Calcium lignosulfonate (CAS 8061-52-7) is a water-soluble anionic polymer from the sulfite pulping of wood, and it is the most widely used lignosulfonate concrete water reducer. Added to a concrete mix at a fraction of a percent by cement weight, it disperses cement grains so the same workability needs less water — which raises strength and improves placement. It also serves as a cement grinding aid, a general dispersant, a dust-control agent, and an animal-feed binder.
What is calcium lignosulfonate?
Calcium lignosulfonate is the calcium salt of lignosulfonic acid, recovered from the spent liquor of the sulfite pulping process. When wood is cooked to free its cellulose fibers, the lignin is sulfonated; neutralizing that liquor with a calcium base yields the calcium salt. The product is a light-to-medium brown powder or liquid that dissolves readily in water.
Like all lignosulfonates it is a UVCB material with no single molecular formula. It is a polydisperse polymer, with chain weights spanning roughly a thousand to tens of thousands of g/mol depending on wood source and process. The chemistry is identical to sodium lignosulfonate apart from the counter-ion, and that one difference is what makes calcium the default for concrete. Being a wood-pulping byproduct, it is derived from a renewable feedstock and is biodegradable, though degradation is slow.
Key properties & specifications
The table lists typical values for a technical-grade calcium lignosulfonate powder. These are representative ranges; the governing figures are on the Certificate of Analysis for the lot you receive.
| Property | Typical value / note |
|---|---|
| CAS number | 8061-52-7 |
| Synonyms | Calcium lignosulphonate, lignosulfonic acid calcium salt, calcium ligninsulfonate |
| Appearance | Light-to-medium brown powder (also supplied as liquid) |
| Ionic charge | Anionic |
| Molecular weight | No fixed value — polydisperse polymer, roughly 1,000 to tens of thousands g/mol |
| Water solubility | Readily soluble in water |
| pH (1% solution) | ~3 to 6 (mildly acidic) |
| Bulk density | ~0.5 to 0.7 g/cm³ (powder) |
| Moisture | Typically ≤7% in dried powder grades |
| Grades | Concrete/admixture, dispersant, dust-control, agricultural, ceramic/gypsum; powder vs. liquid |
A grade note for concrete buyers: residual reducing sugars from pulping can interfere with cement set and extend retardation, so admixture work typically specifies a low-sugar grade. Ask for the reducing-sugar figure on the TDS before a structural trial.
How calcium lignosulfonate works in concrete
Cement grains in water tend to clump, trapping mix water inside the flocs where it does no good for workability. Calcium lignosulfonate breaks that up. Its hydrophobic backbone adsorbs onto the cement grains while the anionic sulfonate groups give each grain a negative surface charge, so the grains repel one another and stay dispersed.
Two things follow. The freed water improves flow, so you can pull mix water out and hold the same slump — a lower water-to-cement ratio, which is the lever for higher strength and durability. The trade-off to plan around: lignosulfonate is a normal (mid-range) water reducer, not a high-range superplasticizer, and it mildly retards set. Modest retardation can help in hot-weather pours, but overdosing can stall set and entrain unwanted air, so the dose is bounded on both ends. For very high water reduction, formulators pair it with a polycarboxylate or move to a Type F/G admixture.
Applications & dosage
Use the figures below as starting points and confirm with a trial on your own cement and aggregates, because lignosulfonate is batch-variable.
Concrete water reducer / plasticizer
This is the primary use and the one to target. Plain calcium lignosulfonate functions as an ASTM C494 Type A (water-reducing) admixture; it meets Type D (water-reducing and retarding) only when formulated with additional retarding or set-control components, so reserve any Type D claim for the finished admixture rather than the raw powder. Typical loading is 0.1-0.3% by weight of cement — lower than the sodium salt’s usual range, which is part of why calcium is the cost-effective default.
Cement grinding aid
Added during clinker grinding, lignosulfonate reduces particle agglomeration and improves mill throughput and flowability of the finished cement. Dose is set by mill conditions and is typically a small fraction of a percent on cement.
Dispersant, ceramics & gypsum
As a general dispersant it stabilizes solids in pigment, dye, and agrochemical formulations; in ceramic bodies and gypsum it acts as a deflocculant and binder. Typical loading runs 0.1-1% of the formulation, tuned to solids content and fineness.
Dust suppression
Sprayed as a dilute aqueous solution on unpaved roads and surfaces, it binds fine particles and holds surface moisture to cut fugitive dust. Because it is water-soluble, expect to reapply after heavy rain.
Animal feed & agriculture
It is used as a pellet binder in animal feed to improve pellet durability and reduce fines, and as a carrier for agricultural micronutrients.
Calcium vs. sodium lignosulfonate
Both salts are lignosulfonate plasticizers and dispersants; the counter-ion sets the use case. Calcium is the cheaper, Portland-compatible workhorse for concrete. Sodium is reserved for places calcium causes trouble — certain dye and agrochemical dispersions, oilfield brines, and lead-acid battery expanders — or where higher solubility and a low-calcium product are required. Full detail is on our sodium lignosulfonate page.
| Attribute | Calcium lignosulfonate | Sodium lignosulfonate |
|---|---|---|
| CAS | 8061-52-7 | 8061-51-6 |
| Counter-ion | Calcium | Sodium |
| pH (1%) | ~3 to 6 | ~4 to 9 |
| Primary use | Concrete water reducer / plasticizer (the workhorse) | Dispersant; specialty water reducer; battery expander |
| Concrete dose (by wt. cement) | 0.1-0.3% | 0.2-0.6% |
| Lead-acid batteries | No | Yes (negative-plate expander) |
| Chosen when | Lowest cost; Portland-cement compatible | Calcium incompatible; high solubility / low-calcium needed |
Packaging, bulk supply & lead time
RawSource is a sourcing partner: we source calcium lignosulfonate in bulk to your specification rather than producing it. Standard formats are 25 kg bags, 500 kg and 1 MT (1,000 kg) bulk bags, and liquid in totes, moving by the pallet, tote, or full truckload. Lead time tracks grade, volume, and current sourcing, and we support container-load quantities and recurring supply programs. Send the application, the grade or spec, and the annual volume, and we will quote it.
Quality & documentation
Technical Data Sheets, Safety Data Sheets, and a batch Certificate of Analysis are available on request. Lignosulfonate is a variable, batch-dependent material, so for concrete work we recommend requesting the lot CoA and confirming performance with a trial mix on your own cement before scaling a new grade into production.
Frequently asked questions
What is calcium lignosulfonate used for?
Its leading use is as a concrete water reducer and plasticizer. It is also a cement grinding aid, a dispersant for pigments and agrochemicals, a deflocculant and binder in ceramics and gypsum, a dust-control agent, and an animal-feed pellet binder.
How much calcium lignosulfonate do I add to concrete?
A typical starting dose is 0.1-0.3% by weight of cement. Because the material is batch-variable and mildly retards set, confirm the loading with a trial mix on your own materials before production use.
Is calcium lignosulfonate a water reducer or a superplasticizer?
It is a normal-range water reducer (ASTM C494 Type A), not a high-range superplasticizer. For very high water reduction it is often paired with a polycarboxylate or replaced by a Type F/G admixture.
What is the difference between calcium and sodium lignosulfonate?
Same chemistry, different counter-ion. Calcium is the low-cost default for concrete because it is compatible with Portland cement; sodium is used where calcium is incompatible, where higher solubility is needed, or in lead-acid battery expanders.
Does calcium lignosulfonate retard concrete set?
Yes, mildly. That retardation can be useful in hot weather, but overdosing can delay set excessively, which is one reason the dose range is kept narrow.
What is the pH of calcium lignosulfonate?
A 1% solution is mildly acidic, typically about pH 3 to 6. The sodium salt tends to be less acidic, around pH 4 to 9.
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