Sodium percarbonate (industrial bleaching agent)

01

Understand its uses and how it is made

PubChem, the US National Library of Medicine's chemical database, describes sodium percarbonate as a colourless, crystalline solid. Citing the OECD SIDS assessment, it lists the chemical as a bleaching agent in household laundry detergents and additives and in dishwasher products, and also in other consumer cleaning products, dental care products and for preserving raw milk. Citing Kirk-Othmer, it lists sodium percarbonate as an alternative to sodium perborate in laundry powders, automatic dishwashing detergents and colour-safe bleaches, with other uses in industrial textile bleaching and denture cleaners. [1]

On manufacture, PubChem cites the OECD: sodium percarbonate is produced by reacting sodium carbonate with hydrogen peroxide in dry, spray granulation or crystallisation processes. Kirk-Othmer adds that crystallisation from aqueous solution is the main route, with sodium carbonate reacted with hydrogen peroxide at 10–20 °C in the presence of stabilisers such as magnesium silicate. Spray processes give a product with a very low bulk density of 0.35 kg/L. [1]

The HERA risk assessment prepared for European detergent makers describes the three routes. In the dry process aqueous hydrogen peroxide is sprayed onto solid sodium carbonate; in the spray process solutions of sodium carbonate and hydrogen peroxide are sprayed into a fluid-bed drying chamber where the water evaporates; in the wet process the product is crystallised, possibly with salting out. It reports 10 to 15 production sites worldwide, about half of them in Europe, and European household-product use of 100,000–150,000 tonnes in 2001, with the household cleaning industry taking more than 95% of European demand. [5]

HERA gives these sodium percarbonate contents in European household products: 7–16% in regular laundry powder, 12–21% in compact powder, 12–24% in compact tablets, 20–40% in powder bleach additives, 25–56% in additive tablets and 3–21% in machine dishwashing powder, with bleach boosters of 65 to 85% also on the market. [5]

US EPA Chemical Data Reporting figures in PubChem put national production at 25 million to under 40 million lb a year in 2021–2023. [1]

Editorial calculation: 25–40 million lb is about 11,300–18,100 t a year.

Give the supplier the grade (crystallised or spray-granulated) and any stabiliser requirement, the active oxygen or available H2O2 content, the particle size distribution and bulk density, the stability or storage test required, the iron and heavy-metal limits, the packing (bags, big bags), the quantity, and the safety data sheet and transport classification you need.

02

Specify available oxygen, coating and particle properties

The FAO/WHO Joint Expert Committee on Food Additives (JECFA) specification gives the formula 2Na2CO3·3H2O2 and a formula weight of 314.0, and sets an assay of not less than 13% available oxygen, equivalent to 85% purity. Available oxygen is measured by dissolving the sample in sulphuric acid and titrating with 0.1 N potassium permanganate. The same specification gives a pH of about 10.5 for a 1% solution and limits lead to not more than 2 mg/kg. [4]

HERA states that, by weight, the pure substance contains 32.5% hydrogen peroxide and 67.5% sodium carbonate. Based on active oxygen, commercial product has a purity above 85% and can contain up to 15% inorganic salts such as sodium carbonate, sodium chloride, sodium silicates, sodium sulfate, magnesium sulfate, sodium hexametaphosphate and borates, present as impurities or used as coatings developed to keep the product stable in household cleaning products. HERA gives an average particle size of 300–900 µm and producer bulk densities of 900–1200 kg/m3. [5]

Solvay's product data sheets (January 2013) show what a coated detergent grade specifies. Oxyper SHC and Oxyper SCM are both described as high-coated, stabilised grades for bleach additives, detergent powders and tablets and machine dishwash products, from plants at Rosignano (Italy) and Bad Hönningen (Germany). SHC lists at least 13% available oxygen and SCM at least 12.8%, both by permanganate titration, with bulk density 900–1200 g/l, mean particle size 650–950 µm, at most 3% above 1600 µm or 10% above 1400 µm, at most 2% below 150 µm, and a dissolution rate of at least 90% after 2 minutes at 2 g/l in 15 °C water. Both give pH 10.4–10.6 for a 1% solution and solubility of 150 g/l at 20 °C and 175 g/l at 30 °C. [6] [7]

Editorial calculation: pure 2Na2CO3·3H2O2 carries three peroxide oxygen atoms per formula unit (3 × 16 = 48 of 314), about 15.3% available oxygen; 13% available oxygen is about 85% of that, matching JECFA's purity equivalence.

Give the supplier the grade (coated or uncoated, crystallised or spray-granulated) and any stabiliser requirement, the minimum available oxygen and its test method, the particle size distribution and bulk density, the dissolution rate and storage stability test required, iron and heavy-metal limits, the packing, the quantity, and the safety data sheet and transport classification you need.

03

Handle and store it as an oxidiser

The ILO/WHO International Chemical Safety Card (ICSC 1744) describes sodium percarbonate as a white crystalline powder that decomposes above 50 °C, with a density of 2.1 g/cm³ and solubility in water of 14 g/100 ml at 20 °C. It is not combustible but enhances combustion of other substances, so there is a risk of fire and explosion and contact with combustible substances must be avoided. It decomposes on contact with water, which generates a fire and explosion hazard. It should be stored cool and separated from incompatible materials, in an area without drain or sewer access. The substance is severely irritating to the eyes. [2]

In aggregated GHS notifications summarised by PubChem, it is classified as H302 (harmful if swallowed) in 97% of reports, H318 (causes serious eye damage) in 95% and H272 (may intensify fire; oxidiser) in 46%. NOAA's CAMEO Chemicals datasheet notes that it may combust in contact with organic materials and refers responders to the oxidiser guide in the Emergency Response Guidebook. [1] [3]

Solvay's data sheets describe the product as an oxidising agent that water, direct heat and catalysts can decompose, releasing oxygen and steam that can support combustion and cause pressure bursts in confined spaces; decomposition with organics can be rapid and highly exothermic. They advise keeping it from moisture, dirt, organic material, acids, alkalis, reducing agents and metallic contamination, out of direct sunlight and in a dry area, and using equipment of suitable materials such as plastic, glass or 316L stainless steel. Packaging options are bulk, big bags, PE-lined paper sacks and PE sacks. [6]

For transport the sheets give UN 3378, class 5.1 (oxidising substance), packing group III, under ADR, IMDG and IATA, with NFPA ratings of health 2, flammability 0, instability 1 and special OX, and EU CLP hazard statements H272, H302 and H318 with the signal word Danger. HERA notes that a melting point cannot be determined because the substance decomposes exothermically on heating, releasing oxygen. [6] [5]

04

Know what the product contains

05

Available oxygen, granulometry and dissolution on the data sheet

Ask for available oxygen and its test method before anything else: JECFA's 13% floor equals 85% purity, and HERA puts the rest of a commercial product at up to 15% inorganic salts, some of them coatings. [4] [5]

06

Send the grade, quality and logistics data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Grade: [coated; uncoated; crystallised; spray-granulated]
Quality: [available oxygen min; particle size; bulk density; dissolution rate; Fe max]
Use: [detergent; textile; cleaning]
Packing: [25 kg bags; big bags; bulk]
Quantity: [t; schedule]
Documents: [CoA; SDS; UN 3378 transport classification]

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