Recycling Solutions - Thanatia: The Destiny of the Earth's Mineral Resources - page 431

Chapter14
Recycling Solutions
14.1 Introduction
Having constructed a global vision as to the problem of mineral resource depletion
throughout the previous chapters of the topic, this last part proposes ways in which
to stop or at least slow it down.
One way to decelerate the primary production of minerals is through recycling.
The objective of this particular chapter is thus to provide a general overview of the
current state of recycling across the world and to analyse the end-of-life technologies
involved in collection, sorting, separation and metallurgical processes from a ther-
modynamic viewpoint. Special attention is paid to the study of minor metals and
the thermodynamic problem of what the authors call “entropic backfire” associated
with their recycling.
14.2 Levels of criticality
There are some elements, such as iron or aluminium which are so abundant in the
crust that they will never reach exhaustion. Others are however scarce, some of
which bestow special properties to the materials used in society.
For those found in abundance, the responsibility of recycling is derived from the
need to save energy (and money) whilst reducing the overall impact on the environ-
ment. The necessity of recycling scarcer minerals which impart special properties,
meanwhile, relates to the entropic level of each process. As these elements appear
very diluted in the crust, the energy to extract and separate them is elevated. The
motive for recycling such elements can be indicated by any one of three types of
entropic criticalities: mine, chemical or absolute scarcity.
The first relates to the scarcity of mines, not the element per se. A shortage
of operational mines can go onto create short term political tensions as monopolies
“manufacture” restrictions in an attempt to control market supply, even if into the
long term there are su cient quantities for Man's development. In this case, recy-
cling becomes an essential technology to combat dependence on a supply controlled
by a limited number of players.
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