Metal: LCM in the Metal Sector
LCA based environmental index for process industries: Model for application in integrated steel plants
Rashtriya Ispat Nigam, India
This paper proposes a method by which principles of LCA and indicator framework are combined to build environmental indicators. A set of 10 environmental indicators [Photo-oxidation, global warming,eutrophication, acidification, ecotoxicity(3types),human toxicity, abiotic depletion,ozone depletion] - are developed that reveal the environmental performance of a process industry in terms of impacts, pressures and performance against minimum and maximum reference environmental flows.
Further a method is developed by which these indicators are aggregated into a ‘synoptic index’ by which the environmental performance of a process industry can be rated on a one to ten scale with industries being motivated to score a ‘perfect ten’
To put this multistage and multilevel method into actual practice, in an integrated steel plant, a software model named ‘SPEED*’ is developed. This method and software model developed for integrated steel plants can be easily emulated by other process industries to have a scientific, uniform, consistent and globally acceptable environmental performance evaluation system.
The process described in the paper provides a solid scientific and technical ground for Type III[ISO 14025, 2006], Environmental labels and declarations by process industries particularly, large scale industries such as Integrated Steel Plants.
* SPEED is not a commercial product
Limits of recycling and "sustainability"
Metals and materials play a pivotal role in society as their properties impart unique functionality to engineered structures and consumer products. Metals are theoretically infinitely recyclable; however, the functionality and design of consumer product complicate recycling due to their ever more complex structures producing un-liberated low grade and complex recyclates. Metallurgical smelting ingenuity, good technology and intelligent use of thermodynamics and transfer processes gets metallurgists and recyclers a far way down the path of creating high recycling rates from a large range of primary concentrates and recyclates. However, the 2nd Law of Thermodynamics teaches us the practical limits of recycling in terms of entropy creation, which is determined by the complexity of the recyclates and hence to the economics of processing/technology and metal/energy recovery. The usual simple accounting type tools do not rise to the challenge. Therefore, a key issue for the creation of “sustainable systems” and hence the minimization of waste (or in other words achieve high recycling rates) is the creation of optimal industrial ecological systems with optimally linked Best Available Techniques (BAT). This must maximize the recovery of materials from ores and recyclates within the boundaries of consumer behaviour, product design/functionality, thermodynamics, legislation, technology and economics. Examples will show how recyclate quality/grade predicted by recycling models affects entropy creation, while also reviewing various published methodologies. This paper shows that simulation models are a prerequisite to designing “sustainable” systems as these can predict recyclate grade/quality/losses/toxicity of streams, the link to entropy and economics and the realization of company ideals and mission statements in this regard. In other words, to dematerialize society requires detail input by engineers, their predictive tools and economic based design approaches to engineer a sustainable future.
Reinventing steel in the auto body – A life cycle perspective.
1Tata Steel Europe, United Kingdom; 2WorldAutoSteel, United States of America; 3World Steel Association, Belgium
As the consensus builds for comprehensive reductions in greenhouse gas (GHG) emissions across international boundaries and industries, there is a growing need to understand the role that materials play in achieving a low carbon society. Active legislation in the automotive industry has focused on the need to reduce tailpipe emissions during the vehicle use phase, and this is often achieved through weight reduction. But weight reduction is only one of the many ways to achieve fuel economy and only makes sense when it is cost effective and achieves the ultimate goal - a reduced vehicle environmen-tal footprint over the complete life cycle.
Studies have demonstrated that weight reduction with alternative materials is a costly route to achiev-ing better fuel economy when compared to electric powertrains, low-carbon fuels and other technical improvements. Through use of its products, the steel industry is helping automakers tackle the problem of rising GHG emissions.
Most automotive structures utilize steel due to its great combination of durability, safety, weight and strength. To demonstrate steel’s effectiveness in achieving environmental goals for vehicle emissions, WorldAutoSteel, a consortium of the world’s largest automotive steel producers, launched a multi-million Euro research initiative called Future Steel Vehicle (FSV). This new initiative is developing non-intuitive, optimized steel auto body concepts that address future emissions regulations and safety re-quirements, with advanced powertrains such as electric, plug-in hybrid and fuel cell systems. The goal of the research is to demonstrate safe, light weight steel bodies for future vehicles that reduce GHG emissions over the entire life cycle.
Life Cycle Assessment (LCA) has been adopted as a means to comprehensively evaluate material choices, and their effect on vehicle life cycle greenhouse gases (GHGs). As vehicles evolve towards electric powertrains and advanced fuel sources, the materials’ contribution to life cycle emissions becomes more relevant, and LCA become even more essential to provide a comprehensive understand-ing of the vehicle’s emissions profile. It is critical to choose materials that not only reduce weight in vehicle structures for use phase savings, but also have a lower environmental burden in the materials manufacturing phase. This will insure that when evaluated from a life cycle perspective, the total vehicle’s life cycle emissions have been reduced.
This presentation will discuss WorldAutoSteel technical programs with a specific focus on the application of LCA tools, aimed at achieving automotive steel solutions that are lighter, safer and reduce life cycle carbon emissions.
Challenges for LCAs of complex systems: The case of a large-scale precious metal refinery plant
1Empa, Switzerland; 2Umicore Precious Metal Refining, Belgium; 3ETH Zurich, Switzerland
The life cycles of precious metals (e.g. platinum group metals) and special metals (e.g. indium and tellurium) are characterized by strong interlinkages of metal streams. This holds true for the primary production, as these metals often are by-products of major metals, but also for secondary production since these metals typically occur in complex mixtures in end-of-life products. Hence, efficient separation and refining processes are playing a key role in i) closing the resource cycle and ii) minimizing environmental impacts early in the supply chain. This contribution presents an LCA for the high-tech industrial metal recovery process of Umicore Precious Metals Refining (Hoboken, Belgium), which recovers 17 different metals from end-of-life consumer products and from by-products of the non-ferrous industry. The Umicore process consists of strongly interlinked sub processes (amongst others smelter, blast furnace, refinery steps), which are characterized by multi-input/multi-output processes, internal loops, changing feed compositions and time lags.
An approach for an attributive gate-to-gate LCA has been developed, in which we especially focus on how to deal with the system characteristics mentioned above in an easy-to-use Excel tool. The approach consists of two steps. First, the system was broken down into over thirty subunits for which real metal flows (including internal loops) were calculated in order to distribute material and energy inputs and outputs over the 17 metals. In this step, different allocation rationales were applied (e.g. mass based or metal price based). The second step comprised the link to LCI data from the ecoinvent database v2.2 respectively to own inventories and calculation of the impacts for different assessment methods.
In our contribution we present LCIA results on the level of one kilogram metal product leaving the plant for different allocation rationales. First results i) show high dependency on allocation choices in the complex system, especially for impacts early in the process flow sheet and ii) indicate the significant impact of the last refining stages, in particular when multiple refining steps are necessary for the production of small tonnages of high-purity metals. Furthermore the challenges in developing an approach for such a complex system will be discussed. The flexibility of the Excel tool proved to be valuable to discuss key LCA issues such as allocation rationales, and also allows for a simple extension with new data as it can be linked to the existing reporting systems in the company.
The benefits of using steel in a multi material society
World Steel Association, Belgium
As the consensus builds for comprehensive reductions in greenhouse gas (GHG) emissions across international boundaries and industries, there is a growing need to understand the role that materials play in achieving a low carbon society. The production and use of these materials are becoming increasingly important as use phase emissions are continually being improved.
Steel has reinvented itself in the form of lighter mass and higher strength grades that enable innovative customer uses in different industries, yet bound together by the common aim of reduced energy and GHG emissions.
Much effort has been focused on the transportation industry, which is responsible for 10% of global anthropogenic GHG emissions. There is a particular need to reduce tailpipe emissions during the driving life of vehicles and lighter vehicles result in reduced fuel consumption and thus reduced use phase emissions. Significant mass reductions in the car body structure can be achieved by replacing conventional steel with Advanced High-Strength Steel. If the body structures of all cars produced worldwide (predicted to be 71 million in 2008) were made of AHSS instead of conventional steel, this would result in total lifetime emissions saving of 156 million tonnes GHGs.
As well as vehicles, shipping and railways are also making use of the properties of steel to help reduce GHG emissions. In the energy sector, steel plays an important role in many renewable energy technologies. High strength frames have enabled the wind turbines to reach greater heights, taking advantage of the greater wind currents with increasing elevation, and thus yielding greater capacity.
In addition, the reusability and recyclability of the steel from all products at the end of their life is a key feature that emphasis the sustainability of steel products. Steel’s re-use and recycling capabilities are profiled in the re-construction of bridge structures, as one specific example. These attributes help steel achieve low life cycle energy and GHG emissions, which can further be explored using LCA models.
Ensuring the whole of the products life cycle is considered throughout a material decision making exercise will ensure that the most appropriate material is chosen for the specific application
Assessing metals recycling performance between effectiveness and efficiency by analyzing concentration vs. dissipation and environmental impacts
University of Bremen, Germany
Recycling metals is essentially a process of concentrating relevant metals into specific target streams. However, in most cases concentration comes along with dissipation: certain metals are unintentionally dissipated into other metals streams, leading to metallurgically sub-optimal combinations while other metals are lost into waste or by-products (e.g. slag). With the ever increasing complexity of products, the mixtures prevalent in recycling operations become more complex, too, and dissipation of critical or scarce metals into other material streams becomes a major issue. In order to fully assess recycling operations, it thus seems necessary to look beyond simple yield ratios of certain focus metals. Instead the effectiveness of the recycling operation should include a measure of the overall concentration, or dissipation respectively, for all of the relevant metals in a recycling stream. The metal specific effectiveness can then be assessed by looking at the concentration of that metal across all output flows using the measure of statistical entropy. The general effectiveness of the recycling operation is then the sum of all metal specific concentration (or dissipation). The efficiency on the other hand, must encompass more than just technical parameters. An efficient operation should also minimize the use of resources and the impacts on the environment. For resource consumption there are really no generally established measures, but cumulative energy demand and entropy production have been proven to be applicable and meaningful. For environmental impacts the LCA methodology provides the necessary categories and characterization factors.
Here we will present a combination of the above mentioned methodologies applied to two different steel dust operations. The results show that although the processes are successful in concentrating certain metals (e.g. Fe and Zn), the increase in overall concentration is in some cases only in the order of 10%. Further, there is substantial dissipation for other relevant metals (e.g. Mo, Mn, Ni). The environmental impacts of the processes and their resource consumption are summarized to allow for a more complete evaluation of the processes efficiency.