Fillers for papermaking: A review of their properties
Solubility varies considerably among different types of mineral products, ranging from highly insoluble materials such as TiO 2, to gypsum (calcium sulfate dihydrate), which has a solubility of about 2 to 4 grams per liter under papermaking conditions (Hofmann et al. 1990). The solubility of a given type of filler can depend on such factors as temperature, pH, and the concentrations of ions that are involved in