HS Code for Hydraulic lime

Hydraulic lime is classified under HS code 2522.30 within Chapter 25, which covers mineral products like salt, sulfur, and stone. Unlike quicklime (2522.10) or slaked lime (2522.20), hydraulic lime contains specific impurities—primarily silicates and aluminates—that allow it to set and harden under water or in damp conditions through a chemical process known as hydration. This material is produced by the calcination of limestone that naturally contains clay or by mixing lime with pozzolanic materials. The classification 2522.30 is specific to this hydraulic property. It is distinct from Portland cement (2523), which is a more highly processed hydraulic binder. The presence of these reactive silicates is the defining characteristic that separates 2522.30 from other forms of lime used in construction and agriculture. It is valued in historic restoration and sustainable building for its breathability and flexibility compared to modern cements.

Products Included

• Natural Hydraulic Lime (NHL 2, NHL 3.5, NHL 5).
• Feebly hydraulic lime used in internal plastering.
• Eminently hydraulic lime used for external masonry in harsh environments.
• Hydraulic lime binders for traditional mortar mixes.
• Argillaceous limestone-derived lime.

Common Misclassification

Hydraulic lime is often misclassified under HS code 2523.10 through 2523.90, which covers Portland and other hydraulic cements. While they share hydraulic properties, lime is chemically distinct and falls under 2522. Another error is using 2522.10 (Quicklime) or 2522.20 (Slaked lime). These types of lime require carbon dioxide from the air to set (carbonation) and will not set under water, thus they do not meet the definition of hydraulic lime. Finally, pure calcium hydroxide is classified in 2825.90, but the commercial construction material remains in Chapter 25.

FAQ

What is the HS code for hydraulic lime?

The HS code for hydraulic lime is 2522.30. This code excludes calcium oxide and hydroxide of heading 2825.

Can hydraulic lime be used for underwater construction?

Yes, the defining characteristic of hydraulic lime (2522.30) is its ability to set and harden through hydration, making it suitable for use in damp conditions or even submerged environments where standard lime would fail.