Review of modern scientific developments in the field of molybdenum recovery from spent catalysts

Abstract

The widespread use of rare metals in industry requires an increase in the amount of their production and expansion of methods for obtaining them. In this regard, the use of secondary raw materials in modern production is growing rapidly and steadily. Molybdenum is a refractory metal, which is used as an alloying element in various steels, heating elements of electric furnaces, special purpose alloys, electrovacuum equipment and other fields. Data on the volume of consumption of catalysts in the oil refining and petrochemical industries, as well as on the import of molybdenum-containing catalysts are given. The technologies for processing spent hydro-treating catalysts with production of molybdenum oxide are considered, including oxidative roasting of the feedstock, as well as such operations as: leaching by sulfuric, hydrochloric, and nitric acids, sodium carbonate [7]. Hydrometallurgical methods of decomposition of raw materials are usually combined with the subsequent extraction of molybdenum by extraction with citric acid [16], MTAA carbonate [15], or ion-exchange sorption. High purity molybdenum is characterized by a number of unique properties that are important for its use in modern technology. Most of the hard-to-remove impurities get into molybdenum oxide from the feedstock, so one of the important tasks is to optimize the leaching process at the stage of uncovering of technogenic raw materials. Recently, more and more attention has been paid to obtaining high-purity molybdenum oxide, as well as to the separation of molybdenum and tungsten. One of the promising processes seems to be ion exchange, which makes it possible to purify solutions from metal impurities from solutions and pulps formed during the decomposition of molybdenite concentrates or during leaching of raw materials. The review was carried out under the agreement between the National University of Science and Technology “MISiS” and JSC “Company Wolfram” (Moscow region, Russia) No. 0422-341 dated April 22, 2021, implemented with the financial support of the Ministry of Science and Higher Education of the Russian Federation by order of the Government of the Russian Federation No. 218 of 04/09/2010.