عنوان مقاله [English]
Nickel-based catalysts are used in most refinery processes. After being regenerated and reused several times, these catalysts are released as used catalysts in nature, which, in addition to environmental risks, are not economically viable due to the presence of the precious metal nickel. Hydro-metallurgical methods are commonly used to extract nickel, which is difficult and expensive. Due to the significant shortage of nickel mines, the use of these secondary resources is quite important. In this study, the possibility of nickel recovery from used catalysts has been investigated. Initially, the cokes were removed, and then the effects of three different acids on nickel leaching were investigated. Sulfuric acid, nitric acid, hydrochloric acid are three main acids which used in this work. Various parameters such as temperature, mixing speed, liquid to solid ratio, particle size and acid concentration were investigated. After the complete leaching of nickel, nickel purification was performed by selective nickel hydroxide precipitation.