Abstract: There is provided a process to reclaim metals from catalysts, said process comprising collecting one or more catalyst containing at least one metal sulfide; leaching the catalyst in an atmospheric leach step; separating the leached slurry into a first liquid stream and a first solid; leaching the first solid in a pressure leach process; separating the second leached slurry into a second liquid stream and a second solid; collecting the first and second liquid streams; oxidizing the combined liquid stream; cooling the oxidized liquid stream; adjusting the pH of the oxidized liquid stream; contacting the cooled oxidized liquid stream with an organic solvent containing an extractant; stripping the soluble metal species from the organic phase; adjusting the pH of the aqueous phase to selectively precipitate at least one metal as a metal salt; and separating the metal salt from the aqueous phase.

Abstract: A selenium-containing aqueous stream may be used as a quenching water stream and optionally a cutting water stream in a delayed coking process to effectuate the removal of selenium from the selenium-containing aqueous stream resulting in the formation of a selenium-coke product. In addition, selenium may be concentrated in selenium-containing stripped sour water streams by recycling the stream in one or more hydroprocessing units and one or more sour water stripper units and subsequently removed by using a portion of the selenium-containing stripped sour water stream as a quenching water stream and optionally a cutting water stream in a delayed coking process.