THE ‘P’ WORD – Plastic in the UK: practical and pervasive … but problematic

Plastics are ubiquitous in modern society, owing to their usefulness, durability and how cheap and easy they are to produce. This makes plastics both a blessing and a curse. We manufacture a myriad of plastic materials, used in countless consumer products, which are highly valued by society. Everything from milk bottles to window frames, from sunglasses to face masks, contains plastic. Plastics are pervasive due to their practicality and profitability. And yet, plastics have a problem. The making, use and disposal of plastics creates challenging pollution issues. Significant CO2e (carbon dioxide equivalent) emissions are released across the life-cycle of plastic products and poor disposal means plastic makes its way into our waterways and oceans, creating serious environmental impacts. Fixing this problem is not simple. Even finding good data, on the production, use, disposal and recycling of plastics is challenging. This report tackles this data problem by mapping plastic flows through UK society, collating data from disparate sources on the production, use, disposal and recovery of plastics. With the resulting map of UK plastic flows, we can understand the latest trends in plastics use and identify opportunities for reducing the impacts of plastics in the future. We found that the way we have been disposing of plastics plays a critical role in two serious environmental impacts: greenhouse gas emissions and plastic ocean pollution. These problems arise because plastics are not circular in the UK. Less than 3% of plastics consumed are made of UK recycled plastics, and the vast majority of waste ends up being incinerated, landfilled or exported. Without any action this problem will get worse, as we will generate more plastic waste in coming decades from all the products made of plastic that we have been accumulating. Recycling more plastics in the UK could reduce incineration emissions, avoid mismanagement of exported waste and replace the need for the production of new plastics. However, current UK recycling capacity is only 12% of waste collected, and this is hampering the benefits recycling could provide. There are several other actions we should take, such as reducing excessive use of plastic packaging, and reducing the range of polymers used in various products to improve recycling yields. These should be combined with improved practices in the petrochemical industry, and enhanced reuse and recycling of plastics to achieve a meaningful reduction in greenhouse gas emissions.Research in this report is funded by UKRI as part of CirPlas: The Cambridge Creative Circular Plastics Centre

Finding the most efficient way to remove residual copper from steel scrap

The supply of end-of-life steel scrap is growing, but residual copper reduces its value. Once copper attaches during hammer shredding, no commercial process beyond hand-picking exists to extract it, yet high-value flat products require less than 0.1wt% copper to avoid metallurgical problems. Various techniques for copper separation have been explored in laboratory trials, but as yet no attempt has been made to provide an integrated assessment of all options. Therefore, for the first time a framework is proposed to define the full range of separation routes and evaluate their potential to remove copper, while estimating their energy and material input requirements. The thermodynamic, kinetic and technological constraints of the various techniques are analyzed to show that copper could be removed to below 0.1wt% with relatively low energy and material consumption. Higher-density shredding allows for greater physical separation, but requires proper incentivization. Vacuum distillation could be viable with a reactor that minimizes radiation heat losses. High-temperature solid scrap pre-treatments would be less energy intensive than melt treatments, but their efficacy with typical shredded scrap is yet unconfirmed. The framework developed here can be applied to other impurity-base metal systems to coordinate process innovation as the scrap supply expands.EPSRC, Cambridge Trust

Scrap, carbon and cost savings from the adoption of flexible nested blanking

Abstract: Steel accounts for 6% of anthropogenic CO2 emissions, most of which arises during steelmaking rather than downstream manufacturing. While improving efficiency in steelmaking has received a great deal of attention, improving material yield downstream can have a substantial impact and has received comparatively less attention. In this paper, we explore the conditions required for manufacturers to switch to a more materially efficient process, reducing demand for steel and thus reducing emissions without reducing the supply of goods to consumers. Furthermore, we present an alternative processing route where parts can be cut in flexible arrangements to take advantage of optimal nesting across multiple part geometries. For the first time, we determine the potential savings that flexible nested blanking of parts could achieve by calculating the potential for grouping orders with tolerably similar thickness, strengths, ductility and corrosion-resistance. We found that 1080 kt of CO2 and 710 kt of steel worth €430M could be saved each year if this scheme was adopted across all European flat steelmills serving the automotive sector

Preventing Wetting Between Liquid Copper and Solid Steel: A Simple Extraction Technique

Abstract: Copper contamination of end-of-life steel scrap is the main barrier to high-quality recycling. Preferential melting of copper from solid steel scrap is a potential extraction technique, which could be integrated into conventional scrap re-melting with little additional energy. However, previous investigations show removal of liquid copper is limited by its adherence to solid scrap. Preventing wetting between liquid copper and steel is essential to enable separation. The carbon content of steel, initial surface oxidation, and applied coatings effect wetting behavior, but have not been systematically studied. In this study, the individual and combined effects of these parameters on wetting behavior in an inert gaseous environment are observed with a heating microscope. Carbon content appears to be the most significant factor: blistering of the oxide scale on medium-carbon steels causes liquid copper to flow rapidly between the oxide and steel substrate. Liquid copper exhibited a stable droplet on low-carbon steel, regardless of the initial level of oxidation. The tested coatings did not consistently improve nonwetting behavior, but impaired the connection between the scale and steel substrate. This study confirms the potential of the preferential melting technique, but further investigation is needed to determine the most robust process conditions to handle diverse, fragmented scrap at an industrial scale

Material Flow Analysis with Multiple Material Characteristics to Assess the Potential for Flat Steel Prompt Scrap Prevention and Diversion without Remelting.

Thirty-two percent of the liquid metal used to make flat steel products in Europe does not end up in a final product. Sixty percent of this material is instead scrapped during manufacturing and the remainder during fabrication of finished steel products. Although this scrap is collected and recycled, remelting this scrap requires approximately 2 MWh/t, but some of this material could instead be diverted for use in other applications without remelting. However, this diversion depends not just on the mass of scrapped steel but also on its material characteristics. To enhance our understanding of the potential for such scrap diversion, this paper presents a novel material flow analysis of flat steel produced in Europe in 2013. This analysis considers the flow of steel characterized not only by mass but, for the first time, also by grade, thickness, and coating. The results show that thin-gauge galvanized drawing steel is the most commonly demanded steel grade across the industry, and most scrap of this grade is generated by the automotive industry. There are thus potential opportunities for preventing and diverting scrap of this grade. We discuss the role of the geometric compatibility of parts and propose tessellating blanks for various car manufacturers in the same coil of steel to increase the utilization rates of steel.EPSR

The influence of UK emissions reduction targets on the emissions of the global steel industry

The steel industry is the world's largest industrial source of CO2 emissions. Recent UK economic policies have led to reduced domestic steel production giving an apparent reduction in national emissions. However, demand for goods made from steel has not reduced. Emissions have thus been transferred not reduced and implementation of UK climate policies may in future expand this 'carbon leakage.' This paper explores how future UK demand for goods made from steel might be supplied while satisfying national climate policies, and how this will influence global CO2 emissions. Current flows and stocks of steel are estimated from existing databases. Evidence from other developed economies suggests that per capita stocks are tending towards a saturation level so future demand is forecast from population growth and the expected rate of replacement of a stable stock. The carbon intensities of five different steel-making routes are used to predict the allowed scale of future domestic steel production within the industrial emissions allowances set in four energy pathways defined by the UK Government. The remaining requirement for steel must be sourced offshore and the associated emissions are predicted, to give an estimate of the global emissions arising from final demand in the UK. The results show that current UK climate strategy may have a limited effect in reducing the CO2 emissions of the global steel industry, unless the UK shifts towards producing more of its own steel products with domestic secondary steel-making. This option would also increase the security of UK supply and support an expansion of UK manufacturing.</p

How much cement can we do without? Lessons from cement material flows in the UK

Cement manufacture is responsible for 5-7% of world CO2emissions. Cement is primarily used in concrete, the most used material on the planet and a critical part of any analysis of emissions reduction strategy. To estimate the potential for reducing demand, this work analyses material flow in the cement industry, using the UK in 2014 as a case study. Combining published data, analytic assumptions, and interviews we estimated the material flow of cement from the production to a breakdown of its use in applications. Having broken down the demand for cement into 25 applications, multiple material efficiency techniques were considered: substituting cement for calcined clay and limestone, reducing the cement content of concrete, post-tensioning floor slabs, using more precast building elements, reducing construction waste, and reducing the overdesign in construction. We produce a final estimate of the total reduction in emissions achievable from material efficiency: 51.3%. Due to overlap and interactions between the methods, the attribution of the carbon abatement depends on the sequence of application. In this analysis, we have applied the reduction of overdesign last, because it is independent of the others, and would require a cultural change. We show then that cement demand from floors, repairs and maintenance, concrete beams, and applications within the transport sector should be targeted. The substitution of cement with calcined clay and limestone has the biggest potential to reduce cement demand (27%) and carbon emissions in the UK. Reducing the amount of cement in concrete has the next highest potential (10%), followed by post-tensioning floor slabs (3%).NMZL/112 RG82144 EPSRC ref EP/N02351X/

The influence of UK emissions reduction targets on the emissions of the global steel industry

This is the author accepted manuscript. It is currently embargoed pending publication.The steel industry is the world?s largest industrial source of CO2 emissions. Recent UK economic policies have led to reduced domestic steel production giving an apparent reduction in national emissions. However, demand for goods made from steel has not reduced. Emissions have thus been transferred not reduced and implementation of UK climate policies may in future expand this ?carbon leakage.? This paper explores how future UK demand for goods made from steel might be supplied while satisfying national climate policies, and how this will influence global CO2 emissions. Current flows and stocks of steel are estimated from existing databases. Evidence from other developed economies suggests that per capita stocks are tending towards a saturation level so future demand is forecast from population growth and the expected rate of replacement of a stable stock. The carbon intensities of five different steel-making routes are used to predict the allowed scale of future domestic steel production within the industrial emissions allowances set in four energy pathways defined by the UK Government. The remaining requirement for steel must be sourced offshore and the associated emissions are predicted, to give an estimate of the global emissions arising from final demand in the UK. The results show that current UK climate strategy may have a limited effect in reducing the CO2 emissions of the global steel industry, unless the UK shifts towards producing more of its own steel products with domestic secondary steel-making. This option would also increase the security of UK supply and support an expansion of UK manufacturing.This work was supported by EPSRC, grant references EP/K011774/1 and EP/K039326/1

How Will Copper Contamination Constrain Future Global Steel Recycling?

Copper in steel causes metallurgical problems, but is pervasive in end-of-life scrap and cannot currently be removed commercially once in the melt. Contamination can be managed to an extent by globally trading scrap for use in tolerant applications and dilution with primary iron sources. However, the viability of long-term strategies can only be evaluated with a complete characterization of copper in the global steel system and this is presented in this paper. The copper concentration of flows along the 2008 steel supply chain is estimated from a survey of literature data and compared with estimates of the maximum concentration that can be tolerated in steel products. Estimates of final steel demand and scrap supply by sector are taken from a global stock-saturation model to determine when the amount of copper in the steel cycle will exceed that which can be tolerated. Best estimates show that quantities of copper arising from conventional scrap preparation can be managed in the global steel system until 2050 assuming perfectly coordinated trade and extensive dilution, but this strategy will become increasingly impractical. Technical and policy interventions along the supply chain are presented to close product loops before this global constraint.K.D. is funded by a Cambridge Trust scholarship. A.S. and J.A. are funded by EPSRC, grant reference EP/N02351X/1

Material Stock Demographics: Cars in Great Britain.

Recent literature on material flow analysis has been focused on quantitative characterization of past material flows. Fewer analyses exist on past and prospective quantification of stocks of materials in-use. Some of these analyses explore the composition of products' stocks, but a focus on the characterization of material stocks and its relation with service delivery is often neglected. We propose the use of the methods of human demography to characterize material stocks, defined herein as stock demographics, exploring the insights that this approach could provide for the sustainable management of materials. We exemplify an application of stock demographics by characterizing the composition and service delivery of iron, steel, and aluminum stocks of cars in Great Britain, 2002-2012. The results show that in this period the stock has become heavier, it is traveling less, and it is idle for more time. The visualization of material stocks' dynamics demonstrates the pace of product replacement as a function of its usefulness and enables the formulation of policy interventions and the exploration of future trends.This work was supported by EPSRC, grant reference EP/N02351X/1.This is the final version of the article. It first appeared from the American Chemical Society via https://doi.org/10.1021/acs.est.5b0501