How to powder silica gel?
Desiccant silica gel is not all that tough. A spinning blade coffee grinder, or a blender should work. When you get it down to powder, leave the top on for 5-10 minutes. The dust will be awful. You shouldn't dull the blades much, unless you make a habit of this. Mortar and pestle would work too, but for the quantities you'll need would probably be tiresome.