Extraction of Nickel from Spent Catalyst Using EDTA as Chelating Agent

Abstract

The extraction of nickel from spent catalyst of primary steam reformer from a nearby fertilizer plant using chelation method is reported in this paper. The chelation was carried out using a di-sodium salt of EDTA (ethylene diamine tetra acetic acid) as a chelating agent. The Ni-EDTA complex formed was dechelated using nitric acid as a solvent resulting into the formation of nickel nitrate (NiNO3) and recovery of EDTA. The recovered EDTA was used for subsequent experiments. The objective was to evaluate nickel removal efficiency of EDTA and reusability of recovered EDTA. The effect of EDTA concentration, time of chelation, catalyst to liquid ratio (S:L) and temperature of chelation were studied in detail. The extraction was up to 95% under the following conditions: 1M concentration of EDTA, solid to liquid ratio 1:10 (g/mL), particle size 1-2 mm, pH 10, 7 hours of chelation time, 400 rpm and 90°C.