Dehydrating with Microwaves?

[DONMAN]

Would it work to dehydrate salts by microwaving them. I was just thinking that the microwaves only effect water molecules, and I was just wondering if the H2O in hydrous salts are still effected by the microwaves?

[Cindor]

I think you probably couldn't do that with Ammonium Nitrate of other salt like this with low B/D P, but probably you could do that with Barium Sulfate... but why don't you try this and tell us what happens ?

[ShadowMyGeekSpace]

The problem is the water molecules (which can superheat, reaching temperatures well above their boiling point) can excite the molecules next to them/react with them. Also, 2.45ghz RF isn't specifically absorbed by water, you're going to see dielectric heating in alot of materials. Using a microwave may be appropriate for some chemicals, but if the chemical is destroyed at 100c(figure 140c or 150c actually, since the water can superheat, and localized heating being a bitch), or gets excited by 2.45ghz microwaves, it's most likely not going to work well.

[nbk2000]

I've used a microwave to dehydrate epsom salt (Mg sulphate) to use it as a drying agent, and it worked well.

[DONMAN]

I tried it with some Na2CO3 heptahydrate, It worked extremely well. I took about 10g and put that in there for about 35 sec and when it came out the Na2CO3 was brilliantly white.

[megalomania]

If you are worried about potential overheating as far as I know every microwave comes with power adjustments (defrost settings) to let you control the output. Mine can be adjusted from 10% to 100% power on the touch pad quite easily. 30 seconds at 100% will liquefy my frozen cool whip, but a minute on 30% thaws in real nice.