P. K. Das, S. Anand, R. P. Das
May 1, 1997
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0
Influential Citations
6
Citations
Journal
International Journal of Mineral Processing
Abstract
Abstract In an earlier work (Das et al., 1995a) it was established that Ni(II) precipitates as Ni x Mn (1− x (NH 3 ) 4 S 2 O 6 .2H 2 O (where x varies between 0.05 and 0.25) from the Ni(II)NH 3 SO 2 MnO 2 system. In the present work it is attempted to determine conditions for minimum precipitation of nickel by varying parameters such as time, reaction temperature (80–120°C), storage temperature (10–30°C) ammonia concentration (20 to 100 g/l) and ammonium sulphate concentration (20 to 200 g/l). The standard conditions maintained were: Ni 1 g/l, NH 3 80 g/l, (NH 4 ) 2 SO 4 80 g/l, (NH 4 ) 2 SO 3 57.1 g/l, pulp density 3.165%, reaction temperature 120°C and storage temperature 30°C, while the above-mentioned parameters were varied one at a time to study its effect. Nickel precipitation decreases from 66 to 16% with the increase in ammonium sulphate concentration from nil to 80 g/l and remains the same when further increasing its concentration to 200 g/l. Precipitation of nickel decreases from 39 to 7% with the decrease of ammonia concentration from 100 to 40 g/l on storing for 68 h at 30°C. Increase in initial nickel concentration from 1 to 3 g/l results in increase of nickel precipitation from 6.5 to 31.5%. The minimum nickel loss (0–6.5%) conditions for the slurry obtained at 120°C were: NH 3 ≤ 40 g/l, (NH 4 ) 2 SO 4 ≥ 80 g/l, Ni(II) 0.75–1 g/l, storage time between 0 and 68 h and storage temperature 30°C. The Eh of the solution for minimum precipitation (0–6.5%) varied between −150 to −200 mV with corresponding pH variation between 9.9 and 10.5.