Soda Ash for Metal Refining — Dense Sodium Carbonate Flux Supplier
Soda Ash for Metal Refining
Dense Sodium Carbonate Flux Supplier
Soda ash for metal refining is sodium carbonate (Na₂CO₃) used as a basic flux — it converts acidic impurities such as silica, phosphorus, sulfur, arsenic and antimony into sodium compounds that report to a fluid slag and are removed from the melt. This page covers the flux chemistry, dense-grade selection, dosage stoichiometry per kilogram of impurity, and the supply terms we export on.
- Grade supplied
- Dense soda ash 99.2% min
- Na₂O equivalent
- 58.5%
- MOQ
- 1 FCL
- Incoterms
- CIF · CFR · FCA · EXW · DAP
- Loading ports
- Mersin · Jebel Ali
- HS / CAS
- 2836.20 · 497-19-8
- 1 FCLMinimum order
- 5 IncotermsCIF · CFR · FCA · EXW · DAP
- 2 originsTurkiye & UAE
- 24 hQuote turnaround
What does soda ash do in metal refining?
Soda ash for metal refining works as a basic flux. Molten sodium carbonate reacts with the acidic impurities in the charge — silica, alumina, phosphorus pentoxide, sulfur and arsenic oxides — and converts them into sodium silicates, phosphates, sulfides and arsenates. Those compounds report to a low-melting slag layer that is immiscible with the metal and can be skimmed or poured off, leaving a cleaner bath and a higher recovery of the metal you are paying for.
Two things make it different from the other alkalis on a plant site. It is alkaline without being caustic to handle, so it can be charged by hand or by screw feeder with ordinary dust protection rather than the full protective equipment that caustic soda flakes demand. And it carries its own gas: as it decarbonates in the melt it stirs the bath, which accelerates contact between slag and metal — useful in a ladle, hazardous in a full furnace if it is added too fast.
Why sodium carbonate works as a metallurgical flux
Four properties do the work. Understanding them is what lets you decide a dosage instead of copying one from a handbook written for someone else's furnace.
1. It delivers 58.5% Na₂O
Flux chemistry is done on a Na₂O basis, not a product basis. One metric ton of dense soda ash carries 585 kg of Na₂O equivalent into the slag. That single number lets you compare it directly against any other sodium source and against the lime you are already charging.
Na₂O equivalent = 61.98 ÷ 105.99 = 58.5% · 1 kg Na₂O needs 1.71 kg Na₂CO₃2. It melts at 851 °C, so it is liquid where you need it
Sodium carbonate melts at 851 °C and has no boiling point — it decomposes on heating instead. Below its melting point it is an additive; above it, a genuine molten flux. At the 1,100–1,300 °C of a copper anode furnace or a steel ladle it is fully liquid, aggressive toward acidic oxides and low enough in viscosity to wet the impurity phase within minutes.
3. It neutralises acidic oxides into slag-forming sodium salts
This is the reaction that removes impurities. Silica is the clearest case, and the same pattern holds for phosphorus, sulfur, arsenic and antimony.
Na₂CO₃ + SiO₂ → Na₂SiO₃ + CO₂↑4. It decarbonates — and that gas is both a tool and a hazard
Fully decarbonated, one metric ton of soda ash releases about 415 kg of CO₂ — roughly 211 m³ of gas at standard conditions. Inside a ladle that gas stirs the bath and speeds up mass transfer. Dumped onto a hot full furnace it evolves inside the slag layer and lifts it, which is the boil that operators recognise immediately. Add in portions, inject below the surface where the practice allows, and keep freeboard during the addition.
A correction worth making
A number of published pages state that soda ash "decomposes at 400 °C" and treat that as its working limit. The figure refers to the onset of slow decomposition in laboratory thermal analysis, not to furnace behaviour: the material still melts intact at 851 °C and functions as a flux well above it. If you are sizing an addition for a 1,200 °C bath, the melting point is the number that matters.
Should you buy dense or light soda ash for a furnace?
Dense, in almost every case. The chemistry is identical; the physics is not, and the physics is what decides how much of the flux you bought actually reaches the melt.
| Property | Dense soda ash | Light soda ash | Why it matters in a furnace |
|---|---|---|---|
| Bulk density | 0.90–1.10 g/cm³ | 0.50–0.60 g/cm³ | Heavier granules penetrate the slag instead of riding on it or blowing off |
| Particle size (d50) | 250–500 µm | 90–150 µm | Fine powder is carried straight into the baghouse by furnace draught |
| Dusting on charge | Low | High | Flux loss, alkaline dust exposure and housekeeping cost |
| Feeder and lance behaviour | Free-flowing, meters reliably | Bridges and packs | Injection practice depends on a consistent mass flow rate |
| Typical market | Glass, metallurgy, mining | Detergents, chemical synthesis | Light grade is priced and specified for a different job entirely |
← Swipe the table sideways to see every column.
Where soda ash for metal refining is actually used
Not every "metal refining" claim made for sodium carbonate stands up. These are the applications where it does real work, with the reaction that explains each one.
01 Steel: desulfurization and dephosphorization
Charged onto hot metal or into the ladle, soda ash fixes sulfur as sodium sulfide and phosphorus as sodium phosphate, both of which float into the slag. It removes both impurities in a single treatment — lime-only practice generally needs separate conditions for each.
Na₂CO₃ + FeS → Na₂S + FeO + CO₂↑The sodium sulfide produced is the same compound sold as a reagent in its own right; if you also buy it, see sodium sulfide. The trade-off is refractory: sodium-rich slags attack acidic and some neutral linings faster than calcium-rich ones, so trim doses beat bulk doses.
02 Copper: arsenic and antimony removal
In anode refining, soda ash injected into blister or molten copper forms a sodium ferrite slag that takes up arsenic and antimony, which conventional oxidation leaves behind. Published smelter work reports that removal rates depend on the injection rate and depth into the bath, and that sodium-carbonate slags can bring anode arsenic and antimony down to levels electrorefining can accept.
Acidic As/Sb oxides + Na₂O (from Na₂CO₃) → sodium arsenate / antimonate → slagThis is the application where granulometry and injection consistency matter most, because the reaction is kinetically limited rather than thermodynamically limited.
03 Gold and silver: smelting and assay flux
Soda ash sits in almost every fire-assay and doré smelting recipe alongside borax and silica. It lowers the fusion temperature of the gangue, attacks silica and base-metal oxides, and keeps the slag fluid enough that precious metal collects into a clean button instead of staying trapped as entrained prills.
Recipes assume a stable Na₂O contribution batch to batch, which is why refiners specify consistency and iron content rather than chasing the lowest assay percentage on the market.
04 Lead, tin and secondary metals: soda slagging
In secondary lead and copper-alloy work, soda ash is used with or without sodium nitrate to slag off arsenic, antimony and tin as their sodium salts. The resulting slag is fluid and skims cleanly, which matters when the charge is scrap of uncertain composition and the treatment has to be repeated in stages.
The same sodium chemistry underpins soda ash roasting of antimony and arsenic bearing precious-metal concentrates, where the carbonate also captures sulfur dioxide that would otherwise leave the furnace.
05 Chromite: soda ash roasting to sodium chromate
Chromite ore roasted with soda ash in an oxidising atmosphere converts chromium into water-soluble sodium chromate, which is then leached out and processed further. Here soda ash is not a flux at all — it is the primary reagent, consumed stoichiometrically, which is why the tonnages involved are an order of magnitude above trim-flux use.
06 Alumina refining: soda make-up, not desilication
In a Bayer refinery, sodium leaves the circuit locked into the desilication product and the bauxite residue. Soda ash is the make-up soda that replaces that loss, then causticised with lime to regenerate the sodium hydroxide digestion actually needs.
Na₂CO₃ + Ca(OH)₂ → 2 NaOH + CaCO₃↓Pages that say soda ash desilicates the bauxite slurry directly have the chemistry the wrong way round — the desilication is done by the caustic liquor, and the carbonate is what has to be put back. Refineries that top up with liquid caustic soda instead are making the same correction by a different route.
07 Flotation and hydrometallurgy: pH control
Ahead of any furnace, soda ash is a standard pH modifier in mineral flotation circuits, holding the pulp in the alkaline window collectors need without the sharp overshoot a strong base gives. It also precipitates calcium and magnesium hardness that would otherwise consume reagent.
More on the upstream side in caustic soda in mining and soda ash in drilling.
08 Off-gas and effluent: SO₂ and heavy metals
Smelter off-gas scrubbing and effluent treatment both use sodium carbonate — it neutralises acid gases and precipitates heavy metals as carbonates that settle and filter. For many smelters this is a second, separate tonnage on the same purchase order as the flux.
Related: soda ash in water treatment and caustic soda for water treatment.
How much soda ash do you need per ton of metal?
The honest answer is that nobody can tell you per ton of metal — the requirement is set by the impurity. Work from stoichiometry, then apply your own plant's measured utilisation. The calculator below does the first half.
Utilisation is a plant-specific number that depends on bath temperature, stirring, slag basicity and contact time. Replace the default with your own measured figure as soon as you have one — a supplier's rule of thumb is a starting point, not a specification.
Indicative for planning a flux balance, not a substitute for a plant trial. The CO₂ figure is the gas volume your freeboard has to accommodate during the addition — the commonest cause of an unexpected boil.
Soda ash vs caustic soda, lime and borax as a refining flux
These four are not substitutes for one another, and the marketing claim that soda ash simply "replaces" lime does not survive a plant trial. Here is the real division of labour.
| Reagent | Strength | Limitation | Best used for |
|---|---|---|---|
| Soda ash (Na₂CO₃) | Fluid slag, works at lower temperature, removes S and P together, safe to handle | Aggressive on refractory lining; gas evolution risks a boil | Impurity trim, As/Sb removal, precious-metal flux, chromite roasting |
| Caustic soda (NaOH) | Highest alkalinity per ton, no gas evolution, available as liquid | Corrosive to handle, higher cost per ton of Na₂O, needs bunded storage | Hydrometallurgy, leaching, alumina circuits, effluent pH |
| Lime (CaO / Ca(OH)₂) | Cheapest basicity by a wide margin, refractory-compatible | Viscous slag, needs high temperature, weak on phosphorus alone | Bulk slag basicity in steelmaking |
| Borax (Na₂B₄O₇) | Dissolves metal oxides at low temperature, very fluid | Costly, narrow application, boron reports to the product in some systems | Precious-metal smelting, used alongside soda ash rather than instead of it |
← Swipe the table sideways to see every column.
The practical answer most plants reach
Lime for bulk basicity because it is cheap, soda ash for the final impurity trim because it is effective at lower temperature and removes what lime leaves behind, and borax where a precious-metal melt needs oxide solubility. Sites running hydrometallurgy alongside the furnace usually buy caustic soda flakes on the same order — current chlor-alkali levels are published on our caustic soda price page.
Dense soda ash specification for metallurgical use
A flux without a specification cannot be balanced. These are the parameters we contract against and report per batch on the certificate of analysis.
| Parameter | Specification | Why a refiner asks for it |
|---|---|---|
| Na₂CO₃ content | 99.2% min | Sets the Na₂O delivered per ton and therefore the flux balance |
| Na₂O equivalent | 58.5% | The figure used directly in slag calculations |
| Sodium chloride (NaCl) | Reported per batch | Chloride attacks some refractories and loads off-gas scrubbers |
| Iron (Fe) | Reported per batch | Critical in precious-metal and any colour-judged product |
| Water insolubles | Reported per batch | Material you pay freight on and then remove as slag |
| Loss on ignition | Reported per batch | Indicates moisture pickup and storage condition on arrival |
| Bulk density | 0.90–1.10 g/cm³ | Feeder calibration and container payload planning |
| Particle size (d50) | 250–500 µm | Dust loss, lance behaviour and slag penetration |
| Appearance | White granular, free-flowing | Caking on arrival means the shipment took moisture |
← Swipe the table sideways to see every column.
- CAS
- 497-19-8
- HS code
- 2836.20
- EC number
- 207-838-8
- Melting point
- 851 °C
- Packing
- 25 kg · 1 MT jumbo · bulk
- MOQ
- 1 FCL
- Loading
- Mersin · Jebel Ali
- Dangerous goods
- Not IMDG classified
- Documents
- COA · SDS · CO · B/L
The soda ash market behind your flux budget
Metallurgical use is a small slice of a very large commodity market, which means your flux price is set mostly by what glass and chemicals are doing — not by anything happening in your own industry.
Where it comes from
- China, Turkiye and the United States together accounted for 81% of world production in 2024, per the USGS
- Turkiye is a top-three producing country and a major exporter — the reason our Mersin loading option is short-haul rather than transhipped
- Natural soda ash from trona uses less energy and releases less CO₂ than synthetic Solvay material
- US production reached an estimated 12 million tons in 2025, about 3% above 2024
What sets the price
- Glass demand — 45% of US end use in 2025, so construction and automotive cycles move the whole market
- Chemicals — a further 28%, the second lever on price
- Energy — calcination and drying are energy-intensive at every origin
- Freight and Incoterm — on a low-value, high-density cargo, the shipping leg is a large share of landed cost
A published benchmark, and why your quote will differ from it
The USGS reports a 2025 average unit value for US natural soda ash of about USD 150 per metric ton, FOB mine or plant (Mineral Commodity Summaries 2026), against roughly USD 169 in 2024 and USD 211 in 2023. That is a domestic mine-gate figure for bulk material — it is not an export price.
Your landed cost adds bagging, inland haulage, port handling, ocean freight, insurance and duty, and it varies by origin, packing and Incoterm. We publish the benchmark here because it tells you the order of magnitude and the direction of travel; the contractable number comes back against your own destination and term.
Buying soda ash for metal refining — MOQ, packing and Incoterms
We are a soda ash supplier and exporter with offices in Ankara and Dubai, shipping dense soda ash to smelters, refiners and foundries. These are the terms an enquiry is quoted against.
Minimum order and packing
- MOQ: 1 FCL. Part-load trial quantities can be arranged but price higher per ton
- 25 kg bags — the standard export format, palletised or loose
- 1 MT jumbo bags (FIBC) — for plants charging by crane or hopper
- Bulk — on request against a suitable discharge facility
Incoterms available
- CIF — goods, ocean freight and marine insurance to your discharge port
- CFR — goods and freight, you arrange your own insurance
- DAP — delivered to a named inland place, import clearance yours
- FCA — handed to your carrier at origin, you control the shipping leg
- EXW — collected at the works, for buyers with their own logistics
Origin and routing
- Mersin, Turkiye — short-haul to the Mediterranean, Black Sea, North and West Africa
- Jebel Ali, UAE — Gulf, East Africa, Indian subcontinent and Southeast Asia
- Ankara and Dubai offices — documentation handled in the same time zone as either origin
- Consolidation with other chemicals on the same booking where volumes allow
Documents and payment
- Batch COA against the contracted specification
- SDS, Certificate of Origin, Packing List, Bill of Lading
- SGS or BV pre-shipment inspection on request
- T/T, L/C at sight or D/P — terms discussed against order size and history
Six lines in your enquiry, one contractable offer back
Metallurgical buyers who send these six details get a firm number the same working day. Enquiries missing the destination or the Incoterm turn into a round of questions instead.
Handling and storing soda ash on a plant site
Sodium carbonate is not a dangerous good for transport, which makes it easy to ship and easy to become careless with. Two failure modes account for almost all of the trouble.
Caking — the one that costs you money
- Store dry and covered, off the ground, bags sealed until the shift that uses them
- Rotate stock — material sitting for many months in humid air hardens into lumps
- Caked flux will not meter through a screw feeder or an injection lance, and breaking lumps by hand creates the dust exposure you were avoiding
- Check loss on ignition on arrival if the container crossed a monsoon route
Alkaline dust and acid contact — the one that hurts people
- Gloves, sealed goggles and dust protection when charging or breaking bags
- Segregate from acids — contact gives a vigorous CO₂ evolution and can burst a container
- Keep well clear of stored sulfuric acid and hydrochloric acid drums
- Eye contact — irrigate immediately and at length; alkaline dust is worse for eyes than its low hazard classification suggests
Soda ash and the other chemicals on a refining site
Soda ash for metal refining — FAQ
Send the specification. Get the contractable number.
Grade, tonnage, destination and Incoterm — that is all it takes. A firm CIF, CFR, FCA, EXW or DAP quotation comes back with the technical data sheet and the certificate-of-analysis format attached, normally within 24 hours on working days. Minimum one full container load, loading from Mersin or Jebel Ali.
