# Life Cycle Assessment of Mortars Produced Partially Replacing Cement by Treated Mining Residues
## 3 Results and Discussion
### Impacts of Mining Residues Management Scenarios in Mortar Production  
Bearing in mind the potential of mining residues as a secondary source of raw materials with high economic potential and in risk of scarcity [49], the ED process was applied to mining residues as a way to contribute for circular economy targets [50]. Furthermore, the thermal treatment prospective for enhancing mining residues pozzolanic reactivity and improve durability properties, could enlarge the applicability of this material in construction products [19]. In this sense, mortars were produced with mining residues treated with the ED technology [27] and with ED plus thermal treatment [20]. To complement the technical analysis of the properties of the mortars produced with treated mining residues, the environmental impacts were determined and compared to the REF (Table 5). Three management scenarios were considered for the mining residues: direct disposal; ED treatment; ED plus thermal treatment. Once REF did not include mining residues, it is assumed that the amount of cement used is the same quantity of mining residues that are directly disposed at the mining site. Based on Table 5 data, the REF presented the higher impacts per t of mortars in GWP (2.07 \(\times\) 10\({}^{2}\) kg CO\({}_{2}\) eq.). ODP (1.44 \(\times\) 10\({}^{-5}\) kg CFC-11 eq. ), POCP (2.32 kg ethene eq. ), and AP (1.91 kg SO\({}_{2}\) eq.). Furthermore, the management scenario selected for mining residues in the REF case (direct disposal), demonstrated higher GWP, ODP, POCP, and AP than the other options (Table 3). This augmented the overall environmental pressures from REF production. The application of the ED technology showed positive achievements, once the lowest impacts were observed in all the categories analysed. In particular, ADP (7.92 \(\times\) 10\({}^{-5}\) kg Sb eq. ), GWP (59.7 kg CO\({}_{2}\) eq. ), AP (1.19 \(\times\) 10\({}^{-1}\) kg SO\({}_{2}\) eq. ), and EP (1.49 \(\times\) 10\({}^{-2}\) kg PO\({}_{4}\)\({}^{3-}\) eq.) were strongly alleviated when 50% of ED mining residues were incorporated in mortars. The reuse of a rejected fraction that is commonly disposed as waste and the removal of harmful compounds, that have severe risks for the environmental, coupled with a sec  
\begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline \multirow{2}{*}{**Motar**} & **Weight of Cement** & **Management** & \multicolumn{6}{c}{**Environmental Impact Category**} \\ \cline{3-8}  & **Cement** & **of Mining** & **ADP** & **GWP** & **ODP** & **POCP** & **AP** & **EP** \\ \cline{3-8}  & **Replaced (\%)** & **kg Sb eq. ** & **kg CO\({}_{2}\) eq. ** & **kg CFC-11 eq. ** & **kg ethene eq. ** & **kg SO\({}_{2}\) eq. ** & **kg PO\({}_{4}\)\({}^{3-}\) eq. ** \\ \hline REF & 0 & Disposal & \(1.59\times 10^{-4}\) & \(2.07\times 10^{2}\) & \(1.44\times 10^{-5}\) & 2.32 & 1.91 & 4.22 \(\times\) 10\({}^{-2}\) \\ \hline ME10 & 10 & ED & \(1.43\times 10^{-4}\) & \(9.83\times 10^{1}\) & \(3.28\times 10^{-7}\) & \(1.80\times 10^{-2  
ondary recovery of raw materials, are the main benefits of using the ED technology. In addition, the land occupied by mining residues discharges is also reduced. These aspects overlap the energy consumed during the ED process. The ODP and POCP were also lower than REF, albeit the impacts increased with ED mining residues incorporation increase in mortars. An impact intensification of 40% and 8% was observed for ODP and POCP, respectively, from ME10 (ODP = 3.28 \(\times\) 10\({}^{-7}\) kg CFC-11 eq. and POCP =1.80 \(\times\) 10\({}^{-2}\) kg ethene eq.) to ME50 (ODP = 5.51 \(\times\) 10\({}^{-7}\) kg CFC-11 eq. and POCP = 1.96 \(\times\) 10\({}^{-2}\) kg ethene eq.). During the ED treatment, the gases that could be formed due to the electrode reactions are commonly released to the atmosphere. The gases generated during the ED process depend on the matrix composition. For instance, chlorine gas could be generated at the anode in systems with high chloride contents [51].