The environmental impact of salt mining by Nobian

Salt is an important raw material that is used for the production of many essential chemicals. Nobian, with both salt mining and salt-chemistry operations, plays an important role in the value chain of many chemical products. Currently, Nobian is working on the continuous improvement of their environmental footprint. Therefore, Nobian wanted to compare the footprint of vacuum salt produced in the Netherlands with other sources of salt, using a Life Cycle Assessment (LCA).

Nobian asked Ecomatters to conduct an LCA on the different options for producing salt for the chemical industry. Nobian extracts salt from below ground in the Netherlands with solution mining. During solution mining, water is pumped into underground salt deposits, creating caverns in which salt is dissolved into brine. This brine is then transported to the salt factory, where it is used to produce vacuum salt by purification and crystallisation. This high-purity salt is mostly used for chemical transformation into essential products in the Chlor Alkali industry. Other means of salt production are the evaporation of seawater (sea salt) and the direct mining of salt deposits in mines (rock salt).

In addition to the impacts of different production operations, the trans-oceanic transport of sea salt and rock salt from various possible overseas sources was included in the comparison. For the transformation of salt into other chemicals, a very high purity of salt is required. As rock and sea salt need to undergo additional purification before they can be used, this process was also incorporated into the LCA. Taking all these factors into account, Ecomatters analysed the CO₂ footprint and the Product Environmental Footprint (PEF) score of the different salt sources.

The study evaluated the different sources and places of origin of salt for chemical transformation. The study concluded that high-purity vacuum salt from the Netherlands had the smallest environmental footprint. It also found that the salt mining and production operations of sea- and rock salt have a smaller footprint than the production of vacuum salt. However, this is not the whole picture. Transporting large quantities of salt across long distances had a notably high impact. The additional purifying efforts, required at the destination for further processing, also further increased the footprint of the alternative salt sources. When focussing on the impact of the production stage alone, using sea or rock salt appears to be a sustainable alternative. However, when considering the entire supply chain, this is no longer the case. This study showed that it is crucial to look at the different aspects of the entire supply chain to evaluate the sustainability of alternative salt sources.

These results provide Nobian with a clear picture on the comparison of different salt sources. Furthermore, the results also help to highlight the hotspots and possible improvements Nobian could make to its own mining operations.

With its sustainability program “Grow Greener Together”, Nobian has the ambition to be one of the most sustainable companies within the chemical industry, with a clear target of being carbon neutral by 2040, with 100% renewable energy. Therefore, adopting energy-saving equipment and switching to fully renewable energy sources are crucial to further reduce the impact of Nobian’s salt mining and processing activities in Europe.