Product Overview
Phosphoric Acid 30% is a clear, colorless, odorless liquid supplied as a reagent-grade aqueous solution. At this concentration it delivers controlled acidity for metal treatment, surface preparation, and process chemistry — without the handling intensity of concentrated phosphoric acid. The product ships under full DOT hazmat classification and is available to order in pack sizes from 1-quart bottles through 330-gallon totes.
Industrial buyers who need phosphoric acid for rust removal, etching, descaling, pH adjustment, or cleaning formulations will find 30% a practical working strength. Maintenance shops, water-treatment operators, and contract metal finishers use it as a direct-application acid or as a convenient dilution starting point.
Why This Concentration
A 30% solution sits at the low end of the phosphoric acid concentration range, and that position is deliberate. It is mild enough to apply directly to ferrous surfaces for rust conversion and passivation without the aggressive fuming or rapid heat generation that higher-strength acids introduce. Operators can work with it in open-air environments with standard PPE — no fume hoods or forced ventilation beyond normal industrial practice.
The trade-off is reaction speed. A 30% solution dissolves oxide layers more slowly than Phosphoric Acid 75% or Phosphoric Acid 85% ACS Grade. For heavy mill scale or production-rate pickling, those concentrated grades move faster. But for controlled etching, light descaling, or processes where over-attack is a reject risk, 30% gives the operator more working time and a wider margin of error.
Buyers whose downstream process requires a food-contact or analytical designation should also evaluate Phosphoric Acid 85% Food Grade, which carries a different grade classification. The reagent designation on this 30% product signals a procurement tier selected for analytical and industrial process work — confirm that it aligns with your specific process requirements before ordering.
Chemical Profile
Phosphoric acid (H₃O₄P, molecular weight 97.995, CAS 7664-38-2) in this 30% w/w aqueous form presents as a clear, colorless liquid with no detectable odor. Its density is approximately 1.18 at 25 °C — noticeably heavier than water, which matters when metering by volume into a process stream. The solution is fully miscible with water in all proportions, so it disperses readily in aqueous baths and rinse tanks. Vapor pressure is water-dominated and not independently characterized at this dilution; in practice, the solution does not fume under normal ambient conditions, which simplifies ventilation planning compared to concentrated phosphoric or mineral acids.
Industrial Applications
Rust Removal and Metal Surface Preparation. Phosphoric acid converts iron oxide (rust) into iron phosphate, a stable, inert layer that can serve as a primer-ready surface or be rinsed away before coating. At 30%, the reaction is gradual enough to treat formed parts, threaded fasteners, and thin-gauge sheet without risk of dimensional loss. Fabrication shops and maintenance crews use it for spot treatment and soak-tank operations alike.
Metal Etching. Circuit board fabricators, engravers, and metal finishers use dilute phosphoric acid to etch aluminum, mild steel, and zinc surfaces. The 30% strength allows controlled material removal — particularly useful on aluminum where over-etching causes pitting.
pH Adjustment in Water Treatment. Municipal and industrial water-treatment plants dose phosphoric acid to lower pH in alkaline feed water and cooling loops. The 30% concentration reduces handling risk at the dosing point while still delivering meaningful acid equivalents per gallon.
Industrial Cleaning and Descaling. Phosphoric acid dissolves calcium carbonate, mineral scale, and hard-water deposits from heat exchangers, boilers, and process piping. At 30%, it can be circulated through CIP (clean-in-place) systems or used in manual scrub applications to remove builite without attacking the base metal as aggressively as hydrochloric acid.
Fertilizer and Agricultural Intermediates. Phosphoric acid is a primary feedstock in phosphate fertilizer production. A 30% solution serves as an intermediate in blending operations or as a direct-application liquid phosphorus source in fertigation systems.
Handling & Storage
Phosphoric Acid 30% carries a signal word of Danger (per the product's GHS classification). The two governing hazard statements are H314 — causes severe skin burns and eye damage — and H290 — may be corrosive to metals (per the product's GHS classification). Treat every contact scenario seriously.
Wear chemical-splash goggles, a face shield, acid-resistant gloves (nitrile or butyl rubber), and a chemical-resistant apron as minimum PPE. In enclosed or poorly ventilated spaces, add respiratory protection rated for acid mist. Skin contact requires immediate flushing with water for at least 15 minutes; eye contact is a medical emergency.
Store in HDPE, polypropylene, or glass containers. Phosphoric acid will attack mild steel, galvanized steel, and aluminum — keep it away from carbon-steel drums, fittings, and shelving. Segregate from strong bases (sodium hydroxide, potassium hydroxide) and oxidizing agents. Store in a cool, dry, well-ventilated area with secondary containment sized for the largest container. The solution is stable under normal warehouse conditions and does not degrade or concentrate over time when containers remain sealed.
Hazmat & Shipping
This product is a regulated hazardous material for transport. Every shipment from Alliance Chemical's Taylor, TX facility is classified, packaged, marked, and documented in accordance with DOT requirements:
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UN Number: UN1805 (per 49 CFR 172.101)
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Hazard Class: 8 — Corrosive (per 49 CFR 172.101)
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Packing Group: III (per 49 CFR 172.101)
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Proper Shipping Name: Phosphoric acid solution (per 49 CFR 172.101)
Packing Group III reflects the lowest severity tier within Class 8, meaning the acid is corrosive but presents less aggressive transport risk than PG I or PG II materials. All required shipping papers, markings, labels, and placards (for bulk loads) are applied by our hazmat-trained shipping team before the carrier takes custody.
Documentation
A Safety Data Sheet ships with every order and is available in English, Spanish, French, and Japanese. A Technical Data Sheet is also available for process-engineering reference. Lot-specific Certificates of Analysis can be requested at the time of order — useful for QC intake, ISO documentation, or customer audits where incoming-material traceability is required.
Why Buy from Alliance Chemical
This product is available to order in sixteen pack-size configurations — from a single quart for bench work or field kits up to 330-gallon totes for production-scale consumption — so you can match your purchase to your actual use rate without overbuying or managing excess inventory. Alliance Chemical has served over 50,000 customers since 1998, operating from our warehouse at 204 S Edmond St, Taylor, Texas 76574. Product and shipping guidance on this page has been reviewed by Andre Taki, DOT Hazmat Specialist.
