Physicochemical and structural evaluation of carbonate-silicate fillers

Procedures are presented for the production of carbonate-silicate fillers and for their surface modification in the course of precipitation. The substrates in the precipitation process involved solutions of calcium hydroxide and sodium metasilicate as well as gaseous carbon dioxide. Monohydric and polyhydric alcohols as well as acrylic derivatives (acrylic acid and methyl acrylate) were used as modifying agents. The carbonate-silicate fillers obtained were subjected to a comprehensive physicochemical analysis. Bulk density and flow-off point were estimated. Morphology of the filler particle surface was examined by microscopy, while X-ray analysis allowed us to determine the crystallographic structure of the fillers. Using inverse gas chromatography, the specific energy of adsorption and acceptor/donor parameters of carbonate-silicate fillers were estimated. The carbonate-silicate filler obtained demonstrated favorable physicochemical parameters following modification with 3 weight parts of acrylic acid. The surface of the so-modified carbonate-silicate filler manifested a typical acceptor (acidic) character.