Solar salt is a high-purity salt obtained through the natural evaporation of seawater using solar energy. Thanks to its consistency, low impurity levels, and cost efficiency, solar salt is widely used across multiple industries, especially in water softening, industrial processing, and chemical applications.

This guide explains what solar salt is, how it is produced, what it is used for, and how it compares to other types of salt.

What Is Solar Salt?

Solar salt is primarily composed of sodium chloride (NaCl) and is produced by evaporating seawater in large outdoor ponds using sun and wind. As the water evaporates, salt crystals form and are harvested, washed, and graded according to purity and grain size. Because the process relies on natural evaporation, solar salt offers a stable chemical composition suitable for technical and industrial uses.

Key Applications of Solar Salt

Industrial & Chemical

Food Industry

Water Softening

De-icing

When salt is added to water, it appears to disappear, but what actually happens at the molecular level? Understanding whether this process is a physical or chemical change is a fundamental concept in chemistry with direct relevance to industrial salt applications, from water treatment to food processing. According to the Royal Society of Chemistry, dissolving is classified as a physical process because no new chemical substance is formed. For more on the chemical properties of salt, see our salt chemical formula guide.

Is Dissolving Salt in Water a Chemical Change?

No. When sodium chloride is added to water, it separates into its ions, Na⁺ and Cl⁻, but the chemical composition does not change. No new substance is formed, which is the defining characteristic of a chemical change.

So, Is It a Physical Change?

Yes. This process is considered a physical change because it can be reversed. When water evaporates, the sodium chloride reappears in solid form with the same chemical formula: NaCl. The substance before and after dissolution is identical.

Why Is It Physical and Not Chemical?

Because:

• No new substance is formed
• The ions separate but remain chemically identical
• The process is reversible through evaporation

Although the salt interacts with water, this interaction does not modify its chemical structure. This is why industrial salt remains chemically stable when dissolved in water treatment and food processing applications. For a full overview of how sodium chloride behaves across industrial processes, see our major uses for industrial salt page.

What Happens at the Molecular Level?

When sodium chloride is added to water:

1. Water molecules surround the Na⁺ and Cl⁻ ions
2. The ionic bonds weaken and separate
3. The ions disperse uniformly in the solution

This process is called dissociation, not a chemical reaction. The Khan Academy explains dissociation as the separation of ions in solution without forming new chemical bonds, a key distinction from chemical reactions such as neutralisation or oxidation. See Khan Academy: Dissolving and Dissociation.

Is It Ever a Chemical Change?

In normal conditions, dissolving sodium chloride in water is a physical process. However, if the dissolved ions react with another substance, for example during electrolysis in chlor-alkali industrial processes, that specific reaction may be chemical. But dissolution alone is not a chemical change.

This distinction matters in industrial contexts. The chlor-alkali process, one of the largest industrial uses of sodium chloride, relies on electrolysis of brine to produce chlorine and sodium hydroxide, a chemical transformation that begins with a physical dissolution step. For more on how salt is used in industrial chemical production, see our industrial salt uses guide.