Separation of Al(III), Mo(VI), Ni(II), and V(V) from model hydrochloric acid leach solutions of spent petroleum catalyst by solvent extraction

Abstract

BACKGROUND: A large number of spent catalysts are regularly discharged by petrochemical industries. The spent catalysts contain some valuable metals, such as molybdenum, nickel, and vanadium. Therefore, it is necessary to recover these high purity metals from the spent petroleum catalysts with environmentally friendly processes. RESULTS: In order to recover valuable metals such as molybdenum, vanadium, nickel, and aluminum from spent petroleum catalysts, a hydrometallurgical process consisting of leaching followed by solvent extraction was developed in the present work. First, molybdenum was separated from the leaching solution by extraction with D2EHPA and the loaded organic phase was stripped by a mixture of NH 4 OH and (NH 4) 2 CO 3. Second, the molybdenum free raffinate was contacted with Aliquat 336-decanol to separate the vanadium, and then a hydrochloric acid solution was employed to strip vanadium from the corresponding loaded extractant. Since the acidity of the leach solution was high, TEHA (tris-2-ethylhexylamine) was chosen for the extraction of hydrochloric acid in order to increase the pH of solution. The loaded TEHA phase was then stripped by distilled water, which enabled the recovery of HCl. The nickel and aluminum in the molybdenum and vanadium free raffinate were separated by the extraction of nickel with saponified Cyanex 301 at a solution pH of 2.5. It was possible to strip nickel from the loaded organic phase by a strong hydrochloric acid solution. CONCLUSIONS: A flow sheet of the proposed process for the separation of Al(III), Mo(VI), Ni(II), and V(V) was presented. The current process can be applied to aqueous solutions containing these four metals from diverse material resources.

Molybdate Recovery by Adsorption onto Silica Matrix and Iron Oxide Based Composites

“…Other technologies used for molybdenum recovery consist in acidic lixiviation of spent catalysts when is obtained a liquid solution containing Mo, Ni, Co, V and Al [ 8 ]. Other technologies that can be used for molybdenum recovery from industrial wastewaters are: selective precipitation [ 15 , 16 , 17 ], solvent extraction [ 17 , 18 , 19 , 20 , 21 , 22 ], adsorption on synthetic resins [ 23 , 24 , 25 , 26 , 27 ] and adsorption on activated carbon [ 15 , 28 ]. In some cases, molybdenum recovery can be done by filtration, coagulation, reverse osmosis, and bioremediation.…”

High Value-Added Utilization of Waste Hydrodesulfurization Catalysts: Low-Cost Synthesis of Cathode Materials for Lithium-Ion Batteries

“…Many researchers have proposed various methods for recovering valuable metals from waste catalysts based on pyrometallurgy and hydrometallurgy processes [6][7][8][9]. Thi et al [10] reported a process for recovering molybdenum and cobalt from spent hydrodesulfurization catalysts.…”

Editorial: Separation and analytical chemistry

“…In the hydrometallurgical approach, the most common methods are chemical leaching in the upstream stage and solvent extraction in the downstream stage, which are employed for extraction and separation processes, and for the purification of desired metals from the secondary phases (Parhi and Misra, 2022). The use of mineral acid solvent reagents such as HCl, H 2 SO 4 , and HNO 3 during conventional leaching, and traditional solvent reagents such as organo-phosphorus derivatives (D2EHPA, PC88A, Cyanex 272, TOPO, TBP), chelating types (LIX series), and secondary/tertiary amines (Alamine 336, Alamine 304, Alamine 308) in the solvent extraction process, are very common (Jyothi et al, 2020;Le and Lee, 2020). These solvents are applied because of their reasonable efficacy and limited selectivity towards the extraction of a metal of interest from an aqueous medium depending on the nature and existence of metals in the respective secondary waste or corresponding leach liquor phases.…”

“…The majority of investigations (Jyothi et al, 2020;Le and Lee, 2020) reveal that the existence of metals as an oxide phase in secondary wastes appears to be highly prone to becoming leached with solvent, namely, HCl, while metals found in sulfide or alloy form and/ or other mixed category in the secondary waste phases are readily subjected to treatment with H 2 SO 4 and HNO 3 in order to dissolve the metal content. Sometimes pre-treatment operations, including roasting, mechanical activation such as ball milling, baking, microwave (MW) treatment, and ultra-sonication (UW), are performed in order to activate or oxidize/ reduce the waste phases for attaining a leachable phase for substantial metal extraction with high efficacy in subsequent leaching stages (Behera et al, 2019).…”