Aluminum recovery from Aluminum dross?

Question

hello,

i have been recently studying the production of aluminum from aluminum dross (recycling of aluminum) .

this chemical equations represents the hydrolization of sodium aluminate to obtain aluminum hydroxide :

Na2Al2O4 + 4H2O -----------> 2Al(OH)3 + 2NaOH

after that the next step is to produce Al2O3

the next step to obtain Aluminum is to pass a current through the solution (electrolysis)

this is the part that i don't get .... how could we electrolyze Aluminium oxide to produce aluminum if we are recycling aluminum ... i mean electrolysis consumes most of the energy and is very expensive .... so how do electrolysis be used in the recycling industry...

please answer ... all answers are really appreciated ....

and correct me if my informations are wrong...

Answer 1

Because aluminium is usually used as an alloy, it has to be treated and extracted from the scrap first. This is done by putting it through the same process as extracting the metal from bauxite, which is extraction of pure aluminium oxide and electrolysing it to get the metal.



I agree that electrolysis of aluminium oxide costs a lot. However, the efficiency of the recycling is higher, since the aluminium is relatively pure (bauxite is not), and it prevents perfectly usable aluminium being consigned to the scrap heap (preventing landfill at the same time).

Answer 2

As Aluminum dross composition will vary from different sources







Electrolytic aluminium dross



w(Al)25.58, w(Al2O3)31.55, w(SiO2)5.56, w(Na2O)2～3, w(MgO)2.0～3.0, w(CaO)<2.00, w(FeO)+ w(MnO)<1.0







Cast aluminum dross



w(Al)10, w(Al2O3)50～60, w(SiO2)3.0～5.0, w(Na2O)1.0～1.5 w(MgO)2.0～3.0, w(CaO)1. 5～3.0, w(FeO)+ w (MnO)<1.0





The most popular way is mechanical recover aluminum from aluminum dross. Rotary furnace and aluminum dross recovery machine can do this work easily and effectively. You can put heating flux in the processing to get the certain temperature for the dross, them aluminum dross can be processed in the rotary furnace or aluminum dross processing machine, aluminum will be recycled from aluminum dross. It is automatic and that is such simple!

Answer 3

OMG Zilla...you're a TC!!! i might somewhat not think of roughly God or the rest seeing via aluminum foil. It makes me experience bare. I positioned on it each and every of the time. undergo thinks that's attractive. :)