Methods for manufacturing hydroxides for precursors of cathode materials for rechargeable batteries

A method for manufacturing a first aqueous slurry comprising first hydroxide or oxyhydroxide particles of at least one element for being used as a seed particles source in a precipitation process of a second hydroxide, wherein the at least one element includes at least one of Ni, Co, and Mn, wherein the method comprises:

• continuously supplying to a reactor vessel a first flow of a metal salt solution comprising the one or more elements;
• continuously supplying to the reactor vessel a second flow of an aqueous solution of one or more alkali hydroxides;
• continuously supplying to the reactor vessel a third flow of an ammonia aqueous solution (NH3(aq)),
• mixing said 1st, 2nd, and 3rd flows to obtain the first aqueous slurry comprising the first hydroxide or oxyhydroxide particles in the reactor vessel, and
• continuously removing a fourth flow of the first aqueous slurry from the reactor vessel, characterized in that:
• the first aqueous slurry has a pH value being at most 13.0 and at least 12.0, said pH value being measured on a sample of the first aqueous slurry at 20° C., and in that
• the supply of the third flow is controlled so that a NH3(aq) concentration in the first aqueous slurry is at least 1.0 g/l and at most 5.0 g/l to limit growth of the first hydroxide or oxyhydroxide particles to a median particle size D50 between a range of at least 0.7 μm and at most 3.0 μm.

A method for manufacturing a second aqueous slurry comprising second hydroxide or oxyhydroxide particles of one or more elements, wherein the one or more elements include at least one of Ni, Co, and Mn, wherein the method comprises:

• a. providing an amount of a first aqueous slurry comprising first hydroxide or oxyhydroxide particles into a reactor vessel, wherein the first hydroxide or oxyhydroxide particles have a median particle size D50 between a range of at least 0.7 μm and at most 3.0 μm;
• b. supplying to the reactor vessel a fifth flow of a metal salt solution comprising the one or more elements;
• c. supplying to the reactor vessel a sixth flow of an aqueous solution of one or more alkali hydroxides;
• and
• d. maintaining conditions in the reactor vessel that cause a precipitation of the one or more elements from the metal salt solution as a hydroxide on the first hydroxide or oxyhydroxide to obtain in the reactor vessel the second aqueous slurry comprising the second hydroxide or oxyhydroxide particles of the one or more elements.