Abstract: A method for recovering metals from solutions is described. A particular embodiment of the method concerns recovering copper metal from aqueous solutions containing copper ions, such as ammoniacal circuit-board etching solutions. A working embodiment of the invention includes first treating a solution containing copper ions with a sufficient amount of an acid to obtain a solution pH of from about 1 to less than about 2.5. A reducing metal, such as iron, is then added to the solution to precipitate metal ions as metals. The reducing metal has a mesh size of about 230 or greater. The metal precipitate is recovered from the solution. The method is generally sufficiently efficient to allow discharge of solutions treated according to the method of the invention into public waste waters wherein the solution has less than about 5 ppm, and preferably less than 2 ppm, metal ions.

Abstract: A method for recovering metals from solutions is described. A particular embodiment of the method concerns recovering copper metal from aqueous solutions containing copper ions, such as ammoniacal circuit-board etching solutions. A working embodiment of the invention comprises first treating a solution containing copper ions with a sufficient amount of an acid to obtain a solution pH of from about 1 to less than about 2.5. A reducing metal, such as iron, is then added to the solution to precipitate metal ions as metals. The reducing metal has a mesh size of about 230 or greater. The metal precipitate is recovered from the solution. The method is generally sufficiently efficient to allow discharge of solutions treated according to the method of the invention into public waste waters wherein the solution has less than about 5 ppm, and preferably less than 2 ppm, metal ions.

Abstract: A method for recovering metals from solutions is described. A particular embodiment of the method concerns recovering copper metal. The method comprises first treating a solution containing copper ions with a sufficient amount of an inorganic acid to obtain a solution pH of from about 1.5 to less than about 2.5. A reducing metal, such as iron, is then added to the solution to precipitate metal ions, such as copper ions, as metals. The reducing metal has a mesh size preferably smaller than about 350, and even more preferably at least as small as about 400 mesh. The metal precipitate is recovered from solution.

Abstract: A simplified, low-cost method of treating pressurized, moving natural gas streams in order to control problems created by entrained water in the gas is provided which facilitates downstream treatment of the gas and increases product yields by lessening the formation of oil and water emulsions and hydrates which can coat and clog processing equipment, while also minimizing corrosion of the latter. The method involves introduction of an agent into the moving gas stream which includes a polymer having recurring quaternized pyridinium groups therein for controlling the emulsion, hydrate and corrosion problems; the method is especially effective when the entrained water contains surfactants, detergents, soaps, and the like. In preferred forms a low molecular weight copolymer of styrene and 2-vinyl pyridine dispersed in water is atomized into the gas stream adjacent cooling and scrubbing stations.