The preparation of silica from the olivine process and its possible use as a catalyst support

Synthesis and characterization of amorphous precipitated silica from alkaline dissolution of olivine

“…5 Enormous effort has been exerted to nd alternative raw materials for the production of APS by the wet process, such as rice husk, rice straw, bagasse ash, naturally occurring silicate rock (olivine), and photonic industrial wastes. [6][7][8][9][10][11][12] However, the selection of silica raw material for commercial APS production has been governed by various factors such as its abundance, cost, availability, and the types and relative concentrations of impurities. Despite the abundance of rice husk, rice straw, and bagasse ash, their use as source materials for APS requires high energy consumption and additional purication steps for the removal of impurities.…”

“…Moreover, studies concerning the dissolution of olivine in acidic media necessarily require additional steps for purication. 4,10,21,22 Despite the fact that mineral acids are good lixiviants, they exhibit a greater tendency to dissolve impurities such as iron from the minerals along with the components of interest (magnesium and silicon), leading to contamination of the products. 23 On the other hand, alkaline solutions cannot dissolve iron from minerals because of their weak dissolving power.…”

The kinetics of the olivine dissolution under the extreme conditions of nano-silica production

“…Under these extreme conditions, the study of the olivine dissolution is still problematic for the following reasons: 1) the concentration of hydrogen ions is not constant because of the lack of pH sensors that could operate in such an aggressive environment; 2) the viscosity rises during the experiment (Lieftink and Geus, 1998); 3) the olivine surface area substantially decreases over time; 4) the quantity of silica released is much higher than the silica solubility. A, k T , and n are given in mol⋅cm -2 ⋅s -1 , E a in kJ/mol and n dimensionless units.…”

The properties of amorphous nano-silica synthesized by the dissolution of olivine

“…The speed of agglomeration of silica particles is catalyzed by the hydrogen ion [11,12]. The texture of nano-silica is a complex topic reviewed by several researchers [13][14][15][16], but only Lieftink [5,16] studied in depth the nano-silica produced from olivine.…”