Superalloys are a group of alloys developed for use during long-term heat exposure above 650 °C. Properties and applications of superalloys are described in the present work. The work includes statistics about superalloys demand, market value and the current price. Division of superalloys according to basic element is mentioned. Nickel-based superalloys are further divided into two groups according to their use. Afterwards, the paper is focused mainly on nickel-based superalloys. Examples of nickel-based superalloys are listed in the work. Recycling possibilities of nickel-based superalloys are stated and analysed. General scheme of processing nickel-based superalloy scrap with regard to the content of rhenium is proposed and shortly discussed. The best-known companies dealing with superalloy scrap recycling are mentioned further.

The subject of interest in this study was lead cementation with zinc from solution after conventional agitate acidic leaching of converter dust from secondary copper production. The kinetics of lead cementation from an acid solution of lead acetate using zinc powder was studied. The optimal cementation conditions for removing lead from the solution were determined to have a stirring intensity of 300 rpm, a zinc particle size distribution mm and an ambient temperature. Under these conditions, an almost 90% efficiency in removing lead from solution was achieved. The cementation precipitate contains Pb, and a certain amount of Cu. Lead is present in the cementation precipitate in the PbO, Pb₅O₈ and Pb(Cu₂O₂) phases. The solution after cementation was also refined from copper. The solution can be used for further processing in order to obtain a marketable Zn-based product. The resulting cementation precipitate can be further processed and modified to obtain a lead-based product. A kinetic study of the process of lead cementation from solution was also carried out. Based on experimental measurements, the value of apparent activation energy (Ea) which was found to be ~18.66 kJ·mol⁻¹, indicates that this process is diffusion controlled in the temperature range 293–333 K.

The presented article deals with the thermodynamic study of copper converter flue dust (CCFD) treatment by hydrometallurgical process. The investigated sample of CCFD contains 38.31 wt.% Zn, 11.35 wt.% Pb, and 2.92 wt.% Sn in the form of oxides (PbO, ZnO, and SnO₂). The leaching of CCFD in sulphuric acid, acetic acid, nitric acid, and sodium hydroxide was thermodynamically studied. Using Pourbaix diagrams for individual metal–S/C/N/Na/–H₂O systems, the possibility of leaching oxides in selected leaching agents was confirmed. A sustainable and environmentally friendly method of processing the sample of CCFD using a hydrometallurgical method is proposed. A suitable selective leaching agent is the acetic acid solution. When leaching in an acetic acid solution, zinc and lead are chemically dissolved to form acetates Zn(CH₃COO)_2(aq) in the form of Zn²⁺_(aq) at a temperature of 20 °C with a pH range of 0–3.5 and at a temperature of 80 °C with a pH range of 0–2.95, as well as Pb(CH₃COO)_2(aq) as Pb²⁺_(aq) at a temperature of 20 °C with a pH range of 0–1.95 and at a temperature of 80 °C with a pH range of 0–2, respectively, while tin remains as a solid residue in the form of SnO_2(s) at the temperatures of 20 °C and 80 °C throughout the whole acidic pH range. Various analytical techniques, such as SEM, EDX, XRD, and AAS, were used to analyse samples before a thermodynamic study of the leaching of CCFD was conducted by applying Pourbaix Eh–pH diagrams.

Pyrometallurgical copper production is carried out in thermal aggregates. Input waste materials with a copper content between 5% and 99% Cu are treated in the individual aggregates. In a shaft furnace, except for molten black copper, slag and shaft flue dust (SFD) are produced as waste. SFD is emitted from the melt and then is captured by fabric filters. This kind of SFD is defined as ‘hazardous waste’ according to the European Waste Catalogue. SFD contains an attractive quantity of valuable metals like Zn, Sn and Pb. This work focuses on the hydrometallurgical treatment of SFD from secondary copper production with the aim of obtaining usable lead-based products.

Copper converter flue dust (CFD) is one of the solid wastes generated during the pyrometallurgical production of secondary copper. Due to its fine-grained character and its content of toxic heavy metals, CFD is classified as hazardous waste. CFD contains lead, zinc, and tin in the form of oxides. The aim of this paper is to design a complex hydrometallurgical process for CFD treatment in order to obtain commercially saleable products based on zinc, tin, and lead. The proposed CFD treatment process consists of leaching in acetic acid, cementation of lead from leachate by zinc, and subsequent precipitation of zinc with carbonate ions.