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.

The present invention provides techniques that selectively recover Re from reductive amination catalysts. In particular, the present invention allows Re to be recovered selectively relative to Ni, Co, and/or Cu, and particularly Ni, that are often present on reductive amination catalysts. The present invention uses a combination of oxidation and extraction techniques to selectively recover Re relative to Ni, Co, and/or Cu. Advantageously, the recovery is selective even when using aqueous solutions for extraction.

A process is presented where a feed stream containing a hydrogen sulfide and another feed component is introduced into an absorber that the feed stream flows upward from the bottom of the absorber and contacts a liquid treatment solution, where the liquid treatment solution contains a sulfur dye catalyst. The hydrogen sulfide is absorbed into the liquid treatment solution and converted into sulfide ions. The other feed component is removed from the absorber vessel substantially free of the hydrogen sulfide and a spent treatment solution is also removed from the absorber vessel and fed to an oxidation vessel where it is contacted with an oxygen containing gas causing the sulfide ions to oxidize to thiosulfate and converting the spent sulfur dye catalyst to regenerated sulfur dye catalyst. The thiosulfate is recovered, and the regenerated sulfur dye catalyst can be recycled as part of the liquid treatment solution.

There is provided a catalyst that exhibits a high denitration efficiency at a relatively low temperature and does not cause oxidation of SO.sub.2 in a selective catalytic reduction reaction that uses ammonia as a reducing agent. A denitration catalyst molded in a block shape contains 43 wt % or more of vanadium pentoxide. The denitration catalyst has a BET specific surface area of 30 m.sup.2/g or more and is used for denitration at 200 C. or lower.

There is provided a catalyst that exhibits a high denitration efficiency at a relatively low temperature and does not cause oxidation of SO.sub.2 in a selective catalytic reduction reaction that uses ammonia as a reducing agent. A denitration catalyst molded in a block shape contains 43 wt % or more of vanadium pentoxide. The denitration catalyst has a BET specific surface area of 30 m.sup.2/g or more and is used for denitration at 200 C. or lower.

The present invention relates to a method for the reactivation of homogeneous catalyst systems from organic reaction mixtures. The catalyst systems are suitable for the oxidation of organic compounds such as, for example, cyclododecene. The reactivation is carried out using an aqueous base.

The present invention relates to a method for the reactivation of homogeneous catalyst systems from organic reaction mixtures. The catalyst systems are suitable for the oxidation of organic compounds such as, for example, cyclododecene. The reactivation is carried out using an aqueous base.

For a denitration catalyst used for a denitration treatment of a combustion exhaust gas, for example, from a coal-fired boiler or the like, such a denitration catalyst is provided that has a sufficient mechanical strength capable of retaining the catalyst shape, has a better catalyst performance than the ordinary denitration catalyst containing crystals of zirconium oxide, is low in production cost. In the denitration catalyst comprising, as a base material, a honeycomb structure consisting of an inorganic fiber sheet, titania, vanadium oxide and/or tungsten oxide, and a zirconium compound (except for crystalline zirconium dioxide) as a shape-retaining binder are supported on the honeycomb structure.

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.