Silica sols having high surface area
AssigneeEka Nobel AB
InventorsHans E. Johansson, Bo V. Larsson
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Abstract
Silica sols having a high content of microgel and aluminum modified particles with high specific surface area. The sols can be prepared by a process comprising acidification of a water glass solution, alkalization at a certain dry substance content, particle growth and aluminum modification. The sols are particularly suitable for use as additives, in combination with cationic polymers, in papermaking.
Claims6
Silica sol comprising silica particles having a specific surface area within the range of from 750 to 1000 m.sup.2 /g which are surface-modified with aluminum to a degree of from 2 to 25 percent substitution of silicon atoms, and wherein the sol has an S-value within the range of from 8 to 45 percent.
A process for the production of a silica sol, comprising the steps of acidifying a water glass solution to a pH within the range of from 1 to 4, alkalizing the acid sol at an SiO.sub.2 content within the range of from 7 to 4.5 percent by weight, allowing particle growth of the sol to a specific surface area within the range of from 750 to 1000 m.sup.2 /g, and subjecting the sol to aluminum modification.
Dependencies are inferred from the claim text.