I am currently researching the effect of lime addition to aluminate/carbonate containg solutions in the bayer process in aluminium refineries. Does anyone know a good source of technical information located on the net?
What is the concentration of NaOH required in a caustic/water solution to cause maximum dissolution rate of aluminium?
We currently use 25% NaOH to dissolve aluminium from extrusion dies.
Does anyone know if it is possible to use cation membranes in a diffusion dialysis system to remove free NaOH and retain sodium aluminate (dissolved aluminium in caustic).
Is this process possible? Can the membranes withstand the 25% NaOH soln and the pH 13? Are there companies out there that...
To my knowledge, aluminium hydroxide best precipitates at pH between 8 and 9 - at a pH of 13, a lot of the aluminium would be redesolved.
The other major contaminant would be sodium carbonate which I believe would also be removed if using membranes - requiring a top up of the caustic solution...
I am currently researching methods to recover a spent sodium hydroxide solution used to dissolve aluminium from extrusion dies.
We have two 900L tanks of 25% NaOH and one 900l rinse tank. When the aluminium concentration reaches about 20-30g/L, the spent solution is dumped (handled by...
