Twenty Thousand Leagues under the Sea

Worldwide, recycling rates of copper are between 40 to 60 percent, with demand far out weighing the availability of scrap for recycling (Graedel et al, p. 54; Lifset et al, p. 98-100; Spatari et al, p. 56-60). Losses in production are only significant in milling and smelting. Refining and fabrication losses can be readily recovered and returned to the system (Lifset et al, p. 12-15). Giurco et al (p. 95-100) estimate that copper recycling using a reverberatory smelter consumes 1200 kWh of electricity and 480kg of fuel oil with material recovery of 88 percent. It is assumed that copper recycled from the cable is of equal quality to virgin material, with a 10 percent loss in the recycling process, thereby replacing 90 percent of the virgin material input. High density polyethylene (HD-PE) recovered from the cable is processed into pellets for reuse. Louw (p. 54-65) describes the material as “top-quality non-virgin material”. Dodbiba et al (p. 693) describe this process as mechanically recycling, where the basic structure of the plastic material is unaffected. Mechanical recycling of plastics is only effective if the recovered material is of high-quality (96% purity).

Tests show that the recovery of the fibre itself is economically unattractive as complete gel removal is not possible. Energy recovery was therefore considered as potentially the best solution for the gel fractions (Arnaiz et al, p. 54). In this study no allowance has been made to recover energy from the gel as it accounts for only 1 percent of the total weight of the lightweight cable. The other main mechanical materials that make up the single armour (SA) and double armour (DA) cables are polypropylene yarn and bitumen. These materials are sealed in drums and sent to a licensed landfill (Louw, p. 98-100). It is assumed that ...