Kj. Schmidt et al., Identification of major species in industrial metal-refining solutions with Raman spectroscopy, APPL SPECTR, 53(2), 1999, pp. 139-143
Raman and resonance Raman spectroscopies were used to characterize industri
al metal-refining solutions containing nitrogen, sulfur, and Ni, Co, Zn, an
d Cu ammine complex species. To identify the species present in these solut
ions, we also recorded Raman spectra of model compounds in similar matrices
. The results indicate that clearly resolved diagnostic bands in the Raman
spectrum can be used to identify and discriminate free ammonia, metal-bound
ammonia, sulfate, sulfamate, and metal species in industrially relevant pl
ant solutions. We roughly estimate that Raman can determine cobalt at the 0
.3 g Co/L level, nickel at the similar to 5 g Ni/L level, and copper at the
2-3 g Cu/L level in these solutions. Also, sulfate and sulfamate can be de
tected at the 1 g/L level with Raman spectroscopy. Finally, the Raman spect
rum can be used to determine bound ammonia with detection limits of about 2
0 g/L. The detection of free ammonia depends on the concentration ratio of
free to bound ammonia because of their overlapping vibrational bands and th
e weaker intensity of free ammonia Raman scattering.