Magnesium lignosulfonate (CAS No. 8061-54-9) is a water-soluble anionic polyelectrolyte polymer derived from the sulfite pulping process of wood, primarily softwood. It appears as a light yellow to brown powder and is used across various industries due to its versatile properties.

Technical Specifications

• Product Name: Magnesium Lignosulfonate (Magnesium Lignosulphonate)
• Appearance: Light yellow to brown powder
• Solubility: 98.5% minimum, easily soluble in cold and hot water
• Lignosulfonate Content: 50–60%
• Dry Matter: ≥95%
• pH: 4–6 (acidic to slightly acidic)
• Moisture Content: ≤7%
• Ash Content: ≤12%
• Water Insoluble Matter: Low (typically <0.5%)
• Molecular Weight: Broad range, typically 1,000–140,000 Da (polydisperse)
• Chemical Formula: Not precisely defined due to its complex polymeric structure
• Main Components: Magnesium salt of lignosulfonic acid, containing sulfonated phenylpropane units

Production Process

Magnesium lignosulfonate is extracted from pulping liquor via purification, evaporation, chemical treatment, and drying. It is a byproduct of the sulfite pulping process, where wood chips are treated with magnesium-based sulfite or bisulfite salts (MgSO₃ or Mg(HSO₃)₂) under acidic conditions (pH 1–5). The process involves sulfonation and hydrolysis, introducing sulfonic acid groups to the lignin structure, enhancing its water solubility. The final product can be supplied as a powder or liquid (approximately 50% solids content after evaporation).

Key Properties

• Water Solubility: Highly soluble, making it effective as a dispersant and viscosity modifier.
• Anionic Polyelectrolyte: Contains sulfonic and carboxyl groups, contributing to its surfactant and dispersion capabilities.
• Binding and Dispersing: Acts as a binder for powdery/granular materials and a dispersant for insoluble solids/liquids in water.
• Plasticizing: Enhances workability in concrete and ceramics by reducing water content.
• Chelating: Can bind metal ions, useful in applications like wastewater treatment.
• Dust Suppression: Forms a high-viscosity, sticky layer when dried, effective for dust control on roads and industrial processes.

Applications

1. Concrete Admixture:
   • Acts as a water-reducing agent, improving concrete flowability while maintaining strength.
   • Reduces water usage by 10–15%, enhancing workability and durability.
   • Compatible with naphthalene and melamine-based water-reducing agents for set-retarding and pumping applications.
2. Dust Control:
   • Used on unpaved roads and in industries (e.g., mining, agriculture) to suppress dust by binding surface particles.
   • Environmentally friendly, non-toxic alternative to calcium chloride, providing a dark grey surface when applied.
3. Ceramics and Refractory Materials:
   • Serves as a binder and plasticizer, improving workability and strength in ceramic tiles and refractory products.
4. Animal Feed:
   • Used as a binder in pelleting to improve pellet durability and reduce dustiness.
   • Non-toxic and approved for use in animal feed by regulatory bodies like the U.S. FDA.
5. Agriculture:
   • Acts as a soil conditioner, enhancing soil structure, water retention, and nutrient availability.
   • Chelates micronutrients, improving fertilizer efficiency and plant growth.
6. Oil and Gas Industry:
   • Reduces viscosity in drilling mud, replacing tannic acids, and acts as a shale inhibitor.
7. Other Uses:
   • Binder in particleboards, coal briquettes, and lead-acid battery pastes.
   • Dispersant in pesticides, dyes, and carbon black.
   • Component in phenolic resin composites for abrasive materials.

Chemical and Physical Characteristics

• Structure: Complex, amorphous polymer with phenylpropanoid units (primarily guaiacyl units). Sulfonation occurs on the side chains, not the aromatic rings, enhancing solubility.
• Vibrational Spectroscopy:
  • Aromatic hydroxyl groups: 3450–3380 cm⁻¹
  • C–H stretching (methyl/methylene): 2950–2930 cm⁻¹
  • Aromatic ring vibrations: 1620–1600 cm⁻¹, 1518–1509 cm⁻¹, 1430–1400 cm⁻¹
  • Carbonyl groups (post-oxidation): ~1700 cm⁻¹ (observed when activated with H₂O₂).
• XPS Analysis:
  • Carbon (C 1s A): 284.7 eV (aromatic rings)
  • Carbon (C 1s B): 286.2 ± 0.2 eV (C–O–C, C–OH)
  • Carbon (C 1s C): ~287.3–287.4 eV (carbonyl groups, post-oxidation)
  • Carbon (C 1s D): 288.9 ± 1.3 eV (O=C–O– groups).
• Stability: Stable at room temperature under normal storage conditions. Avoid strong bases, acids, and excessive heat.

Safety and Toxicological Data

• Hazards: Non-toxic, non-irritating, non-mutagenic, and non-genotoxic. Not classified as hazardous under standard handling conditions.
• Health Effects:
  • Eyes: May cause irritation; flush with water for at least 10 minutes.
  • Skin: Non-poisonous but may cause irritation; wash with soap and water.
  • Inhalation: No specific acute effects; remove to fresh air if irritation occurs.
  • Ingestion: Seek medical attention or contact poison control.
• Environmental: Biodegradable, mobile in soil, and environmentally friendly. Toxic levels in surface water are high, posing low risk to aquatic life.
• Regulatory: Approved for use in animal feed, food contact materials, and pesticide formulations by the U.S. FDA. Registered under REACH in the EU.

Disposal and Handling

• Disposal: Dispose of in approved landfills or apply at recommended rates. Follow federal, state, and local regulations.
• Handling: Wear overalls, safety glasses, gloves, and a dust mask if excessive dust is present. Avoid generating dust and wash hands after use.

Additional Notes

• MSDS Availability: Material Safety Data Sheets are available from suppliers like Green Agrochem.
• Suppliers: Companies like Green Agrochem provide magnesium lignosulfonate in various forms. For pricing or samples, contact suppliers directly
• Research Applications: Used in studies for phenolic resin composites and as a bio-adhesive in particleboard manufacturing with low formaldehyde emissions.

Conclusion

Magnesium lignosulfonate is a highly versatile, eco-friendly material with a wide range of applications due to its water solubility, anionic properties, and multifunctional capabilities. Its role as a binder, dispersant, plasticizer, and chelating agent makes it essential in industries like construction, agriculture, animal feed, and environmental management. With a well-established safety profile and regulatory approval, it is a sustainable choice for industrial and research applications. For specific grades, pricing, or technical support, contact reputable suppliers like Green Agrochem or refer to their websites for detailed product data.