The properties that matter for fertilizers and soil inputs are solubility, pH, calcium content, complexing ability and compatibility with nutrient salts. This page gives the agricultural-grade values and explains how each property affects granulation, solutions and tank mixes.
- Solubility: 0.2% max water-insoluble matter (agri grade).
- pH: 4–7.
- Calcium + magnesium: 5–6% (as sulfate).
- Functional groups: sulfonate, phenolic hydroxyl and carboxyl groups.
Agricultural Grade Values
| Parameter | GAC-CaLS-AGRI (TDS Rev. 2.0) |
|---|---|
| Appearance | Yellow-brown powder |
| Lignosulfonate content | 60% min (dry basis) |
| Dry matter / moisture | 95% min / 5% max |
| Water-insoluble matter | 0.2% max |
| pH | 4–7 |
| Total calcium and magnesium (as sulfate) | 5–6% |
| Sulphate | About 5% |
| Sugar | 15% |
| Total NPK | About 10% |
Typical values from the current TDS. Each lot ships with a COA.
What Each Property Means for Fertilizers
| Property | Effect in fertilizer and soil products | Check |
|---|---|---|
| Water solubility | Dissolves into binder solutions and liquid fertilizers; low insolubles protect nozzles and drip filters | Filter test with process water |
| pH 4–7 | Mildly acidic to neutral; affects stability of some micronutrients and actives | pH of the final mix |
| Calcium content | Can precipitate with phosphate or sulfate at high concentration | Jar test with all salts |
| Complexing groups | Hold Fe, Zn, Mn and Cu in solution over a pH range | Stability on dilution and storage |
| Anionic charge | Disperses fine particles in suspensions and wettable powders | Suspensibility and sedimentation |
| Sugar (15%) | Adds tack in granulation; can feed microbes in stored liquids | Storage stability of solutions |
| Hygroscopic powder | Picks up moisture and can cake | Sealed storage; reseal bags |
Complexing and Micronutrients
Lignosulfonates hold metal ions through phenolic and carboxyl groups. This is complexation, which is weaker and more pH-dependent than chelation by synthetic agents such as EDTA. In the EU, lignosulfonic acid was added to the list of authorised complexing agents for micronutrient fertilisers by Regulation (EU) No 223/2012. A comparison with synthetic chelates is in lignosulfonate vs EDTA chelates; formulation guidance is in micronutrient complexes: Fe, Zn, Mn.
Compatibility Testing
Before scaling up, mix the calcium lignosulfonate with every other ingredient at use concentration in your water and watch for precipitation, sediment and foam over 30 minutes and 24 hours. Step-by-step instructions are in the jar test for lignosulfonate tank mixes.
Storage and Handling
Store in a cool, dry, ventilated area and reseal opened bags. Shelf life is 24 months in the original unopened packaging. Use the SDS for handling details.
Agricultural vs Industrial Grade Properties
| Grade | Lignosulphonate (dry basis) | Appearance | pH | Water-insoluble | Ca + Mg (as sulfate) |
|---|---|---|---|---|---|
| CaLS Grade One | 55% min | Light yellow-brown powder | — | 1.5% max | 5 – 8% |
| CaLS Grade Two | 50% min | Dark brown powder | 7 – 9 | 2% max | 5 – 8% |
| CaLS Grade Three | 50% min | Yellow-brown powder | about 6 | 0.5% max | 5 – 6% |
| CaLS Agri (GAC-CaLS-AGRI) | 60% min | Yellow-brown powder | 4 – 7 | 0.2% max | 5 – 6% |
Typical values from the current TDS; dry matter 95% min for all grades.
Preparing a Solution
- Add the powder slowly to water under stirring; it is fully water-soluble.
- Prepare the concentration you need for granulation liquid or spray tank.
- Check pH and filter a sample through the nozzle or drip filter you will use.
- Use stored solutions promptly; sugars can support microbial growth over time.
FAQ
Is calcium lignosulfonate soluble in water?
Yes. The agricultural grade lists 0.2% max water-insoluble matter, so it dissolves almost completely. Check dissolution in the actual process water, since hard water and salts can change the result.
What pH does it have?
The GAC-CaLS-AGRI TDS gives pH 4–7. Check pH again after mixing with fertilizer salts.
Does it complex micronutrients?
Its phenolic and carboxyl groups can complex metal ions such as iron, zinc and manganese. Lignosulfonic acid is an authorised complexing agent under EU fertiliser rules (Regulation (EU) No 223/2012).
Is it compatible with fertilizer salts?
Usually, but calcium can precipitate with phosphate and sulfate at high concentration. Run a jar test with the complete mix.
What are the main properties of calcium lignosulfonate?
Water-soluble, anionic, pH 4 – 7 (agri grade), 5 – 6% calcium and magnesium as sulfate, with complexing and dispersing ability.
Is calcium lignosulfonate soluble in water?
Yes, it is fully water-soluble; the agri grade has 0.2% max insolubles.
Grades and Documents
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