Kelex-100

• Molecular formula: C₂₀H₂₉NO
• Molecular weight: 299.46
• Appearance: A dark reddish-brown viscous liquid
• Purity: Typically ≥97%
• Boiling point: Approximately 430°C (760 mmHg)
• Flash point: approximately 214°C
• Storage: Store refrigerated at 2–8°C, tightly sealed and protected from light

• Dual functional group chelation: Containing a quinoline ring tertiary nitrogen (protonated in acidic media, binding an anion) and an 8-hydroxy group (dissoicated in neutral/alkaline media, binding a metal cation), enabling extraction across a wide pH range.

• High selectivity: Demonstrates strong chelating capacity for metal ions such as gallium, copper, zinc, cadmium, germanium, and cobalt, while exhibiting extremely low selectivity for monovalent ions (approximately 5000:1).

• Excellent oil solubility: Easily soluble in organic solvents such as kerosene and xylene, with extremely low water solubility, making it suitable for liquid-liquid extraction systems.

1. Gallium (Ga) recovery: Selective extraction of gallium from the alkaline mother liquor of the Bayer process bauxite smelting, one of the mainstream industrial processes.

2. Copper/Zinc/Cadmium Separation: High-efficiency extraction of copper, zinc, and cadmium in acidic media, applicable for ore leaching solutions and wastewater treatment.

3. Germanium (Ge) extraction: Separation and enrichment of germanium from acidic solutions such as coal ash and zinc smelting slag.

4. Precious metal/rare earth separation: Used for the separation and purification of cobalt, nickel, and rare earth elements (e.g., neodymium), often combined with formulations such as Cyanex 272.

Metals are extracted through dual mechanisms: cation exchange (neutral/weakly acidic) and anion exchange (strongly acidic). The metal-loaded organic phase can be back-extracted with dilute acid (e.g., 1–2 M H₂SO₄), enabling metal recovery and regenerating the extractant.

• Irritancy: Irritates the skin, eyes, and respiratory tract; protective eyewear, chemical-resistant gloves, and a fume hood are required during handling.

• Environmental risks: Avoid direct discharge; handle as hazardous waste.

• Incompatibility: May decompose and lose efficacy when exposed to strong oxidizers, strong acids, or strong bases at high temperatures.

Common Confusion Alert

Kelex-100 (an extractant, liquid) = Chelex 100 (a chelating resin, solid, branded by Bio-Rad, used in molecular biology); the two products have entirely different applications and formulations.