Hello cr panigrahi,
I have a suggestion, but am not familiar with your process.
Here is something you may want to consider, and you will be the person to know if this works or not.
Pre-heat the SiO2 to 180 C - this will evaporate available water. If the sand is moist, then increase the length of time the sand is exposed to 180 C.
Next, inject the sand either through an addition system that adds it to the nutrient in a random - but consistent mixing system. This can be a continuous or batch system.
Any other thoughts?
Sincerely,
Eugene