage (c) involves (1) batch-wise extraction(s) with at least partly water-miscible organic solvent to a water content of less than 50 wt%, followed by (2) continuous extraction with at least partly water-miscible organic solvent. An independent claim is included for a method for the production of an olefin polymerisation catalyst by making a xerogel as above, doping the xerogel with a chromium compound and calcining at 350-1050[deg]C under oxidising conditions.