Ah. Martins, The influence of calcium, magnesium, phosphorus and silica on vanadium precipitation in acidic sulfate solutions, BRAZ J CH E, 17(2), 2000, pp. 219-231
The experimental research work was carried out in accordance with the Facto
rial Design Statistical Method to evaluate and analyze the influence of cal
cium, magnesium, silica and phosphorus on the precipitation of vanadates, P
recipitation was performed by neutralization with H2SO4 of alkaline aqueous
solutions containing vanadium pentoxide (V2O5) at 60+/-2 degrees C. The ex
perimental responses measured were percent of vanadium recovery and vanadiu
m pentoxide content in the precipitate. These impurities are considered rep
resentative of those present in a leach liquor from the ore obtained at Cam
po Alegre de Lourdes (Brazil). The operational variables in this work were
used under optimum conditions as determined by the statistical approach.
Among the impurities under study, phosphorus exhibited the highest negative
influence on the experimental responses. Phosphorus diminished the percent
of vanadium recovered from 98.9 to 34.5 and the vanadium oxide content in
the precipitate from 91.2 % to 39.3 %.