Sodium sulphate is one of those chemicals that turns up almost everywhere in industry and yet is rarely the star of the product it goes into. It fills detergent powder, keeps the kraft pulping cycle topped up, clears bubbles out of molten glass and helps dye sit evenly on fabric. Because the jobs are so different, the spec that matters changes with the application — and buying the wrong grade is an expensive way to find that out. Here is where Na₂SO₄ goes, and what to check before you order.
Sodium sulphate (Na₂SO₄) is a white crystalline powder — neutral, odourless and highly soluble in water. The anhydrous grade is the one traded in bulk for industry; the hydrated form, sodium sulphate decahydrate, is the old Glauber's salt. In Chinese-speaking trade it is usually called 元明粉.
Chemically it is unremarkable, and that is exactly the point. It does not react with much, it does not decompose in storage, it dissolves cleanly, and it is cheap relative to the actives it sits alongside. That combination is why it ended up as the default filler, carrier and process chemical across four large industries.
Most sodium sulphate produced in the world ends up in powder detergent, and it is not there by accident. Surfactants and enzymes are the cleaning actives, but a detergent powder still has to pour out of the box, flow through a filling line, resist caking in a humid warehouse and dose consistently in a scoop. Na₂SO₄ does that structural work: it provides bulk, carries the actives, keeps the powder free-flowing and gives the batch a stable, repeatable density.
For detergent buyers, two specs dominate:
Insoluble matter matters too, particularly for liquid or dissolving applications, since anything that will not dissolve shows up as residue.
The kraft process — literally the "sulphate process" — cooks wood chips in a liquor of sodium hydroxide and sodium sulphide to free the cellulose fibres. That liquor is recovered and reused, but sodium and sulphur are lost around the loop, so the mill has to top the system back up. Sodium sulphate is the classic make-up chemical: added to the recovery cycle, it is reduced to sodium sulphide in the recovery furnace and rejoins the cook.
What a mill cares about here is what rides along with the Na₂SO₄:
In a glass furnace, sodium sulphate is a refining (fining) agent. Molten batch traps gas; if those bubbles stay in, you get seeds and blisters in the finished glass. Sodium sulphate decomposes at melting temperature and releases gas that sweeps the small bubbles out, while also breaking down the scum layer of unmelted silica floating on the melt and helping wet out the sand. The result is a cleaner, more homogeneous melt at a workable pull rate.
Glassmakers are buying consistency more than anything: a fining agent that varies batch to batch changes furnace behaviour. Low iron matters here as well, since iron carries straight into the glass as colour — a serious problem for clear and flint glass.
In dyeing — particularly reactive and direct dyes on cellulosic fibre — sodium sulphate is used as an electrolyte and levelling agent. Adding it to the dyebath drives dye exhaustion onto the fibre, so more of the dye you paid for actually fixes rather than washing away. Just as important, it slows and evens the strike so the shade builds up uniformly instead of blotching.
This is the application where trace hardness is unforgiving:
Every line on the certificate maps to a real risk somewhere downstream. Read it against your own process rather than against the headline assay alone:
| Item | Standard | Typical Result |
|---|---|---|
| Assay (Na₂SO₄) | 99.0% min | 99.79% |
| pH | 7.0 ± 1.5 | 8.66 |
| Moisture | 0.20% max | 0.01% |
| Insoluble matter | 0.05% max | 0.0048% |
| Chloride (Cl) | 100 ppm max | 63.65 ppm |
| Iron (Fe) | 100 ppm max | 0.46 ppm |
| Calcium (Ca) | 50 ppm max | 4.36 ppm |
| Magnesium (Mg) | 30 ppm max | 7.63 ppm |
| Whiteness | — | 94.87% |
These are typical values from our anhydrous grade, not a best-ever result. Read them the way a buyer should: 99.79% assay against a 99.0% minimum, moisture an order of magnitude inside spec for detergent flow, iron at 0.46 ppm against a 100 ppm ceiling for pulp and glass, and calcium and magnesium comfortably low for dyehouse work.
We supply sodium sulphate in 50kg bags and 1MT jumbo bags — 50kg for blending lines and manual handling, jumbo for high-volume users feeding hoppers or bulk dosing. Both ship from Telok Gong, Klang, close to Port Klang for local delivery and export markets. Store under cover and keep bags closed: the material itself is stable, but moisture pickup is what turns a good powder into a caked one.
LSM Industries (M) Sdn Bhd supplies sodium sulphate as an industrial chemicals trader — we source, stock and deliver it, and every product ships with a Certificate of Analysis, with full test reports available on request. What that buys you is the ability to check the material against your application before it reaches your line, instead of discovering a chloride or hardness problem three batches in. Tell us the application and the volume and we will confirm the grade, send the COA and quote.
Tell us the application and volume — we'll confirm the grade, send the COA and quote 50kg or 1MT jumbo.
