The vast application base of lithium-ion batteries and subsequent production will inevitably lead to a large number of spent lithium-ion batteries after their useful life. Recycling of the spent lithium-ion batteries is an essential route to safeguard the environment and to have a sustainable supply of valuable metals contained by these batteries. This paper explores two routes of recycling process (acidic leaching and baking) and compares their environmental and economic impacts along with the extraction efficiency and purity of cobalt oxalate. The paper uses Box–Behnken method to optimize operating conditions of these two routes, and polynomial equation based on the experimental data of both the routes are developed for the extraction efficiency of cobalt oxalate. Various environmental indices given in GaBi software are studied for these routes. The environmental impact (GWP 100) of these two routes are found to be 4.38 and 6.37 kg CO2 equivalent. The optimum extraction efficiency and purity of the cobalt oxalate using acidic leaching route are found as 85.40 and 89.80%, whereas for the baking route, these values stand at 93.87 and 99.20%, respectively. Acidic leaching is found to be a greener route with an economic advantage over the acidic baking route. The acidic baking route may be used if we desire to have high purity cobalt oxalate, irrespective of its weaker economics and harsher environmental impact.