A simple white powder the world makes 71 million tonnes of a year — and there are two completely different ways to get it: mine a rare mineral, or build it chemically from salt, limestone and a clever recycling loop known as the Solvay process.
You've almost certainly touched soda ash today — without ever seeing it.
The journey
Soda ash is made in two completely different ways. The natural route digs up a mineral that is already most of the way there and finishes it with heat and water. The synthetic route — the Solvay process — builds the same powder from salt and limestone through a chain of reactions. Which one a country uses is decided almost entirely by what's under its ground.
There isn't one way to make soda ash — there are two, and they barely resemble each other. One is mostly heat and washing; the other is a chemical relay race.
Tap any stage to see what happens — both routes end at the same powder
Soda ash is just sodium carbonate — Na₂CO₃. The interesting part isn't the product; it's that two completely different sets of raw materials both arrive at exactly the same powder.
Soda ash is the common name for sodium carbonate (Na₂CO₃), a white, water-soluble alkaline powder. Humans have used it since the Egyptians made glass with it around 5,000 years ago; today it's the tenth most-consumed inorganic compound on Earth (WE Soda, 2026). What varies isn't the chemical — it's where the sodium and carbonate come from.
Recipe 1 — the natural route
Sodium sesquicarbonate (Na₂CO₃·NaHCO₃·2H₂O) — a mineral that is already about 70% sodium carbonate by weight. Just heat and water finish the job: nature has already done most of the chemistry.
Recipe 2 — the Solvay route
Sodium chloride, pumped from underground as brine — the sodium source, and one of the cheapest raw materials on Earth.
Calcium carbonate — roasted to supply the carbon dioxide, and the quicklime that later frees the ammonia for reuse.
The natural route is almost embarrassingly simple, and that simplicity is its whole advantage. Trona is a mineral that is already largely soda ash — chemically it is sodium sesquicarbonate, a mix of sodium carbonate and sodium bicarbonate that is about 70% carbonate by weight before you do anything to it. To finish the job you roast it to drive off water and carbon dioxide, dissolve the result, filter out the mud, then crystallise the clean liquor back into powder. No ammonia loop, no calcium-chloride waste, and generally much lower energy demand than the synthetic route.
There are two ways to get the trona out of the ground — and they look completely different underground:
Miners go underground and cut the trona out in a grid, leaving pillars of ore standing to hold up the roof. Only about 45% of the seam is recovered.
Pump hot water down one well; it dissolves the trona over months, and the brine is pumped back up another. No miners underground, and the rock stays put. WE Soda's Eti plant (Turkey) was the first to do this commercially, reaching ore ~450 m down once thought unmineable (WE Soda, 2026).
The catch isn't chemistry — it's geography. Rich trona sits in only a few places on Earth: Wyoming, around Ankara, and parts of China and the East African Rift. If you're not sitting on it, this route simply isn't available.
Where there's no trona, chemistry fills the gap. The Solvay process, invented by Ernest Solvay in 1861, builds soda ash from salt and limestone — two things almost every country has. Its elegance is that ammonia does the work but is handed back at the end, cycling round and round rather than being used up.
The trick the process solves: you can't push salt and carbonate together directly. So ammonia is used to make the brine reactive; bubbling in CO₂ then precipitates sodium bicarbonate, which is barely soluble and drops out as a solid. Heating that solid gives soda ash. Meanwhile quicklime (from the same limestone) strips the ammonia back out of the leftover liquid so it can be reused.
Tap any step to see the reaction and what's happening
China runs a smarter variant, the Hou process (modified Solvay), which captures the ammonium chloride as a saleable fertiliser instead of dumping calcium chloride — turning the waste stream into a product.
| Natural (trona) | Synthetic (Solvay) | |
|---|---|---|
| Raw materials | Trona ore only | Salt + limestone + ammonia + coal |
| Chemistry | Simple: heat & wash | Multi-step recycling loop |
| CO₂ per tonne soda ash | ~0.3–0.7 t | ~1 t |
| Energy intensity | Lower | Higher |
| Process water | Baseline | ~4–5× more |
| Main waste | Insoluble clay / shale | Calcium-chloride effluent |
| Where it can be built | Only near trona | Almost anywhere |
| Share of world output | ~27% (19 Mt) | ~73% (52 Mt) |
A historical footnote worth one sentence. Before Solvay there was the Leblanc process (1791), which reacted salt with sulphuric acid and left behind acidic gas and foul-smelling waste — one of the first industrial pollution scandals. It's obsolete now, but it's why soda ash and sulphuric acid share a history.
Continues elsewhere The Making of Glass Soda ash's biggest job by far: the flux that lets sand melt into glass. See where the powder goes next.Soda ash almost never reaches you as itself. It's a maker's ingredient — it does its job in the factory and disappears into the product.
More than half of all soda ash ends up making glass; the rest is spread across detergents, chemicals, metals, paper, water treatment and, increasingly, batteries. In glass it is the flux — it lowers sand's melting point from around 1,700 °C to something a furnace can reach, which is why no cheap glass exists without it (WE Soda, 2026).
Shares are global demand, rounded and approximate (Wyoming Mining Association, 2024; WE Soda, 2026); regional splits differ. The fastest growth is elsewhere: over 80% of future demand growth is expected to come from solar PV glass and lithium-ion batteries.
Coarse, heavy, free-flowing and low-dust — the preferred grade for glass, because it mixes evenly with sand and doesn't blow around.
Finer and more reactive, with better blending — used mostly in detergents and chemical manufacturing. Same chemical; different crystal size.
The world makes about 71 million tonnes of soda ash a year, and three countries make roughly four-fifths of it. But the two things that decide production — a rare mineral and cheap salt — pull the map in opposite directions.
Note the split personality: China leads on sheer volume with the synthetic route, while the US and Turkey punch above their weight on natural soda ash. China recently overtook Turkey for second place after opening a huge natural-soda-ash operation in Inner Mongolia in 2023 (USGS MCS, Feb 2026; Chemical Market Analytics, 2026).
Output for 2025, rounded (USGS MCS, Feb 2026). Around a quarter of all soda ash is shipped internationally; the US exports more than half its output and is the world's largest single exporter (Chemical Market Analytics, 2026).
Soda ash sits in the "hard-to-abate" corner of industry: the CO₂ isn't just from the fuel, it's baked into the chemistry. The cleanest fix on offer is oddly old-fashioned — dig more, synthesise less.
Both routes emit carbon dioxide, but not equally. Synthetic Solvay releases about 1 tonne of CO₂ per tonne of soda ash and uses several times more water; the natural route emits perhaps half to a third of that (Baral et al., 2025). So the single biggest decarbonisation lever isn't a new gadget — it's the market steadily shifting from synthetic toward natural production as new trona capacity opens in China and the US.
For Europe, which has no trona and runs around 16 Solvay plants, this is an existential squeeze: high energy prices, a coal-supply shock, and the looming full cost of EU carbon permits all fall on exactly the dirtier route. Producers are responding by cutting emissions and reinventing the process rather than abandoning it (C&EN, 2023).
Meanwhile demand is being pulled upward by the clean-energy transition itself: low-iron solar glass and lithium-ion (and emerging sodium-ion) batteries both need soda ash, and account for the majority of forecast demand growth. So the same green transition that punishes the dirty route also grows the market for the whole material.
The market's own move toward mined soda ash, where the deposits exist.
Source CO₂ from flue gas instead of limestone; sell the by-product as fertiliser.
Co-produce soda ash and lime, or pull CO₂ from the air. Still pre-commercial.
Most novel routes remain lab- or pilot-scale, held back not by chemistry but by economics — cleaner almost always means costlier (Rahimpour et al., 2024; Baral et al., 2025; Gutierrez et al., 2025).
One material, two ways to make it — and a future in which the older, simpler one quietly wins on carbon, even as the material itself becomes more essential than ever. If you found this interesting, see how glass, limestone & lime, ammonia and sulphuric acid are made — soda ash touches them all.