Agglomerates of precipitated silica, method for their preparation and their use as filter medium for gas filtration
AssigneeSvenska Aerogel AB
InventorsSven-Peter Norberg, Jörgen Abrahamsson, Lars Gösta Lindahl
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Abstract
A method of producing a material including agglomerated particles of precipitated silica, including preparing a solution of at least two metal salts (Me), wherein the metal ions are divalent or polyvalent. A solution of alkali metal (M) silicate having a molar ratio SiO2/M2O of 1-4 is prepared. The solutions are mixed and the mixture stirred, allowing a coagulum to immediately form. The coagulum is rinsed, collected, dewatered, impregnated and processed to provide a material having a dry matter content of >75%, preferably >97%. A material obtainable by the process is also provided.
Claims14
A method of preparing agglomerates of precipitated silica comprising the following steps:
- preparing a solution of at least two metal salts (Me), wherein the metal ions are divalent or polyvalent;
- preparing a solution of alkali metal (M) silicate having a molar ratio SiO2/M2O of 1-4;
- mixing said solutions and stirring the mixture whereby a coagulum immediately forms;
- rinsing the coagulum in water;
- collecting the coagulum;
- impregnating the coagulum with impregnation chemicals selected from the group consisting of KMnO4, C2H2O4, C6H8O7, Na2S2O3, NaClO, KOH, NaOH, KI, NaI, K2CO3, Na2CO3, NaHCO3, and KHCO3;
- processing the coagulum to provide a dry matter content of >15;
- and
- shaping and drying the impregnated coagulum to a dry matter content of >75%.
Dependencies are inferred from the claim text.