Highly dispersible precipitated silica and method of preparation thereof

A process for preparation of highly dispersible precipitated silica comprising the steps of:

• a) preparing an alkaline silicate solution having reduced dielectric constant in a first reactor vessel by digesting biogenic silica source with an alkaline solution at a temperature ranging from 80-120° C. such that soluble organic compounds in the biogenic silica source leach into the alkaline silicate solution;
• b) adding water into a second reactor vessel and maintaining a suitable temperature;
• c) adding the alkaline silicate solution as obtained in step (a) and an acidifying agent simultaneously to the second reactor vessel while maintaining suitable pH in the range of 8-8.5 and a suitable temperature for a suitable time so as to reach a final silica concentration range of 20-80 g/L;
• d) stopping the addition of the alkaline silicate solution and continuing adding the acidifying agent so as to reach a pH of 3-4 to obtain an aqueous silica dispersion;
• e) filtering the aqueous silica dispersion to obtain a filtered cake;
• and
• f) washing and drying the filtered cake to obtain the highly dispersible precipitated silica;
• wherein the biogenic silica source and the alkaline solution are in a ratio of 1:4 to 4:1;
• modulus of the alkaline silicate solution is in the range of 2 to 3.3 and
• the highly dispersible precipitated silica has the following pore size distribution of mesopores measured by Mercury Intrusion Porosimetry (MIP):
• Pore Volume by
• Pore Volume by
• Mercury
• Pore Volume by
• Mesopore
• Mercury Intrusion
• Intrusion (ml/g)
• Mercury Intrusion
• size
• (ml/g)
• MIP surface
• (ml/g)
• Interval
• MIP surface area
• area 240-280
• MIP surface area
• (nm)
• 200-240 (m2/g)
• (m2/g)
• 140-200 (m2/g)
• 10 to 20
• 0.05-0.15
• 0.15-0.25
• 0.05-0.2
• 20 to 30
• 0.15-0.4
• 0.4-0.5
• 0.1-0.3
• 30 to 40
• 0.2-0.5
• 0.1-0.2
• 0.25-0.35
• 40 to 50
• 0.1-0.25
• 0.1-0.2
• 0.1-0.3.