Bioleaching of Spent Catalyst using Moderate Thermophiles with Different Pulp Densities and Varying Size Fractions without Fe Supplemented Growth Medium

Bioleaching of spent catalyst using moderate thermophilic chemolithotrophic acidophiles in growth medium without Fe source was investigated with two different pulp densities and three different size fractions. All the experiments were conducted on shake flasks at a temperature of 65 °C. The leaching yield of Ni and Al was found to be promising with very high leaching yield of 92-96% followed by Al as 41-76%, which means both Ni and Al leaching were favored by the moderate thermophilic bioleaching compared to the mesophilic bioleaching. The acid consumption was comparatively higher for the 10% pulp density experiments. Comparatively minimal difference in the leaching yield with different size fractions and different pulp densities show no requirement of grinding and using low pulp density less than 10%. This process would rather be economical as well as eco-friendly process for future optimization of the recovery of metal values from spent catalyst.

• Haragobinda Srichandan
• Chandra Sekhar Gahan
• Dong-Jin Kim
• Seoung-Won Lee

• Bioleaching
• spent catalyst
• leaching yield
• thermophile.

[1] M. Marafi, and A. Stanislaus "Options and processes for spent catalyst
handling and utilization" J. Hazard. Mater. Vol. 101, p. 123-132, 2003.
[2] M. Marafi, and A. Stanislaus "Spent catalyst waste management: A
review Part IÔÇöDevelopments in hydroprocessing catalyst waste reduction and use. Conserv. Recycling. Vol. 52, p.859-873, 2008.
[3] D. Pradhan, D. Mishra, D.J. Kim, J.G. Ahn, G.R. Chaudhury, and S.W.
Lee "Bioleaching kinetics and multivariate analysis of spent petroleum catalyst dissolution using two acidophiles. J. Hazard. Mater. Vol. 175, p.
267-273, 2010.
[4] V. Bosio, M. Viera, and E. Donati "Integrated bacterial process for the treatment of a spent catalyst" J. Hazard. Mater. Vol. 154, p. 804-810,
2008.
[5] R.M. Gholami, S.M. Borghei, and S.M. Mausavi "Bacterial leaching of
a spent Mo-Co-Ni refinery catalyst using Acidithiobacillus ferrooxidans
and Acidithiobacillus thiooxidans" Hydrometallurgy. Vol. 106, p. 26-31,2011.
[6] D. Mishra, D.J. Kim, D.E. Ralph, J.G. Ahn, and Y.H. Rhee "Bioleaching of vanadium rich spent refinery catalysts using sulfur
oxidizing lithotrophs" Hydrometallurgy. Vol. 88, p. 202-209, 2007.
[7] D. Mishra, J.G. Ahn, D.J. Kim, G.R. Chaudhury, D.E. Ralph "Dissolution kinetics of spent petroleum catalyst using sulfur oxidizing
acidophilic microorganisms" J. Hazard. Mater. Vol. 167, p. 1231-1236, 2009.
[8] F. Beolchinia, V. Fontia, F. Ferell, and F. Veglio "Metal recovery from
spent refinery catalysts by means of biotechnological strategies" J.
Hazard. Mater. Vol. 178, p. 529-534, 2010.
[9] D.J. Kim, D. Pradhan, J.G. Ahn, and S.W. Lee "Enhancement of metals
dissolution from spent refinery catalysts using adapted bacteria culture-
Effects of pH and Fe(II)" Hydrometallurgy. Vol. 103, p. 136-143, 2010.
[10] G. da Silva, M.R. Lastra, and J.R. Budden "Electrochemical passivation
of sphalerite during bacterial oxidation in the presence of galena" Miner. Eng. Vol. 16, p. 199-203, 2003.
[11] C.S. Gahan, J.E. Sundkvist, and Å. Sandström "A study on the toxic
effects of chloride on the biooxidation efficiency of pyrite" J. Hazard.
Mater. Vol. 172, p. 1273-1281, 2009.