Removal of heavy metals and lanthanides from industrial phosphoric acid process liquors

Journal Article · Mon Nov 01 04:00:00 EST 1999 · Separation Science and Technology

DOI:https://doi.org/10.1081/SS-100100818· OSTI ID:20017406

Koopman, C; Witkamp, G J; Van Rosmalen, G M

To diminish the discharge of heavy metals and lanthanides by the phosphoric acid industry, these impurities have to be removed from the mother liquor before their incorporation in the gypsum crystals. This can best be achieved by means of solvent extraction or ion exchange during the recrystallization of hemihydrate to dihydrate gypsum. Various commercial carriers and two ion-exchange resins were screened for their efficiency and selectivity. Light and heavy lanthanide ions are extracted from the recrystallization acid by didodecylnaphthalenesulfonic acid (Nacure 1052) and di(2-ethylhexyl)phosphoric acid (D2EHPA), and the heavy-metal ions by bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301) and by bis(2,4,4-trimethylpentyl)monothiophosphinic acid (Cyanex 302). Mercury is also extracted by the anion carriers tri(C{sub 8}-C{sub 10})amine (Alamine 336) and tri(C{sub 8}-C{sub 10}) monomethyl ammonium chloride (Aliquat 336). Both Dowex C-500 and Amberlite IR-120 extract lanthanide and heavy-metal ions. Unfortunately, D2EHPA, Nacure 1052, and the two ion-exchange resins also show affinity for ions present in much higher concentrations, like calcium or iron ions.

• Research Organization: Delft Univ. of Technology (NL)
• OSTI ID: 20017406
• Journal Information: Separation Science and Technology, Journal Name: Separation Science and Technology Journal Issue: 15 Vol. 34; ISSN 0149-6395; ISSN SSTEDS
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
54 ENVIRONMENTAL SCIENCES
CHEMICAL INDUSTRY
ION EXCHANGE
ION EXCHANGE MATERIALS
MERCURY
PERFORMANCE TESTING
PHOSPHORIC ACID
RARE EARTHS
SPENT LIQUORS