July 22, 2024
What sodium lignosulfonate?
- Sodium lignosulfonate is a byproduct obtained from the sulfite pulping process in the paper/pulp industry.
- In the sulfite pulping process, lignin is separated from wood materials using sulfurous acid or calcium bisulfite. This generates lignosulfonic acid as a byproduct.
- Sodium lignosulfonate consists of the sodium salts of this lignosulfonic acid. It contains sodium ions bonded to sulfonate groups on the lignin polymer.
- Its chemical formula is C6H6O4S2Na. It is a light to dark brown, water-soluble powder with a slight sulfurous odor.
- It is made up of polydisperse polymers with a wide range of molecular weights between 1000-50000 g/mol.
- The polymer backbone consists of phenylpropane units. Sulfonation occurs on these units, making it highly hydrophilic.
- This structure gives it excellent dispersing, emulsifying and stabilizing properties useful in many industrial applications.
- It is commonly used as a dispersant, surfactant, binder and thickening agent. Main applications include concrete admixtures, ceramics, mining, agriculture, oil drilling etc.
- As a concrete admixture, it acts as a water reducer and plasticizer to improve workability.
- Sodium lignosulfonate is non-toxic, biodegradable and considered GRAS status by FDA for use in some foods.
- Chemical formula – C6H6O4S2Na
- It is a byproduct obtained from the sulfite pulping process in the paper industry. Lignin from wood is separated using sulfite and the byproduct obtained is sodium lignosulfonate.
- It consists of sodium salts of lignosulfonic acid. Sulfonate groups make it water-soluble.
- It is a polydisperse polymer with a molar mass between 1000-50000 g/mol. The structure consists of sulfonated phenylpropane units.
- Commercially available as a dark brown water-soluble powder with sulfurous odor.
- Used as a dispersing agent, binder, emulsifier, etc. due to its surfactant properties.
- Common applications include concrete admixtures, oil well drilling, dust suppression, ceramics processing, agricultural applications, etc.
- As concrete admixture, it improves workability and strength. Acts as a water reducer and set retarder.
- Other uses – thickening agent, suspending agent, scale inhibitor, anti-caking agent, etc.
- Considered Generally Recognized as Safe (GRAS) for use in foods.
- Biodegradable and has low toxicity, hence widely used in various industries.
- Commodity chemical produced globally in bulk quantities as a pulp industry byproduct.