The real value of salt: past and future

Salt plays an essential role in daily life. It is the basis for thousands of products that we use every day, and will also help society to become more sustainable in a variety of important – and sometimes unexpected - ways.

In July 1918, we founded the first salt mining company in the Netherlands and 100 years later, we are one of the biggest salt producers in the world, supplying 6 million tons of salt each year.

Once reserved for tickling your taste buds and food preservation, over the past century salt has become the basis for products touching every aspect of our lives – from your house to your car to your medicine. Nils van der Plas, General Manager Salt & Salt Specialties, says, “With a growing need to reduce the impact of our activities on the planet, we are preparing for another transformation in the role of salt as we look forward to the next 100 years.”

Saving energy with salt

Over 85% of our salt is used by industry for a chemical process called electrolysis. During this process, electricity is used to split salt water into three products: chlorine, caustic soda, and, in smaller amounts, hydrogen.

These products form the basis of an entire chemical industry and are essential for countless products we use in everyday life. Chlorine, for example, is used so widely that even a simplified diagram chemists use to describe its many applications, called the ‘chlorine tree’, is nevertheless filled with a complex array of interconnected branches.

Demand for chlorine as well as caustic soda (and thus for salt) is increasing as part of a drive for energy efficiency based on the use of light-weight materials and insulation. This includes the use of chlorine for epoxy resins for wind turbine blades and electric cars, as well as polyurethane for insulation in construction. Caustic soda, for its part, is mainly used to make aluminum, another champion of light-weight products used in cars and construction.

Solving the energy challenge

Van der Plas continues, “Paradoxically, while electrolysis of salt is vital in the drive for improved energy efficiency, the process itself is very energy intensive.” This can be partially improved by using the latest technology and high purity salt, made of 99.99% sodium chloride.

To minimize CO2 emissions AkzoNobel Specialty Chemicals uses steam from incinerators running on household waste or scrap wood, connected directly to waste companies or energy companies by pipeline.

For electrolysis, the key to sustainability is to use large amounts of renewable power. To provide enough capacity for our largest electrolysis site in Rotterdam, we have signed purchase agreements directly with local energy collectives to enable the construction of two new wind parks.

As we increase our share of renewable power (currently at 45%) however, we reach another limit, as increasing amounts of wind energy on the grid cause large swings in supply. To help balance this, our latest electrolysis facilities use a technology called e-flex, which automatically adjusts production to the level of power supply, helping balance the grid and keep costs down.

Towards circular chemistry

“After sustainable energy, the next big challenge of the industry is raw materials,” states Van der Plas. “Our experience in salt production gives us the tools and expertise needed to make the sourcing of raw materials much more sustainable and move towards circular chemistry.”

Salt is abundantly available, with large underground deposits left by ancient seas easily stretching 100 years into the future. However, the other key ingredient of the chemical industry – carbon – is still mostly taken from non-renewable sources like oil and gas.

To change this, we are working on pilots to make new products with carbon from waste or even from CO2 emissions. These technologies require large amounts of hydrogen, which can be produced sustainably using a familiar process: electrolysis.

To further advance the transition to a circular economy, we are working on large-scale production of hydrogen from water, using the lessons we’ve learned from salt production during the past century to prepare us for the next 100 years.