Method for obtaining silver rhenate(VII) using waste materials

Abstract

The subject of the application is a method for producing silver rhenate(VII) by reacting soluble silver compounds with rhenium compounds in the VII oxidation state, as a result of which a crystalline product and a solution containing Re and Ag are obtained, requiring management, which is characterized in that the silver-bearing raw material is solutions containing at least 0.5 g / dm3 of Ag, resulting from the leaching of waste materials generated during the production of electrolytic zinc, from which silver is first separated by cementation with copper powder used in the amount of at least 0.7 g per gram of silver contained in the solution, the obtained cementate is first leached at a temperature of 40°C-70°C with a solution of sulfuric acid(VI) with a concentration of 10% - 20% with portions of 30% H2O2 solution added in the amount of 10% to 30% of the volume of the H2SO4 solution used, copper is separated from the solution obtained in this way by known methods,while the residue is dissolved in a 20% HNO3 solution with 30% H2O2 solution added in portions, with continuous stirring at a temperature not exceeding 50°C, NaOH is then added to the obtained nitrate solution with continuous stirring until the pH of the mixture is above 8.0, the whole is heated to a minimum of 60°C and stirred at this temperature for at least 15 minutes, then the separated Ag2O precipitate is filtered and washed on the filter with water, the washed precipitate is dissolved in a mixture of 25% NH3aq and NH4ReO4 to obtain a solution of silver diaminates (VII), the undissolved residue is returned to the Ag2O precipitation stage, and a HReO4 solution containing a minimum of 200 g / dm3 Re is added to the solution until the pH of the mixture is 5.0, the separated crystalline AgReO4 precipitate is filtered, washed with water and dried until constant mass is obtained at a temperature 110°C, the obtained silver rhenate(VII) is stored away from light and air, the solution after collecting the product is returned to the Ag2O digestion stage,