Wet process for recovering valuable metals from lithium battery

A wet process for recovering valuable metals from a lithium battery, comprising the following steps:

• subjecting a waste lithium battery powder to first-stage leaching in a first acid liquor introduced with a hydrogen sulfide gas, and conducting solid-liquid separation to obtain a first-stage leaching residue and a first-stage leaching liquor;
• wherein a solid-to-liquid ratio of the waste lithium battery powder to the first acid liquor is 100 to 250 g/L;
• and the first-stage leaching is conducted at a temperature of 20-90° C., a pH of 3.0-3.5, and a pressure of 0-6 MPa;
• adjusting the pH of the first-stage leaching liquor with an alkali liquor to sequentially remove aluminum and manganese to obtain a lithium-containing filtrate;
• wherein a process of the sequentially removing aluminum and manganese is:
• adjusting the pH with the alkali liquor to 5.0-5.5 first, and conducting solid-liquid separation to obtain a filtrate containing manganese and lithium, and an aluminum residue;
• and further adjusting the pH of the filtrate with the alkali liquor to 10.5-11.0, and conducting solid-liquid separation to obtain a lithium-containing filtrate and a manganese residue;
• adding sodium carbonate to the lithium-containing filtrate, then conducting a solid-liquid separation to obtain lithium carbonate and a salt-containing wastewater;
• adding a second acid liquor to the first-stage leaching residue for second-stage leaching, and conducting a solid-liquid separation to obtain a second-stage leaching liquor containing nickel and cobalt ions;
• adding iron powder to the second-stage leaching liquor, conducting a solid-liquid separation to remove a copper residue;
• adding an oxidant to a resulting copper-removing second-stage leaching liquor, adjusting the pH to 3.5-4.0, and conducting a solid-liquid separation to remove an iron residue to obtain a solution of nickel salt and cobalt salt.