*2.2.4 Selective dissolution-precipitation process (SDP)*

The basic principle of this approach is the immersion of the Al-PE laminate in a carefully selected solvent and under specific temperature conditions with the aim of the dissolution of the LDPE in the solvent. What follows is the removal by means of filtration of additives and impurities. Lastly an antisolvent is added, and as a result precipitation of the dissolved polymer follows. To maximize LDPE and pure aluminum recovery, the SDP process is repeated three times.

The LDPE produced is of quality that matches that of the virgin product while the aluminum collected is also of high purity. Along with the hydropulping process, this is a very promising option for Tetra Pak recycling. However, the procedure is not without drawbacks: firstly, because of the cost-effective energy consumption needed to separate the solvent-antisolvent mixture and secondly, due to its high environmental impact. The economic viability of this technique rests upon whether the solvent-antisolvent mixture can be separated cheaply (**Figure 9**) [33].
