Characterisation and material flow analysis of end-of-life portable batteries and lithium-based batteries in different waste streams in Austria.

Although separate collection systems for portable batteries (PBs) have been installed years ago, high amounts of batteries still do not enter the collection systems of the member states of the European Union (EU). In Austria, the collection rate has recently dropped to the EU target value of 45%. For the purposes of this study, a comprehensive survey was conducted to identify the destinations of the other end-of-life batteries. A literature survey and an assessment of different waste streams (WSs) were followed by sampling and sorting campaigns for highly relevant WSs (residual waste, lightweight packaging waste, metal packaging waste, and small waste electrical and electronic equipment). The results underwent material flow analysis, showing that more than 800 metric tonnes of portable batteries are misplaced into non-battery-specific collection systems, 718 metric tonnes of them entering residual waste collection. Considerable amounts of batteries are stockpiled, stored or hoarded in Austrian households. Lithium-based batteries, representing a serious risk of fire to the waste industry and making up for 30% of the marketed amount, are still scarcely arriving in waste management systems.

Stepwise treatment of ashes and slags by dissolution, precipitation of iron phases and carbonate precipitation for production of raw materials for industrial applications.

The purpose of this study was to test the feasibility of a specific mineral carbonation reaction route applied to different types of alkaline industrial residues, i.e. biomass, paper sludge and municipal solid waste incineration bottom ashes and stainless steel slags and dust. This new approach includes the dissolution of industrial residues in hydrochloric acid (HCl), followed by precipitation of iron compounds from the resulting aqueous solutions and the precipitation of calcium carbonates to employ in industrial applications (Carbon Capture, Utilisation and Storage, CCUS). The aim of this work is to apply this stepwise treatment to different types of poorly valorised industrial residues to assess which may be the most promising ones to employ for the process, in terms of total content of specific elements in the obtained products. Our results clearly indicate that the investigated ashes and slags consist of 20-30 wt% CaO which is bound in a broad variety of mineral phases. Reaction of slags and ashes with HCl leads to the formation of Si-rich solid residues and Ca-rich aqueous solutions. Dissolution residues from ash treatment might be used as lightweight concrete aggregate in case of appropriate mechanical properties, whereas dissolution residues from slag treatment might serve as metallurgical Cr concentrates. Resulting aqueous solutions show high concentrations of Ca (>10 g/L), up to 27 g/L of Fe and significant amounts of heavy metals like Pb, Ba, Zn, Cu, Ni. The concentration of dissolved Fe decreases to 2 mg/L by adding NH3 which leads to the precipitation of amorphous iron phases. Finally, calcium carbonates with a purity of 79-97% are precipitated by injecting CO2 at pH 9. These carbonates present lower heavy metal contents than the input materials (e.g. 0.3 wt% ZnO compared to 0.9 wt% for EAF-FD).