FIELD: chemical or physical processes.
SUBSTANCE: invention can be used in production of cathode-active material of lithium secondary battery. Method of extracting nickel and cobalt from raw material, which is a mixed hydroxide residue containing mixed nickel and cobalt hydroxide, includes a leaching step, including the first leaching stage with heating at atmospheric pressure and the second leaching stage with heating at atmospheric pressure. At the leaching step, the mixed hydroxide residue (MHP) is heated and leached at atmospheric pressure in an acid solution to form a solution of the leaching product containing nickel, cobalt and impurities. First leaching stage is carried out at temperature of 50–70 °C and at pH 2.7–3.3, the second leaching stage is carried out at temperature of 80–100 °C. Then, an extraction step is carried out to separate the leaching product solution into a first filtrate containing nickel and impurities, and a first organic layer containing cobalt and impurities, by adding an extractant solvent to the leach product solution. Further, a step of removing by sedimentation is carried out, which comprises the deposition and removal of impurities, including magnesium, calcium or a mixture thereof, by adding a precipitating agent to the first filtrate. Finally, a step of precipitating the desired material is carried out, involving selective precipitation to obtain a nickel-containing precipitate on a filter, by adding a neutralizing agent to the first filtrate, from which impurities are precipitated and removed.
EFFECT: invention increases extraction of nickel/cobalt, reduces power consumption, as well as the risk of fire and explosion due to use of an organic solvent at the extraction stage.
10 cl, 3 dwg, 9 tbl, 1 ex
