Silica beads still exist. Most craft stores seem to stock them. And with the instructions for speeding up the process in the microwave they are a fast way to dry a lot of flowers. Though, the microwave way made my flowers either really brittle or not all the way dry no matter how I timed it.
I have read articles on drying flowers by layering then in sand. It is almost the same thing as the silica crystals that are sold in craft stores. I believe you put a layer of sand in the box, then the flowers and gently layer in more sand.