Abstract: The present invention provides a method of recovering silver safely and efficiently from a chloride or bromide bath containing various metals. Specifically, a method of recovering silver from a hydrochloric acid solution containing alkali and/or alkaline earth metal chloride, silver, copper and iron ions, comprising the steps of: (1) bringing the solution into contact with a strong-base anion-exchange resin to adsorb silver, copper, and iron on the anion-exchange resin; (2) then washing the anion-exchange resin with water to remove the adsorbed copper and iron; and (3) then bringing the ion-exchange resin into contact with a hydrochloric acid solution to elute the adsorbed silver, is provided.

Abstract: The present invention provides a method of recovering silver safely and efficiently from a chloride or bromide bath containing various metals. Specifically, a method of recovering silver from a hydrochloric acid solution containing alkali and/or alkali earth metal chloride, silver; copper and iron ions, comprising the steps of: (1) bringing the solution into contact with a strong-base anion-exchange resin to adsorb silver; copper, and iron on the anion-exchange resin; (2) then washing the anion-exchange resin with water to remove the adsorbed copper and iron; and (3) then bringing the ion-exchange resin into contact with a hydrochloric acid solution to elute the adsorbed silver, is provided.

Abstract: Metal is electrolytically precipitated on a cathode plate except for a portion thereof. The non-precipitated portion enables easy peeling of the precipitated metal from the cathode plate. The ceramic coating film is formed on the non-precipitated portion and prevents intrusion of electrolytic acid between the ceramic coating film and the cathode plate. The life of the coating is prolonged. The polishing of the cathode plate can be automatized.

Abstract: A method of purifying a copper electrolytic solution circulated in a copper electrorefining system, wherein a portion of the solution is withdrawn and recycled to the system after purification treatment. The purification treatment includes the addition of a hydrosulfide to the withdrawn solution to generate only the necessary quantity of hydrogen sulfide gas required in the reaction. The hydrogen sulfide gas generated is utilized for purification treatment. One process comprises dividing the solution withdrawn into two portions. Sodium hydrosulfide is added to the first portion to precipitate and separate metals as sulfides. Excess sodium hydrosulfide is further added to the first portion for reaction with residual sulfuric acid in the solution to generate hydrogen sulfide gas, then contacting the second divided portion with the hydrogen sulfide gas thus produced to precipitate and separate metals in the form of sulfides. The filtrate is then recycled to an electrorefining system.