METHOD FOR REPROCESSING A SPENT MOLYBDENUM- AND TUNGSTEN-CONTAINING CATALYST Russian patent published in 2022 - IPC B01J38/64 C22B3/04 C22B7/00 C22B34/34 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of hydrometallurgy and can be used in the technology of comprehensive reprocessing of spent catalysts of petroleum or gas processing processes for producing highly pure molybdenum (VI) oxide powder. Method for reprocessing spent molybdenum- and tungsten-containing catalysts is characterised by leaching the catalyst with a soda solution. After that, the soda leaching solution is boiled for at least 30 minutes, then the solution is sent to a reactor, and the pH of the solution is reduced from 8.5-11 to 6.5-8. A 30% aqueous solution of a mixture of iron and aluminium chlorides is then added to the resulting solution in an amount of 0.5 to 1.5% vol.; the resulting solution is boiled for at least one hour while constantly stirring; the forming deposit is filtered, and the pH of the filtrate is set to 6.5-8.5. Then the solution is supplied into a sorption column containing anionite ion exchange resin with a flow rate of 300 l/(m²*h). The sorption process is conducted until the content of tungsten in the solution exiting the sorption column raises above 10 mg/l; then the sorption process is stopped. Molybdenum oxide is then desorbed from the sorbent by passing a 7-10% ammonia solution, the desorption product is evaporated, resulting in ammonium paramolybdate crystals. The product is then dried and calcined until a solid molybdenum (VI) oxide powder is produced. The catalyst soda leaching solution is therein produced as a result of pulp production when a crushed catalyst is mixed with a soda solution with a concentration of 150-300 g/l in a S:L volume ratio = 1:3-5, the ratio of iron and aluminium chloride solutions in the mixture is 1:1.

EFFECT: increase in the purity of the resulting molybdenum oxide.

1 cl, 8 ex