Microwave-assisted selective leaching of nickel from spent hydrodesulphurization catalyst: A comparative study between sulphuric and organic acids

作者：Pinto Isabel S S; Soares Helena M V M^*

来源：Hydrometallurgy, 2013, 140: 20-27.

DOI：10.1016/j.hydromet.2013.08.009

• Spent catalyst
• Nickel
• Microwave
• Ethylenediaminetetracetic acid (EDTA)
• Nitrilotriacetic acid (NTA)

Hydrodesulphurization (HDS) spent catalysts are hazardous solid wastes from petroleum refining industries that contain valuable metals in appreciable concentrations. In this work, removal of Ni from a spent Ni-Mo catalyst was studied. In order to evaluate selective extraction of Ni from Al and Mo, ethylenediaminetetracetic acid (EDTA) leaching was performed using conventional and microwave-assisted methods and compared with the sulphuric acid (H2SO4) performance. Microwave-assisted leaching with nitrilotriacetic acid (NTA) solutions was also performed. Results showed that EDTA leaching, using conventional heating, had a very restricted Ni extraction, even when time and concentration were increased. When microwave-assisted process was applied, Ni dissolution reached 80% at optimum conditions (4 heating cycles of 60 s each, 0.1 M EDTA, pH 10.8 and S/L = 50 g/L). Even though this value was lower than the results obtained with 0.8 M H2SO4 (%26gt;= 90%), both Al and Mo extractions were significantly lower, leading to a more selective extraction. Ni leaching with NTA was not as efficient as EDTA, even though Mo and Al extractions were reduced.

• 出版日期2013-11