Potassium hydroxide (KOH)

What Is Potassium Hydroxide?

Potassium hydroxide (KOH; CAS 1310-58-3), universally known as caustic potash, is a strongly alkaline inorganic compound typically supplied as a white flake or pearl solid, or as 48% clear liquid. It dissolves readily in water and ethanol, releasing substantial heat on dissolution; it is deliquescent — pulling moisture from the air — and absorbs carbon dioxide to form potassium carbonate, which is why handling discipline centers on keeping it dry and covered. Concentrated solutions are highly alkaline and corrosive, demanding the respect any strong base commands.

How KOH Is Produced

Caustic potash comes from the chlor-alkali electrolysis of potassium chloride brine: electric current splits KCl into KOH at the cathode and chlorine gas at the anode, with hydrogen as by-product. Membrane-cell technology dominates modern plants for energy and purity reasons, delivering 48% liquid KOH that is concentrated further or flaked in falling-film evaporators to the 90% solid. The economics couple KOH to chlorine markets and electricity prices — context buyers feel in cyclical pricing. The parallel process on sodium chloride brine produces sodium hydroxide; the two caustics share chemistry but not markets, and the K-chemistry side trades at a premium supported by fertilizer, glass and battery demand.

Grades and Forms

• 90/95% flakes or pearls — the standard international trading form; economical to ship, dissolve on arrival.
• 48% liquid (also 45/50%) — the workhorse of plants with tank infrastructure; no dissolution step.
• Electronic and photo grades — low sodium, chloride and metal traces for semiconductor, display and photographic chemistry.
• Technical versus high-purity — matched to end use, certified per lot.

Applications in Depth

Potassium Chemicals: the Derivative Family

The largest single use of KOH is manufacturing other potassium chemicals: potassium carbonate for glass melting, television and display glass, and powder detergents; potassium phosphates and acetates for food, pharma and de-icing fluids; potassium permanganate and other specialty salts. Each derivative inherits its economics from caustic potash input cost, which is why K-chemical producers watch chlor-alkali markets closely.

Liquid Soaps and Detergents

Potassium soaps are softer and more water-soluble than sodium soaps — saponifying fats with KOH yields liquid hand soaps, shampoos and shaving formulations, while NaOH gives hard bar soap. This single solubility difference built the entire liquid-soap segment, and detergent formulators use KOH-based potassium salts as builders in liquid systems.

Batteries and Electrochemistry

Alkaline primary batteries and nickel-based rechargeables (Ni-Cd, Ni-MH, and alkaline fuel-cell and electrolyzer systems) run on concentrated KOH electrolyte — its high ionic conductivity and stability define the chemistry. Electroplating, electroless plating and etching of silicon wafers (anisotropic KOH etching is a MEMS-industry standard) complete the electrochemical family.

Fertilizers and Agriculture

Potassium hydroxide feeds potassium nitrate and monopotassium phosphate production — fertilizers prized for chloride-free potassium, essential for chloride-sensitive crops and fertigation systems.

Food Industry

Food-grade KOH serves as pH adjuster and peeling agent (lye peeling of fruits and vegetables), cocoa and chocolate alkalization (Dutch processing), and pretzel and olives surface treatment — narrow, precisely regulated uses under food-chemical codices.

Pharmaceuticals and Dyes

As a strong base and potassium source, KOH appears in active-ingredient salt formation, intermediate synthesis and dye chemistry — the roles our pharma and dye customers know it for.

Biodiesel and Esters

Transesterification of triglycerides to biodiesel runs classically on KOH catalyst — fast, effective at low loading, and soluble in the methanol phase. Glycerol by-product routes back to the co-product markets covered in our glycerol guide.

Industrial Cleaning and pH Control

Boiler and pipeline cleaning, wastewater pH adjustment and gas scrubbing (KOH solution captures acid gases more efficiently, weight for weight, than NaOH) round out the demand picture.

KOH vs NaOH: the Practical Selection

Chemistry is parallel; selection follows the cation. Need the potassium end-product (K2CO3, potassium soaps, chloride-free fertilizer, KOH electrolyte)? Caustic potash. Need commodity alkalinity at the lowest rupee per mole (general cleaning, paper, commodity soap)? Caustic soda. Where both work, KOH’s higher solubility and different salt solubilities sometimes decide — potassium salts of many acids stay dissolved where sodium salts precipitate, an old separation trick. Price premium: KOH historically trades 1.5–2.5x NaOH per ton of alkali, so the premium must buy something real.

Safety, Handling and Storage

KOH flake is UN 1813 Class 8 (corrosive); 48% liquid UN 1814. It is corrosive to skin, eyes and metals, and dissolution is strongly exothermic — always add flakes to water, never water to flakes, slowly with agitation. Store sealed against moisture and CO2; opened bags of flake drift in assay as they absorb ambient moisture and carbonate. PPE: goggles or face shield, alkali-resistant gloves; safety showers wherever it is handled. The SDS covers emergency response — quench spills with careful dilution and containment, never dry-sweep dust into the air.

Packaging and Supply

25 kg bags with liner (flake), 200 kg steel or blue plastic drums for liquid-tight solid handling, 1000 kg jumbo bags, ISO tanks for 48% liquid. Each EastChem lot ships with COA covering assay (90% or 48% basis), K2CO3 content, chlorides, sodium and water; electronic grades add metal traces. We are a 19-year chemical manufacturer with three subsidiaries holding deep fresh stock — quality is the foundation, and the service around it is what makes a supplier reliable. MOQ one 20-foot container, samples about 2 days, T/T or L/C.

Chlor-Alkali Economics: Why KOH Prices Move

Caustic potash pricing follows its production logic. Chlor-alkali plants co-produce chlorine and KOH in fixed stoichiometry: every 1.12 tons of KOH (as 100%) arrives with one ton of chlorine. When chlorine demand from vinyls, epoxies and disinfectants runs hot, caustic output is strong and KOH softens; when chlorine weakens, caustic supply tightens. Electricity is the other swing factor — electrolysis is energy-intensive, so power prices pass through directly. Add potassium salt feedstock cycles and seasonal fertilizer pull, and the buyer’s job is clear: contract across the cycle rather than chasing the spot price at the wrong moment. We hold deep stock precisely so our customers’ consumption plans do not have to track the electrolyzer schedule.

Reading a KOH Specification Sheet Like a Chemist

Beyond assay, four trace figures do the discriminating work. Potassium carbonate (from CO2 absorption): high carbonate signals sloppy handling and plagues processes needing strong alkali without carbonate interference. Chloride: follows from brine carryover; critical for electronic grades and corrosion-sensitive uses. Sodium: the sister-caustic crossover, meaningful where potassium chemistry must be pure (pharma salts, catalysts). Iron and heavy metals: color and catalysis concerns. A COA reporting these with detection limits, against the right grade class, is the difference between buying chemistry and buying a label.

A Worked Example: K2CO3 Production

Take the largest single derivative. Potassium carbonate is made by carbonating KOH with carbon dioxide, then crystallizing — and every impurity in the caustic arrives in the carbonate: sodium becomes sodium carbonate contamination, chloride carries through, iron colors the product. Glass and detergent makers downstream of that carbonate specify against exactly these traces. This is why serious K2CO3 producers audit their KOH supplier’s COA discipline rather than just its price — and why our per-lot trace documentation, retention samples and consistent grades build the downstream confidence they need.

Formaldehyde-and-Cleaning Chemistry: KOH in Daily Industry

Two further uses round out the KOH file. Cleaning formulations use it where organic grease and protein soils resist ordinary detergent — brewery and dairy clean-in-place systems, oven and grill degreasers — where its saponifying power turns baked-on fat into soluble soap on contact. And in resins, KOH catalyzes condensation and neutralization steps where the potassium cation outperforms sodium on solubility or reaction selectivity. Both uses consume modest volumes but buy strong loyalty: formulators standardize on a grade, document it, and keep it for decades — which is precisely the demand profile our standing stock and per-lot consistency are built to serve. For buyers aggregating these smaller uses with the larger derivative streams, consolidation turns a fragmented purchase into one disciplined program.

Packaging detail completes the practical file: flake moves in 25 kg lined bags palletized at roughly one ton per pallet, drums and IBC totes serve plants preferring contained handling, and ISO tanks move 48% liquid where tank infrastructure exists. Each form carries its own assay basis on the COA — buyers comparing quotes across forms should normalize to active alkali content before judging price, the small arithmetic that occasionally decides tenders.

About this guide: application guidance and handling notes reflect standard industrial practice for caustic potash and our certified specifications; the SDS governs safety procedure. Buyers across potassium chemicals, soap, battery, fertilizer and food channels can request grade-specific documentation and consolidation with the wider catalog.

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Dongying, Shandong, China