Guiding Future Research on the Valorisation of Shredder Fine Residues: A Review of Four Decades of Research

Abstract

Millions of tonnes of shredder fines are generated and disposed of globally, despite compelling reasons for its recovery. The absence of a review of previous literature, however, makes it difficult to understand the underlying reasons for this. Thus, this study attempts to investigate and assess what, to what extent, and in what ways shredder fines have been addressed in previous research. In doing so, guidelines are drawn for future research to facilitate the valorisation (upgrading and recovery) of shredder fines. Previous research concerning shredder fines was identified with respect to three main research topics. The material characterisation studies are predominantly confined to the occurrence of metals due to their recovery and contamination potential. The process development studies have often undertaken narrowly conceived objectives of addressing one resource opportunity or contamination problem at a time. Consequently, the full recovery (the retrieval of valuable resources and the bulk-utilisation as substitute material) potential of shredder fines has been largely overlooked. The main limitation of policy and regulation studies is the absence of in-depth knowledge on the implications of governmental waste- and resource-policies (macro-level) on actors’ incentives and capacities (micro-level) for fines valorisation, which is necessary to understand the marketability of fines-derived resources. Undertaking a systems perspective is the key to recognising not only the different aspects within the individual research topics but also the inter-relations between them. It also facilitates the internalisation of the inter-relations into topical research.

Can we go circular? : On the multifaceted challenges of facilitating shredder fines valorisation in the Swedish context

“…In that regard, the specificity of regulatory standards and local-authority practices in regulating waste recovery applications indicate the extent to which the potential fines recovery is facilitated in the country. Previous fines research lacks studies investigating the influence of governmental regulation on the management of the residue (Gunaratne et al, 2019). The other type of institutions is the informal institutions and consists of SRM markets, which are particularly important regarding the potential valorisation of fines, and reutilisation of fines-derived SRMs.…”

“…The actor level is addressed in relation to two types of aspects. One is the internal organisational aspects of the shredding company, which is entirely unaddressed in previous fines research (Gunaratne et al, 2019). In that regard, corporate management is addressed as it makes decisions concerning the longterm approaches to managing fines (strategic management).…”

“…The valorisation of a given residue is only realisable given the availability of systemic knowledge on the current situation concerning the material and its management. However, previous fines research is scattered in isolated research topics (Gunaratne et al, 2019), and lacks systemic knowledge in relation to multiple technical, organisational, market, and policy aspects concerning the management of the residue, thus making the development and implementation of valorisation strategies difficult. This thesis portrays the current picture of fines and its management in the context of Sweden by using a socio-technical systems perspective, where the resource potential of fines and the underlying factors of the current practice of its management were investigated on the material, actor, and institution levels.…”

“…Assessment of the resource potential of a given residue should comprehensively reveal the occurrence of potentially recoverable resources as well as possible material constraints. However, previous fines research is often confined to the assessment of a few targeted valuable materials, for example, base metals (Gunaratne et al, 2019). In this thesis, fines has been characterised in terms of the occurrence of a broad range of chemical and physical properties in order to enable the identification of multiple potential recovery applications and possible material constraints.…”

“…In this thesis, fines has been characterised in terms of the occurrence of a broad range of chemical and physical properties in order to enable the identification of multiple potential recovery applications and possible material constraints. Unlike previous fines research that has only analysed a few random or representative samples (Gunaratne et al, 2019), strategic and systematic sampling has been performed to establish the average and over-time variation levels of the material composition in order to provide essential process design information (Allegrini et al, 2014) for upgrading and resource recovery. Additionally, in contrast to previous fines research that has analysed either a single size fraction or few broad-range size fractions (Gunaratne et al, 2019), the distribution of the material composition across several incremental size fractions of fines is assessed in order to enable process development targeting specific particle sizes.…”