What drives the price of caustic soda flakes

A caustic soda quotation is a snapshot of several moving parts, not a list price. Knowing which parts move — and which ones are fixed by your own order — is what lets you compare two offers properly instead of arguing over a single number.

The cost floor: power, salt and the chlorine balance

Caustic soda is made by electrolysing brine. The two largest inputs are salt and electricity, with steam for the evaporation step that turns the liquid into flakes. Electricity dominates: a chlor-alkali plant is one of the most power-intensive chemical operations there is. Published industry estimates put electricity at roughly 40–60% of chlor-alkali production cost, with membrane-cell plants consuming in the region of 2,000–3,000 kWh per tonne of caustic soda produced — we quote those as industry ranges, not as our own plant figures. That is why flake capacity clusters where power is cheap rather than where the buyers are — in China, the northern and western provinces rather than the coast. When power prices, coal supply or provincial energy policy shift, the cost floor shifts with them, and every producer in the region moves together.

The second half of the equation is co-production. An electrolysis cell makes caustic soda and chlorine together, in a ratio fixed by chemistry rather than by demand — on the order of one tonne of each, with the exact figure set by cell efficiency. When chlorine demand from PVC producers and other users is weak, plants cut current and caustic output falls with it. When chlorine is easy to place, cells run harder and caustic supply loosens. This coupling is why the price of caustic soda can move for reasons that have nothing to do with caustic soda buyers — the market you are competing with is the chlorine market.

Operating rates and the calendar

Supply also tightens on a calendar you can predict. Northern Chinese provinces impose winter power and environmental restrictions; plants schedule maintenance turnarounds; and logistics slow over public holidays, when trucks and vessel space get scarce at the same time. Add restocking behaviour: importers who must refill before a holiday or a seasonal production run tend to buy in the same weeks, which is why quiet markets and tight markets often alternate faster than the underlying chemistry changes.

On the supply side, China holds a large share of world chlor-alkali capacity and has added to it faster than its own demand has grown, which is why Asian export prices have often sat below European and North American levels in recent years. Industrial estimates put alumina refining at around a fifth of global caustic soda demand, with chemicals, pulp and paper, and textiles taking most of the rest — so an alumina refinery restarting or closing is the single biggest demand swing a buyer should watch, together with PVC margins, which decide how hard the chlorine side of the plant runs.

Freight, packing and Incoterms sit inside the price

Two offers quoted on different Incoterms are not the same object. FOB Tianjin (Xingang) means you arrange and pay the sea freight; CFR and CIF mean the seller books it, and the number then carries the freight market and the dangerous goods handling — caustic soda ships as UN 1823, Class 8, so surcharges and space allocation are part of the cost. A freight market that moves in your favour can make a higher FOB offer cheaper on your dock, and vice versa.

Packing does the same. 25 kg bags and 1 MT jumbo bags differ in the cost of the bag, the labour to load and unload, how many tonnes fit in a container, and what your warehouse can accept. Pallets add cost but cut labour; loose loading saves money if your site has the equipment. Options and container loading are set out in packing and container loading.

What a serious quote states

A price on its own is not yet comparable. A usable offer contains all of the following:

• Grade and specification — the NaOH content and the impurity limits stated, not just the headline assay. See the specification.
• Packing — bag weight, jumbo or 25 kg, palletised or loose.
• Incoterm and named port — FOB Tianjin, or CFR/CIF to your port.
• Validity period — a spot market quote is a snapshot; a serious exporter says how long it holds.
• Payment terms — stated on the proforma invoice, paid to the party named on the invoice and the bill of lading.
• Lead time and documents — when it ships, and which papers come with the offer. Our list is on documents and downloads.

If something is missing, ask before you compare. And a price well below every other offer is usually one of four things: a different specification, a grade substitution, costs appearing later on the invoice, or no intention to ship at all.

How to compare two quotes properly

Put both on the same basis: USD per tonne, delivered to your warehouse, same grade, same packing, same documents. That means adding sea freight, dangerous goods handling, insurance and import duty, and allowing for what pallets cost you in labour if your site cannot take loose bags. Then compare the parts that do not appear in the number at all — batch traceability, whether the certificate of analysis carries the producing plant's name, and whether the supplier answers a technical question in one line or negotiates instead. A worked comparison of the three physical forms of the same chemical is in flakes vs pearls vs liquid; the wider checks are in how to check a Chinese supplier.

The number to actually compare: landed cost

A lower FOB quote is not a lower purchase. Landed cost is what reaches your cost sheet, and every line below belongs in it:

• Goods — FOB price per tonne on the same grade and packing, which is what a CFR or CIF offer already includes.
• Freight and marine insurance — container rates on the lane move faster than the product price does.
• Dangerous goods handling — caustic soda is UN 1823 Class 8, and DG port handling is billed separately from ordinary container freight.
• Duty, VAT and any trade measure — import duty usually follows HS 2815.11, and some markets add anti-dumping or countervailing duty that depends on the country of origin (see below).
• Port, inland and unpacking costs — terminal handling, delivery to your warehouse, and the labour to break pallets or restack bags if you take loose loading.
• Working capital — a cheaper origin 30 days further away ties up money and stock for a month longer, which is a real cost even when it does not appear on the invoice.

Trade measures: check before you compare

Sodium hydroxide from China has been subject to anti-dumping investigations and duties in several destination markets in recent years — India since 2002, with further cases opened during 2026 — and the measures change with each review. Two suppliers can quote the same FOB China number and land at materially different costs in the same port if one ships material of another origin, or if the duty applies to China-origin material only. So before you treat the lower FOB as the cheaper offer, ask your customs broker what applies to HS 2815.11 from China in your market — and ask the supplier, in writing, which origin the material ships from. Ours ships from China, from our own plant, under our own export rights; where a destination measure makes that uneconomic, we would rather tell you at quotation stage than have you discover it at clearance. How the scope text, the country of origin and the named producer decide what you actually pay is set out in HS 2815.11, customs and duty.

Questions buyers ask about price

How we quote

We quote FOB Tianjin (Xingang) as standard, with CFR and CIF on request, and we state the validity period on the offer. Because we are the plant, we also say in the quotation when your specification needs a production run rather than standard material — rather than discovering it at the loading port. Send the grade, quantity, packing and destination port through the enquiry form and we will come back with the price, the packing options and the specification sheet, normally within one working day.

Related: flakes vs pearls vs liquid · how to check a supplier · receiving and checking a shipment.