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

Abstract

The subject of the application is a method for producing lead(II) rhenate(VII) by reacting lead compounds with rhenic(VII) acid, as a result of which a lead-rhenate solution is obtained, from which lead(II) rhenate(VII) is separated and dried, which is characterized in that solid sulphate waste from the zinc industry and containing at least 5% Pb is leached using an aqueous solution of triethylenetetramine (TETA) and subsequently a lead carbonate intermediate is separated from them using known methods, and the solution formed after carbonation and the precipitate remaining after leaching are directed to Zn recovery using known methods, while the lead carbonate intermediate, which contains 72% - 78% Pb, is purified in three stages, in the first stage with an aqueous solution of ammonia with a concentration of 0.5% - 1.0% at room temperature, using 0.01 - 0.03 dm3 for each 10 g of precipitate ammonia solution, washing is performed for 15 to 30 minutes, in the second stage it is cleaned with water at a temperature of 75°C - 95°C,using 0.02 - 0.05 dm3 of water for every 10 g of sediment, washing is carried out for 15 to 30 minutes, and in the third stage with ethanol at a concentration of >90% at a temperature of 20°C - 28°C, using 0.05-0.10 dm3 of ethanol for every 10 g of sediment, for 5 to 10 minutes, the ammoniacal and water washings resulting from the purification are combined and recycled to prepare an aqueous solution of triethylenetetramine, and the purified lead(II) carbonate(IV) is added to an aqueous solution of rhenic(VII) acid with a concentration of >300 g / dm3 Re, so that the final pH of the solution is not lower than 6.4, and such a mixture is stirred intensively at a temperature not exceeding 78°C, for a minimum of 2 hours, monitoring the pH all the time, after which the remaining precipitate of unreacted carbonate is separated from the solution and is sent to the next stage of carbonate dissolution in HReO4, and the solution with a minimum pH of 6.6 is evaporated at a temperature not exceeding 78°C, the separated precipitate of the hydrated form of lead(II) rhenate(VII) is sent to drying at a temperature of 175°C,until the dry mass is obtained, the resulting precipitate of anhydrous lead(II) rhenate(VII) is stored in conditions without access of air.,