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AssigneeUnited States Leather Holdings, Inc.
InventorsPaul R. Erickson, Lloyd J. Uhren, Jeffrey M. Waszgis
Estimating the term…
An improved method and apparatus for treating chromium containing leather scrap to recover chromium compounds and to produce a protein hydrolysate. The leather scrap is fed into an upstream mixing zone of a reaction vessel along with an alkali metal solution and the scrap and the solution are mixed by a plurality of kneading paddles carried by a rotating shaft. The mixture is then passed to a downstream hydrolyzing zone and conveyed through the hydrolyzing zone by a spiral flight. The mixture is heated by the injection of steam to thereby produce a hydrolyzed mixture comprising a protein hydrolysate containing suspended, insoluble particles of chromium compound. The hydrolysate is separated from the precipitated chromium compounds and can be recirculated to the reaction vessel while the chromium compounds can be recovered for use in the tanning process. The concentrated hydrolysate can be subjected to electrophoresis to increase the concentration of any desired amino acid in the hydrolysate.
An apparatus for hydrolyzing chrome leather scrap, comprising a vessel having an upstream section and a downstream section, a horizontal shaft disposed in said vessel, drive means operably connected to the shaft for rotating the shaft, first feeding means in the upstream section of the vessel for feeding a mass of chrome leather scrap to said upstream section, second feeding means for introducing an aqueous alkali solution to said upstream section, mixing means mounted on the shaft and located in the upstream section for mixing said scrap and said solution to provide a mixture, conveying means mounted on the shaft and located in the downstream section for conveying the mixture in a downstream direction, and outlet means in the downstream section of the vessel for discharging protein hydrolysate containing suspended insoluble chromium compounds from the vessel, separating means for receiving said protein hydrolysate and said suspended insoluble chromium compounds from the downstream section of the vessel and separating said insoluble chromium compounds from said protein hydrolysate, and recirculating means for recirculating a portion of the protein hydrolysate to the upstream section of the vessel.
An apparatus for hydrolyzing chrome leather scrap, comprising a vessel having an upstream section and a downstream section, a horizontal shaft disposed in said vessel, drive means operably connected to the shaft for rotating the shaft, first feeding means in the upstream section of the vessel for feeding a mass of chrome leather scrap to said upstream section, second feeding means for introducing an aqueous alkaline solution to said upstream section to provide a mixture of leather scrap and aqueous alkaline solution, a plurality of mixing members disposed on the shaft and located in said upstream section, a helical flight mounted on the shaft and disposed in said downstream section for conveying the mixture in a downstream direction, heating means disposed in said downstream section for heating the mixture to provide a protein hydrolysate containing suspended insoluble chromium compounds, outlet means in the downstream section of the vessel for discharging said protein hydrolysate containing said suspended insoluble chromium compounds from the vessel, and separating means for separating the protein hydrolysate from said insoluble chromium compounds.
A method for hydrolyzing chrome leather scrap, comprising the steps of introducing chrome leather scrap into an upstream end of a reactor zone, adding an aqueous alkaline solution having a pH greater than 12.0 to said upstream end, mixing said solution and said leather scrap to provide a mixture, conveying the mixture to a downstream end of said reactor zone, heating the mixture with steam as it is conveyed to the downstream end to provide a protein hydrolysate containing suspended insoluble chromium compounds, and separating the insoluble chromium compounds from said protein hydrolysate.
A method for hydrolyzing chrome leather scrap, comprising the steps of introducing chrome leather scrap into an upstream end of a reaction zone, adding an aqueous alkaline solution having a pH greater than 12.0 to said upstream end, mixing said solution and said leather scrap to provide a mixture, engaging the mixture with a helical flight to convey the mixture to a downstream end of said reaction zone, heating the mixture as it is conveyed to the downstream end to provide a protein hydrolysate containing suspended insoluble chromium compounds, and separating the insoluble chromium compounds from said protein hydrolysate.
A method for hydrolyzing chrome leather scrap, comprising the steps of introducing chrome leather scrap into an upstream end of a reaction zone, adding an aqueous alkaline solution having a pH greater than 12.0 to said upstream end, mixing said solution and said leather scrap to provide a mixture, conveying the mixture to a downstream end of said reaction zone, heating the mixture as it is conveyed to the downstream end to provide a protein hydrolysate containing suspended insoluble chromium compounds, and separating the protein hydrolysate from said insoluble chromium compounds when the pH of the mixture is decreased to a value of about 8.5.
A method for hydrolyzing chrome leather scrap, comprising the steps of introducing chrome leather scrap into an upstream end of a reaction zone, adding an aqueous alkaline solution having a pH greater than 12.0 to said upstream end, mixing said solution and said leather scrap to provide a mixture, conveying the mixture to a downstream end of said reaction zone, heating the mixture as it is conveyed to the downstream end to provide a protein hydrolysate containing suspended insoluble chromium compounds, separating the insoluble chromium compounds from said protein hydrolysate, and recirculating a portion of the separated protein hydrolysate to the upstream end of said reaction zone.
Dependencies are inferred from the claim text.