The importance of pre-treatment of spent hydrotreating catalysts on metals recovery

Química Nova. 2011;34(1):145-150 DOI 10.1590/S0100-40422011000100027


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Journal Title: Química Nova

ISSN: 0100-4042 (Print); 1678-7064 (Online)

Publisher: Sociedade Brasileira de Química

Society/Institution: Sociedade Brasileira de Química

LCC Subject Category: Science: Chemistry

Country of publisher: Brazil

Language of fulltext: Portuguese, Spanish; Castilian, English

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Alexandre Luiz de Souza Pereira (Universidade Federal do Rio de Janeiro)
Cristiano Nunes da Silva (Universidade Federal do Rio de Janeiro)
Júlio Carlos Afonso (Universidade Federal do Rio de Janeiro)
José Luiz Mantovano (Comissão Nacional de Energia Nuclear)


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Time From Submission to Publication: 12 weeks


Abstract | Full Text

This work describes a three-step pre-treatment route for processing spent commercial NiMo/Al2O3 catalysts. Extraction of soluble coke with n-hexane and/or leaching of foulant elements with oxalic acid were performed before burning insoluble coke under air. Oxidized catalysts were leached with 9 mol L-1 sulfuric acid. Iron was the only foulant element partially leached by oxalic acid. The amount of insoluble matter in sulfuric acid was drastically reduced when iron and/or soluble coke were previously removed. Losses of active phase metals (Ni, Mo) during leaching with oxalic acid were compensated by the increase of their recovery in the sulfuric acid leachate.