Sciencemadness Discussion Board

Boron oxide reduction with Aluminium?

Foeskes - 3-5-2017 at 14:52

Most videos on the topic uses magnesium powder, which is pretty much almost impossible to find around me. But I found on Wikipedia that apparently it's possible to do it. Do I need a booster?(like the calcium sulfate and Aluminium).
I am new to calculating entropy but I tried anyway and what I calculated was -421 KJ/M.

Nicholas Barnes - 4-5-2017 at 00:37

How do you want to proceed?

It depends the procedure, what would work good here. With Calcium sulphate and Aluminium it should be possible though. :)

AJKOER - 4-5-2017 at 05:00

Good description of historical methods are available at

http://boron.atomistry.com/production.html

Pok - 4-5-2017 at 05:26

It's not possible to make pure boron by reduction with aluminium. The best you can get is Aluminium Dodecaboride (AlB12). Here is a document (in German) which describes the reaction: 50 grams waterfree boron trioxide an 75 grams of flowers of sulfur are mixed with 100 grams of coarse aluminium powder. Put 10 grams of CaF2 on the bottom of the crucible and start the reaction with 10 grams of a starting mixture (Mg + BaO2 in the ratio 3:2).

Foeskes - 4-5-2017 at 18:53

I'll try that after I get more Aluminium powder, and some sodium fluoride. (Calcium fluoride seems to be impossible to find here, so I'll probably have to make it from sodium fluoride and calcium chloride)

MrHomeScientist - 5-5-2017 at 05:28

The real problem is that even if you can make boron with aluminum, it's impossible to separate from the aluminum boride side product. Magnesium really is the way to go; you can dissolve literally everything else in hydrochloric acid and leave pure boron powder behind. It's tedious, but you can make Mg powder by filing down fire starter blocks. It's also widely available online.

Foeskes - 5-5-2017 at 17:00

Doesn't aluminum boride(s) react with HCl to form borane gas?

Pok - 7-5-2017 at 15:47

The reactivity of AlB12 is comparable to that of boron. It won't react even with boiling HCl or 40 % HF. These acids are used to purify AlB12 (see Brauer handbook). Boron combines with aluminium in different ratios, so there will probably not even be a tiny trace of pure boron in the product, which could be isolated.

Foeskes - 7-5-2017 at 20:05

Is there any effective way to get magnesium powder from the ribbon then?
Because I'm sure my country has to restrict it somehow.

j_sum1 - 7-5-2017 at 21:17

Ribbon to powder...
You could try a ball mill. I would imagine that would work reasonably well.

If you can find a block of Mg you could make some turnings. These probably won't be fine enough to be truly effective in a thermite. But remember that you are reacting with B2O3. When I did it I had to tediously grind the glassy B2O3 to a powder in a mortar. There is no reason why you could not grind your Mg turnings at the same time. The hard glass will do a pretty good job of tearing up the magnesium. And you will get a reasonably intimate mix.

If you are starting with ribbon I would recommend cutting to small lengths and then bashing them up a bit in a food processor or coffee grinder. After that grind the pieces with the B2O3 in a mortar or a ball mill.

Good luck. It is a fun little experiment.

Foeskes - 8-5-2017 at 04:52

Is it to possible to reduce it with sodium metal? I just realized it's not very expensive and really easy to find.

Jstuyfzand - 8-5-2017 at 04:57

Sodium easy to find? Inexpensive?
Where?!

Foeskes - 8-5-2017 at 05:53

I double checked, oops it's not that cheap like right now it costs half a dollar per gram. And ALL the chemistry stores I know sell it.

MrHomeScientist - 8-5-2017 at 06:10

How do you have 'easy" and "cheap" access to sodium metal but can't get magnesium powder?

United Nuclear has it, and there's currently several listings on eBay. Plenty of other sources out there, easily found by Google.

Foeskes - 8-5-2017 at 21:39

At first I was going to buy it there but that might be a hassle since they don't sell outside of the us.