Sciencemadness Discussion Board

MgSO4 to MgO

Korialstrasz69 - 2-10-2015 at 08:59

Yeah.and preferably by wet chemical ways(if possible).thanks ahead.
EDIT:Sorry forgot to mention,i want good purity stuff.if possible too.

[Edited on 2-10-2015 by Korialstrasz69]

unionised - 2-10-2015 at 09:41

Wet chemistry probably isn't an option because MgO reacts with water.
In principle, heating to a very high temperature will cause MgSO4 to decompose to MgO and SO3 but the temperature needed is very high, near 1100 C.

Dissolving the MgSO4 in water and adding NaOH solution or Na2CO3 solution will precipitate the Mg as the hydroxide or carbonate.
You can then filter those off and wash them then heat them to get the oxide.
The carbonate decomposes at about 900C
The hydroxide decomposes at a much lower temperature. About 330 - 400C will do the job, but the precipitating agent (NaOH) is more hazardous to work with.

If you are really concerned about purity this might help
http://pubs.rsc.org/en/content/articlelanding/1962/tf/tf9625...

Detonationology - 2-10-2015 at 09:45

Make a super saturated solution of magnesium sulfate and another using a metal carbonate (no solids). Mix together, and the precipitate will be MgCO3, since MgCO3 is 2700x less soluble MgSO4. Then, simply heat the MgCO3 in order to release CO2 and the MgO.

deltaH - 2-10-2015 at 10:15

Magnesium hydroxide calcines at a lower temperature than the carbonate (332°C), so perhaps better to precipitate the hydroxide using something like sodium hydroxide, although filtering and washing the hydroxide might be considerably harder than the carbonate.

blogfast25 - 2-10-2015 at 10:20

Quote: Originally posted by deltaH  
Magnesium hydroxide calcines at a lower temperature than the carbonate (332°C), so perhaps better to precipitate the hydroxide using something like sodium hydroxide, although filtering and washing the hydroxide might be considerably harder than the carbonate.


Even better: ammonia. Ammonium salts wash out more easily and traces of them sublime off on calcining.

Detonationology - 2-10-2015 at 10:33

The OP is from Syria. Please be mindful that not all "common" reagents are available to many people in war-torn areas.

[Edited on 10-2-2015 by Detonationology]

deltaH - 2-10-2015 at 10:36

Quote: Originally posted by Detonationology  
The OP is from Syria. Please be mindful that not all "common" reagents are available to many people in war-torn areas.

[Edited on 10-2-2015 by Detonationology]


Hmm, meaning ammonia?

Detonationology - 2-10-2015 at 10:49

Quote: Originally posted by deltaH  
Quote: Originally posted by Detonationology  
The OP is from Syria. Please be mindful that not all "common" reagents are available to many people in war-torn areas.

[Edited on 10-2-2015 by Detonationology]


Hmm, meaning ammonia?

In a the "HELP(sulfuric acid)" thread posted by the OP here, I believe that he already attempted to get NH3 from ammonium sulfate using a microwave and said
Quote:

"i have already dealt with hot ammonia in my fucking kitchen..."

It's only an assumption, but I don't think that he enjoys working with ammonia.

ave369 - 2-10-2015 at 10:58

Quote: Originally posted by deltaH  
filtering and washing the hydroxide might be considerably harder than the carbonate.


Second that. Magnesium hydroxide precipitates as white snot-like mucus that covers any filter with a slimy film and clogs it instantly. Vacuum does not help.

[Edited on 2-10-2015 by ave369]

Detonationology - 2-10-2015 at 11:04

Quote: Originally posted by ave369  
Quote: Originally posted by deltaH  
filtering and washing the hydroxide might be considerably harder than the carbonate.

Magnesium hydroxide precipitates as white snot-like mucus
[Edited on 2-10-2015 by ave369]

Gotta hate that Milk of Magnesia! Yuck! Anyway, just from analyzing the chemicals that the OP has identified as available to him, it seems to me that the epsom salt + baking soda to yield magnesium hydrogen carbonate, which can easily be decomposed at ~300˚C seems to be the most viable method, yet not very pure since sodium sulfate isn't very soluble either.

[Edited on 10-2-2015 by Detonationology]

[Edited on 10-3-2015 by Detonationology]

Korialstrasz69 - 2-10-2015 at 14:03

Thanks everybody.
"The hydroxide decomposes at a much lower temperature. About 330 - 400C will do the job, but the precipitating agent (NaOH) is more hazardous to work with"
i do have NaOH and can probably deal with it,but i have some problems with filtering since i filter with ordinary tissue(Yes.).any advice about filtering ?
and yes i hate ammonia so much the kitchen now smells like ammonia it's disgusting.

ave369 - 3-10-2015 at 02:29

Quote: Originally posted by Korialstrasz69  
i filter with ordinary tissue(Yes.).any advice about filtering ?


If so, stay away from magnesium hydroxide. You will not be able to filter it off. I use a Buchner set, and still have problems with it.