Dynamic Material Flow Analysis Research Articles

Exploration of a new path to reduce air pollutant emissions in the sinter plant of steelworks

Tremendous air pollutant emissions have become an obstacle to curbing the green development of the steel industry. How to minimize the air pollutant emissions? In this study, the gas flow network model of the sinter plant was first established by using the dynamic material flow analysis method. Moreover, based on the circulation theory, the waste gas recycling of the sinter plant was constructed and the gas flow network model was optimized. Therefore, the waste gas and air pollutant emissions can be reduced. The results showed that the actual air consumption in the sinter plant was 79.40% higher than the theoretical value, with a serious waste of air resources. After waste gas recycling, the waste gas emissions from the production of per ton sinter were reduced by 49.54%, and the emissions of SO2, NOX, and soot were reduced by 4.5 g, 9.1 g, and 1.8 g, respectively.

Dynamic material flow analysis of titanium sponge in China: 2000–2019

Titanium is vital to daily life and national security. And titanium sponge is the most important raw material in the production of titanium industry. Therefore, understanding the material cycle flow of titanium sponge in China can help to understand the future use of titanium at global and national levels. This paper traces titanium sponge flows, stocks, and loss in China using dynamic material flow analysis from a life cycle perspective from 2000 to 2019. Combined with the analysis of Shared Socioeconomic Pathways (SSPs) scenarios, we forecast potential changes characteristics of titanium sponge demand in the future. We find that firstly, due to the difficulty of critical technologies in the production of aviation-grade titanium sponge, more than 70% of high-quality titanium sponge is heavily dependent on imports. Secondly, many middle to low-end fields use titanium materials, and the social stock in the chemical industry is relatively large, accounting for 47%. As China's economic development rate increases, the demand for titanium sponge may increase by 150%–250% from 2020 to 2060. In addition, the demand for middle to high-end areas will be a crucial area in the future. Relevant policy measures should pay more attention to the production, processing, and recycling stages of titanium sponge to promote the healthy and sustainable development of titanium sponge in the future. Notably, the scenario results reveal key opportunities and demand trends for developing titanium sponge in the future. It is extremely important to the Chinese and global titanium industry.

Sector‐specific scenarios for future stocks and flows of aluminum: An analysis based on shared socioeconomic pathways

Aluminum is an energy-intensive material that is typically used as an alloy. The environmental impacts caused by its production can potentially be spread out over multiple uses through repeated recycling loops. However, inter-alloy contamination can limit the circularity of aluminum, which highlights the importance of analyzing prospective stock dynamics of aluminum at an alloy and alloying element level to inform a more sustainable management of this resource. A dynamic material flow analysis (MFA) of aluminum alloys was developed in line with the shared socioeconomic pathways (SSP) framework to generate consistent scenarios of the evolution of aluminum stocks and flows from 2015 to 2100 covering 11 economic sectors in 5 world regions. A sector-specific and bottom-up modeling approach was developed. Results show no saturation of global stock per capita before 2100, reaching a range between 200 and 400 kg per capita according to different socioeconomic scenarios. For the business-as-usual scenario, the global annual inflow rises to 100 Mt in 2050 and peaks at 130 Mt in 2090, showing a saturation in total stock. Electricity-sector demand has the highest relative growth over the century, while building and construction demand saturates and decreases from 2090. No major mismatch between inflows and outflows of aluminum alloy is observed. This means that with appropriate dismantling and sorting, changes in alloy demand would not limit the implementation of a closed-loop aluminum industry. This study demonstrates the advantages of combining detailed MFAs and SSPs, both for greater consistency in circular economy modeling and for furthering scenario development efforts. This article met the requirements for a gold-gold JIE data openness badge described at http://jie.click/badges

Coupled Dynamic Material Flow, Multimedia Environmental Model, and Ecological Risk Analysis for Chemical Management: A Di(2-ethylhexhyl) Phthalate Case in China.

Di(2-ethylhexhyl) phthalate (DEHP) is a widely used plasticizer that has adverse effects on ecosystems and human health. However, data about its stocks, flows, emission rates, as well as ecological risks are generally unknown in China, one of the world's largest producers of chemicals including DEHP, limiting sound management of chemicals. Herein, dynamic material flow analysis, coupled with a multimedia environmental model and ecological risk analysis, was performed to fill the data gap about DEHP in China mainland from 1956 to 2020. Results indicate that the in-use stocks of DEHP increased from 6.54 × 106 kg in 1956 to 8.40 × 109 kg in 2020. With growth in the emission rates, DEHP concentrations in air, soil, water, and sediment kept increasing from 1956 to 2010, which declined after 2010 and regrew after 2015. Sediment was a main sink of DEHP with the highest ecological risk quotient of >10 after 1999, necessitating measures for controlling the risk, for example, technology innovation to reduce DEHP emission rates, and substitution of DEHP with low-toxic alternatives. The coupled models that connect socio-economic data with ecological risk output may provide a systematic methodology for verification of the data necessary for risk control of chemicals.

Investigating lanthanum flows and stocks in China: A dynamic material flow analysis

Rare earth elements (REEs) are irreplaceable in modern societies due to rising demands, especially amidst the urgent energy transition background. As the first ordered and the second most produced REE, lanthanum is widely used in conventional fields. This study investigates lanthanum flows and stocks in China by conducting a dynamic material flow analysis for the period of 2011–2020. The main results are that: 1) The registered quota production of La from 2011 to 2020 is 235,306 tons, and net La import accounts for 24.79% of the total input flows. 2) The accumulative surplus of La under the circumstance of quota production is 35,929 tons, with the in-use stock being 148,556 tons. 3) China is the net La importer of concentrates (133,769 tons) and net La exporter of primary, intermediate, and final products. The net La export is mainly in the form of primary products (76.27%). 4) The consumption of La increases steadily from 21,708 tons in 2011 to 31,580 tons in 2020. The top 5 applications are FCC (45.58%), rechargeable NiHM battery (16.97%), alloy (10.77%), optical glass (8.95%), and polishing powder (4.86%). Policy suggestions include expanding the demand market, adjusting the quota production system based on REEs, and improving investment in and guidance for R&D.

Global Resource Circularity for Lithium-Ion Batteries up to 2050: Traction and Stationary Use

The use of the lithium-ion battery (LIB) in both traction and stationary applications has become ubiquitous. It is essential that retired LIBs are wisely treated, with a basis in the concept of the circular economy, to mitigate primary resource use. A closed-loop repurposing and recycling treatment is required. Thus, using the concept of total material requirement as an indicator of natural resource use based on mining activity, a dynamic material flow analysis was executed considering the degradation of the battery, its lifespan, and demand patterns under several scenarios. Then, the effect of circularity on the savings in global natural resource use involved across the entire lifecycles of LIBs was evaluated. It was found that the global resource use for LIBs will increase to between 10 and 48 Gt in 2050. Circularity has the potential to contribute to an 8–44% reduction in the global resource use associated with LIBs in 2050. It was also found that a longer lifespan in the years leading up to 2050 would have a greater impact on the reduction of resource use for LIBs, despite the lower effectiveness of circularity, because it would reduce the demand for LIBs.

The dynamic stock-flow and driving force analysis of the building metal and non-metal resources at a city scale: An empirical study in Macao

The construction industry is often seen as one of the most dynamic sectors, referring to large resource consumption and waste generation, and has grown rapidly in the last few decades. Under the background of “Zero Waste City,” it will be essential to understand the metabolic stock-flow process and the driving forces of urban building resources. By combining the top-down and bottom-up methods, this study establishes a dynamic material flow analysis (MFA) model to clarify the stock and flow characteristics, driving forces, and future trends of urban building resources in Macao China. The result shows that the total material stock increased from 14.13 million metric tons (Mt) in 1999 to 32.75 Mt in 2018, with an average annual growth rate of 4.29%. In 2018, metal resources accounted for 10.73% of the total building stock (steel and aluminum resources accounted for 10.30% and 0.43%, respectively), and non-metal resources accounted for 89.27%. The construction demolition waste (CD&W) increased from 0.02 Mt in 1999 to 0.69 Mt in 2018. Among metal materials, steel and aluminum accounted for 7.11% and 0.4%, respectively. The demolition quantity of metal resources increased from 1.6 kilotons (kt) in 1999 to 51.8 kt in 2018 (an average annual increase of 1.59%) and peaked at 95.2 kt in 2007. The IPAT (I-environment impact; P-population factor; A-social affluence factor; T-technology factor) method results show that the economy and population are always the driving force for urban building resources stock in Macao China. The scenario analysis shows that, by 2035, the maximum stock of urban building materials in Macao will reach 65.19 Mt, about twice in 2018. The results are expected to provide a theoretical basis for establishing scientific resource management and recycling systems for urban buildings.

Improving aluminium resource efficiency in China: Based upon material flow analysis and entropy analysis

Aluminium is one widely used metal that plays an important role in China's industrial and economic development. The life cycles of aluminium products involve high energy inputs, intensive material consumption and heavy environmental emissions. China has released its ambitious climate change targets, namely reaching carbon peak in 2030 and achieving carbon neutrality in 2060. It is therefore urgent to take appropriate actions to reduce the overall greenhouse gas emissions from aluminium production and increase resource efficiency along the entire aluminium life cycle. Under such circumstances, this study aims to explore China's aluminium recycling potential through dynamic material flow analysis for the period of 2000–2019, covering its whole life cycle and including relevant international trade activities. An entropy analysis method is also applied to identify optimal pathways to improve aluminum resource efficiency and circularity. Results indicate that China has experienced fast growth of aluminum production and consumption during the last two decades, with its output of primary aluminium increasing from 4.18 Mt in 2000 to 35.11 Mt in 2019 and its aluminium consumption increasing from 2.99 Mt in 2000 to 32.5 Mt in 2019. Such rapid growth has resulted in significant environmental impacts. For instance, environmental loss of aluminium at the production stage accounted for 46% of the total loss throughout its entire life cycle in 2000, while such a rate increased to 69% in 2019. As such, entropy analysis results reflect that at the stage of waste management, the relative entropy of aluminium is rising, which indicates that any pollutants discharged into the environment will cause significant damage. Scenarios analysis results further help to identify the optimal pathway of aluminium metabolism system. Finally, several policy recommendations are proposed to improve the overall aluminium resource efficiency.

Uncovering the Key Features of Dysprosium Flows and Stocks in China.

Dysprosium (Dy) is a critical rare earth element and plays an indispensable role in clean energy technologies, such as wind turbines and electric vehicles. However, its flows and stocks in the whole life cycle and potential barriers to sustainable supply remain unclear, although the demand for Dy is increasing and its reserves are limited. This study aims to track China's Dy cycle for the period of 2000 to 2019 by employing dynamic material flow analysis. The results show that (1) demand for Dy had increased by 117-fold, with an accumulative use of 37,317 tons, of which 50% was obtained from illegal mining; (2) 33% of the overall Dy resource was used in wind turbines in 2019, followed by air conditioners and electric vehicles (22 and 17%, respectively); (3) China's net Dy export had increased by 10-fold from 2000 to 2019, with Dy concentrates and final products being the dominant import and export products, respectively. Illegal mining, inadequate recycling policies, and limited Dy supply sources are potential barriers influencing sustainable Dy supply.

Estimation and prediction of plastic losses to the environment in China from 1950 to 2050

The widespread use of plastics has resulted in serious environmental problems. Large amounts of plastic waste are released into the environment. A dynamic material flow analysis model was employed to estimate the plastic losses to the environment in China, distributed into different polymers, sources, environmental media, and lifecycle processes. Microplastic and macroplastic losses entering the environment were 352.1 kt/a and 12.7 Mt/a, of which polyethylene terephthalate (PET) (29.1% and 32.2%) accounted for the highest proportion, and the loss stocks in the ocean and soil were 4.0 and 173.7 Mt in 2020. The main microplastic and macroplastic losses were associated with the release during the use stage and mismanaged waste management. Considering the impacts from reducing plastic losses, the losses and loss stocks in 2050 would be approximately twice and four times those in 2020, respectively. The results of this study provide scientific support for reducing plastic pollution.

Dynamic material flow analysis of silicon photovoltaic modules to support a circular economy transition

AbstractSolar photovoltaics (PV) are the fastest growing renewable energy technologies for clean, cheap, and sustainable electricity generation. To prepare for rapid scale‐up, the PV industry needs to project material requirements to build out all aspects of the supply chain appropriately and plan to handle large volumes of module waste. Impacts of deploying different material circularity strategies to reduce waste and conserve primary resources need to be quantified to inform sustainable material management. Here, we introduce the photovoltaic dynamic material flow analysis (PV DMFA) model based on PV electricity generation. The model quantifies material flows and stocks in the cradle‐to‐cradle life cycles of utility‐scale c‐Si PV systems in the United States through 2100. We present case studies for solar flat glass and aluminum frame materials under various scenarios to project the impacts of PV performance, reliability, and processing parameters, material circularity strategies, and module design shifts. In the absence of circularity measures, ~100 million MT of flat glass and ~12 million MT of aluminum would be needed for PV installations by 2100 to meet projected growth in domestic utility PV demand to nearly 1000 TWh in 2100. With optimistic but feasible improvements in efficiency, reliability, and circularity, material intensity and waste could be reduced by nearly 50%. Efficient module collection, minimally intrusive recycling, and careful scrap handling and cleaning could improve material circularity in the PV value chain. This model serves as a sustainability data support tool that may aid in the circular economy transition for PV systems.

Life-cycle greenhouse gas emissions and the associated carbon-peak strategies for PS, PVC, and ABS plastics in China

The plastic industry is a high carbon emission industry in China. Previous studies mainly focused on the flows and stocks of polystyrene (PS), polyvinyl chloride (PVC), and acrylonitrile-butadiene-styrene (ABS) plastics. However, there is limited detailed information on the GHG emissions of PS, PVC, and ABS in China and the key paths of carbon peak in 2030. Therefore, we established the GHG accounting model of PS, PVC, and ABS based on dynamic material flow analysis and life cycle assessment, and further analyzed the carbon peak path and strategy in 2030. The results show that the main source of GHG is the production and manufacturing stages. Notably, the key paths of GHG emissions are the manufacturing process of PS STP&C and foam plastics, PVC film and STP&C, and ABS STP&C. Moreover, the cumulative GHG emissions of these plastics reached 230.34, 677.43, 143.12 Tg CO2e in 2007-2017, respectively. From 2007 to 2017, the trends of GHG emissions from the PS, PVC, and ABS had their characteristics. PVC had the largest GHG emissions. Different from PVC and ABS, GHG emissions from PS showed a trend of slow rise and then slow decline in this period. According to the current trend, the life-cycle GHG emissions of PS, PVC, and ABS would not reach the carbon peak in 2030. Under some mitigation strategies, the carbon peak would be achieved before 2030. This study clarifies the main sources of life-cycle GHG emissions of these plastics, and reveals the path and strategy of carbon peak in 2030.

Assessing samarium resource efficiency in China: A dynamic material flow analysis

Samarium is one rare earth element that plays a vital role in the emerging high-tech sectors. However, few studies have been conducted to investigate this element. This study aims to investigate samarium flows and stocks in China for the period of 2011–2020 through dynamic material flow analysis. Also, a linear programming method is employed to predict future samarium demand and supply until 2035. The results show that the annual demand for samarium significantly increased from 162 tons in 2011 to 726 tons in 2020, while its supply remained stable with an annual amount of 600 tons. Due to this supply-demand imbalance, the total samarium surplus decreased to 1140 tons in 2020. Without any intervention policies, samarium resource will be depleted before 2025. From a trade perspective, China has exported more samarium resources to other countries due to its abundant reserves, which may influence its domestic supply. Finally, several policy recommendations are proposed to improve the overall samarium resource efficiency, including economic instruments, technological support, and the implementation of circular economy.

Life cycle assessment of urban uses of biochar and case study in Uppsala, Sweden

Biochar is a material derived from biomass pyrolysis that is used in urban applications. The environmental impacts of new biochar products have however not been assessed. Here, the life cycle assessments of 5 biochar products (tree planting, green roofs, landscaping soil, charcrete, and biofilm carrier) were performed for 7 biochar supply-chains in 2 energy contexts. The biochar products were benchmarked against reference products and oxidative use of biochar for steel production. Biochar demand was then estimated, using dynamic material flow analysis, for a new city district in Uppsala, Sweden. In a decarbonised energy system and with high biochar stability, all biochar products showed better climate performance than the reference products, and most applications outperformed biomass use for decarbonising steel production. The climate benefits of using biochar ranged from − 1.4 to − 0.11 tonne CO2-eq tonne−1 biochar in a decarbonised energy system. In other environmental impact categories, biochar products had either higher or lower impacts than the reference products, depending on biochar supply chain and material substituted, with trade-offs between sectors and impact categories. However, several use-phase effects of biochar were not included in the assessment due to knowledge limitations. In Uppsala’s new district, estimated biochar demand was around 1700 m3 year−1 during the 25 years of construction. By 2100, 23% of this biochar accumulated in landfill, raising questions about end-of-life management of biochar-containing products. Overall, in a post-fossil economy, biochar can be a carbon dioxide removal technology with benefits, but biochar applications must be designed to maximise co-benefits.

Toward carbon neutrality: Uncovering constraints on critical minerals in the Chinese power system

China has set up its ambitious carbon neutrality target, which mainly relies on significant energy-related carbon emissions reduction. As the largest important contributing sector, power sector must achieve energy transition, in which critical minerals will play an essential role. However, the potential supply and demand for these minerals are uncertain. This study aims to predict the cumulative demand for critical minerals in the power sector under different scenarios via dynamic material flow analysis (DMFA), including total demands, supplies and production capacities of different minerals. Then, these critical minerals are categorized into superior and scarce resources for further analysis so that more detailed results can be obtained. Results present that the total minerals supply will not meet the total minerals demand (74260 kt) in 2060. Serious resource shortages will occur for several key minerals, such as Cr, Cu, Mn, Ag, Te, Ga, and Co. In addition, the demand for renewable energy will be nearly fifty times higher than that of fossil fuels energy, implying more diversified demands for various minerals. Finally, several policy recommendations are proposed to help improve the overall resource efficiency, such as strategic reserves, material substitutions, and circular economy.

Behind of the criticality for rare earth elements: Surplus of China’s yttrium

Yttrium (Y), mainly using for phosphors, is considered as one of critical rare earth elements (REEs) in several countries. However, its flows and stocks in the whole life and fundamental supply and demand are still unclear, leading to that it is difficult to measure its criticality. This study aims to estimate China’s Y flows and stocks for the period of 2000–2019 by applying dynamic material flow analysis. The results indicate that: (1) 146 kilo tons (kt) Y concentrates were flowed into anthropogenic system, and 33 kt Y were used in fluorescent lights, accounting for 80% of the total final use; (2) Y supply had been imbalanced with its demand, generating 39 kt Y surplus during the study period; (3) accumulative net Y export was 55 kt, in which primary products and final products accounted for 84% of the total export. Finally, three policy implications are proposed, including dynamic and specific list of individual critical REE, emergent Y recycling plans, and comprehensive stockpile policies.

Assessing recycling, displacement, and environmental impacts using an economics‐informed material system model

Material production drives an increasingly large fraction of CO2-equivalent emissions. Material efficiency strategies such as recycling serve to reduce these emissions. Current analyses of the effectiveness of such strategies do not include economically induced rebound effects, overestimating the associated environmental benefits. We present a dynamic supply chain simulation model for copper through 2040 incorporating inventory-driven price evolution, dynamic material flow analysis, and life cycle assessment alongside mine-level economic evaluation of opening, closing, and production decisions. We show that permanent increases in recycling displace ∼0.5 kilotonnes mine production per kilotonne increase in scrap supply on average, while short-lived recycling policies can lead to increased mine production. We find evidence for supply chain evolution pathways minimizing the rebound effect and maximizing displacement of primary material, where increasing refined copper and concentrate prices and decreasing demand serve to decrease mining. However, even in best-case scrap supply scenarios, CO2e emissions from the copper sector increase 25% by 2040 relative to 2018 due to demand growth, ore grade decline, and lower displacement among large scrap supply changes. With implementation of best available technologies across all supply chain components, we estimated 2040 CO2e emissions 10% below those of 2018 are possible, though still well short of 2°C emissions targets. We find increasing mine taxes and royalties, reclamation costs, and exploration costs further increase displacement, as does the inclusion of scrap prices on major futures exchanges. These results highlight the importance of considering the economics of the entire material supply chain when implementing material efficiency strategies. This article met the requirements for a Gold-Gold JIE data openness badge described at http://jie.click/badges.

Forecasting quantities of critical raw materials in obsolete feature and smart phones in Greece: A path to circular economy

Mobile phones represent an ever-increasing waste stream due to the increasing ownership and short lifetime. In particular, smartphones are among the most valuable e-waste because of their extremely high content of numerous key metals, specifically in the printed circuit board and magnets. As feature and smart phones contain different key metals at different concentrations, it is important to distinguish between the two phone types to make reliable estimations. This study presents estimations of obsolete mobile phones quantities, generated in Greece in 1995–2035 and the Critical Raw Materials (CRMs) and Precious Metals (PMs) embedded in them, making a differentiation between feature and smart phones. The dynamic material flow analysis is adopted, the lifespan is evaluated by the Weibull distribution and future sales are predicted by the logistic model incorporating phases of growth, saturation and decline. Then, the future wastes are predicted by the Market Supply A model. According to the results, the generation of obsolete smartphones is constantly increasing, while the waste flows of feature phones are declining. Efficient recycling of obsolete phones (1995–2020) can cover the demand for key metals (Au, Pd, Co) in the new smartphones for more than a decade in Greece, while the demand for Ag, Sb, Si, Zn, Be, Ti will be covered for more than 15 years. In 2020–2035 the accumulated amounts of CRMs and PMs, only from the smartphone waste, will be 1292.02 and 14.11 tonnes, respectively. The findings can contribute to the management of a valuable e-waste category closing the loop between resources-products-wastes.

A dynamic material flow analysis of the global anthropogenic zinc cycle: Providing a quantitative basis for circularity discussions

Accurate and up-to-date accounting of material stocks and flows is an important quantitative basis for current Circular Economy discussions. Herein, we describe the application of dynamic material flow analysis to model the global anthropogenic zinc cycle in the period 1900 to 2019 and yielding results for 1980–2019. Results show that approx. 250 Mt of zinc were globally in use in 2019, which equals the 19-fold mine production of the same year. Between 2010 and 2019, 34 Mt of Zn in fabrication and manufacturing scrap (new scrap) and 77 Mt of Zn in end-of-life products (old scrap) became available for recycling. Of these, approx. 52 Mt of zinc were recycled, the majority (42 Mt) via direct reuse in production processes and a smaller part via refineries. The recycling input rate of 29% and the end-of-life recycling rate of 27%, both averaged between 2010 and 2019, point to opportunities for increased circularity. Nearly half of the overall cycle losses occur in the end-of-life waste collection, so that measures for more circularity should be taken at this lifecycle phase. Further considerable zinc losses arise within steel recycling, where zinc transfers to steel mill dusts. These dusts are more and more used for zinc recycling, but still underutilized. Despite existing recycling challenges, the overall modeling results show that recycling flows and recycling rates rose in the last decade.

Dynamic material flow analysis of aluminum from automobiles in China during 2000–2050 for standardized recycling management

Aluminum has been playing a significant role in the development of global vehicles light-weighting for mass reduction and energy conservation. Owing to the limited lifespan of automobiles, the huge wave of obsolete automotive aluminum (OAA) has come. China, the country with the largest vehicles ownership in the world, will be facing with the OAA boom as well inevitably. However, the typical statistics of China’ automotive aluminum are absent and the waste management of OAA is disorganized which might result in resource inefficiency. Herein, we build a model based on dynamic material analysis to figure out the historical data of China's OAA and forecast the future trend from life cycle perspective (mining, production, usage, waste, recycle), followed by proposing a standard system to promote the OAA standardized recycling management. We found that: During 2000 to 2050, 1) around 75% of China's OAA were not recycled annually, or even being recycled, most of which were downgraded into less valuable products; 2) China's annual OAA would peak around 2035 while the accumulated amount of recycled OAA in China would reach 14–130 million tons in different scenarios. If all recycled, approximately 44–406 million tons of bauxite could be saved and 600–5500 million CO2 -eq emission could be avoided; 3) the recycled OAA in some regions are in conflict with local affiliated constructions. These vital findings could provide scientific data for formulating targeted policies on effectively reusing automotive aluminum for resource conservation, regional circularity and carbon reduction.