Process for removing precious metal from precious metal-containing catalyst form bodies comprising form bodies and precious metal, whereby the precious metal to be removed is at least one precious metal selected from the group consisting of Au, Ag, Pd, Pt, Ir, Rh, Ru, Os, and Re, comprising the steps of: (a) producing a mixture of precious metal-containing catalyst form bodies in at least one mineral acid that is at least 1N; (b) supplying inert or oxidizing gas into the mixture containing noble metal-containing catalyst form bodies and mineral acid; (c) introducing at least one oxidation agent, in solid or liquid form, into the mixture containing noble metal-containing catalyst form body and mineral acid; and (d) separating the form bodies from the liquid.

Process for removing precious metal from precious metal-containing catalyst form bodies comprising form bodies and precious metal, whereby the precious metal to be removed is at least one precious metal selected from the group consisting of Au, Ag, Pd, Pt, Ir, Rh, Ru, Os, and Re, comprising the steps of: (a) producing a mixture of precious metal-containing catalyst form bodies in at least one mineral acid that is at least 1N; (b) supplying inert or oxidizing gas into the mixture containing noble metal-containing catalyst form bodies and mineral acid; (c) introducing at least one oxidation agent, in solid or liquid form, into the mixture containing noble metal-containing catalyst form body and mineral acid; and (d) separating the form bodies from the liquid.

Described are methods of dephosphorylation. Methods of dephosphorylation include contacting a phosphate containing substrate with one or more CeO.sub.2 nanocrystal. Also described is modifying the pH of the dephosphorylation reaction to affect the amount and rate of dephosphorylation. Further described are methods of making CeO.sub.2 nanocrystals of the present disclosure.

Described are methods of dephosphorylation. Methods of dephosphorylation include contacting a phosphate containing substrate with one or more CeO.sub.2 nanocrystal. Also described is modifying the pH of the dephosphorylation reaction to affect the amount and rate of dephosphorylation. Further described are methods of making CeO.sub.2 nanocrystals of the present disclosure.

Methods, systems, and compositions related to the recycling and/or recovery of activating materials from activated aluminum are disclosed. In one embodiment, an aqueous solution's composition may be controlled to maintain aluminum ions dissolved in solution during reaction of an activated aluminum. In another embodiment, aluminum hydroxide containing the activating materials may be dissolved into an aqueous solution to isolate the activating materials.

Methods, systems, and compositions related to the recycling and/or recovery of activating materials from activated aluminum are disclosed. In one embodiment, an aqueous solution's composition may be controlled to maintain aluminum ions dissolved in solution during reaction of an activated aluminum. In another embodiment, aluminum hydroxide containing the activating materials may be dissolved into an aqueous solution to isolate the activating materials.

Digestion of impure alumina with sulfuric acid dissolves all constituents except silica. The resulting sulfatesaluminum sulfate, ferric sulfate, titanyl sulfate, and magnesium sulfate for alumina contaminated with iron-, titanium-, and/or magnesium-containing speciesremain in solution at approximately 90 C. Hot filtration separates silica. Solution flow over metallic iron reduces ferric sulfate to ferrous sulfate. Controlled ammonia addition promotes hydrolysis and precipitation of hydrated titania from titanyl sulfate that is removed by filtration. Addition of ammonium sulfate forms ferrous ammonium sulfate and ammonium aluminum sulfate solutions. Alum is preferentially separated by crystallization. Addition of ammonium bicarbonate to an ammonium alum solution precipitates ammonium aluminum carbonate which may be heated to produce alumina, ammonia, and carbon dioxide. The remaining iron rich liquor also contains magnesium sulfate. The addition of oxalic acid generates insoluble ferrous oxalate which is thermally decomposed to ferrous oxide and carbon monoxide which is used to reduce the ferrous oxide to metallic iron. Further oxalic acid addition precipitates magnesium oxalate which is thermally decomposed to magnesium oxide.

Methods for regenerating and/or rejuvenating catalysts, particularly dewaxing catalysts, as well as methods for performing dewaxing of diesel or distillate boiling range feeds with the regenerated and/or rejuvenated catalyst are provided herein. The regeneration and/or rejuvenation methods can include calcining spent catalyst followed by contacting the calcined catalyst with a solution comprising a complexing agent, which can restore hydrotreatment (HDT) activity and dewaxing activity of the spent catalyst such that it may be reused during hydroprocessing.

Methods for regenerating and/or rejuvenating catalysts, particularly dewaxing catalysts, as well as methods for performing dewaxing of diesel or distillate boiling range feeds with the regenerated and/or rejuvenated catalyst are provided herein. The regeneration and/or rejuvenation methods can include calcining spent catalyst followed by contacting the calcined catalyst with a solution comprising a complexing agent, which can restore hydrotreatment (HDT) activity and dewaxing activity of the spent catalyst such that it may be reused during hydroprocessing.

The present invention discloses a process for recovery and regeneration of rare earth metals or salts thereof used as catalyst and which is conveniently integrated within the overall flow sheets of manufacturing dialkyl carbonates. Alkyl carbamate, alcohol and a rare earth metal salt as catalyst selected from the lanthanide series are added in a reactor to afford dialkyl carbonate. The rare earth metal catalyst is selected from samarium, cerium, lanthanum, neodymium, ytterbium, europium and gadolinium. Ammonia is added to a portion of the reaction mixture to precipitate the catalyst and the separated deactivated catalyst is dissolved in acid to afford regenerated catalyst, e.g., in triflic acid in the case of samarium triflate catalyst.