Caustic soda is sold in several physical forms. All are sodium hydroxide, but they differ in how easy they are to handle, store, dose and transport. Choosing the right form saves money and trouble.
Flakes
Thin white flakes, about 98 to 99% NaOH, packed in 25 kg bags.
- Good for: most industrial users, batch processes, sites far from the supplier.
- Pros: high strength, easy to store on pallets, flexible quantities.
- Cons: must be dissolved on site, which releases heat; dusty if handled roughly.
Pearls (prills)
Small round beads, also around 99% NaOH.
- Good for: automatic feeders, small-scale weighing, laboratories.
- Pros: free-flowing, less dust, easy to meter.
- Cons: usually cost a little more than flakes.
Pellets
Laboratory forms, often in analytical (AR) or laboratory reagent (LR) grade, sold in small containers for preparing standard solutions.
Liquid caustic (lye)
A solution, usually 48 to 50% NaOH, delivered in drums, IBCs or tankers.
- Good for: large continuous users with dosing pumps and bulk tanks.
- Pros: no dissolving, easy to pump.
- Cons: about half the weight is water, so transport and storage cost more per kg of NaOH; a 50% solution starts to crystallise at around 12 °C.
Quick comparison
| Form | NaOH | Handling | Typical user |
|---|---|---|---|
| Flakes | ~99% | Dissolve on site | General industry |
| Pearls | ~99% | Free-flowing, easy to meter | Automated feed, labs |
| Pellets | Lab grades | Small containers | Laboratories |
| Lye 48 to 50% | ~50% | Pump and dose | Large continuous users |
How to compare prices
Convert every quote to the cost of one kg of pure NaOH delivered to your site. Divide the price by the NaOH content, then add delivery. This usually shows flakes as the cheapest form for small and medium users.
Example of a published price
Few suppliers publish caustic soda prices. For a working example of a daily published price with rates by order size, see this caustic soda price page from our group company in Oman, which supplies flakes 99% within Oman.
