Nitrate process for manufacturing transition metal hydroxide precursors

A process for the preparation of a metal-bearing precursor for the synthesis of cathode material suitable for secondary lithium-based batteries, comprising the steps of:

• leaching one or more metals and/or metal compounds using HNO3 in an aqueous solution, thereby producing an aqueous solution containing metal nitrates, and, optionally, a first gaseous phase containing NOx, which is separated;
• precipitating a precursor from the solution containing metal nitrates using an alkali hydroxide or carbonate in an aqueous solution, thereby producing a solution containing alkali nitrates, and a solid phase containing the metal-bearing precursor, which is separated, and optionally washed;
• decomposing the alkali nitrates in the solution containing alkali nitrates, thereby producing a solid or liquid phase containing the alkali, and a second gaseous phase containing NOx, which is separated;
• and
• regenerating HNO3 using the first and second NOx gaseous phases separated in the steps of leaching and of decomposition, and recycling the HNO3 to the step of leaching.