Sodium formate (CAS 141-53-7), NaHCOO, is the sodium salt of formic acid – a white crystalline solid with a molecular weight of 68.01 that dissolves readily in water to give a mildly alkaline solution. It sits at the intersection of three markets: a reducing and buffering agent in leather and textile processing, a brine salt for drilling and completion fluids, and – in its granular form – a chloride-free de-icing agent.
We supply two commercial specifications that are genuinely different products rather than marketing variants: an industrial crystalline powder at 92%, 95% or 98% minimum assay, and a granular de-icing grade at 97% minimum, 2-6 mm, pH 8.0-11.0. The specification table below covers both.
Specification
| Parameter | Industrial grade (powder) | Granular de-icing grade | Why it matters |
|---|---|---|---|
| Assay (as NaHCOO) | Min 92% / 95% / 98% | Min 97% | Three industrial tiers exist because the downstream user rarely needs 98%. Leather and textile users buy 92-95%; brine and synthesis users buy 95-98%. Buying 98% for a job that tolerates 92% is the most common avoidable cost in this product |
| Organic impurities | Max 2% | Not normally specified | The balance in the industrial powder is mainly residual sodium formate homologues and moisture carried from the synthesis. High organic load shows up as colour in the finished liquor |
| Moisture | Max 2% | Declared per batch | Sodium formate is hygroscopic. Moisture above spec is what makes a “free-flowing powder” cake solid in the bag within weeks |
| Appearance | White crystalline powder | White irregular granules | Off-white or grey material usually signals iron pickup from the dryer or a poorly washed centrifuge cake |
| Particle size | Powder, typically 40-100 mesh | 2-6 mm granules | The whole reason the granular grade exists – see below |
| pH | Typically 7-9 in solution | 8.0 – 11.0 | The granular grade is deliberately alkaline. That alkalinity is a corrosion-control feature on steel, and a handling caution on aluminium and skin |
| Chloride | Low by route | Declared; the point of the product | Whether a “chloride-free” claim is real depends on the manufacturing route, not on the spec sheet alone |
Reading the two specifications side by side
The industrial sheet is written by a chemist and the de-icing sheet is written by an application engineer. That is why the industrial sheet lists organic impurities and moisture, while the de-icing sheet lists only particle size and pH and leaves assay at a single 97% floor.
Particle size is the specification. A municipal spreader, a runway de-icer and a bagged consumer product all meter solids by volume through a spinner or auger. Powder fluidises, blows off the target area and dusts the operator; 2-6 mm granules fall where they are thrown and blend with rock salt without segregating. If a supplier offers “sodium formate” without a size distribution, they are offering the powder grade and you will lose a measurable fraction of it to the wind.
pH 8.0-11.0 is a functional window, not a labelling detail. The alkaline reserve neutralises the acidic run-off that chloride salts produce and keeps the pH over steel and galvanised steel in a range where the oxide film stays intact. The same alkalinity is a caution for aluminium, copper and zinc-rich coatings, and it means the material should not be handled with bare hands for long periods.
How it is made
Most sodium formate is produced by neutralising formic acid with sodium hydroxide, or as a co-product of pentaerythritol and neopentyl glycol manufacture, where sodium formate is the stoichiometric by-product of the crossed Cannizzaro reaction and is recovered by crystallisation. The recovery route matters commercially: co-product material carries a different colour and organic-impurity profile from synthesised material, and it is why 92% and 95% grades exist as legitimate products rather than as off-spec lots.
Granulation to the 2-6 mm de-icing size is a separate finishing step – compaction and crushing, or prilling – and it is the reason the granular grade carries a premium over the powder at the same assay.
Where each grade is used
| Grade | Applications |
|---|---|
| Industrial powder | Leather deliming, pickling and chrome-tan masking; reducing agent in dyeing and printing; drilling and completion brines (high-density, solids-free, chloride-free); concrete and mortar admixtures; intermediate for formic acid, oxalic acid and sodium dithionite; flue-gas and water treatment; silage additive |
| Granular de-icing | Runways, taxiways and aprons where chloride run-off is unacceptable; bridges, ramps and multi-storey car parks with galvanised or post-tensioned steel; loading docks and cold stores; blends with rock salt to extend the working temperature |
Packaging, storage and documentation
| Item | Detail |
|---|---|
| Packaging | 25 kg bags (paper with PE liner for powder, woven PP for granular), 1000 kg jumbo bags, and bulk bags for de-icing contracts |
| Storage | Dry, sealed, under cover. The granular grade tolerates outdoor silos better than the powder, but both are hygroscopic – a silo that breathes humid air will bridge |
| Documentation | Batch COA (assay, moisture, pH, particle size), SDS, and for de-icing tenders the corrosion and biodegradability data the tender document asks for |
| Regulatory | No chlorides and no heavy-metal content, which is normally what lets the granular grade into runway and drinking-water-catchment specifications; confirm the exact test list against the tender before quoting |
Related products: calcium formate (CAS 544-17-2) for the calcium analogue used in concrete and feed, magnesium chloride hexahydrate (CAS 7791-18-6) and calcium chloride 94% (CAS 10043-52-4) for the chloride-based de-icing comparison.
Contact PolyBlueChem for a current COA, the size distribution curve of the granular grade, and pricing on bagged or bulk-bag de-icing quantities.
