Fritz Benjamin, Aichele Carin, Schmidt Mario
Institute for Industrial Ecology, Pforzheim University, Tiefenbronner Str. 65, 75175 Pforzheim, Germany.
Faculty of Sustainability, Leuphana University Luneburg, Universitatsallee 1, 21335 Luneburg, Germany.
Int J Life Cycle Assess. 2020;25(10):1930-1941. doi: 10.1007/s11367-020-01809-6. Epub 2020 Aug 25.
The gold routes satisfying the global gold supply are mining (74%), recycling of high-value gold (23%), and electronic scraps (3%). Besides its applications in the investment, jewelry, and industrial sector, gold also has a bad image. The gold production in industrial as well as artisanal and small-scale mines creates negative impacts such as resource depletion, extensive chemical use, toxic emissions, high energy consumption, and social concerns that are of great importance. On the other hand, almost all gold is recycled and has historically always been. In common life cycle assessment (LCA) databases, there is no data on recycling of high-value gold available. This article attempts to answer the question what the ecological benefits of this recycling are.
In this study, we were able to collect process data on the most commonly used high-value gold scrap recycling process, the aqua regia method, from several state-of-the-art German refineries. With this data, life cycle inventories were created and a life cycle model was produced to finally generate life cycle impacts of high-value gold scrap recycling.
This study contains the corresponding inventories and thus enables other interested parties to use these processes for their own LCA studies. The results show that high-value gold scrap recycling has a considerably lower environmental impact than electronic gold scrap recycling and mining. For example, high-value gold scrap recycling in Germany results in a cumulative energy demand (CED) of 820 MJ and a global warming potential (GWP) of 53 kg-CO-Eq. per kg gold. In comparison, common datasets indicate CED and GWP levels of nearly 8 GJ and 1 t-CO-Eq. per kg gold, respectively, for electronic scrap recycling and levels of 240 GJ and 16 t-CO-Eq. per kg gold, respectively, for mining.
The results show that buying gold from precious metal recycling facilities with high technological standards and a reliable origin of the recycling material is about 300 times better than primary production.
满足全球黄金供应的黄金来源途径包括采矿（74%）、高价值黄金回收（23%）和电子废料（3%）。除了在投资、珠宝和工业领域的应用外，黄金也有负面形象。工业以及手工和小规模矿山的黄金生产会产生负面影响，如资源枯竭、大量化学品使用、有毒排放、高能源消耗以及社会问题等，这些都至关重要。另一方面，几乎所有黄金都被回收利用，而且历史上一直如此。在常见的生命周期评估（LCA）数据库中，没有关于高价值黄金回收的数据。本文试图回答这种回收利用的生态效益是什么的问题。
在本研究中，我们能够从几家德国先进的精炼厂收集关于最常用的高价值黄金废料回收工艺——王水法的过程数据。利用这些数据，创建了生命周期清单并生成了生命周期模型，最终得出高价值黄金废料回收的生命周期影响。
本研究包含了相应的清单，从而使其他感兴趣的各方能够在自己的LCA研究中使用这些工艺。结果表明，高价值黄金废料回收对环境的影响远低于电子黄金废料回收和采矿。例如，德国的高价值黄金废料回收产生的累计能源需求（CED）为820兆焦，全球变暖潜势（GWP）为每千克黄金53千克二氧化碳当量。相比之下，常见数据集表明，电子废料回收的CED和GWP水平分别约为每千克黄金8吉焦和1吨二氧化碳当量，采矿的水平分别为每千克黄金240吉焦和16吨二氧化碳当量。
结果表明，从技术标准高且回收材料来源可靠的贵金属回收设施购买黄金比初级生产要好约300倍。
