PHOSPHORIC ACID- ▸ Metal treatment: pickling, rust-proofing and brightening of metals
- ▸ Fertilizers: feedstock for superphosphates and phosphate salts
- ▸ Water treatment: conditioning and corrosion control in water systems
- ▸ Food and beverage: acidulant in foods and soft drinks
- ▸ Electronics: etchant in semiconductor manufacturing
A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.
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Transport classification per the UN Model Regulations / 49 CFR 172.101 Hazardous Materials Table. Confirm against the grade-specific SDS (Section 14) before shipping.
Phosphoric acid (orthophosphoric acid; H3PO4, CAS 7664-38-2) is a versatile, medium-strength mineral acid supplied as a clear, colorless, syrupy aqueous solution (commonly 75–85%). It is a core metal-treatment and cleaning acid — phosphating, rust conversion, passivation and acidic descaling — and, in food grade, a beverage acidulant. Grades run from technical through food (FCC) to electronic. Identity: PubChem.
What is phosphoric acid?
Phosphoric acid is the triprotic mineral acid H3PO4. It is less aggressive and less oxidizing than sulfuric or nitric acid, water-miscible in all proportions, and it forms phosphate films and soluble phosphate salts — the basis of both its metal-conversion chemistry and its scale/rust removal. It is sold as aqueous concentrations (75% and 85% are typical) and in distinct purity grades for different industries.
Grades
Technical/industrial grade for metal treatment, cleaning and water treatment; food grade (FCC) for beverage and food acidulation; electronic/semiconductor grade for high-purity etching. Specify concentration (e.g. 75% or 85%) and grade on the RFQ; the CoA documents the lot.
Applications by sector
Metal treatment. Iron- and zinc-phosphating pretreatment before paint, rust conversion and rust-converter primers, metal brightening, electropolishing and passivation. Cleaning. Acidic descaler and brightener for hard-water scale, dairy/CIP and equipment cleaning. Food & beverage (food grade). Acidulant and pH control in colas and other beverages. Water treatment. Corrosion and scale control (phosphate chemistry). Phosphates & fertilizer. Intermediate for phosphate salts and fertilizers. Match grade and concentration to the application.
Handling and documentation
Phosphoric acid is corrosive to skin, eyes and many materials; handle with appropriate PPE and compatible materials of construction per the current Safety Data Sheet (SDS). Each lot ships with a Certificate of Analysis (CoA); food and electronic grades carry the relevant documentation.
Bulk supply and RFQ
RawSource stocks and supplies phosphoric acid in bulk — drums, totes, IBCs and bulk — from domestic US stock to metal-finishing, cleaning, food/beverage and water-treatment buyers. Specify grade (technical/food/electronic), concentration and target quantity for a quote with CoA and SDS. Related metal-treatment and descaling chemistries: hydrofluoric acid, ammonium bifluoride, phosphoric acid, oxalic acid, sulfamic acid.
Typical Properties
Typical reference values, not a specification; the Certificate of Analysis (CoA) for the lot governs.
| Property | Typical Value |
|---|---|
| Chemical Name | Phosphoric acid (orthophosphoric acid) |
| CAS Number | 7664-38-2 |
| Molecular Formula | H3PO4 |
| Molecular Weight | ~98.0 g/mol |
| Appearance | Clear, colorless, syrupy liquid (aqueous; 75% / 85% typical) |
| Solubility | Miscible with water in all proportions |
| Grades | Technical; Food (FCC); Electronic/Semiconductor |
| Hazard / handling | Corrosive — refer to the current SDS |
Regulatory & registration requirements
- TSCA (US):
- REACH (EU):
- EC number: 231-633-2
Source: EPA TSCA Inventory (July 2025 release) · ECHA CHEM — retrieved 2026-07-12
Solutions Using This Product
Process-solution guides on this site that specify this chemistry:
- Potassium Phosphite & Phosphorous Acid for Phosphite Nutrition (Agriculture)
- Phosphate Conversion Coating Chemicals (Industrial Manufacturing)
- Acids & Thickeners for Clinging Toilet Bowl Cleaners (Home & Industrial Care)
Frequently Asked Questions
What is phosphoric acid used for?
Phosphoric acid (CAS 7664-38-2) is used for metal phosphating and passivation, rust conversion and removal, metal brightening and electropolishing, acidic descaling/cleaning, beverage acidulation (food grade), and as a phosphate/fertilizer intermediate.
What grades and concentrations of phosphoric acid are available?
It is supplied as aqueous solutions (75% and 85% are common) in technical/industrial, food (FCC) and electronic/semiconductor grades. Specify the concentration and grade for your application on the RFQ.
Is phosphoric acid used in rust removal?
Yes. Phosphoric acid both removes rust and converts it to a stable iron-phosphate layer, which is why it is used in rust removers, rust converters and metal-phosphating pretreatments before painting.
What is the formula and CAS of phosphoric acid?
Phosphoric (orthophosphoric) acid is H3PO4, CAS 7664-38-2 (PubChem CID 1004), ~98.0 g/mol. The CoA documents grade and concentration.
How is bulk phosphoric acid supplied and quoted?
RawSource supplies it in drums, totes, IBCs and bulk from domestic US stock, with CoA and SDS per lot. Pricing is quote-based on grade, concentration and volume; submit an RFQ with your target quantity and ship-to.
What is the REACH and TSCA regulatory status of Phosphoric Acid (Orthophosphoric Acid)?
Phosphoric Acid (Orthophosphoric Acid) (CAS 7664-38-2) is subject to U.S. TSCA Inventory requirements; supplying it into the EU requires valid REACH registration ((EC) No 1907/2006). RawSource cannot verify a third-party supplier's registrations — buyers should require documented TSCA and REACH compliance for their jurisdiction and volume (EC 231-633-2).