Method for obtaining copper(II) rhenate(VII) using waste materials

Abstract

The subject of the application is a method for producing copper(II) rhenate(VII) by reacting copper compounds with rhenic(VII) acid, as a result of which a copper-rhenate solution is obtained, from which copper(II) rhenate(VI) is separated and dried, which is characterized in that the sludges containing Cu, formed during the production of electrolytic zinc, also containing Zn, Pb, Cd, Co and Ni are leached in two stages, firstly in sulfuric(VI) acid, in the acid concentration range of 10% to 25%, using the water phase to solid ratio of 5:1 to 10:1, the leaching is carried out at a temperature of 70°C - 95°C, for 1 - 3 hours, in order to leach Zn, Cd, Ni, Co and subsequently the sludge remaining after the first leaching stage is leached in sulfuric(VI) acid with the addition of oxidizers, using the water phase to solid ratio of 3:1 to 8:1, and leaching is carried out at a temperature of 70°C - 95°C, for 0.5 - 2 hours, the Pb-containing sludge remaining after the second leaching is directed to the separation of Pb(ReO4)2,and the resulting solutions are sent for processing, i.e. the solution formed after the first leaching is sent for the recovery of Zn, Ni, Co and Cd using known methods, and the solution formed after the second leaching is sent for the separation of Cu, CuO is separated from the solution after the second leaching stage using NaOH in the form of an aqueous solution with a concentration of 200 to 400 g / dm3 to >pH 11, precipitation is carried out in the temperature range of 50°C - 80°C, for 0.5 to 1.5 hours, the CuO thus precipitated is sent to the purification stage, while the solution is returned to the precipitation of CuO or sent for the recovery of sodium sulfate(VI) using known methods, the purification of raw CuO is carried out cyclically, first with water 2 - 5 times, at a temperature of 20°C - 40°C, using 0.01 - 0.05 dm3 of water for every 10 g of oxide, and then with an alcohol mixture consisting of with at least 60% by volume of isopropanol alcohol and / or ethanol and / or methanol,constituting / constituting the remainder and subsequently an alcohol mixture consisting of at least 50% by volume of ethanol and / or isopropanol alcohol and / or methanol, constituting / constituting the remainder, using in both cases 0.01 - 0.05 dm3 of the mixtures for each 10 g of oxide, the washings after water purification are combined and recycled to prepare a solution for the first stage of sludge leaching, and the alcohol washings are combined and recycled to the first purification or sent to the separation stage using known methods, the CuO thus purified is added to an aqueous solution of rhenic (VII) acid with a rhenium concentration of at least 100 g / dm3 so that the final pH of the solution is not lower than 6.0, and such a mixture is stirred intensively at a temperature not exceeding 74°C for at least 1.5 hours, monitoring the pH all the time, after which the remaining precipitate of unreacted copper (II) oxide is separated from the solution and sent to the separation stage dissolution in rhenic acid(VII),so that the amount of copper(II) oxide from the recycled solution does not exceed 20% of the total copper(II) oxide, and the solution with a minimum pH of 6.7 is evaporated to dryness at a temperature not exceeding 68°C, while the separated precipitate of the hydrated form of copper(II) rhenate(VII) is sent for drying at a temperature of 185°C until dry mass is obtained, the resulting precipitate of anhydrous copper(II) rhenate(VII) is stored in conditions without access of air.,