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Recovery of Nickel from Spent Catalyst Using Edta as a Chelating Agent

Beena Singh, Rakesh Shrivastva, K. K. Pant, V. V. Krishnan, and K.D.P. Nigam. Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India

Metals like Ni, Mo, Co, etc. are widely used as catalyst in fertilizer industries. After periodical use due to poisoning effect of foreign material and impurities catalyst will become inactive.. In such cases, fresh catalysts have to be replaced and the spent catalyst will be discarded as waste material. Therefore, a suitable and economically viable method is required for recovery of metal from spent catalyst.

Metal extraction and recovery experiments were conducted with varying EDTA concentration (.1-.75M), precipitant concentration (5- 10mL) with and without NaOH, and pH (recovery at 7-12).This work deals with the extraction and recovery of chelating agent. Effects of parameter such as EDTA concentration, precipitant type its concentration, and pH related to extraction and recovery efficiencies of the chelator as well as workable recovery conditions. After extraction period of 4hrs it was filtered and analyzed for Ni content by UV spectrophotometer.

The results showed that EDTA was capable of extracting Ni. from the catalyst and could be recovered by the use of NaOH and H2SO4 precipitants in alkaline pH conditions more than 82% Ni was achieved by the .5M conc. of EDTA stoichemetric.EDTA (90%) was recovered, leaving behind the Support material alumina free from metal which could be recycled. Thus, EDTA proved to be strong and reusable chelating agent for Nickel metal from spent catalyst, which makes it valid remediation agent for metal extraction from spent catalyst. Maximum recovery of Ni was obtained at .5 m concentration of EDTA and solid /liquid ratio was kept 1:50 at this ratio we are getting the maximum recovery of Ni metal from catalyst.