Spent hydrodesulfurization (HDS) catalysts containing large amounts of valuable metals, such as Mo and V, are hazardous solid wastes but also valuable secondary resources. However, the current recovery process suffers from the difficulty of balancing the leaching efficiency of Mo and V and their selectivity over Al. This work focused on the effect of phase transformation during roasting operation on the leaching behavior Mo, V, and Al and adopted an oxidation roasting followed by mixed alkali of NaCO and NaOH leaching process to recover Mo and V from spent HDS catalysts. The results indicated that the phase transformation of Mo, V, and Al species during oxidation roasting process played a crucial role in achieving efficient leaching of Mo and V, as well as reducing leaching efficiency of Al. This transformation involved the change in Mo and V species changed from low valent compounds to high valent oxides, and AlO from γ-phase to θ- and α-phases. In addition, efficient and selective leaching of 99.3% Mo and 97.8% V was realized, with only 0.03% Al being dissolved, by roasting the spent catalysts at 700 °C for 2 h and then leaching with a mixed solution of 1.2 mol/L NaCO and 1.6 mol/L NaOH. The efficient and selective leaching of Mo and V can significantly reduce the burden of subsequent separation and purification, which provided an important prerequisite for the development of a new process for the recovery of Mo and V from HDS spent catalysts in alkaline systems.

中文翻译：

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通过氧化焙烧和 Na2CO3 和 NaOH 浸出，从废加氢脱硫催化剂中高效选择性回收 Mo 和 V


废加氢脱硫（HDS）催化剂含有大量钼、钒等有价金属，是危险的固体废物，但也是宝贵的二次资源。然而，当前的回收工艺难以平衡Mo和V的浸出效率及其相对于Al的选择性。本工作重点研究了焙烧操作过程中相变对Mo、V和Al浸出行为的影响，并采用氧化焙烧后NaCO和NaOH混合碱浸出工艺从废HDS催化剂中回收Mo和V。结果表明，氧化焙烧过程中Mo、V和Al物质的相变对于实现Mo和V的高效浸出以及降低Al的浸出效率起着至关重要的作用。这种转变涉及Mo和V物质从低价化合物转变为高价氧化物，以及Al2O3从γ相转变为θ和α相。此外，通过将废催化剂在700 ℃下焙烧2 h，然后用1.2 mol/L的混合溶液浸出，实现了99.3% Mo和97.8% V的高效选择性浸出，仅溶解了0.03% Al。 NaCO 和 1.6 mol/L NaOH。 Mo和V的高效选择性浸出可以显着减轻后续分离纯化的负担，这为开发在碱性体系中从HDS废催化剂中回收Mo和V的新工艺提供了重要前提。