Sprotz
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Extracting Magnesium from Wood Ash
Can someone tell me how to go about extracting Magnesium from Wood ash and separating it from calcium, and other metal oxides present ?
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ThoughtsIControl
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You could just rinse, filter, repeat a few times. Calcium and some other contaminants you have will be water-soluble. Magnesium is insoluble. By
rinsing and filtering, it should be easier to sift through everything. Magnesium is quite shiny. Plus, it's paramagnetic. So there will be a weak
attraction towards magnets if you wanted to sift through with one.
Hope this helps! 
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j_sum1
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Quote: Originally posted by ThoughtsIControl  | You could just rinse, filter, repeat a few times. Calcium and some other contaminants you have will be water-soluble. Magnesium is insoluble. By
rinsing and filtering, it should be easier to sift through everything. Magnesium is quite shiny. Plus, it's paramagnetic. So there will be a weak
attraction towards magnets if you wanted to sift through with one.
Hope this helps! |
That's perhaps a wee
bit snarky here.
The point being made of course is that Mg won't be found in wood ash. Magnesium cojmpounds will be. And isolating them will be a pain A lot more
trouble than it is worth.
Firstly you have a mixture of cations. K will be dominant. I would anticipate that Mg compounds will be in very low proportions.
Secondly, you have a decent mixture of anions. That makes the isolation chemistry difficult.
Thirdly, you will find it difficult to separate out Mg from other ions that behave similarly. Even finding a wet chemistry metho to distinguish
Mg2+, Ca2+, Zn2+ and Al3+ is tricky. But that would be my start point. (There are good YT vids on this.) Then take the principles employed and use
them to isolate your Mg compound.
Get set for some disappointment. 
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Boffis
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I can't imagine a more ridiculous starting material than wood ash for the isolation on magnesium salts. The Mg content of wood ash is very low.
There are numerous much better sources of magnesium than wood ash; epsom salts, various magnesium hydroxide and basic carbonate rich preparations for
gardening/horse etc, magnesium rich rocks like dolomite, serpentinite, etc. Just down the road from where I am now they used to extract magnesium from
sea water. The process may be of interest to you since it offer a method of separating Mg from most other common cations in sea water. They used to
add saturate lime water to the sea water. This precipitates the Mg as a basic carbonate which was simply settled out and finally dewatered in a filter
press. I'm sure this route could be used to extract Mg from most things if modified carefully.
If you are trying to prepare Mg metal the process is going to be several orders of magnitude more difficult.
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Sprotz
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Yes, the intention is getting magnesium metal. I know the method of getting magnesium from salt water, I also know that Magnesium is found in
Laxatives, I was just checking if wood ash was a good source. So there is no easy way to get magnesium metal? The easiest possible way I heard is by
reduction of molten magnesium chloride by potassium metal at 700 C, and there is an easier way recently developed that uses a lower temperature but
the method is proprietary and they won't divulge the secret.
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Mateo_swe
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Is there any reason why you cant just buy the Magnesium metal?
Its not expensive, in a fast ebay search i found 99.99% Mg rods 9cm tall, 16mm thick going for 2 Euros per rod.
Or are you doing this for the experience of extracting a metal from a common source?
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G-Coupled
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Isn't Magnesium contained in Chlorophyll? Maybe green leaves might be a better source of Mg than wood is.
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SWIM
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If you're doing this to make magnesium from a natural source as opposed to from some prepared chemical then maybe you can find or buy some magnesium
containing mineral for your project.
Much higher yields for the extraction.
The tough part will be reducing it to metal I bet.
How about dolomite?
https://m.media-amazon.com/images/M/MV5BMDc3MGIyZjktNGRhNS00...
Oops, typo.
https://mahaveermineral.com/wp-content/uploads/2017/02/dolom...
[Edited on 1-6-2020 by SWIM]
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DraconicAcid
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I doubt it. The amount of magnesium in chlorophyll is very small.
https://www.researchgate.net/figure/Chemical-composition-of-...
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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ThoughtsIControl
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"The easiest possible way I heard is by reduction of molten magnesium chloride by potassium metal at 700 C, and there is an easier way recently
developed that uses a lower temperature but the method is proprietary and they won't divulge the secret"
Using thermite would be an easier method to reach those temperatures as compared to a wood fire. However, I'm sure there are alternatives since
thermite is dangerous.
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draculic acid69
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It's a terrible starting material. potassium and calcium could probably be isolated but I don't think magnesium could be recovered in any more than
tiny amounts. If u poured a packet of Epsom salt over a wood fire and then worked up the ashes u might end up with some mg oxide which with carbon
might be reduced to the metal.but it's a terrible way to go.
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Sprotz
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I can buy it if need be but I just want to gather knowledge on how to make it and other chemicals ourselves in case of some future survival situation
or in case the market changes.
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Fery
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Sprotz - when you want to extract something from wood ash in survival situation it is K2CO3 which is used for producing soap.
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Mateo_swe
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I seem to remember something about a guy trying to extract nitrates from the soil where many people had urinated over a long timeperiod.
Some nitrate would be useful in a survival situation as it can be used to make explosives, aid in starting a fire and many other things.
Not so nice to process the pee saturated soil though.
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metalresearcher
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Forget it. Mg is harder to isolate than K or Na.
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