METHOD OF EXTRACTING MOLYBDENUM AND CERIUM FROM SPENT IRON OXIDE CATALYSTS FOR DEHYDROGENATING OLEFIN AND ALKYL AROMATIC HYDROCARBONS Russian patent published in 2014 - IPC C22C7/00 C22B34/34 C01F1/00 C22B3/04 C22B3/10 C22B3/20 B01J23/745 

FIELD: chemistry.

SUBSTANCE: extraction of molybdenum and cerium is carried out in two steps, where molybdenum is extracted at the first step and a cerium compound is extracted at the second step. The first step involves crushing a catalyst, adding a solution of a leaching agent in weight ratio to the spent catalyst of (0.5-10):1, in concentration of not less than 0.1 mol/l, stirring the suspension for 4-10 hours at temperature of 90-95°C, filtering the mixture to separate the residue and washing the residue with water. A mixture is then prepared from the filtrate and water from washing the residue containing molybdenum. The mixture is the evaporated to obtain an end product. The second step of extracting the cerium compound is then carried out, where the residue of the crushed catalyst is completely dissolved in hydrochloric acid, water is added and then evaporated to the initial volume of the solution, the undissolved portion is separated by filtering, the remaining solution is neutralised to pH 3.5-4.5 with control thereof, the solution is heated to 90-100°C while stirring, followed by successively adding a calcium salt solution in ratio of calcium to the catalyst from 1:100 to 5:100 and a saturated oxalic acid solution in ratio to the catalyst from 5:1 to 10:1, stirring at temperature of 70-100°C for 2-6 hours, holding the solution to precipitate the cerium compound for 4-24 hours at room temperature, separating the precipitate from the mother solution by filtering, washing and drying to constant mass. The invention also discloses a method of extracting molybdenum only from said catalyst and a method of extracting cerium only from said catalyst.

EFFECT: extracting molybdenum and cerium with high percentage output and purity by preventing the effect of the extracted components on each other.

19 cl, 2 tbl, 18 ex