Phosphoric Acid CAS 7664-38-2 | 85% Food Grade & Industrial Grade

About Phosphoric Acid

Phosphoric acid (orthophosphoric acid, H3PO4, CAS 7664-38-2) is a mineral inorganic acid with three dissociable acidic protons. The standard commercial form is an 85% aqueous solution — a clear, colorless, odorless, syrupy liquid fully miscible with water and ethanol.

Two production routes are available. The wet process reacts phosphate rock with sulfuric acid and serves fertilizer and general industrial demand. The thermal process burns elemental phosphorus and yields higher purity for food, pharmaceutical, and electronic applications. Phosphoric acid is the primary industrial source of phosphorus for fertilizers, phosphate salts, food additives, water treatment chemicals, and specialty intermediates.

Available Grades & Specifications

UETChem supplies three standard purity grades. Custom specifications are available for volume orders.

Parameter	Industrial Grade	Food Grade	Electronic Grade
H3PO4 Content	≥ 85.0%	≥ 85.0%	≥ 85.0%
Color (APHA)	≤ 20	≤ 10	≤ 5
Arsenic (As)	≤ 50 ppm	≤ 0.5 ppm	≤ 0.01 ppm
Heavy Metals (as Pb)	≤ 50 ppm	≤ 0.5 ppm	≤ 0.01 ppm
Chloride (Cl-)	≤ 50 ppm	≤ 5 ppm	≤ 1 ppm
Iron (Fe)	≤ 50 ppm	≤ 5 ppm	≤ 0.1 ppm
Sulfate (SO4 2-)	≤ 1000 ppm	≤ 500 ppm	≤ 50 ppm
Production Route	Wet process	Thermal process	Thermal + purification

75% concentration is available for all grades. The 75% solution has a lower freezing point around -10°C and is preferred for cold-climate storage and shipping. 85% acid freezes at approximately 21°C.

Applications

Fertilizer & Agriculture

Primary feedstock for ammonium phosphates (MAP, DAP), superphosphates, and NPK compound fertilizers. Industrial-grade wet-process acid at 75% is standard. Typical consumption runs 150-300 kg per metric ton of finished NPK fertilizer, depending on target P2O5 content.

Food & Beverage

Acidulant, pH buffer, and flavor enhancer in carbonated beverages, jams, dairy, and processed foods. Typical dosage is 0.05-0.1% by weight in colas. Also used as a degumming agent in edible oil refining. Meets FCC, E338, and GB 1886.15 standards.

Metal Surface Treatment

A 10-20% solution with zinc or manganese accelerators produces a phosphate conversion coating on steel, improving paint adhesion and corrosion resistance. Zinc phosphating is used for automotive and appliance parts; manganese phosphating for high-corrosion environments. Chloride should stay below 20 ppm to avoid pitting.

Water Treatment

pH adjuster in cooling water and boiler systems. Phosphate provides mild carbon steel corrosion inhibition. Typical dosage is 10-50 mg/L. Raw material for organophosphonate scale inhibitors such as HEDP and ATMP.

Other Uses

Catalyst manufacturing, activated carbon production, flame retardant synthesis, dental cement, and fuel cell electrolyte. Electronic-grade acid is used for semiconductor wafer etching and LCD cleaning, with total metallic impurities below 10 ppb.

Quality Control & Documentation

Each batch carries a unique lot number and is tested before release:

Raw material inspection for purity and impurity profiles
In-process monitoring of concentration, density, and color
Finished product testing: H3PO4 by titration, chloride by ion chromatography, arsenic by AAS, heavy metals by ICP-OES
Batch-specific COA with actual test results accompanies every shipment
500 mL retained sample per batch held for 6 months
SGS or BV pre-shipment inspection available on request

Available documentation includes COA, TDS, SDS/MSDS, food safety certificates, HALAL, KOSHER, and all dangerous goods shipping documents.

Storage & Handling

Store in a cool, dry, ventilated area separated from alkalis and food products. Use HDPE, PVC, or rubber-lined containers — not carbon steel or aluminum. 85% acid crystallizes below 21°C; warm to 30-35°C and agitate before use if crystallization occurs. Shelf life is 24 months under proper conditions.

Wear chemical goggles, face shield, acid-resistant gloves, and protective clothing. The material is corrosive to skin and eyes. In case of contact, flush with water for 15 minutes and seek medical attention.

Frequently Asked Questions

Is phosphoric acid the same as orthophosphoric acid?

Yes — both refer to H3PO4. “Orthophosphoric acid” is the IUPAC name that distinguishes it from condensed polyphosphoric acids. Phosphorous acid (H3PO3) is a different compound and should not be substituted.

75% or 85% — which concentration should I order?

85% is standard for most applications. 75% is preferred for cold-climate storage and shipping due to its lower freezing point. Choose based on your process requirements and logistics.

Are samples available?

500 mL samples are available for qualification testing (courier charges apply). Delivery takes 3-7 days via DHL or FedEx.

What shipping terms and lead time?

FOB, CFR, and CIF terms are available. UN 1805, Class 8 corrosive; all DG documentation is provided. Lead time is 5-10 working days for stock items.

Phosphoric Acid CAS 7664-38-2 | 85% Food Grade & Industrial Grade

About Phosphoric Acid

Available Grades & Specifications