Calcium lignosulfonate is obtained from the spent sulfite and sulfate pulping liquor of wood or from
the sulfate (kraft) pulping process. It may contain up to 30% reducing sugars.
This dossier contains toxicity data on calcium lignosulfonate (40-65). Calcium lignosulfonate (40-65)
is produced from softwood in the sulfite pulping method for manufacturing paper. In this process,
bisulfite ions react with the native lignin polymer of the wood to form sulfonated lignin
(lignosulfonate). This reaction increases the water solubility of the hydrophobic lignin polymer.
Calcium lignosulfonate contains <5% reducing sugars. The calcium bisulfite provides the calcium ions
that stabilise the anionic sulfonate groups in the lignosulfonates. The average molecular weight is in
the range of 40,000 to 65,000 daltons, with >90% ranging from 1,000 to 250,000 (EFSA, 2010).
Calcium lignosulfonate (40-65) is of higher purity than calcium lignosulfonate, with a higher degree
of polymerisation and lower content of sugars.
CALCIUM LIGNOSULFONATE CHEMICAL NAME AND IDENTIFICATION
Chemical Name (IUPAC): Calcium lignosulfonate
CAS RN: 8061-52-7
Molecular formula: Not applicable.
Molecular weight: Unknown
Synonyms: Calcium lignosulfonate; lignosulfonic acid, calcium salt; lignin calcium sulfonate
3 PHYSICO-CHEMICAL PROPERTIES
Calcium lignosulfonate and calcium lignosulfonate (40-65) occur as a brown, amorphous polymer
(EFSA, 2010). They are soluble in water, but not in any of the common organic solvents.
The pH of a 1:100 aqueous solution of calcium lignosulfonate is between ca. 3 and 11 (EFSA, 2010).
CALCIUM LIGNOSULFONATE APPLICATION
Calcium lignosulfonate is a material that is used in the field of adsorption. It is a brown, free-flowing powder with a particle size of 10 to 20 μm and contains hydroxyl groups, nitrogen atoms, and langmuir adsorption isotherms. The calcium content ranges from 40% to 60%. Calcium lignosulfonate has an activity index of 0.1 g/g at 25°C and can be used as an adsorbent for benzimidazole compounds. Calcium lignosulfonate exhibits a basic structure that consists of layers of alternating hydroxyl groups and benzimidazole rings. This material also shows electrochemical impedance spectroscopy properties that are different than other materials.
Calcium lignosulfonate can be used as a dispersant, emulsifier, wetting agent, etc. It can be used in industrial detergents, pesticides, insecticides, herbicides, fungicides, brick and refractory materials, concrete, cement, coke and charcoal processing, dyes and pigments, casting, gypsum products, granulation processing, petroleum, electroplating Bath, leather tanning, wax emulsion, etc.
