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[sayhello2sagar]

I am working on a project on recovering fluorine from spent bath i.e.( material left over in aluminium reduction pots is spent bath). The spent bath contains around 30-35% fluorine which can be extracted and adsorbed on alumina , to be reused to reduce the consumption of aluminium fluoride in reduction pots.

The process involves heating ~ 50 gm of spent bath with 30% fluorine with concentrated sulphuric acid at 180 deg.C . The reaction between H₂SO₄ and spent bath liberates HF gas which is adsorbed on alumina. The set-up consists of a closed reaction vessel with agitator and heater for mixing of acid and spent bath ( see the attachment). The gas liberated is passed through a bed of alumina ( ~ 100 gm) in a chamber.

With this we are achiveing ~ 85% recovery of fluorine from spent bath, but the adsorption is only 20%. We have tried various tests with higher quanity of alumina , but the adsorption is low.

I wanted to calculate the tower height required for effective adsorption by increasing the contact time between gas and alumina.

Can anybody please help me in this,

Attached Files

•  HF New set-up.JPG   2.7MB   1 downloads