This work presents the research results on the development of an innovative, hydrometallurgical technology for the production of manganese(II) perrhenate dihydrate from recycled waste. These wastes are scraps of Ni-based superalloys containing Re and scraps of Li–ion batteries containing Mn—specifically, solutions from the leaching of black mass. This work presents the conditions for the production of Mn(ReO₄)₂·2H₂O. Thus, to obtain Mn(ReO₄)₂·2H₂O, manganese(II) oxide was used, precipitated from the solutions obtained after the leaching of black mass from Li–ion batteries scrap and purified from Cu, Fe and Al (pH = 5.2). MnO₂ precipitation was carried out at a temperature < 50 °C for 30 min using a stoichiometric amount of KMnO₄ in the presence of H₂O₂. MnO₂ precipitated in this way was purified using a 20% H₂SO₄ solution and then H₂O. Purified MnO₂ was then added alternately with a 30% H₂O₂ solution to an aqueous HReO₄ solution. The reaction was conducted at room temperature for 30 min to obtain a pH of 6–7. Mn(ReO₄)₂·2H₂O precipitated by evaporating the solution to dryness was purified by recrystallization from H₂O with the addition of H₂O₂ at least twice. Purified Mn(ReO₄)₂·2H₂O was dried at a temperature of 100–110 °C. Using the described procedure, Mn(ReO₄)₂·2H₂O was obtained with a purity of >99.0%. This technology is an example of the green transformation method, taking into account the 6R principles.

This paper presents a method for obtaining cobalt(II) perrhenate from waste derived from two types of materials, i.e., Li-ion battery scrap, or more precisely, battery mass, and superalloy scrap. Both of the above-mentioned materials are a source of Co. However, a source of rhenium is perrhenic acid produced from ammonium perrhenate (recycled) by the ion exchange method using resins. Co(OH)₂ can be precipitated from solutions resulting from the leaching of Li-ion battery mass, sludge from the Zn-Pb industry and superalloy scrap. The compound, after proper purification, can be used in a reaction with perrhenic acid to form Co(ReO₄)₂. The reaction should be conducted under the following conditions: time 1 h, room temperature, 30% excess of cobalt(II) hydroxide, and rhenium concentration in HReO₄ from about 20 g/dm³ to 300 g/dm³. This work shows that with the use of Co(OH)_2, obtained from waste, an anhydrous form of cobalt(II) perrhenate can be obtained, containing < 1000 ppm of the cumulative metal impurities.

Laboratory tests were conducted for the production of high-purity perrhenic acid using a membrane technique—electrodialysis. Four solutions were used in the tests: diluate, concentrate, anolyte, and catholyte. The experiments were carried out in a two-stream system. The influence of basic process parameters, including the flow rate of process streams or current density, on the purity of the obtained perrhenic acid were examined. Electrodialysis was also carried out as part of this research, aiming to concentrate the perrhenic acid >100 g/dm³. The concentrate solution obtained in the concentration tests, with a concentration of 148.7 g/dm³ HReO₄ and 530 mg/dm³ NH₄⁺, was then sent to the purification process using the electrodialysis method. The purification process was carried out until the concentration of NH₄⁺ ions was <100 mg/dm³ in the concentrate. Finally, perrhenic acid was obtained with the following composition: 169.7 g/dm³ HReO₄ and 70 mg/dm³ NH₄⁺. Based on this research, a technological scheme for producing high-purity HReO₄ by electrodialysis was developed.

This study outlines findings from an investigation into the development of a hydrometallurgical process for manufacturing various forms of zinc perrhenate, entirely from waste from recycling and from the Zn–Pb industry. Scraps of Re-bearing Ni-based superalloys and acidic waste, circulating zinc solutions generated during the production of Zn by the electrolytic method and which contain >45 g/dm³ of Zn, Na, Mn, and Mg, were used in the research. In the publication, the conditions for the production of three types of zinc perrhenate, i.e., Zn(ReO₄)₂·4H₂O, Zn(ReO₄)_2, and Zn(ReO₄)₂·2H₂O, are presented. As a result of the analysis of the obtained results, it was concluded that to obtain the above-mentioned forms of zinc perrhenate, zinc carbonate can be used, precipitated from acidic, waste, and multi-component solutions after their prior neutralization to pH 4.0 and partial purification from Mn, Mg, and Na using metallurgical zinc oxide. Zinc carbonate should be precipitated using Na₂CO₃ at pH 6.3 and subsequently purified from other impurities, i.e., Mg, Na, and Mn, using aqueous ammonia solutions. As a result, zinc carbonate was obtained, which was used in a reaction with an aqueous solution of HReO₄ to produce zinc perrhenate. The precipitated forms of Zn(ReO₄)₂ were obtained by appropriately drying the crude and hydrated Zn(ReO₄)₂ to obtain its tetrahydrate, dihydrate, and anhydrous forms, respectively, using drying temperatures of 55, 135, and 185 °C. The developed technology has been submitted for a patent and is an example of a technology founded on the principles of sustainable development, with a particular emphasis on the minimalization of loss of rhenium and zinc at all stages of its realization.

Methods for obtaining high-purity perrhenic acid (with metallic impurities content below 100 ppm) of a high concentration > 200 g/dm³ and entirely from secondary raw materials were compared. Comparative analyses of three methods were performed: electrodialysis, solvent extraction (research carried out directly as part of the Small Grant project acronym RenMet), and ion-exchange (developed as part of previous projects implemented by Łukasiewicz-IMN). The basic process parameters were selected as comparative indicators: efficiency and selectivity of the process, purity of the obtained product, availability and consumption of raw materials and reagents, equipment necessary to carry out the process, the profitability of the technology, and the ecological aspects, i.e., the possibility of managing the generated solid waste and post-production solutions. Analysis of the verified indicators allowed us to select the most economically and ecologically advantageous method of obtaining high-purity perrhenic acid from secondary raw materials. Its preparation using the ion-exchange method emphasizes the product’s purity and the process’s simplicity, using readily available waste materials and renewable ion-exchange resin, and is based on a sustainable circular economy.

The work presents the research results regarding the development of an innovative technology for the production of lithium perrhenate. The new technology is based entirely on hydrometallurgical processes. The source of lithium was solutions created during the processing of Li-ion battery masses, and the source of rhenium was perrhenic acid, produced from the scraps of Ni-based superalloys. The research showed that with the use of lithium carbonate, obtained from post-leaching solutions of Li-ion battery waste and properly purified (by washing with water, alcohol, and cyclic purification with CO₂), and perrhenic acid, lithium perrhenate can be obtained. The following conditions: room temperature, time 1 h, 30% excess of lithium carbonate, and rhenium concentration in the acid from 20 g/dm³ to 300 g/dm³, allowed to produce a compound containing a total of 1000 ppm of metal impurities. The developed technology is characterized by the management of all aqueous waste solutions and solid waste and the lack of loss of valuable metals such as rhenium and lithium after the initial precipitation step of lithium carbonate.