Caustic Soda Flakes

About This Product

Caustic soda flakes are solid sodium hydroxide (NaOH, CAS 1310-73-2, EC 215-185-5). They are made by cooling an anhydrous caustic melt on a rotating drum and scraping it off as thin, irregular white flakes, typically around a millimetre thick. Chemically they are the same material as caustic soda pearls; the difference is physical. Flakes are the most widely produced solid form, which makes them the usual choice for plants that tip whole bags into an agitated make-up tank rather than dosing by weight from a feeder. The listed technical grade is 99.0% NaOH minimum with low carbonate, chloride and iron. Technical grade covers cleaning, pH control, effluent neutralisation and most chemical processing. Rayon grade tightens the limits on iron, heavy metals and silica for viscose fibre production, while food grade (E524) and pharmacopoeia grades are separate products with their own purity criteria and documents, so technical flakes must not be used in food or pharmaceutical processes. Flakes break into fines during handling and can bridge in hoppers, which is why they suit tip-and-stir addition better than automatic metering. In heavy-duty, oven and drain cleaners and in clean-in-place make-up, the hydroxide saponifies fats and swells protein soils so that they lift from surfaces. In effluent treatment it neutralises acidic streams and raises pH to precipitate dissolved metals as hydroxides without adding the hardness and sludge that lime brings. Soap makers use it to convert oils into sodium soaps, pulp and paper mills use it in cooking and bleaching stages, textile plants scour cotton with it, and chemical manufacturers use it as the base for sodium salts and for pH control in synthesis. Buyers normally agree the NaOH assay, sodium carbonate, sodium chloride and iron. Carbonate rises as the product absorbs carbon dioxide from the air, chloride is lower in membrane-cell material, and iron matters wherever white goods or colour-sensitive products are involved. Agree the limits in writing and check each batch certificate of analysis against them. Sodium hydroxide is classified under CLP as causing severe skin burns and eye damage (H314) and as possibly corrosive to metals (H290). Solid caustic soda ships as UN1823, SODIUM HYDROXIDE, SOLID, Class 8, packing group II, in UN-approved packaging, and classifies under HS 2815.11 whatever its solid form. The safety data sheet for the supplied product is the controlling document. For imports into the EU or Great Britain, ask which company holds the REACH or UK REACH registration that covers your import and use, and check that the safety data sheet reflects it. Flakes are strongly hygroscopic, so keep bags sealed, off the floor and in a dry, covered store away from acids, ammonium salts and aluminium, zinc or galvanised steel, which react to release hydrogen. Dissolve them by adding flakes slowly to cold water while stirring, never water to caustic, and wear goggles with a face shield, alkali-resistant gloves and protective clothing. When you enquire, state the grade, the NaOH minimum and impurity limits you need, the pack format, your volume per shipment and per year, the destination and Incoterms, and the documents you need with each batch.