## 2 Materials and Methods
### Materials
In the case of phosphorus, the content of this component ranged from 0.97% to 1.25%. No heightened chlorine content was identified in all the analyzed battery masses. In the case of XRD analysis (Figure 1), graphite was identified in all the materials. In addition, in Material I, combinations of lithium, cobalt, manganese and other less valuable components were visible. In the case of Material II, a lithium and cobalt phase in the form of LiCoO\({}_{2}\) could be seen in the diffraction pattern. The same phase was identified in Material III, but a lithium-nickel phase was also visible in it. As can be seen, the battery masses used in this research were extremely diverse materials--both in terms of phase and chemical compositions. For this reason, the industrial leaching method must take into account wide fluctuations in the composition of the leaching material, which in real conditions may be as follows (amount per ton of the processed battery mass): Al--35 kg; Co--69 kg; Cu--22 kg; Fe--20 kg; Li--24 kg; Mn--29 kg; Ni--100 kg; P--6 kg; F--29 kg; and C--340 kg. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  & & & \multicolumn{6}{c}{**Chemical Composition (wt%)**} \\ \hline
**Material** & **C** & **Co** & **Ni** & **Mn** & **Li** & **Al** & **Cu** & **P** & **F** & **Cl** & **Fe** \\ \hline I—module car & 34.30 & 9.33 & 9.83 & 8.70 & 3.64 & 4.28 & 2.73 & 0.84 & 3.22 & 0.04 & 0.31 \\ \hline II—table and laptops & 38.20 & 29.70 & 1.96 & 0.81 & 3.79 & 1.57 & 1.53 & 0.49 & 1.84 & \textless{}0.01 & 0.39 \\ \hline III—mobile phones & 39.20 & 27.00 & 2.66 & 1.51 & 3.79 & 1.35 & 1.37 & 0.47 & 2.02 & \textless{}0.01 & 0.34 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Chemical composition of the tested battery masses—Material I, Material II, Material III. Figure 1: _Cont._  
Single-Stage Acid Leaching Method with the Addition of Hydrogen Peroxide--Selection of the Leaching Agent  
The tests of single-stage acid leaching with the addition of hydrogen peroxide were carried out with the use of 1 kg of the battery mass and 5 dm\({}^{3}\) of 15% and 20% sulfuric acid solution. The material was added to the acid solution in portions over 5 min, and the leaching solution was heated to a temperature around 10 \({}^{\circ}\)C lower than the set temperature before leaching. Then, after reaching the set temperature, depending on the sample, 1 dm\({}^{3}\) or 2 dm\({}^{3}\) of 30% hydrogen peroxide was added in equal portions during 1-2 h. Initial tests were carried out at 60 \({}^{\circ}\)C for 2 h, with a solid-to-liquid-phase ratio of 1:5. After that, the obtained suspension was filtered using a Buchner funnel and washed with water (0.5 dm\({}^{3}\) of water per 1 kg of the battery mass). In the case of samples with the addition of 2 dm\({}^{3}\) of hydrogen peroxide, the battery mass was washed with an additional portion of 0.5 dm\({}^{3}\) of water. In each test, the volume of the leaching solution was measured, in which the concentration of Co, Ni, Li, Cu, Mn, Fe, P and F ions was analyzed. The pH of the main solution after leaching was measured and the content of free sulfuric acid was  
Figure 1: XRD analyses of the tested battery masses—Material I, Material II, Material III. determined. The leaching efficiency of individual components (_L_) was calculated according to the following formula:  
\[L=\frac{V\cdot C}{m\cdot z}\cdot 100\ [\%] \tag{1}\]  
where \(V\) is the volume of the solution after leaching (dm\({}^{3}\)), \(C\) is the concentration of the component in the solution after leaching (g/dm\({}^{3}\)), \(m\) is the weight of the battery mass used for testing (g) and \(z\) is the coefficient of the content of the given component in the battery mass. Single-Stage Acid Leaching Method with the Addition of Hydrogen Peroxide--Selection of the Phase Ratio  
Phase ratio selection tests for the single-stage acid leaching with the addition of hydrogen peroxide were carried out for two values of the solid-to-liquid-phase ratio--1:5 and 1:4. The experiments were performed for three materials--I, II, III.