Microwaving is highly effective but can damage desiccants. You're relying on the water evaporation to keep the temperature under control and when it's gone the desiccant will rapidly overheat. Brittle desiccants like silica gel can also crack if you try to microwave them dry too fast. The problem is made worse by the uneven heating of microwaves. This isn't insurmountable, because you can dry a large enough quantity at a time to slow and even out the drying, and stop with sufficient safety margin (desiccant moisture level can by measured by weighing it), but safety margin means you'll need more desiccant to get the same drying performance.
I've dried maybe > 2kg of desiccant in the microwave by now. Always as slow as possible on low power, but a small percentage of beads overheated anyways and turned a very dark color.
So now my silica is orange with black dots.
I noticed many of these beads are misshapen and smaller than normal. I suspect they got unlucky with the wavelengths somehow, even though they are so small.
