Sub-Product

Vacuum salt, also known as vacuum evaporated salt, is a type of salt purified through a unique manufacturing process. This process involves heating the salt to high temperatures in a vacuum chamber, removing impurities and moisture, resulting in a pure, high-quality salt^[1].

Types of Vacuum Salt

• Undried Vacuum Salt: Produced through evaporation without drying, resulting in a higher moisture content.
• Dried Vacuum Salt: Evaporated and then dried, resulting in a lower moisture content^[1].

Manufacturing Process

Vacuum salt is typically produced through evaporative crystallization, using energy sources such as steam or electricity, and various plant configurations, including Multiple Effect Evaporation (MEE), Thermal Vapour Recompression (TVR), or Mechanical Vapour Recompression (MVR)^[1].

Properties

• Crystalline sodium chloride (common table salt)
• High purity level
• Can be extracted from underground salt layers using vacuum evaporation^[1].

Industrial Applications

• Used as an ingredient in heavy-duty detergents, providing a fibre-friendly effect and neutral behavior towards wastewater
• Regulates viscosity in liquid soaps, detergents, and rinsing agents
• Basic material for detergent processing^[1]

Salt Purity

Vacuum salt is considered the purest form of salt, with a high-quality standard suitable for various industrial and potentially food-grade applications^[1].

The following table shows the typical compositions of sodium chloride used in chlor-alkali electrolysis^[2]:

References

1. Brave Search Summarizer, 29^th Jul 2024, Vacuum Salt
2. Kirk-Othmer, 2002, 'Chlorine', Kirk-Othmer Encyclopedia of Chemical Technology.