Circular Steel: How Information and Actor Incentives Impact the Recyclability of Scrap PDF

Journal of Sustainable Metallurgy https://doi.org/10.1007/s40831-021-00436-1 RESEARCH ARTICLE Circular Steel: How Information and Actor Incentives Impact the Recyclability of Scrap Reinol Josef Compañero1 · Andreas Feldmann2 · Anders Tilliander1 Received: 21 June 2021 / Acce...

Journal of Sustainable Metallurgy https://doi.org/10.1007/s40831-021-00436-1 RESEARCH ARTICLE Circular Steel: How Information and Actor Incentives Impact the Recyclability of Scrap Reinol Josef Compañero1 · Andreas Feldmann2 · Anders Tilliander1 Received: 21 June 2021 / Accepted: 1 September 2021 © The Author(s) 2021 Abstract Recycling plays a vital role in preserving resources like steel and consequently in a circular economy. Scrap dealers and steel mills, the main business units in this system, often encounter opposing financial and sustainability incentives in using scrap as feedstock because regular sorting and scrap-preparation infrastructure cannot deal with the increasing complex- ity of steel scrap. Mismatches between the inputs and the target composition of the recycled steel result in trade-offs that favor the economics at the expense of resource efficiency. By examining literature and interviewing several actors, different scrap characteristics were identified as dimensions of scrap quality. Quality is typically associated with chemical composi- tion, which is important, but this study aims to elaborate the concept of quality further and to connect it to the realities of scrapyard operations. Industry actors have different definitions for desired content, physical condition, shape and size, and homogeneity, based on their needs. Very few studies examine these details. Additionally, the relationship of quality and the level of information about the characteristics of the material was established. Having more definitive information on scrap increases opportunities for resource-efficient actions. This work offers an alternative perspective on how to address issues pertinent to recycling. Graphical Abstract The contributing editor for this article was Markus Reuter. Extended author information available on the last page of the article 13 Vol.:(0123456789)  Journal of Sustainable Metallurgy Keywords Recycling · Steel · Scrap quality · Compositional information Introduction practices inadvertently decrease the ability to effectively recycle steel over multiple iterations. Steel is extensively recycled due to its capacity to retain its intrinsic properties after the use phase. It can be found in a wide range of applications in large volumes, Literature Review leading to a high recycling rate that accounts for nearly 30% of the total crude steel production globally [3, 4]. In Challenges in Scrap‑Based Steel Production addition to economic incentives, recycling saves energy [5, 6] and reduces carbon emissions per unit output [7, Desrochers pointed out that today’s recyclables were con- 8] when coupled with a clean energy mix. van Beukering sidered waste until somebody treated it as a resource. noted that recycling both reduces the need to extract The attitudes of the business entities that now make up natural resources and addresses a solid waste issue. the recycling system towards the environmental impact of Because of this, steel is the most recycled material waste—which include profit-seeking, compliance, corpo- and is therefore often mentioned as a model case for the rate social responsibility, exploring new business opportu- circular economy narrative. However, product design nities, and changing social values —impact recycling decisions, consumption patterns, and the level of collec- efficiency. But researchers seldom examine how recycling- tion and sorting infrastructure create constraints on its based enterprises’ business models are reflected in their recycling, as do the challenges of its separation thermody- actual operations. namics [11–15]. Closed loops conserve both the material Steel is an iron-based alloy that contains a variety of other and the utility of that material ; by this definition, steel elements that are purposely added or retained at con- recycling remains open for scrutiny, especially if much of trolled levels [33–35]; these elements impart specific proper- the value added during the original production is lost. ties that give it its broad range of utility. The feedstock for This study focuses on the aspect of scrap quality scrap-based steel production has a higher degree of varia- because this determines to which steel grades the scrap tion than ore-based production [36, 37], because steel scrap will be used in. Mills can easily use high-quality scrap carries with it a wide variety of alloying elements from its. But scrap is seldom homogenous and—depending on previous production [38, 39]. The complex composition of its source, composition, and the level of knowledge about modern steel products is simply not aligned with the level of these characteristics [19–24]—it may require significant current scrap processing practices in the recycling industry preparation before remelting to ensure that it has the right [40, 41]. physical and chemical properties for a particular use [25, From the perspective of the steel mill, some scrap is eas- 26]. A mismatch between the input scrap and the target ier to use than others. Every stage in the life cycle of steel composition of the new steel requires interventions that generates scrap , and the more similar scrap is to the are inefficient, resource-wise. Therefore the circularity of desired product, the easier it is to use. Pre-consumer scrap steel is affected by the adequacy of the steps in place to generated during steelmaking includes home scrap used generate the information needed to mitigate losses internally in the mill and prompt scrap from downstream associated with producing new steel. Each time scrap manufacturers [43, 44]. Home scrap is readily accessed for steel is recycled, it can accumulate additional elements: production as its composition is readily known. Prompt alloys and impurities, deliberately added or not [28, 29]. scrap is likely handled by a scrap dealer , although steel Impurity, tramp, and contaminant are used synonymously mills and their customers sometimes have direct take-back throughout the paper to refer to unwanted elements that agreements for it [45, 46]. Additional steps may be required inhibit resource-efficient steel recycling. This concern before prompt scrap can be utilized, but its composition is deserves more attention. still well known. This paper examines the steel recycling system and for- The other type of scrap is post-consumer or obsolete scrap mulates a link between how scrap quality is described in from disposed goods or steel that has lost its functionality the literature and how it is reflected in transactions between [19–24] and consequently contaminated with other materials key actors in the reverse flow of end-of-service steel. It also [48, 49]. With around 3500 different grades of steel, with expands the definition of quality to include the importance varying service lives restricting access and availability , of obtaining compositional information, because actors man- it is more difficult to achieve a specific target composition age their operations according to the extent to which this using this scrap as feedstock. The trend towards expanding information is known. The argument is that current industry product ranges is bound to continue, as companies seek to 13 Journal of Sustainable Metallurgy produce products distinct from those of the competition in iron, elements such as copper, tin, nickel, cobalt, molyb- terms of price, properties, and quality [51, 52]. Price com- denum, and tungsten favorably report to the metal phase petition drives producers to continuously refine recipes to than to the slag or furnace atmosphere. Several studies have keep their products attractive. Thus, even within gen- looked at this problem from the perspective of process met- eral categories of steel, the chemical composition between allurgy and others from a system perspective. The sys- products can vary. tem perspective is of general projections of scrap supply Defining scrap categories is complicated as it must take and stocks , contaminant accumulation [71, 72], and its into account not only technical, but also aspects such as relationship to policy. trust between actors , actors’ tacit knowledge , and Production involves carefully planned scrap mixes the transferability of standards across regions. The discrep- together with fluxes as a form of process control, but once ancy between the variety of scrap and the limited number problematic elements are in the melt, it is difficult, expen- of categories results in mismatches. Scrap pieces whose sive, and sometimes impossible to remove them. Mills characteristics fall in between classes further complicate the sometimes encounter element content that exceeds the toler- picture. For example, the Institute of Scrap Recycling Indus- ance levels for a product. The current solution is diluting the tries classifies ferrous scrap into 82 types, with another 40 melt with additional virgin steel to lower the contaminant’s classes for railroad scrap. Product origin or source are concentration [75, 76]. This operationally simple fix allows used as broadly defined categories. Knowledge of the the final product to accommodate the problematic elements compositional identity of steel diminishes with each transfer without compromising the production batch. From a cir- of ownership downstream from the steelmaker on through cularity perspective, however, it is flawed, as it passes the to obsolete scrap. Regaining this information becomes contaminant along in the recycled product and contributes laborious and costly, yet critical, because it is the basis for to a loss of valuable metals. defining the quality of scrap exchanged between businesses Finally, whether an element is considered a contaminant in the recycling system. or an alloying component depends on the context. Elements In developed countries, recycling is a formal activity in the steel scrap are desirable in some cases, tolerated in characterized by functioning systems. Discussions usu- others, and unwanted in some [35, 77]. Consider the fact ally revolve around increasing recycling rates, especially for that even Fe is a contaminant in Al–Si alloys. Direct- metals such as steel, aluminum, and copper [12, 58], and ing scrap to the production batch that is most similar to its topics such as forecasting supply or describing flows composition is the more resource-efficient way to recycle.. Accelerating recycling entails technical, economic, and operational challenges (see Table 1). This study focuses on the information-driven consequences of these challenges Scrap Quality as they are enacted in the scrapyard. The technical challenges described are due to the inad- Makar noted that dealing with steel scrap reveals the equacy of the current process to remove some elements [61, complexity and sophisticated nature of modern-day recy- 62] if they are overlooked and end up in the melt. Alloy cling, which is affected by increasing quality requirements designs for target applications complicate recycling [63, 64] and scrap mixture complexity. These two factors are both and require concessions between cost and the recyclability of linked to the complex designs of products [80, 81] and different elements, since their behavior in the process envi- lower tolerances for contamination in steel grades with ronment needs to be considered. Nakajima et al. [66, specially designed properties. The steel products that 67] used thermodynamic analysis to evaluate the recyclabil- enable societies to go farther, deeper, and higher, and build ity of elements present in scrap and found that together with lighter and stronger (especially steels supporting low-carbon Table 1  Challenges in material Challenge Description efficiency when increasing recycling rates Technical Diminishing purity of the material through the processing chain Mixed material products Economic High cost of collection and separation Correlation between material value and ease of recycling Loss of valuable alloying elements Operational Availability of recycled material and balancing supply and demand Logistics and infrastructure of collection and sorting Varying service lives of goods An additional point was added under economic challenge 13  Journal of Sustainable Metallurgy technologies) require new combinations of elements within similar to the steel being produced [84, 97, 98] or its clean- its matrix and lead to an increasingly complex scrap ness, i.e., low degree of contamination [22, 67, 99–102]. stock. Noro et al. also discuss the association between scrap Post-consumer scrap is considered lower quality and shape (heavy, shredded, or pressed) and contamination, as may introduce contaminants into the melt ; this means heavy pieces are assumed to be less contaminated because it requires additional measures to make it fit for use in pro- these were traditionally made from ore. Contaminants duction. The issue of contamination is not the presence are problematic and can exist in the pure state together of elements per se, but the fact that these may end up in with the steel scrap as coating material on the steel, or a steel grade where they are unacceptable and accumulate as alloying additives. Miranda et al. found that over recycling iterations. According to Bell et al. , the steel scrap and other metals intermix, i.e., copper in elec- distinction between alloying and tramp elements is that the tric motors and white goods. While unintended and the former positively affect the steel. They found that impurities standard in liberating Fe from these products, shredding due to inadequate sorting and classification and lax scrap entangles copper with steel [49, 103]. preparation methods become pathways for these impurities This means that identifying and sorting steel scrap into to enter the melt. In addition, scrap steel is a traded com- groups with similar characteristics is critical to its recy- modity [84–86] and thus scrap generated in one location cling. These steps determine the success of the operation, may be processed elsewhere. Numerous sources and little because even the residual presence of any unwanted ele- traceability mean that recycling actors lack information on ment can affect the properties of the steel product [77, composition, production, and utilization history ultimately 99]. Yellishetty et al. summarized several studies impacting the recyclability of scrap. All these concerns on contaminants in recycling, identifying two categories: impact quality; this study synthesizes the scrap characteris- (a) those that are very difficult to remove and thus accu- tics described in literature to identify relevant dimensions of mulate in each recycling pass (e.g., copper, tin, nickel, quality. Muchová and Eder discuss these classification and molybdenum) and (b) those that can be handled with properties, which Table 2 expands on. properly executed metallurgical extraction (e.g., copper, The literature defines scrap mostly in terms of specific manganese, zinc, and lead). Furthermore, these elements, parameters. Quality is linked to its acceptability for steel- together with phosphorus and sulfur, are normally found in making. Furthermore, the quality rating of scrap is goods with shorter lifespans, such as automobiles, electric usually regarded as a function of its chemical profile— and electronic equipments, and municipal solid waste [99, either the degree to which its composition is known and 105]. Table 2  Examples of scrap characteristics referred to in the literature and consolidated as quality dimensions Quality dimensions Description References Desired content Primary alloying/sec- Alloying elements enhance at least one material property of the steel, while tramp elements have no [29, 35] ondary alloying/tramp useful purpose elements Residual elements Additional indicator of contamination even from non-ferrous sources Unwanted elements In scrap charge optimization, the presence of unwanted elements may lead to deviation from the prod- uct standard Physical condition That pieces are cut to size or are aggregated by pressing or briquetting to reduce difficulty in using [74, 89] loose pieces of scrap Moisture and organic matter interfere with the removal of residual tin via chlorination Shape and size Density High-density scrap is preferred when loading buckets Shape The shape of the scrap is sometimes associated with its production pathway, and by extension, the level of contamination Loading the Electric Arc Furnace (EAF) requires scrap to be classified as light, heavy, or with small dimensions Homogeneity Chemical The chemical composition of the scrap can be used as an input variable for predicting electrical energy consumption in the EAF, if the scrap compositions stay the same Property Process control systems rely on consistency of scrap properties 13 Journal of Sustainable Metallurgy Methods were selected for interviews and site visits (see Table 3). Due to the interconnectedness of the system and the lim- Research Design and Pre‑study ited number of actors, the system is relatively homogenous in principle, even though different steel mills manufacture This study examines one national system for steel scrap recy- different products. Together, these case companies repre- cling and can be considered a single-case study but with sent well over 50% of the volume in the scrap-based system embedded cases. Single-case studies allow for in- and can therefore be considered representative of its major depth investigations and are suitable for building theory on actors. Smaller actors, such as foundries and small scrap complex issues [107, 108]. The Swedish steel scrap system dealers, were excluded from the sample. was selected as a representative case of a mature national system, with both extensive scrap collection and production Semi‑structured Interviews of specialized steel grades using scrap. The data for this study were collected in two phases. The An interview protocol (see Table 6 in Appendix) was devel- Sweden scrapped steel system was first broadly mapped oped for the semi-structured interviews based on the litera- using public documents on case companies and organiza- ture review and previous experience, which provided a basic tions, in particular, the Swedish scrap book , which understanding of the network. The questions were formu- defines the scrap grades used by Swedish scrap dealers and lated and grouped into the main topics of general informa- steel mills. In line with the literature [23, 99], three types tion, supply chain, operations, and other data. Actor-specific of actors were identified: scrap dealers, steel mills, and one questions were also included. Persons who were interviewed broker (see Fig. 1). In this phase, relevant documents were were selected based on their positions and knowledge of reviewed, and pre-interviews were conducted with the bro- their company’s scrap operations. ker and one of the steel mills. In the second data collection All but one of the interviews was on-site in conjunction phase, a sample of four steel mills and four scrap dealers with corresponding facilities tours. A consultant was also interviewed to confirm the findings and to get updates on industry trends. Table 3 summarizes the particulars of the interviewees. Manufacture new steel product Buy processed scrap Steel Mills All interviews followed the general outline of the proto- Liase between the processors and col, which allowed interviewees to elaborate while main- Brokers taining consistency across interviews. The interviewers took steel mills Buy and upgrade scrap notes independently to capture as much material generated Upgrade by: that is typical of semi-structured interviews , and indi- Sorng/Idenficaon vidual notes were compared afterward. All data were veri- Processors Torching/Cung Baling fied against the available literature and other discussions. Shredding In addition, the researchers reviewed corporate and public documents from each of the companies. Fig. 1  Typical roles performed by actors in the scrap steel trade, The transcripts were then analyzed, and data were adapted from [23, 99] aggregated into the topics of scrap compositional Table 3  Record of interviews Company Number of people Role of person(s) interviewed Scrapyard visit performed for the study interviewed Steel mill 1 1 R&D expert in metallurgy Yes Steel mill 2 2 Raw materials department manager Yes Steel mill 3 2 Process development metallurgy group man- Yes ager & manager of steel melting shop Steel mill 4 1 Raw materials department manager No Scrap dealer 1 2 CEO and owner No Scrap dealer 2 1 Site manager Yes Scrap dealer 3 1 Site supervisor Yes Scrap dealer 4 1 R&D expert No Broker 2 CEO & purchasing manager N/A Consultancy 1 CEO N/A 13  Journal of Sustainable Metallurgy information, thoughts on scrap quality, operational and Compositional Information and Physical Dimension logistical effects on quality, and other relevant points, such of Scrap as the general outlook for scrap availability and anticipated disruptive future events that companies were monitoring. In Sweden, 15 out of the 32 unalloyed or low-alloy scrap classes and all 6 of the stainless-steel classes have cat- egorical requirements related to chemical composition (see Table 5 in Appendix). That the requirements were desig- Findings nated this way does not mean that the overall chemical com- position of scrap is unimportant. Rather, it reflects the fact According to Jernkontoret (the Swedish iron and steel pro- that within the industry, there is information on specific steel ducers’ association), the Swedish steel industry produces products embedded in knowledge of their origin or how they approximately 4.8 Mt of steel per year (primarily special were produced. Actors implicitly know what a given scrap is grades), accounting for almost 4% of the country’s total composed of or what to expect from it, even if these are edu- exports. Around 45% of the steel produced uses locally cated estimates. At the same time, having specific elements sourced scrap, which is therefore a major resource for a explicitly declared means that there were observed trends in nation that exports most of its steel production. On the the supply and affecting production that necessitated the set- consumption side, the specialized nature of Swedish pro- ting of thresholds. With regard to physical dimensions, only duction means it typically imports standard grades and two classes—steel chippings and cast iron chippings—have exports special grades of finished steel. Sorting and no declared requirements, which is expected given the physi- scrap preparation infrastructure increasingly need to be cal nature these scrap types. able to generate reliable information on scrap to prevent Scrap categories are described based on existing under- contamination in the melt due to the use of essentially standings among actors that exist outside their formalization imported feedstock, whose sparse information availability in the “scrap book.” As a result, descriptions may change increases the likelihood of a mismatch between the input depending on current industry needs. For example, an ear- material and the target steel product. lier edition of the scrap book specified the maximum lead In terms of the size of Sweden’s steel recycling indus- threshold for scrap class 21 as 0.01% and the maximum try, there are ten scrap-based steelmaking plants operated chromium content as 1% ; however, only chromium by eight companies , and six major scrap dealers content is specified in the current version of the book. that dominate the system in terms of both volume Because the published scrap book serves to regulate spec- and influence. The sole scrap broker, JBF, is co-owned by ifications for purchasing and production of different grades, six of the steel mills. JBF handles major transactions for quality dimensions tend to be generalized as an aid to trade. end-of-life, unalloyed and low-alloy scrap, and to a lesser Some classes have defined tolerances for composition and extent, scrap from stainless steel. Each company’s scrap physical dimensions, indicating two things. First, a tolerance volume requirements vary widely, which may be why not range means that an element will be considered an impurity all scrap-using steelmakers buy through it. For example, a only if it exceeds a certain value. Second, local producers representative from a metal powders company mentioned are only concerned about specific elements that may be his- that they require lower volumes than the companies who torically problematic for them. The scrap book is routinely source through JBF. The JBF-partnered steelmakers ful- used by Swedish scrap dealers and steel mills and reflects fill their post-consumer scrap needs primarily through their collective understandings of these quality dimensions. JBF-facilitated transactions with scrap dealers, with the reminder filled through mill-specific orders arranged A Broader Definition of Scrap Quality directly with dealers. The typical feedstock typically consists of 50–60% One common theme in the interviews was the desire to find post-consumer scrap, 20–30% internal or pre-consumer a steady supply of “good, clean scrap,” a concern for both scrap, and the 15–20% virgin materials used to dilute con- scrap dealers and steel mills. Further inquiry revealed that taminants to achieve the desired final alloy composition. transactions between them were faster when the required The role of scrap dealers is vital, as most post-consumer quality level was met. The business of transferring scrap scrap flows through them from different sources. Their from dealer to steel mill showed that information and quality transactions affect the quality of scrap that is recycled. go hand in hand. Post-consumer scrap is typically traded according to the Information-based quality levels are established in the scrap classes defined in the Swedish scrap handbook: 32 scrapyards. Scrap dealers usually follow the course of action for unalloyed or low alloyed steel and another 6 classes of that allows them to meet customer demand at the lowest stainless. possible cost. Before incoming scrap deliveries are directed 13 Journal of Sustainable Metallurgy to specific piles, dealers make decisions based on whether The physical condition of scrap as it arrives in the scrapy- the available information is sufficient for it to be forwarded ard is another component of quality. For both dealers and to the next stage or if further steps need to be taken. This mills, hazardous content is unacceptable. Moisture, mean- routine is similar for the actors. Most collection, sorting, while, is not an immediate concern during delivery and stor- classification, and preparation occur at the dealer’s scrapy- age but becomes a critical problem during melting. This is ard. Complex pieces may include wires and motors from also true for other requirements, such as removal of oil and white goods, scrapped vehicles, coated or surface-treated grease, emptying of fuel tanks, etc. Sometimes such require- steels, and oversized items. The available technologies attain ments reflect changing policies on the handling of waste: for limited separation: in motors, for example, copper cannot be example, painted scrap is now classified as hazardous, and completely separated from steel. With the objective of mak- so pieces are sandblasted before delivery. Moisture manage- ing a successful delivery, the dealer decides which pile to ment must also be considered under the desired dimension, send the pieces to, ready for transport. After scrap arrives at and it is conceivable that specifications regarding moisture the mill, there is a limited time window for steps to obtain or could be incentivized. There are, however, risks from con- recover information needed to determine if the delivery will flicting incentives for moisture since wet scrap weighs more be accepted. The mill then goes through the same process and weight affects pricing. Regarding apparent density, the of deciding which pile to send it to, ready for production. interviewees did not specify values other than a preference Interpreting the standard scrap category definitions into for heavier or denser scrap. actions and the effectiveness of these actions depends on One current situation that illustrates the increasing selec- available information. Scrap quality as defined in litera- tivity of mills in terms of raw materials is the case of a scrap ture is now further developed by incorporating the actors’ dealer that was able to obtain material similar to what they perspectives. There is a necessity to better understand the had consistently supplied at a lower price point but found dimensions of quality in this context, because operationally, it difficult to sell. Mills require homogeneity, and stringent quality goes beyond the specifications in formal scrap clas- about the consistency of their inputs; they were therefore sifications. Table 4 synthesizes the interviewees’ responses cautious about buying an unknown type of scrap. Trust came when asked to elaborate on what quality means in their up in several interviews as an important aspect. Steel mills operations. do not want to have to check every piece of scrap that arrives Desired content is an apt descriptor for compositional and trust long-term suppliers to deliver to their specifications content of scrap, especially in Sweden, where steelmaking is and notify them of any deviations in their deliveries. specialized. This is because mills are niche players, working By understanding these dimensions, the demands for with hundreds of unique recipes, and thus their requirements scrap quality can be linked to recovering and establishing for scrap differ. When they buy scrap, they prefer the mate- a material’s identity, not only in terms of chemical compo- rial most suitable for the steel they make. One mill might be sition, but also its physical and chemical properties, both concerned about limiting phosphorus, while another pays within and across delivery batches. Actors in the recycling a premium for higher nickel content. It follows that scrap system have specific requirements for the material they dealers will find it easier to make sales if they can offer their want to source, and thus collection is important, but does customers what they specifically need. As one interviewee not guarantee that scrap will be recycled. A mill must pur- put it, “high quality” means being able to deliver more spe- chase it, and this requires dealers to prepare it in such a cific and better-defined scrap grades. way that its quality characteristics are actualized. Thus, in a Table 4  Expanding scrap quality dimensions with perspectives of the steel industry actors Dimension Description Steel mills Scrap dealers Desired content Preference of buying scrap with the lowest levels of con- Finding the cheapest supply of scrap with minimum prepa- tamination and/or a high content of element needed in their ration required that meets the requirements the mill they products deliver to Physical condition Related to the safety of operations by preventing scrap that pose radioactive, health, and explosive hazards from entering the scrapyard or the steel plant Shape and size Steel mills prefer denser scrap to load EAF better. This is a Related to scrap preparation with the observed increase in function of the shape and size of the scrap value for scrap of higher density Homogeneity The expectation that the category of scrap supplied to them Establishing trusting relationships with customers with the are free from abrupt deviations in and across delivery consistency of their deliveries batches 13  Journal of Sustainable Metallurgy wider perspective, recovering information is a prerequisite that is compositionally more varied than the specification for resource efficiency. for the class they are labeled as. A successful melt means that the final composition matches the specifications of Operational and Logistical Effects on Quality the steel product. Thus, even if the melt composition can be adjusted, contaminants persist, and the resulting steel Looking at the system as a value chain, in which a series product would be scrapped for the next recycling round. of underlying steps transform scrap into new steel, reveals The following points, raised during discussions on how the points of concern that a functioning recycling system con- operations and logistics of the system are set up, elaborate tends with. For example, sorting scrap into categories helps on this observation. capture the intrinsic value of the alloying elements but is difficult to execute, as there are hundreds of different steel Delivery requirements: Mills require a minimum vol- products to separate into a limited number of categories. The ume as a delivery unit—an Economic Lot Size (ELS). nature of the forward supply chain means information from This is especially true for transactions made via JBF. end-of-life products is often lacking. Compositional infor- The dealer’s challenge is to procure enough volume mation at end-of-life is recovered through educated guesses, of one category for delivery, and this impacts scrapy- coupled with chemical analyses of samples. Different actors ard operations. Dealers keep stocks of scrap that get somehow implement the same structure of combining expe- replenished either from customers selling or disposing rience and systematic methods to obtain the information that of their scrap or from collection points such as con- is important for their operations. Each actor takes action struction sites. based on the maximum cost they are willing to bear.   It is typical to receive pieces that that potentially could These considerations appear in industry guidelines as be compliant in multiple classes. Working with such a conditions for delivery. If local steelmakers become con- variety of scrap, dealers allocate these “middlings” (a cerned about how a specific element or scrap characteristic term from mineral processing) as needed to meet their will affect their output, this concern becomes codified in a supply agreements with steelmakers. This usually takes given scrap class specification. This is seen in the Swedish minimal resources and effort to achieve the necessary context with elements such as copper, phosphorus, and man- quantities. The operation itself makes sense from a busi- ganese. Here again the significance of information is seen: if ness perspective, but it increases the probability of con- a steel type being manufactured is sensitive to trace amounts tamination and the compositional variation within each of an element, then more samples are taken and analyzed. delivery batch. The less information the dealer has on the Incidents of radioactive materials accidentally ending up material, the more likely it is that these two issues will in the melt have resulted in radiation checks at the gate, occur. The same thing happens with delivery require- and indoor stockpiling is now used to prevent trapped and ments specifying physical conditions such as density. unchecked moisture from causing explosions during melting. Reducing holding costs: Another factor is the need to Scrapyard operations are driven by business necessities, move material quickly due to limited yard space. Inbound such as how to deal with scrap pieces whose characteristics and outbound deliveries happen continuously, and stocks may fall into different categories. Business factors then influ- must be managed. Similar, smaller piles may be com- ence which scrap pile they are assigned to. Because deal- bined, for example, during periods when there are fewer ers handle most of the sorting and scrap preparation, their buildings being demolished. Combining scrap from dif- operations have the greatest impact on scrap quality, even if ferent sources improves cycle time and space utilization steel mills’ management of scrap also has impacts due to the and therefore return on capital. It also reduces land costs upstream influence on how dealers act. Before examining the since less scrap is held at any one time. Even weather points related to dealers, the effect of steel mill production becomes a consideration if weatherproof storage is una- schedules on quality should be mentioned. Recipes deter- vailable, and scrap must be therefore moved quickly. mine which type of scrap, and how much of it, is picked Scrap prices: Scrap is a globally traded commodity, and and fed into the furnace for melting. Ideally, steelmakers prices change constantly. If one category commands a select scrap that closely matches the steel being produced, higher price, then other piles with similar characteris- although this is limited by availability and the order batch tics that can be reclassified with minimum effort may be that must be fulfilled. The mill’s production schedule is thus reallocated. Scrap pricing also influences mixing in this a significant part of the supplier agreement that dealers must way: if scrap dealers are unable to sell locally, then their consider. scrap will be sold someplace where the regulations or The scrap mix that is loaded to the furnace indirectly requirements are laxer or production has lower quality affects the quality of future steel scrap. Additionally, mills demands, resulting in scrap classes that are mixed with draw from piles that scrap dealers have supplied—material indifference. 13 Journal of Sustainable Metallurgy These factors are interrelated, and the scrap dealers’ A Better Understanding of Scrap Quality primary concern is fulfilling the specifications in their sup- ply agreements. Other than economic gain, there seems Traditionally, scrap quality has been mainly associated with to be little incentive for scrap dealers to allocate more chemical composition and physical condition. The literature resources than needed to meet the minimum requirements review reflects this, and its inherent multi-dimensionality is in their contracts. Once delivery arrives at the mill scrapy- summarized in Table 2. The quality dimensions of desired ard, inspections and control checks confirm whether the content, physical condition, shape/size, and homogeneity quality specifications in the contract are met. The sampling are indicators that industry actors use in their operations plan and the method and frequency of characterization and transactions, as Table 4 shows. Defining chemical com- depend on the size and source of the delivery. The need to position in terms of desired content helps clarify that the inspect and test scrap deliveries also depends on the his- presence of certain elements may be useful or harmful only tory with the supplier. If the supplier consistently delivers in the context of a particular steel mill or a particular steel per specifications, then the testing frequency may be lower product. A quick glance at the scrap book indicates than with a new supplier. that copper is only a contaminant, but in reality, it is an This compromise is a short-term fix and affects recy- alloying element for certain steel grades. cling because impurities accumulate with each cycle and Again, the industry has preferences regarding how scrap make it harder steelmakers to use scrap down the line. should be delivered. Consider moisture: in colder areas, the Moreover, diluting an unwanted element locks it into a concern is the risk of explosion , but it can also inter- product as a contaminant, even if it could find a useful fere with the removal of residual tin via chlorination. purpose as an alloying element for a different product— Thus, while there is no universal definition of scrap quality, reducing resource efficiency. Better information about guidelines such as the scrap book and other steel scrap speci- scrap can result in better resource allocation, insofar as fications exist to facilitate trading in a way that reflects it allows steel mills to expand their respective recipes to industry need—defined by steel recycling actors, for actors. accommodate not just a higher fraction of scrap but also There is also an intangible, relational aspect at work a wider range of scrap types. This, in turn, will stimulate in establishing quality categories. This means that change the secondary market due to higher demand. within the industry is possible, whether stricter measures on Steel mills generally comment that scrap is getting issues like contamination, balancing economic and sustain- “dirtier.” This is not just a matter of improving sorting but ability incentives, or even influencing policy. also considers aspects such as products or alloys designed Retained content is an additional aspect of quality that with recycling in mind. Car frames, for example, are interviewees did not explicitly mention in the interviews but becoming thinner and lighter by increasing phosphorus, that concerns future demands for metals in association with titanium, and niobium content. This issue will need to be downcycling. Elements such as niobium, cobalt, tungsten, addressed through systemwide actions because steel scrap and vanadium that are present in the scrap mix can end up will remain a significant feedstock material in the future. in a steel product where they are unessential and in negligi- ble quantities that do not require addressing but are of par- ticular interest because of their inclusion in the EU Critical Raw Materials list. When they are blended into a steel Discussion product, they are no longer accessible during the product’s lifetime, and they can potentially become so diluted that it Recognizing that the businesses involved in recycling are becomes more attractive to obtain them from ore. The per- motivated and restricted by economic potential is impor- ception that the loss of critical elements is simply an eco- tant when investigating this system. There is a limit as to nomic loss neglects the larger risk of future scarcity which how far economics can align with sustainability incentives. could be a barrier to sustainable production. The environmental stimulus may exist not as a priority, but Quality depends on information and information transfer rather as a consequence of the activity. The incentives that because companies cannot act on what they do not know. govern company motivations are central to the discourse Recovering enough information to establish a satisfactory on how actors value scrap as a resource. This study aims to quality level for scrap and the exchange of information expand the definition of quality to include actors’ perspec- between dealer and steel mill are fundamental to the suc- tives in a way that reflects the relationship between quality cess of recycling. One reason is that this makes given scraps’ and information and the realities of scrapyard operations. ideal use clearer and prevents what Rong and Lahdelma con- Doing so provides additional insights into the challenges sider as a failure: when elements in the melt and the prod- of steel recycling. uct standard become mismatched. Another reason is that such information increases the desirability of scrap for 13  Journal of Sustainable Metallurgy purchase, and in turn, for recycling. Expanding the definition to pick and load the furnace with the right qualities and of scrap quality is a practical approach to understanding the quantities to minimize or eliminate the use of virgin material demands of everyday scrapyard operations. while maintaining product tolerances. Therefore, there is a direct link between information on Challenges in Steel Recycling scrap and the use of virgin materials. The more that is known about scrap, the less virgin material is needed to compensate Converting or breaking down scrap into its constituent ele- or adjust the content of the melt. While the current cost of ments is uncommon in the steel recycling system. Rather, using virgin materials is an acceptable solution to retain the the objective is to reuse scrapped steel to produce new steel value embedded in scrap steel, it raises questions about the with minimal processing and preparation. Both the litera- circularity of the process. If these costs were to increase, ture review and interview subjects agree that this is compli- the system would likely rebalance through improved char- cated by the fact that the identity of steel scrap is not readily acterization, sorting, and preparation. The sustainable action known. This means that elements end up as contaminants is to ensure that the use of virgin material is minimized and and require interventions that contradict the idea of circular- the use of specific elements already in the scrap where they ity. System entropy observably increases with each cycle, are needed is maximized. This also prevents the premature because elements already in the melt are hard to remove [61, downcycling of materials when special steel grades are recy- 62]. Even so, the final steel product composition must be fol- cled into more common types [120–122]. lowed. The subsequent adjustment to achieve the target steel More to the point, this confirms that business entities are grade composition results in a degradation of the feedstock understandably inclined to save money first, and material with every production cycle as tramp elements accumulate. second. This is to be expected under the current economic Pinto and Diemer describe this as steel scrap down- paradigm where companies need to make a profit. One cycling and will persist until the system incorporates much motivation for recycling metals is to consume less energy more selective sorting and scrap preparation infrastructure. in production [89, 123], which also lowers costs. But mills The industry is currently organized by defining scrap catego- will readily shift to other sources of iron if the economics of ries that function as standards for exchange, as discussed in doing so become more attractive. the previous section. The motivation of different actors has long been estab- lished to affect the supply chain. This study shows that Conclusion this is quite true in the Swedish scrap system as well. One scrap class that may contain a combination of three other Recycling is seen as an especially viable sustainable solution scrap types, for example, possible due to the three types for metals like steel, where economic and environmental being so similar that mixing has become common practice, incentives generally align. This study takes a closer look at or possibly because quantities demanded are hard to col- steel recycling actors and how they exchange and use scrap, lect and therefore require aggregation of different classes. finding that there is a limit point at which economic consid- Scrap dealers are motivated to make successful deliveries erations lead to less environmentally sustainable choices of at the lowest possible cost, while steel mills are motivated action. This paper has three major contributions as a result: to secure feedstock that balances between the required blend First is establishing the relationship between informa- at the lowest cost. Dahmus and Gutowski note, with tion and scrap quality. As more information is available or concern, that material mixing reduces product recyclabil- recovered, a higher quality level can be achieved. The ideal ity, and the current trend is to develop complex, composite scenario is to obtain all the information needed to ensure products without developing the infrastructure to recapture that specific elements end up in the correct steel product and these materials. This study confirms and elaborates on this their intrinsic value is preserved. However, actors’ efforts to observation. Recycling vehicle motors is one such example. ensure this outcome depend on the value they get in return The extent to which copper in motors can be separated and for their efforts. This study found that information is valu- prevented from entering the melt in excess is a challenge to able for both actors at certain thresholds. be addressed. Success will depend on the resources recyclers Next is that there are multiple dimensions to quality. Sys- are willing to allocate to pull out wires or dismantle motors tem actors require quality levels that are specific to their and sell it separately. For mills, success is being able needs. The meaning of high quality for one steel mill is not 13 Journal of Sustainable Metallurgy necessarily the same as for another, and this affects how Steel recycling is established and functioning in Sweden, suppliers act. and these findings could guide future research into similar Finally, showing that operational behavior impacts scrap issues. The business paradigm is the same everywhere: com- quality and information—and ultimately, circularity. Deal- panies need to make a profit. This study makes it clear that ers want high-quality scrap because it is easy to sell, and pushing for circularity in industrial systems requires a mul- mills want it because it is easy to use. But the reality is that tidisciplinary perspective, because the enterprises involved scrap needs to be delivered, and steel needs to be produced, need to earn profits to continue operating. While recycling under complicated conditions. Thus, actors make trade-offs benefits the environment, this added value could eventually that always prioritize economic considerations rather than weaken due to concerns such as the ones raised here. material resource efficiency. More specifically, this study found that operational drivers such as lot sizes, and eco- nomic drivers such as inventory holding costs, lead to the downcycling of scrap. Appendix See Tables 5 and 6. Table 5  Compositional Scrap class Name Compositional information information requirements for select unalloyed and low-alloy 12R Reinforcement bars Cu max 0.35% steel scrap in the Swedish scrap 177 Fragmented scrap Cu max 0.40% book 21 Chippings Cu max 1.0% 23 Briquetted chippings Cu max 1.0% 300 Prime, loose uncoated sheet metal, analysis-secure P ≤ 0.0125% Mn < 0.25% Cu < 0.05% 302 P ≤ 0.0155% Mn < 0.5% Cu < 0.05% 321 Prime, pressed sheet metal, analysis-secure P ≤ 0.0125% Mn < 0.25% Cu < 0.05% 322 P ≤ 0.0155% Mn < 0.5% Cu < 0.05% 37 T Tin cans Sn allowed to be higher than 0.02% 612 Manganese-alloyed scrap Mn max 16% 622 Copper-alloyed scrap Cr max 1.25% Ni max 0.65% Cu max 0.75% 633 Silicon-alloyed, loose sheet metal Si max 4.5% 634 Silicon-alloyed, pressed sheet metal Si max 4.5% 711 Prime cast iron scrap P at most 0.2% 721 Second-rate cast iron scrap P at most 0.5% 13  Journal of Sustainable Metallurgy Table 6  Guide questions used during the interviews Questions Expected response General information Name of company? Name Name of respondent? Name Name/location of site? Name When did operations start at this site? Year What is the origin of the site? Acquisition or not Annual turnover? Number (previous year). Stable, declining, or increasing trend? Number of employees? Number (current date). Stable, declining, or increasing trend? Number of steel scrap employees? Number (current date). Stable, declining, or increasing trend? Roles of steel scrap employees? Job titles, e.g., operator Supply chain information relating to steel scrap Who are your suppliers? Names Number? Number (current date). Stable, declining, or increasing trend? Sizes? Small, medium, big supplier of steel scrap Locations? Countries/regions/cities Volume of external supply? Number in tons (previous year). Stable, declining, or increasing trend? Volume of internal supply? Number in tons (previous year). Stable, declining, or increasing trend? Logistics? Type and supplier, e.g., ferry, local haulage firm by truck, train. Also, distance—same city, region, country, or internationally Planning? Time horizon, who, collaboration with buyers and suppliers, variations Seasonal variations? Yes or no. Small, medium, or big Suppliers’ requirements? Price, product quality, product performance, delivery speed, on-time delivery, volume flexibility, product range, ability to customize the product, other Drivers? Explanation, e.g., lower costs Barriers? Explanation, e.g., lower costs Your requirements? Cost, quality, delivery, flexibility, other Drivers? Explanation, e.g., lower costs Barriers? Explanation, e.g., lower costs Who are your customers? Names/industries Number? Number (current date). Stable, declining, or increasing trend? Sizes? Small, medium, big supplier of steel scrap Locations? Countries/regions/cities Volume of sales? Number in tons (previous year). Stable, declining, or increasing trend? Logistics? Type and supplier, e.g., Maersk by ferry, local haulage firm by truck, Green Cargo by train. Distance—same city, region, country, or inter- nationally Planning? Time horizon, who, collaboration with buyers and suppliers, variations Seasonal variations? Yes or no. Small, medium, or big Customers’ requirements? Price, product quality, product performance, delivery speed, on-time delivery, volume flexibility, product range, ability to customize the product, other Drivers? Explanation, e.g., lower costs Barriers? Explanation, e.g., lower costs Your requirements? Price, product quality, product performance, delivery speed, on-time delivery, volume flexibility, product range, ability to customize the product, other Drivers? Explanation, e.g., lower costs Barriers? Explanation, e.g., lower costs Operational information What types of operations do you perform at this site? Description, e.g., disassembly of cars, WEEE sorting, steel scrap qual- ity control 13 Journal of Sustainable Metallurgy Table 6  (continued) Questions Expected response Relationship between steel scrap and other types of scrap? One of many, few, or only Proportional relationship between steel scrap and other types of Low, medium, high scrap? How do you use the Swedish steel scrap book? Description, e.g., in operations, for quality control Same or different classes? Yes or no Same, fewer, or more classes? Choose alternative. Number if not sensitive Utopian situation? E.g., 1 class, 5000 How do you work with material quality? Description, e.g., responsible roles, points of control Input control? Yes or no. Description of what happens when supply enters the scrapy- ard Internal control? Yes or no. Description of what happens at what points internally Output control? Yes or no. Description of what happens when steel scrap exits the scrapyard For steel producers—control in production process? Yes or no. Description of what happens at what points internally Collaboration with suppliers? Yes or no. Description, e.g., daily contact Collaboration with buyers? Yes or no. Description, e.g., daily contact How do you work with separation? Description based on choice How do you work with identification? Description based on choice How do you work with sorting? Description based on choice Level of technology for steel scrap? Low, medium, high Share of high technology equipment for steel scrap? Low, medium, high What parts are manual? Description based on choice What parts are semi-automatic? Description based on choice What parts are automated? Description based on choice What technologies do you use? Description based on choice What is the volume of material loss annually? Number in tons (previous year). Stable, declining, or increasing trend? What is it that you lose? Description Specific for steel producer How does your steel scrap-based production work? Description. Why? How do you match input with output? Description. Why? What would the impact of bad quality be? Description, e.g., higher costs. Why? Drivers for better quality? Description, e.g., lower costs. Why? Barriers to better quality? Description, e.g., lower costs. Why? Types of steel scrap? Description, e.g., unalloyed Percentage bought per type? Numbers and type of supply, e.g., direct contract, via JBF Extra information What is your outlook for scrap-based production in the short term? Description, e.g., growth What is your outlook for scrap-based production in the long term? Description, e.g., growth How do you work with sustainability? Description, e.g., calculate carbon footprint, core business What is sustainability to you? Definition, e.g., triple bottom-line Acknowledgements This study was supported by Jernkontoret through Declarations the Jernkontorsfonden för Bergsvetenskaplig Forskning, enabling the visits to the steel mills and scrap dealers. The authors would like to Conflict of interest On behalf of all authors, the corresponding author thank the following: the interviewees for taking time and allowing a states that there is no conflict of interest. closer look into the recycling system and Dr. Peter Samuelsson, KTH, for discussions that helped in making this paper clearer. Open Access This article is licensed under a Creative Commons Attri- bution 4.0 International License, which permits use, sharing, adapta- Funding Open access funding provided by Royal Institute of tion, distribution and reproduction in any medium or format, as long Technology. as you give appropriate credit to the original author(s) and the source, 13  Journal of Sustainable Metallurgy provide a link to the Creative Commons licence, and indicate if changes 18. U.S. Geological Survey (2020) Mineral commodity summaries were made. The images or other third party material in this article are 2020. Reston, VA included in the article's Creative Commons licence, unless indicated 19. OECD (2012) Steelmaking raw materials: market and policy otherwise in a credit line to the material. If material is not included in developments. Paris the article's Creative Commons licence and your intended use is not 20. Carlson AS, Gow CB (1936) Scrap iron and steel industry. 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