Page 102 - Materials Chemistry, Second Edition

Life Cycle Evaluation for Alkaline Battery Waste Treatment 83

transport, and use) are not taken into account. The functional unit chosen for this study
is one batch of BP weighing 105 kg. BP is the remaining material after the preliminary
separation of iron, plastics, and paper from the collected battery wastes.
The scheme in Figure 5.2 shows the boundaries of the system examined.
The batteries are disassembled, and after the separation of iron scraps, plastic,
and paper, the remaining material is BP, which makes up approximately 50% by
weight of the original battery. Thereafter, the BP undergoes the recycling treatment.
The metal composition of the BP mass is shown in Table 5.2.

5.4.2 inventory anaLySiS (Lci) of the hydrometaLLurgicaL proceSS
Table 5.3 shows the analysis of the flows of materials and energy related to the hydro-
metallurgical process. The analysis refers to the initial batch. It does not take into
consideration at this stage the selection of waste battery operations or transportation
of the materials.

5.4.3 aSSumptionS
The sulfuric acid solution used is regenerated after each batch process. After three
times, it requires an electrolytic process in the cell to be regenerated, and after 20
times, the sulfuric acid solution must be neutralized. In the reactor, 400 kg of H SO
4
2
H 2 SO 4
KOH
Acid
BP
Batteries Mechanical Chemical Electrolysis Zn oxalate
treatment treatment K 2 SO 4

Iron Sol. BPf.
plastics Zn/M
paper

FIGURE 5.2 System boundaries consisting of the hydrometallurgical process.

TABLE 5.2
Composition of Metal BP Mixture Laboratory Data and
Percentage Composition
Test Method EPA 6010C 2007 Results (mg/kg) Percentage (%)
Manganese 405,882 53.3
Zinc 330,095 43.35
Potassium 25,140 3.3
Iron 206 0.02