The invention discloses a method for comprehensively recycling valuable metals from a spent 
lithium ion battery. The method comprises the following steps: carrying out 
electric discharge treatment on a spent battery, crushing, pre-
roasting at 300-400 DEG C, adding a 
reducing agent, and carrying out reduction 
roasting at 450-700 DEG C; carrying out 
water extraction and evaporative 
crystallization on fine aggregates obtained through the reduction 
roasting, so as to obtain a high-purity 
lithium product, leaching 
copper, 
nickel and 
cobalt from leached 
slag and roasted lump materials by virtue of 
ammonia oxide, carrying out 
magnetic separation and sieving on 
ammonia leaching 
slag so as to obtain iron and aluminum enriched products, and carrying out reduction acid leaching, purification and edulcoration on sieved products, so as to obtain a high-purity 
manganese sulfate solution; and carrying out extraction and selective reverse extraction on 
ammonia leaching liquid, so as to obtain a high-purity 
nickel sulfate solution and a high-purity 
copper sulfate solution, and carrying out 
vulcanization cobalt precipitation, oxidation acid leaching and 
extraction purification on 
raffinate, so as to obtain a high-purity 
cobalt sulfate solution. The method is high in extraction rate of valuable metals and applicable to the treatment of multiple waste 
lithium ion battery raw materials and efficient utilization of multiple elements, and sorting is not required.