Lignosulfonate (lignosulphonate) is a water-soluble salt of lignosulfonic acid, recovered from the sulfite pulping of wood. It is a brown, odourless powder or liquid used as a dispersant, binder, water reducer and dust suppressant.
Types of Lignosulfonate
| Type | CAS No. | Typical uses |
|---|---|---|
| Sodium lignosulfonate | 8061-51-6 | Concrete, dispersants, dyes, ceramics, batteries |
| Calcium lignosulfonate | 8061-52-7 | Concrete, binders, dust control, drilling mud |
| Magnesium lignosulfonate | 8061-54-9 | Binders, dispersants |
| Ammonium lignosulfonate | 8061-53-8 | Dust control, binders |
Key Properties
- Dissolves in water at any pH; practically insoluble in organic solvents.
- Anionic polymer with sulfonic and carboxylic groups, giving surface activity and dispersing power.
- Composition varies with wood type and pulping conditions; grades are defined by lignosulfonate content, sugar, Ca + Mg and insoluble matter.
Main Industrial Uses
| Industry | Function |
|---|---|
| Concrete and cement | Plasticizer, water reducer, grinding aid |
| Ceramics and refractories | Binder and deflocculant |
| Lead-acid batteries | Expander in negative plates |
| Mining, briquettes, ore | Binder for fines and pellets |
| Oil drilling | Drilling mud thinner |
| Roads and yards | Dust-control binder |
| Dyes and pesticides | Dispersant |
Properties and CAS numbers in more detail: lignosulfonate CAS numbers and properties. How it is made: from lignin to lignosulfonate.
| Grade | Lignosulfonate content | Water-insoluble | Other key values |
|---|---|---|---|
| Sodium lignosulfonate GAC-NaLS-1 | 55% min (dry basis) | 1.5% max | pH 7.0–9.5; Ca + Mg 0.5% max; reducing sugar 7% max |
| Calcium lignosulfonate GAC-CaLS-1 | 55% min (dry basis) | 1.5% max | Ca + Mg 5–8%; reducing sugar about 7%; ash 12% max |
How Lignosulfonate Is Made
Wood chips are cooked with a sulfite solution. The cooking liquor sulfonates the lignin and dissolves it, leaving cellulose fibres for pulp. The spent liquor is refined (salt conversion, sugar reduction where needed), concentrated and spray-dried. Details: how sodium lignosulfonate is made.
Lignosulfonate vs Other Concrete Dispersants
| Lignosulfonate | SNF (naphthalene) | PCE (polycarboxylate) | |
|---|---|---|---|
| Type | Normal-range water reducer | High-range water reducer | High-range water reducer |
| Source | Wood (sulfite pulping) | Petrochemical naphthalene | Synthetic polymer |
| Typical use | General concrete, blends, cement grinding | Precast, high-strength concrete | Self-compacting and high-performance concrete |
| Cost | Lowest | Medium | Highest |
Our Grade One sodium lignosulfonate lists a water-reducing capacity of 8% min in its TDS. See SNF superplasticizer and lignosulfonate water reducer for concrete.
Frequently Asked Questions
What is lignosulfonate?
A water-soluble salt of lignosulfonic acid recovered from sulfite pulping of wood, used as a dispersant, binder, water reducer and dust suppressant.
What is lignosulfonate used for?
Concrete plasticizers, ceramic and briquette binders, battery expanders, drilling mud thinners, dust control and dispersants for dyes and pesticides.
Is lignosulfonate natural?
It comes from wood lignin, a natural polymer, but it is chemically modified (sulfonated) during sulfite pulping.
