Recent progress and application of materials life cycle assessment in China

Zuo-ren NIE, Feng GAO, Xian-zheng GONG, Zhi-hong WANG, Tie-yong ZUO

College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China

Received 18 October 2010; accepted 23 December 2010

Abstract: Life cycle assessment (LCA) is a technique for systematically analyzing the environmental impacts and resources used throughout a target’s life cycle, i.e. from raw material acquisition, via production and use phases, to waste management. It is an effective tool that gives a detailed information of environmental profiles of a material or a product. More importantly, the value of life cycle thinking lies in its ability to provide the decision–making basis for sustainable development, making the products, industries and even the whole industry chain act more in line with the principles of sustainable development. The recent developments of LCA methods and applications of materials life cycle assessment in China were reviewed. In the sections on LCA methodology, the data quality analysis, the impact of land use and abiotic resource depletion as well as the weakness in life cycle impact assessment were discussed. In relation to the applications, the Chinese materials database (SinoCenter Database) and several representative case studies such as life cycle analysis of civilian buildings and metal production in China were introduced. Key words: materials; life cycle assessment; LCIA methodology

including the development of LCA methodology, basic 1 Introduction database and software, as well as the establishment of environmental certification standard of typical materials For the manufacture, application, and disposal of under the support of the National High-Tech R&D materials, rapid depletion of resource reserves and other Program, the National Basic Research Development environmental problems such as climate change have Program, the National Key Technology Research and been major threats to the species during the recent years. Development Program and the National Natural Science In order to meet these challenges, many tools and Foundation of China[3]. indicators for assessing environmental impacts of different systems have been developed. The usual 2 Development in LCA methodology analysis methods mainly include life cycle assessment (LCA) and materials flow analysis (MFA). LCA has been LCA is a tool for estimating and assessing the extended to many aspects of production and consumption, potential environmental impacts attributable to the life including eco-design of products, cleaner production, cycle of a product, including raw material extraction, environment label, green purchase, resource management, processing, manufacture, usage, recycle and disposal. wastes management and environment strategy, etc[1−2]. Data quality and the option of life cycle impact With the rapid economic development of China, the assessment（LCIA）methods are more concerned. The confliction between economic development and high quality data are an important premise to carry out environment protection becomes more and more severe. LCA and the data reliability directly influences the It is important to improve resources and energy capability of the results and its application. LCIA is the efficiency and reduce pollutants emission of Chinese stage that has more difficulties and needs to be further materials industry by performing LCA as technical and developed. decision-making support to gain the target of energy-saving and emission-reducing. There is much 2.1 Data quality analysis progress made in Chinese LCA research in recent decade, With the request of the reliability of LCA results,

Foundation item: Project (2007CB613706) supported by the National Basic Research Program of China; Project (2081001) supported by the Beijing Natural Science Foundation; Project (2007AA03Z432) supported by the National High-Tech Research and Development Program of China; Project (50525413) supported by the National Natural Science Foundation of China; Project (X0009011200902) supported by the Scientific Research Initiative Foundation of Beijing University of Technology Corresponding author: Zuo-ren NIE; E-mail: [email protected] 2 Zuo-ren NIE, et al/Progress in Natural Science: Materials International 21(2011) 1−11 the definition and evaluation of data quality have already in 1999, almost all the declines of ecosystem in the last attracted much attention. In recent years, some century are related to physical changes in land international organizations devoted to the study on this utilization[13] which may also have significant impacts, area. SETAC put forward a qualitative evaluation whether positive or negative, in the life cycle of framework of LCI data quality, which recommended production system, from the exploitation of resource and uncertainty analysis and sensitivity analysis, as the energy in raw materials acquisition phase, the building important parts of impact assessment, to evaluate the for production and living in manufacture phase, the variety of LCA results caused by data and models. The construction of road and railway in transportation phase revision of the ISO series 14040 proposed that the until the landfill in final disposal phase. However, there character of data should meet with the goal and scope of is no consensus that how land use impacts should be study, and date quality should be assessed by qualitative incorporated in LCA, although the concern for the and quantitative methods, and data collection and inclusion of land use impacts in LCA has led to many combination methods, so as to correctly represent publications internationally in recent years[14−16]. A reliability of results[4]. working group within the UNEP/SETAC Life Cycle The researches of LCI data quality method mainly Initiative has been formed and the integrated focus on two aspects: environmental assessment methods with a focus on soil 1) To introduce data quality indicators from quality and land use will be developed further. representative data, such as regional and temporal data, In our study, a model with characterization factors or data collection methods. was proposed to qualify the land use impact based on the 2) To adopt the uncertainty to represent the land quality change presented by net primary integrated data quality and analyze the dataset productivity (NPP) during the land use duration, which uncertainty related to the process to denote the can be incorporated into the LCA framework to improve uncertainty of LCI results. the basis for decision making in industry and other There are a number of methods to analyze the organizations. In this model, land occupation and land uncertainty, including Gaussian error propagation transformation are considered as the basic land use formulas, Monte Carlo simulation, stochastic simulation activities that result in either damage or benefits to based on probability distribution, interval algorithm and ecosystem quality (land transformation creates a change fuzzy logic approaches[5−8] and so on. in ecosystem quality and land occupation delays changes Up to the present, appropriate methods and ideas for to its quality). On the other hand, the permanent impact the data quality analysis of LCA are still not available due to human usage is suggested to be described in although several methods for evaluating the consistency, quality unless the data are available. Based on this model, continuity, sensitivity and uncertainty of the inventory the characterization factors of both land occupation and data were proposed by LCA practitioners[9−10]. The land transformation are calculated using Chinese primary data source of LCI study in China is public empirical information on NPP, which can be applied to statistical data of which uncertainty is difficult to be Chinese LCA case study to fill an important gap in life identified and quantified. Thus, the accumulation of field cycle impact assessment of land use in China[17]. monitoring data is especially important for LCI data According to geographic position of China, the land collectors to perform the uncertainty analysis. form with the highest NPP value (evergreen broadleaved In view of the data deficiency of LCA research in forest) is defined as natural state. As the defined natural China, the missing data are predicted and imputed state, the occupation in the form of evergreen logically based on the information known in life cycle inventory by using three methods: complete case analysis, broadleaved forest will not cause any environmental linear regression analysis and Markov Chain Monte impact in the model, while the occupation impact of the Carlo (MCMC) method. Moreover, a comparative other land types will increase with the decrease of their analysis between the application of these three methods NPP values. The occupation factors are shown in Table 1. is performed. A data quality analysis system to reduce For convenient usage, only transformation factors the interference from the missing data is set up[11]. between primary land types are calculated, and the result Based on the grade-matrix model and the expected value is shown in Table 2. The transformation impact will methods, the transformation from determinated LCA increase with the difference of NPP value between two model to stochastic LCA model was developed and an land types, and the factors will be negative when LCI stochastic model was also established for an converted from low-NPP land type to high-NPP land exemplification of eco-cement production[12]. type, namely, causing a beneficial impact to environment. In order to gain experiences in using and comparing 2.2 Impacts of land use the different methods in practice, some case studies According to a report by World Resources Institute closely related to the impact of land use, such as sintered Zuo-ren NIE, et al/Progress in Natural Science: Materials International 21(2011) 1−11 3

Table 1 Characterization factor of land occupation in China −2 −1 Primary land type Secondary land type LUFocc/(g(C)·m ·a ) Subtropical evergreen coniferous forest 66 Temperate evergreen coniferous forest 223 Evergreen broadleaved forest − Forest Deciduous needle-leaf forest 247 Deciduous broadleaved forest 185 Temperate mixed forest 191 Tropical/ subtropical mixed forest 115 High-density shrub 137 Shrub Low-density shrub 441 Meadow-herb swamp 266 Grassland High-density grassland 218 Low-density grassland 502 One crop annually 312 Two crops annually 261 Farmland Paddy-upland rotation annually 240 Double cropping rice 169 Semidesert 597 Desert Harsh desert 562 Sand desert 608 City City 476

Table 2 Characterization factor of land transformation in China (103g(C)·m−2·a−1) Land type Forest Shrub Grassland Farmland Desert City Forest − −3.04 −8.38 −6.10 −16.2 −11.8 Shrub 3.04 − −5.34 −3.06 −13.2 −8.79 Grassland 8.38 5.34 − 2.28 −7.83 −3.46 Farmland 6.10 3.06 −2.28 − −10.1 −5.74 Desert 16.2 13.2 7.83 10.1 − 4.37 City 11.8 8.79 3.46 5.74 −4.37 − brick production, agricultural products and waste reusage At present, there are mainly three kinds of models are conducted. for resource depletion. 1) Use the ratio of resources extraction volumes to 2.3 Abiotic resource depletion reserves to measure the level of the abiotic resources Abiotic resource depletion is one of the most depletion. These methods use a number of characteristic important categories in life cycle impact assessment. The factors, such as 1/R，U/R and U/R2, among them R current level of recognition for the mineral resource represents the reserves of a certain resource while U depletion issue, however, is still far lower than that for denotes the current volumes of use or extraction of this the issues, such as the greenhouse effect, and kind of resource. The CML method developed by the acidification effects, that arise in the process of group of Leiden University in Netherlands, reflects this developing and utilizing mineral resources[18]. There view[22−23]. also exists much controversy on the characterization We chose the CML method, combined with Chinese methods of the abiotic resource depletion impacts, and characteristics of resources and statistical data, so as to the focus of this controversy is largely centered on a modify important parameters involved in this model, and number of fields, such as the determination of resources thus calculated Chinese characterization factor set of function parameters, the rationality of choosing the mineral resource depletion as well as normalization characteristic factors of resource depletion, as well as the factor of resource depletion in 2004. The comparison impacts caused by resource extraction, substitution and with the original method highlights the fact that recycling technology on resource depletion[19−21]. geographical distribution differences of resources are 4 Zuo-ren NIE, et al/Progress in Natural Science: Materials International 21(2011) 1−11 unavoidable in the LCA study. Through case studies, the category with the development of exploration technology, differences between the modified model and the CML and the expansion of human demand, because some model in the application are comparatively illustrated in important parameters, such as resources reserves and Table 3 and the causes for these differences are discussed, extraction volumes, are regionally different and thereby a feasible basis for suggesting the modified sensitively time-bound. And the degree of correlation model as the characterization method assessing Chinese between characterization factors of abiotic resource mineral resource depletion provided[24]. depletion and economic-social factors still needs to be further studied. Table 3 Summary of characterization results for resources 3) Exergy-based model. Exergy, which is defined as category from two LCIA procedures the work potential of energy at a stated surrounding, is an CML Modified method appropriate function to express the quality of energy. The Resource (kg antimony eq.) (kg antimony eq.) exergy model for elements was proposed by Szargut[26], Dolimite 0 47.1 who selected reference species at atmosphere for 9 kinds Silica 6.52×10−8 1.31×10−2 of elements, hydrosphere for 23 kinds of elements, lithosphere for 53 kinds of elements, and calculated the Iron(from ore) 2.23×10−5 1.20×10−3 exergy values of elements. Subsequently, methods and −1 Fluorite 6.50×10 1.89 data based on this exergy model were developed for 2 −3 Coal 1.20×10 1.02×10 natural resources in life-cycle assessment by Finnveden Crude oil 2.05 1.44×10−2 and östlund[27]. In order to fill the gap of the lack of Natural gas 1.43 9.05×10−6 exergy consumption data, a series of Cumulative Exergy Demand (CExD) indicators were set up to assess exergy 2) Use the expected results generated by resource scores for a large number of materials and processes[28]. exploitation as a basis for characterization. This point of It is likely that CExD indicators could suitablely assess view suggests that mankind’s current extraction of energy and resource demand in product life cycle high-grade resources will cause more serious assessments. environmental and economic impacts when exploiting The exergy for some Chinese minerals was low-grade resources in the future. Such kind of views are calculated to describe the depletion of exergy caused by represented by the Eco-indicator 99 method[25], which the use of natural minerals. For the non-aluminum- uses the energy demand required for exploiting containing minerals, there is no distinct difference low-grade resources as the damage factor to measure between the results from Szargut’s and Rivero’s data[29] resource depletion, and which believes that this kind of of element exergy, but for the aluminum-containing “additional energy” is able to interlink the functionality minerals, especially for the minerals which contain a with technical development of the abiotic resources, large number of aluminum, it will cause a significant rather than directly relying on estimates of difference on the results when using different models. hardly-predictable resources reserves and annual The main reason for this significant difference is the consumption volumes in the future. choice of standard mole Gibbs’s free energy of formation The Eco-indicator 99 method uses a large number for aluminum reference species (sillimanite). And the of theoretical assumptions, and the calculation of element exergy from Rivero’s results is inappropriate to parameters requires the support of a large amount of data, calculate the exergy for some aluminum-containing in particular the need for continuous statistical data of minerals, which will get some unreasonable results[30]. ore extraction volumes and ore grade in a longer period of time. According to the current actual statistical 2.4 Development of methodology of life cycle impact situation of Chinese mineral resources, the statistical data assessment of ore grade of the majority of non-metallic mineral So far, the development of the methodology and the resources cannot be obtained, thereby limiting the benchmark system of the life cycle impact assessment general applicability of this model. Furthermore, the (LCIA) phase is still in progress, and there are several calculation process is relatively complicated, and has models used to calculate the characteristic indicators higher requirements for data quality, thus affecting the connecting inventory data with environmental impact operation of the model. categories. However, widely accepted uniform standard The characterization model of abiotic resource is still not available. Internationally, a variety of methods depletion was modified and improved in terms of have been proposed to implement impact assessment, localization in our study. However, the characteristic which can basically be divided into two types: midpoint factors of the abiotic resource depletion need to be methods[31] and endpoint methods[32]. The former expanded in terms of both time span and resource focuses on the environmental impact categories and their Zuo-ren NIE, et al/Progress in Natural Science: Materials International 21(2011) 1−11 5 function mechanism, using characteristic factors to 14048)[34] for LCA data exchange is formulated by describe the relative importance of various International Organization for Standardization (ISO), environmental disturbance factors. And the latter focuses which put forward a normative information format more attention on the causality of the environmental including process information, model information and impact issue. management information. Whereas, more detailed Although significant progress has been made in the criterions for data selection and technology requirement LCIA characteristic methods, their scientific connotation are demanded for actual LCA study. still need to be continuously improved and enriched Several national and international public databases, mainly in the following several areas[33]: such as the Swiss ecoinvent database[35], the European 1) To quantify the uncertainties of impact indicators. Reference Life Cycle Database (ELCD)[36], the In the decision making process, the uncertainty analysis Japanese JEMAI database[37], the US NREL method needs to be established to improve the accuracy database[38], and the Australian LCI database[39], have and reliability of LCA results. been released in recent years. These databases evolved 2) The differences of environmental impacts caused from publicly funded projects cover a variety of by spatial and temporal differentiation need to be inventory data on products and basic services including identified. raw materials, electricity generation, and transport forms 3) In accordance with the requirements for as well as waste disposals and services. consistency and comparability, the depth and breadth of The efficiency of LCA implement can be improved simulating environment mechanism need to be increased. and the cost of time and manpower can be reduced by the The correlation between the characterization results and application of LCA software which is often divided into the environment needs to be further proved so as to three groups: general software for LCA experts and enable the potential environmental impact assessment consultants, professional software for the decision of results to facilitate integrated decision making. engineering design, sale or environment and waste 4) Related disciplines need to be further developed management, application software for specific users to improve the development of the method for comparing (mainly the enterprise users). At present, the amount of the impact categories, such as resource depletion, human LCA software related to material and production is more health, land use, and water use, thereby providing better than twenty worldwide, the environment database support for integrated decision making. exceeds one thousand, and over three thousand commercial softwares with embedded default database 3 LCA database and software are sold, in which some famous tools (such as Simapro[40], Gabi[41], Team[42]) have been widely Generally, not only large numbers of environment applied in LCI, LCIA, Eco-design and cost analysis. burden data with high regional limitation but also different LCA models are involved in LCA application. 3.2 Research status of Chinese LCA database These data with the properties of universality, regionality In recent year, the research of LCA in China and complexity, are the basis for each LCA study and developed rapidly due to the high attention from the supposed to be managed effectively. Therefore, owing to public and government, although started relatively late. the advantage of database technology in data In the support of National High-Tech R&D Program, management area, the development of LCA database and which was initiated by Beijing University of Technology evaluation software has become one of the most (BJUT) and co-operated with other colleges, research important directions of LCA research recently. institutes and material corporations, the environment burden data of main material production (steel, cement, 3.1 Research status of international LCA database aluminum, engineering plastics, architectural coatings, and software ceramic, etc) was collected and processed, and based on For promoting the communion of LCA information, these data a basic material life cycle assessment (MLCA) a current format for data exchange was established by database and related softwares with independent Society for Promotion of Life-cycle Assessment intellectual property were also developed[43]. As a result Development (SPOLD), which performed a detailed of the exploration and development within recent ten meta-data division on each inventory record in order to years, a research and consultation platform of LCA with assure the independence, handleability and procurability the largest data quantity which covered the widest range of life cycle inventory. Moreover, the SPOLD format is of materials in China was established in BJUT, involving an open source and can be embedded in different LCA six servers, firewalls and routers, eleven workstations software for the data exchange between these tools. and related professional evaluation softwares (Gabi4.0, Furthermore, an international standard (ISO Simapro7.0, UmberTo4.0[44], Team3.0, etc). 6 Zuo-ren NIE, et al/Progress in Natural Science: Materials International 21(2011) 1−11 Furthermore, the website of Center for National Materials Life Cycle Assessment (CNMLCA, 4 Representative case studies www.cnmlca.com.cn) has been opened to society and public in order to propagandize the development and The development of China economy will spur a application of LCA, introduce the latest research trend significant growth in energy and raw materials industries. and result around home and abroad, promote the Using LCA methods to adjust industrial layout and to formation and wide development of ECO-material think choose, optimize and design technique processes, such as and evaluation, and most importantly, support the LCA energy supply as well as the production and and ECO-design performance in China. By far, the manufacturing of materials, will be able to provide practice of life cycle assessment in China has attracted scientific decision making and technical guidance for attention with several international LCA institutions. The Chinese materials industry to achieve cleaner production research center has widely cooperated with ISO and PRé and to carry out energy-saving and emission-reducing Consultants, and participated in the establishment of targets. global LCA union. SinoCenter system established by Windows 4.1 Energy Advance Server and MSQL Server Enterprise version is The life cycle inventory (LCI) of the production of an internet oriented platform that focused on research primary energy and the major secondary energy is the and development, which consisted of several connected fundamental data to carry out LCA for the materials sub-database, and management tools[45], etc (Fig.1). industry and even all industrial products. In order to The majority of database systems are based on unit further develop Chinese materials LCA database, we process data representing specific technologies of have worked out the inventories of primary energy, Chinese materials industry. Presently, more than one including the energy consumption and emissions hundred thousand records are involved and the concrete involved in the extraction process of coals, crude oils and classification includes energy supply (primary energy natural gas, and have compiled a full data inventory from and secondary energy), transportation, mineral resources, “cradle to gate” of several major downstream products materials (metal materials, building materials, chemical derived from coals and crude oils, such as cleaned coal, materials, etc), LCA methods and standards. coke, gas, petrol, diesel oil and fuel oil[46]. The inventory of energy consumption of power generation, as well as the emissions of gaseous pollutants, liquid pollutants and solid wastes were also investigated. The comparison with emissions related to 1 kW·h of electricity distributed between the Japan's electricity industry and Chinese is shown in Fig.2[47]. These fundamental energy inventories have already been applied in Chinese environmental impact assessment of materials and products as well as in international comparative studies. With the enlargement of Chinese

Fig.1 Structure and function of SinoCenter platform

These unit process data provide the possibility for choosing the technologies that are appropriate in the case investigated, and allowing the LCA practitioner to review underlying details of the process data and methodological choices for environmental assessment of a product or service. Quality and consistency are key issues related to inventory data. The SinoCenter database is also designed to address inventory data and to help support the exchange of data amongst the many LCA tools and databases in the contexts of consistency and quality assurance building on existing achievements, e.g. Fig.2 Comparison of emissions related to 1 kW·h of electricity the ISO TC 14048. distributed between China and Japan Zuo-ren NIE, et al/Progress in Natural Science: Materials International 21(2011) 1−11 7 economy scale and the rapid increase of energy improvement of the atmospheric environment quality in requirement in recent years, the inventory data of energy Beijing and for the phased objective achievement of consumption especially the electricity generation have reducing and controlling air pollution[49]. been updated to reflect the tendency of changing situation. A carbon footprint analysis of thermal power, 4.3 LCA analysis of civilian buildings which is 81.83% of Chinese electricity generation in The green building system currently advocated is to 2006, showed that the carbon emission of 1 kW·h net consider, from the perspective of sustainable thermal power is a little higher than that of 2002. development, the impacts on resources, energy and environment during a whole life cycle of buildings. The 4.2 Design of eco-cement and structural adjustment total floor area of buildings in China has reached over of Beijing cement industry 40×109 m2, and the direct energy consumption during the The cement industry accounts for about 15% total construction and use of buildings accounts for 30% of amount of carbon emission in China, which is in the third the total amount consumed by the whole society. In order place preceded only by steel and power industry. In to meet the urgent demand for the development of addition, millions of tons of cement kiln dust and other energy-saving buildings and green materials, we have gaseous emissions each year were released to contribute cooperated with Canada Wood Group to jointly analyze to respiratory and human health risks. A process-oriented the environmental impacts produced by three different method to calculate CO2 emissions due to cement types of construction structures of multi-story and manufacture was established and a case study for a multi-residential civilian buildings in Beijing, including certain plant was provided for eco-cement products concrete framework construction (CFC), light gauge design[48]. steel framework construction (SFC) and wood Combining the process LCA analysis and the framework construction (WFC), during the stages of regional material flow analysis (MFA), under the building materials production, construction and use. In premise that guarantees both the cement demands of this analysis, the life cycle inventory of a wide range of Olympic construction and environmental protection materials, including metal materials, gypsum materials, requirements, we put forward the 2008 Beijing’s cement cement and concrete materials, materials for doors and industry layout adjustment program. Under the windows and vinyl materials, as well as fossil energy, circumstance that keeps the cement output basically electricity and transportation are all derived from the unchanged, the overall consumption volume of materials SinoCenter database. Through the calculation of and energy in Beijing’s cement plants, through characteristic indicators of 11 types of environmental adjustment, combination and technological upgrading, impacts as well as the uncertainty and sensitivity analysis was basically the same as in 2001, but the emissions of of the results, we determined that, among these three atmospheric pollutants, including soot, fumes and sulfur different kinds of construction structures, wood structure dioxide, were decreased by 50%, 11% and 2%, shows very obvious advantages because it ranks lowest respectively, compared to 2001 (Fig.3). This program in 8 kinds of environmental impact category, especially provides an extremely important reference for significant in the climate change, radiation effects, ozone depletion and land resources damages, all of 4 are closely related to human survival and life (Fig.4).

4.4 Iron and steel Environmental load data of iron and steel materials derive from research into the production situation of more than 70 major Chinese iron and steel manufacturing plants as well as from industry statistical reports. The scope of the data covers the life cycle stages ranging from “cradle-to-gate”, representing the environmental load of enterprises in different regions and with different levels of technology. Through the assessment of energy-saving and wastes recycling and reuse technology during the iron and steel production process, a program for large-scale integrated iron and steel enterprise to carry out the practice of recycling Fig.3 Comparison of materials and energy consumption economy was put forward[50]. For a large-scale between 2001 and 2008 for Beijing cement production integrated iron and steel enterprise with an annual 8 Zuo-ren NIE, et al/Progress in Natural Science: Materials International 21(2011) 1−11

compounds (PFCs), carbon tetrafluoride (CF4) and carbon hexafluoride (C2F6) to decrease by 75% in 2006 compared to that in 2003. When the overall energy consumption for alumina production is reduced to 700 kg coal eq per ton, GHG emissions will be able to basically reach the world average level in 2000. With the decline of overall electricity consumption for electrolytic aluminum, the greenhouse gas (GHG) emissions from the aluminum industry in 2010 and 2020, in comparison with that in 2006, will decrease by 6.2% and 12.3%, respectively[59].

Fig.4 LCIA comparison of impact categories for CFC, SFC and WFC in their life cycle where the largest score of each category is set to 100% production output of 10×106 t, the use of the new recycled iron and steel production process is able to, annually, absorb from the market 1.2×106 t of scrap steels and 2×105 t of waste plastics, generate 9×109 kW·h 6 of electrical power, and produces 3×10 t of high-grade cement through digesting wastes produced by itself, Fig.5 Comparison of GHG emissions between China and world thereby yielding huge economic and social benefits. average level

4.5 Aluminum 4.6 Magnesium It is a complex system for primary aluminum Since 1990s, China magnesium industry has gained production. The development of this industry has been a rapid development, and China is the largest primary restrained to a large extent by the issues related to magnesium producer and supplier in the world. So far, resources, energy and environment. With the initiation the international LCA research on both the production of and promotion by the International Aluminum Institute primary magnesium and the magnesium products is still (IAI), LCA has been introduced into the environmental underway[60−62], and it also needs to further study the assessment system for aluminum and aluminum environmental impacts on the extensive use of the products[51−58]. At present, China has become the magnesium products. world’s largest aluminum producer. Because of the According to the actual situation of China characteristics of nationwide bauxite resources and the magnesium production, we analyzed the environmental energy consumption, especially the structure of the impacts on the directly coal-burning technics. The results electricity industry, the specific overall energy showed that the reduction process accounts for 50% for consumption of China aluminum production is 50% the global warming potential, followed by the calcination higher than that of the world average level, thereinto the process, being at 45%. For the acidification potential, the aluminum smelting 45% higher, and alumina production contribution of the refinement process and the reduction 56% higher. process accounts for 56% and 35%, respectively. The The life cycle analysis result showed that the global human toxicity potential mainly occurs in the reduction warming potential (GWP) of China primary aluminum process which accounts for 95%. Based on different fuel production in 2003 is nearly 1.7 times higher than that of use strategies, the environmental impacts of three the world average level in 2000, and the contribution of scenarios were analyzed and compared (Fig.6). The the process shown in Fig.5 is also different. The efforts direct coal-burning (Scenario 1) showed the poorest of raising the control level of electrolytic pots and environmental performance. The overall environmental reducing the coefficient of anode effects from 0.5 to 0.2 load of producer gas (Scenario 2) as the main fuel enabled the GWP caused by two perfluorocarbon decreased by 1.9%, but the GWP were 14% higher Zuo-ren NIE, et al/Progress in Natural Science: Materials International 21(2011) 1−11 9 compared with the direct coal-burning. The for China situation, and databases for the inventory environmental load using coke oven gas as major fuel for analysis, and examples of energy and materials life cycle magnesium production (Scenario 3) decreased by 17.5% analysis. However, some areas including LCA tools, and compared with that of the direct coal-burning. This methods for assessment of impacts on ecosystem from means that a positive and environment-friendly land use and water use, and weighting methods still need improvement can be achieved by integrated a sort of to be further developed. In general, the applications of production networks based on the materials flow and LCA in China are still limited in several demonstration supply, by-product exchange and the waste heat fields and there is still a wide gap between evaluation utilization[63]. results and the criteria people expected. Therefore, the development of LCA study should not only extend the application range of industry and agriculture fields, but also improve LCA methodology in economic and social aspects. Although the researches of LCA methods and its application still need to make a deep investigation, it has been accepted and made important progress in the definition of goal and scope, framework, and the challenge of LCA. It is an effort for Chinese materials industry to perform the work of energy-saving and emission-reducing, and we think that LCA method is a great potential tool to provide the decision-making and technical support for the achievement of the target. Fig.6 Final single results for three scenarios of magnesium production References 4.7 Other materials LCA of the materials industry is a [1] REBITZERA G, EKVALLB T, FRISCHKNECHT R, et al. 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