3. Results and discussion
3.1. Biodegradability of sulfide mineral flotation collectors
The degradation curves of collectors are given in Fig. 1.
It can be seen in Fig. 1 that the degradation curves of sodium
diethyldithiocarbamate and ammonium butyl-dithiophosphate
are similar. Sodium diethyldithiocarbamate and ammonium butyl-
dithiophosphate can be degraded quickly, the degradation extent
can reach 59.3% and 46.2%, respectively in 2 d. The
degradation curves of n-butyl xanthate and ethylthionocarbamate
have a short stagnant phase during 2–4 d. The ethylthionocarbamate
had the slowest degradation with a degradation extent in
2 d of only 13.8%. The degradation curves of these collectors have
a similar characteristic that there was a fast increase at the beginning,
with the time increased the growth of degradation extent became
more and more gentle. In the whole process, sodium
diethyldithiocarbamate had the fastest degradation, followed by
ammonium butyl-dithiophosphate, n-butyl xanthate, while ethylthionocarbamate
had the slowest degradation. The biodegradation
extent in 8 d of sodium diethyldithiocarbamate, ammonium butyldithiophosphate,
n-butyl xanthate and ethylthionocarbamate was
97.1%, 93.7%, 81.8% and 37.3%, respectively.