Abstract： According to the characteristic of spent catalyst which contains cobalt and chromium, a economical and reasonable technical process of roasting, the acid dissolution and the extraction separation has been proposed comparing with many separation methods. The characteristic of this technical process is higher recovery rate of cobalt and chromium, simpler technological route and lower cost，compared with the single chemistry precipitation.
In the process of roasting and dissolution, better technological conditions can be got as follows by single factor experiment: roasting temperature is 400°C, the reaction time is 4 hours, the mass ratio of spent catalyst to the sodium carbonate is 1：1, spent catalyst padding granularity is 60 items, the fluid-to-solid ratio is 10：1, the solution temperature is 120 ° C，the dissolution time is 1h，40% sulfuric acid as the solvent substance. Based on the above conditions, the dissolution ratio is more than 99%.
In the process of extraction and separation, better technological conditions can be got as follows by single factor experiment: the content of extracting agent is 30%, the saponification ratio is 60%, the solution pH is 2.0, the solution’s temperature is room temperature, the equilibrium time is 3min, the cobalt extraction ratio is up to 99%, the chromium extraction ratio is less than 5%.
After the process of roasting, dissolution, and the extraction separation, the products cobalt oxalate and the chromic hydroxide from the spent catalyst can be prepared.
Keywords： Spent catalyst; Dissolution ratio; P507 extraction; Chromium recovery
