Abstract: The present invention generally relates to polysilicate microgels. More specifically, the invention relates to a process for preparing aqueous polysilicate microgels which comprises mixing an aqueous solution of alkali metal silicate with an aqueous phase of silica-based material having a pH of 11 or less, to polysilicate microgels per se and to the use thereof as flocculating agents in paper making and water purification. The invention further relates to a process for the production of paper from a suspension of cellulosic fibers, and optional filler, which comprises adding to the suspension at least one cationic or amphoteric organic polymer and a polysilicate microgel, forming and draining the suspension on a wire.

Abstract: The present invention relates to a method for preparing cerium oxide coated silica particles and cerium oxide silica particles obtainable by the method. The invention further relates to cerium oxide coated silica particles and the use thereof for polishing.

Abstract: The present invention generally relates to polysilicate microgels. More specifically, the invention relates to a process for preparing aqueous polysilicate microgels which comprises mixing an aqueous solution of alkali metal silicate with an aqueous phase of silica-based material having a pH of 11 or less, to polysilicate microgels per se and to the use thereof as flocculating agents in paper making and water purification. The invention further relates to a process for the production of paper from a suspension of cellulosic fibers, and optional filler, which comprises adding to the suspension at least one cationic or amphoteric organic polymer and a polysilicate microgel, forming and draining the suspension on a wire.

Abstract: A method for production of high purity silica sols comprising the steps: (a) adding a phosphonic acid-based complexing agent to the silicic acid-containing solution forming complexes with metal cations present in said solution; (b) forming in said silicic acid-containing solution a precipitation containing phosphonic acid-based complexing agent and metal cations; (c) removing the precipitation from the solution; and, (d) polymerising the silicic acid in the solution to obtain a silica sol. The invention also relates to silica sols containing at least one phosphonic acid-based complexing agent.