Baking Magnesium Chloride

[Bryan]

Have a couple containers of Magnesium Chloride and it appears they have absorbed a lot of moisture from the air. I live in a area of higher humidity than most areas. Can I bake the Mag Chloride in a oven at say 250 degrees to drive off the moisture.

 

[tennesseebob]

I'd be worried about it changing how it changes the effect on water chemistry. Like with baking soda and soda ash, baking soda slightly lowers ph, while soda ash raises it significantly. But I honestly know nothing about it lol. Maybe toss a couple media bags of rice in with your mag. Chloe. From now on to absorb the excess humidity. I have a lot where I live too.

 

[Bryan]

Yes, baking Sodium bicarbonate changes to Sodium Carbonate, not sure what if any change will take effect with baking Mag Chloride. Although the rice trick sounds like a good idea.

 

[toothybugs]

What do you suppose happens to anhydrous mag chloride when you put it in water?

 

[Hobster]

I live in the "land" of never ending humidity. Even my salt in a bag and in a sealed 5 gal bucket turns into a solid rock.

Just get a clean hammer and chisel and bust it up, been doing it for years,

 

[GroktheCube]

Assuming you mean 250F, that's fine. It starts to decompose into magnesium metal and chlorine gas around 300C (~570F).

 

[bertoni]

If you are using the magnesium chloride to make a 2-part or a DIY supplement, using it as is likely is close enough. Heating it will drive off the water, but I don't know how much would go or how long it'd take. Magnesium chloride products we get usually are magnesium chloride hexahydrate, that is, with 6 water molecules attached. I don't know how easy it might be to convert what you have to that or the anhydrous form. I can do some looking if you want to do this, but I'm not sure that baking it is worth the effort.

 

[Dan_P]

Have a couple containers of Magnesium Chloride and it appears they have absorbed a lot of moisture from the air. I live in a area of higher humidity than most areas. Can I bake the Mag Chloride in a oven at say 250 degrees to drive off the moisture.

Appearance can be deceiving. Did you really purchase anhydrous magnesium chloride? If not, just break up the lumps (I assume this is what you observed) and use it.

If you bought anhydrous magnesium chloride, dehydrating it can lead to formation of hydrogen chloride, hydrochloric acid in the presence of water (not chlorine as someone suggested) and magnesium hydroxide or oxide. This would not be good for the interior of your oven, your kitchen, oven hood... Use it without treating it. The worst that will happen is that the magnesium level in the aquarium will not rise as high as you calculated.

 

[Bryan]

Thanks Dan P. the issue is that with the absorbed water it makes it difficult to measure accurately to adjust based on calculators. But the hassle of baking and the possible consequences probably outweigh any advantage. Worst case I end up using more of the test kit trying to adjust Magnesium as you point out. Next time I buy some I will throw a bag of rice in the bucket <g>