Process for the production of silicon dioxide particles
The present invention relates to a process for producing spherical submicron particles of amorphous silicon dioxide, in which silicon dioxide and a reducing agent is injected into a reaction vessel of zirconium oxide in molten state, said zirconium oxide is serving as a heat reservoir, in which silicon dioxide reacts with the reducing agent producing a silicon-sub-oxide vapor, said silicon-sub-oxide vapor is oxidized into said spherical submicron silicon oxide particles.
1. A process for producing spherical submicron particles of amorphous silicon dioxide comprising
injecting silicon dioxide and a reducing agent into a reaction vessel, the reaction vessel comprising a molten pool of zirconium oxide based material, wherein said molten pool of zirconium oxide based material is serving as a heat reservoir, in which silicon dioxide reacts with the reducing agent producing a silicon-sub-oxide vapour, SiO;
oxidizing the produced silicon-sub-oxide vapour into spherical submicron particles of amorphous silicon dioxide.
2. The process according to any of the preceding claim 1 , wherein the temperature of the zirconium oxide based material comprised in the vessel is at least at the melting point of the material.
3. The process according to claim 1 , wherein the temperature of the zirconium oxide based molten pool is selected from the group consisting of the following ranges: 2650-2800° C., 2700-2710° C., 2710-2720° C., 2720-2800° C., 2800-2900° C., and 2900-3000° C.
4. The process according to claim 1 , wherein said obtained spherical silicon dioxide particles possess a size selected from the group consisting of the following ranges: 10 −9 -10 −6 m, 10 −9 -10 −8 m, 10 −8 -10 −7 m, and 10 −7 -10 −6 m.
5. The process according to claim 1 , wherein the reducing agent is carbon.
6. The process according to claim 1 , wherein a gas is injected into the zirconium oxide.
7. The process according to claim 6 , wherein the gas is an inert gas or nitrogen.