Calcium lignosulfonate is used in ceramics in two main ways: as a temporary binder that gives unfired (green) ware handling strength, and as a deflocculant that lowers the viscosity of clay slips. It burns out during firing. This page is an overview by ceramic product and process, with links to our more detailed guides.
Binder or deflocculant?
| Function | Where it is used | What to measure |
|---|---|---|
| Binder (green strength) | Pressed tiles, extruded bricks, refractory shapes, granulated bodies | Green and dry strength, edge damage, compaction, release |
| Deflocculant (dispersion) | Casting slips, spray-dryer slurries, glaze and engobe suspensions | Viscosity at the target solids, settling, viscosity drift |
The best addition for dispersion is usually not the best for binding, so test them separately. Reference texts such as Reed, Principles of Ceramics Processing, list lignosulfonates among the organic binders and dispersants used in ceramic forming.
Use by ceramic product
- Wall and floor tiles: binder in spray-dried granules for pressing and dispersant for the slurry. See calcium lignosulfonate for tile manufacturing.
- Pressed and extruded bodies, refractories: green-strength binder. See calcium lignosulfonate ceramic binder.
- Slips and slurries: dispersion and flow control. See calcium lignosulfonate for ceramic processing.
- Pottery and studio ceramics: slip, green binding and firing trials. See calcium lignosulfonate for pottery.
Sodium lignosulfonate grades are covered separately, for example in liquid sodium lignosulfonate for ceramics and lignosulfonate as a ceramic plasticizer.
Choosing a calcium lignosulfonate grade
| Grade | Key TDS values | Typical ceramic use |
|---|---|---|
| Grade One (GAC-CaLS-1) | Lignosulfonate 55% min (dry basis); water-insoluble 1.5% max; ash 12% max | Binder for pressed and extruded ware |
| Grade Three (GAC-CaLS-3) | Water-insoluble 0.5% max; reducing matter 18 – 20% | Binder where low insolubles matter |
| Dispersant Grade (GAC-CaLS-Dispersant) | Lignosulfonate 55% min (dry basis); pH 7 – 10 (5% solution) | Slip and slurry dispersion; supplier-recommended starting trial range 0.1 – 1.0% by material weight |
Full specifications and documents are on the calcium lignosulfonate product page.
Firing and quality points
- Calcium lignosulfonate is organic and burns out; check for black coring, bloating or pinholes in thick ware and with fast firing.
- Its brown colour and calcium content may not suit some white bodies and glazes; run fired-colour tests.
- Sugars in the grade can affect slip stability during storage; watch viscosity drift and microbial growth in stored slurries.
Earlier versions of this page quoted fixed figures such as a doubling of green strength. Those were not from our own tests, so we have removed them; the effect depends on the clay body and process and must be measured.
Frequently Asked Questions
Is calcium lignosulfonate a binder or a deflocculant in ceramics?
It can be both. At low additions in slips it mainly disperses clay particles; in pressed or extruded bodies it acts as a temporary binder that increases green strength. Test the two functions separately.
What is a lignosulfonate binder for ceramics?
It is a water-soluble lignosulfonate added to a ceramic body or granulate to hold particles together before firing. It burns out in the kiln.
How much calcium lignosulfonate is used in ceramics?
For our dispersant grade the TDS gives 0.1 – 1.0% by material weight as a supplier-recommended starting trial range. Binder additions are set by green-strength tests on the actual body.
Send your body recipe, forming method and firing schedule to info@greenagrochem.com for a trial sample.
