Sodium lignosulfonate (NaLS) is commonly used as a binder in the production of pellets. Pellets are small, compressed units of material, such as wood chips or sawdust, used as a fuel source or as a feedstock-handling form in various industries.
Sodium lignosulfonate is a sulfonated lignin derivative — a class of compounds that contain a sulfonate group (-SO3-) bonded to a lignin-derived backbone, produced as a byproduct of the sulfite pulping process.
Properties Relevant to Pellet Binding
- Binding Strength: Sodium lignosulfonate has a high affinity for water, which supports its effectiveness as a binder for wet materials like wood chips.
- Thermal Stability: Sodium lignosulfonate is resistant to elevated temperatures, which supports its use in high-temperature applications like power-plant fuel pellet production.
- Handling Properties: Request the current SDS for the specific grade for hazard classification, flammability, and handling guidance — do not assume “non-toxic” or “non-flammable” status without SDS confirmation for the grade in use.
- Compatibility: Sodium lignosulfonate can be used in combination with other materials, such as clay and silica, to support a stable and consistent pellet composition.
Typical Process Steps
- Preparation: The raw material, such as wood chips or sawdust, is cleaned and sorted to remove impurities or contaminants.
- Mixing: The raw material is mixed with sodium lignosulfonate binder to create a homogeneous mixture.
- Compression: The mixture is compressed into pellets using a compression machine.
- Drying: The pellets are dried to remove excess moisture, supporting stability and strength.
- Final Processing: The dried pellets are further processed to remove remaining impurities and prepare them for use.
Use Across Pelletized Materials
Sodium lignosulfonate can be used as a binder in pellet formation for various materials, including coal and iron ore:
- Pellet Formation: Sodium lignosulfonate is added to the raw material as a binder; the mixture is then subjected to pressure and/or heat to form pellets, with the lignosulfonate acting as an adhesive that helps bind individual particles into a cohesive structure.
- Mechanical Strength: The binding properties of sodium lignosulfonate can support mechanical strength and integrity, helping pellets withstand handling, transportation, and processing stresses such as furnace or reactor charging.
- Durability: Sodium lignosulfonate binders can support physical and thermal stability, potentially reducing breakage, abrasion, and degradation during handling and processing.
- Uniformity: Use of sodium lignosulfonate as a binder can support formation of more uniformly sized and shaped pellets, which matters for material handling, feeding, and processing operations.
- Sourcing: Sodium lignosulfonate is derived from a renewable byproduct stream and is generally considered biodegradable; it can serve as an alternative to some synthetic or inorganic binders depending on the application.
Optimal dosage varies depending on the material being pelletized, desired pellet properties, and the specific pelletization process — establish the effective range through trials for the specific application rather than assuming a universal figure, and request the current TDS for the grade under consideration for a starting reference range.
Exact formulation and processing conditions depend on the specific application and requirements of the pellet production process. Request the current TDS, SDS, and COA for the applicable grade before formulation.
