Heap-leaching of low-grade nickeliferous laterites with sulphuric acid resu
lts in a need to remove magnesium from the leach liquors produced during th
e hydrometallurgical process of nickel and cobalt recovery. Magnesium was p
recipitated from synthetic solutions with the aid of sodium carbonate, sodi
um bicarbonate or both. The effect of the precipitation conditions (precipi
tating agent, agent concentration and temperature) on the removal of magnes
ium as well as on the characteristics of the precipitate, which determine i
ts use as a filler, were investigated.