Process for recovering components from pickling acid residue
AssigneeCrisolteQ Ltd
InventorsKenneth Ekman, Peik Ekman, Elina Lappalainen, Jan-Peter Blomquist
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Abstract
A novel process for treating and recovering valuable metals and other components from pickling acid residue (PAR) has been developed. The metals and other components are recovered by neutralizing the pickling acid residue using a magnesium compound or a mixture of magnesium compounds, and separating components of the resulting mixture (metals and sulfates) into products that can be reused, such as magnesium sulfate, nickel sulfate, iron and chromium phosphate, or various metal hydroxides or oxides.
Claims10
A method for recovering sulfates and metals from a sulfuric acid containing pickling acid residue comprising the steps of:
- a) mixing the sulfuric acid containing pickling acid residue with at least one magnesium compound selected from the group consisting of magnesium oxide, magnesium hydroxide and magnesium carbonate to obtain a modified pickling acid residue having a pH in the range of 7-10,
- b) heating the modified pickling acid residue to a temperature of 70-90° C. and bringing magnesium into solution from the modified pickling acid residue as magnesium sulfate at a stable pH in the range 5.5-7, optionally adjusting the pH with sulfuric acid,
- c) recovering the magnesium sulfate as a magnesium sulfate solution by filtration, and
- d) obtaining a FeNiCr residue as a precipitate.
Dependencies are inferred from the claim text.