Purpose

The assessment of potential environmental impacts associated to mineral resource use in LCA is a highly debated topic. Most current impact assessment methods consider the extraction of resources as the issue of concern, while their dissipation is an emerging concept. This article proposes an approach to account for mineral resource dissipation in life cycle inventories (LCIs), with application to a case study.

Methods

The definition of mineral resources is first discussed considering both current main LCA practice and the context of resource dissipation. Secondly, the approach is described: considering a short-term perspective (25 years), any flow of resources to (i) environment, (ii) final waste disposal facilities, and (iii) products-in-use in the technosphere, with the resources not providing any significant function anymore (including due to non-functional recycling), is suggested to be reported as dissipative at the level of unit processes. This approach first requires to map the flows of mineral resources into and out of the unit processes under study (“resource flow analysis”), before identifying the dissipative flows and reporting them in LCI datasets.

Results and discussion

The approach is applied to analyze the direct dissipation of mineral resources along the primary production of copper, using Ecoinvent (v3.5) datasets. The production of 1 kg of copper cathode generates 0.88 kg of direct dissipative flows of resources (primarily calcium carbonate, copper, and to a lower extent iron), with important contributions of “tailings disposal,” “pyrometallurgy,” and “mining and concentration.” Moreover, this article discusses (i) how the developed approach would change the interpretation of results regarding mineral resources in LCA, (ii) how far some key methodological aspects of this approach (e.g., the temporal perspective) can affect the inventory results (e.g., in the case of the primary production of copper, considering a long-term perspective implies a significant shift in main contributions regarding both unit processes and resource flows), and finally (iii) the issue of new data requirements, in terms of availability and adequacy.

Conclusions

As demonstrated in the case study, existing LCI datasets and supporting documentation contain at least part of the data and information required to consistently compile the dissipative flows of resources at the unit process level, yet with the need for some complementary data and assessments. This approach may be particularly relevant to better support the development of more resource-efficient techniques or product designs. It is still open how to adapt characterization approaches to account for the impact induced by these resource dissipative flows.

中文翻译：

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生命周期清单中的矿产资源耗散

目的

在LCA中与矿产资源使用相关的潜在环境影响评估是一个备受争议的话题。当前大多数影响评估方法都将资源的提取视为关注的问题，而资源的消耗却是一个新兴的概念。本文提出了一种方法来解决生命周期清单（LCI）中矿产资源的耗散问题，并将其应用到案例研究中。

方法

首先讨论矿产资源的定义，同时考虑当前的主要生命周期评估实践和资源消散的背景。其次，描述了该方法：考虑到短期的角度（25年），到（i）环境，（ii）最终废物处理设施和（iii）技术圈中使用产品的任何资源流，以及建议将不再提供任何重要功能的资源（包括由于非功能性回收所致）在单元过程级别上视为耗散的。这种方法首先需要在确定耗散流量并将其报告到LCI数据集中之前，将矿产资源流入和流出所研究的单位过程的流量映射（“资源流量分析”）。

结果与讨论

该方法适用于使用Ecoinvent（v3.5）数据集分析沿铜初级生产的矿产资源的直接耗散。1公斤阴极铜的生产会产生0.88公斤直接耗散的资源流（主要是碳酸钙，铜和少量铁），对“尾矿处理”，“火法冶金”和“采矿与浓缩”具有重要贡献。 。” 此外，本文讨论了（i）所开发的方法将如何改变有关LCA中矿产资源的结果的解释，（ii）该方法的一些关键方法论方面（例如时间方面）会在多大程度上影响库存结果（例如在初级生产铜的情况下，

结论

如案例研究所示，现有的LCI数据集和支持文档至少包含在单元过程级别上一致地编译耗散资源流所需的数据和信息的至少一部分，但还需要一些补充的数据和评估。此方法可能对更好地支持开发更具资源效率的技术或产品设计特别有用。如何采用表征方法来解决这些资源耗散流所引起的影响，仍然是一个公开的问题。