Recovery of Molybdenum from Spent HDs Catalyst Leach Liquor by Solvent Extraction using Aliquat 336

Abstract

Recycling spent catalysts is very important due to its generation in large amount, enormous economic values and environmental concerns if disposed off directly. This work describes the recovery of Mo from spent hydro-desulph-urization (HDS) catalysts (NiMo/A1204). Catalyst was roa-sted at 500°C to eliminate volatile impurities and leached. The leach solution was subjected to solvent extra-ction to recover Molybdenum. Several solvents such as D2EHPA-TBP, LIX 84-IC and Aliquot 336 were tried and aliquat was finally used for further studies. Conditions for maximum extraction of Mo were optimized by varying different parameters such as pH of the feed solution, sol-vent concentration, aqueous / organic phase ratio etc. Under optimized condition the stage requirement for complete extraction of molybdenum was determined and with 1:2 phase ratio, more than 98% extraction of molybdenum was achieved at pH of 1.5. The molybdenum from loaded organic was stripped with 0.4MNaOH.