Regeneration of the Slurry-Phase Hydroconversion Catalyst Precursor.

The relationships of the two-step regeneration of the slurry-phase hydroconversion catalyst separated as a component of a solid powder from the vacuum residue after distillation of the product obtained by hydroconversion of a mixture of petroleum tar and polymer waste were studied. The low-temperature oxidation of Mo sulfides was studied as the first step. High degree of oxidation of Mo sulfides to oxygen compounds of molybdenum in the highest oxidation state was reached at 250–400°С depending on the heat treatment time (from 30 to 150 min). The efficient oxidation is confirmed by the degree of transfer of the Mo oxides into an ammonia solution in the second step, leaching of the oxidation products obtained in the first step. The low-temperature oxidation of the catalyst concentrate as a component of the toluene-insoluble residue from the hydroconversion of a mixture of petroleum tar and polymer waste allows virtually complete (>95%) recovery of molybdenum compounds by leaching with 10% aqueous ammonia. [ABSTRACT FROM AUTHOR]