solar_plasma
Well-known member
Since I am not satisfied with the known methods to treat acidic metal chloride waste solution (thinking of kovar right now) from recovery processes, I thought a lot about it in the last time. Maybe I have got an idea (or I just forgot, that I read it somewhere) and I'd like to hear some opinions:
What if...
♦ we cement most, maybe even all, metals with aluminium (having AlCl3 left)
♦ filter at low pH
♦ then add NaOH to form gelatinous aluminium oxide hydrates at pH4-5(maybe up to 7) and NaCl
♦ vaporize most of the water
♦ calcine to form Al2O3
♦ wash&filter
♦ the NaCl solution pH could be raised to pH9-10, filtered again if any solids precipitate and brought back to pH7.
We would be left with dry metal powders, NaCl solution, dry Al2O3 powder. The advantage should be, that the solids should be easier to filter.
The only new thing would be the calcination step.
???
What if...
♦ we cement most, maybe even all, metals with aluminium (having AlCl3 left)
♦ filter at low pH
♦ then add NaOH to form gelatinous aluminium oxide hydrates at pH4-5(maybe up to 7) and NaCl
♦ vaporize most of the water
♦ calcine to form Al2O3
♦ wash&filter
♦ the NaCl solution pH could be raised to pH9-10, filtered again if any solids precipitate and brought back to pH7.
We would be left with dry metal powders, NaCl solution, dry Al2O3 powder. The advantage should be, that the solids should be easier to filter.
The only new thing would be the calcination step.
???