Product Overview
Phosphoric Acid 85% ACS Grade is a clear, colorless viscous liquid supplied at the highest commercially distributed concentration of orthophosphoric acid. At 85% H₃PO₄ by weight, this is a dense, syrupy acid that delivers maximum active-acid content per container — fewer drums, less freight, less dilution math on the floor.
The ACS Grade designation is the one analytical laboratories, QC departments, and R&D teams typically specify when their processes are sensitive to purity variation between lots. If your purchase order or SOP calls out ACS Grade, this is the line item that satisfies that procurement requirement.
Available to order from 1-quart bottles through 330-gallon totes, scaling from bench trials to continuous industrial use.
Why This Concentration
85% is the practical ceiling for phosphoric acid in liquid distribution. Above this concentration the acid becomes too viscous to pump reliably at ambient temperatures, so 85% represents the densest form you can receive, store, and meter without heated lines or special transfer equipment.
That concentration advantage is straightforward: more acid per drum means fewer containers on the dock, fewer change-outs on the feed system, and a lower per-pound freight cost compared to pre-diluted grades. For a plating shop running a phosphate conversion line or a fertilizer blender dosing phosphoric acid into a mix tank, the 85% concentration minimizes handling steps.
Not every application needs that density. If your operation is rust removal, descaling, or surface prep where the acid goes on at working strength and precise concentration control is secondary, Phosphoric Acid 30% ships ready to apply — no dilution, no mixing PPE beyond what the job already requires. Phosphoric Acid 75% splits the difference: concentrated enough for most industrial processes but easier to pour and pump than the 85%.
The ACS Grade distinction matters when your downstream work — analytical reagent preparation, chemical synthesis, or instrument calibration — is sensitive to trace-level variation. If your application is food processing or beverage production and the purchase order calls for a USP or food-grade designation instead, see Phosphoric Acid 85% USP Food Grade.
Chemical Profile
This product is a clear, colorless viscous liquid with no discernible odor. Its molecular formula is H₃PO₄ (CAS 7664-38-2, molecular weight 97.995 g/mol). At 85% concentration and 25 °C the solution has a density of 1.685 — roughly 1.7 times the weight of water, a factor that matters for freight calculations and container weight limits. A full 55-gallon drum of this material weighs substantially more than a drum of water; confirm your dock plate and lift capacity accordingly. The acid is fully miscible with water in all proportions, and its vapor pressure is low at 0.3 kPa (20 °C), meaning it generates negligible vapor under normal warehouse and handling conditions. That low volatility is one reason phosphoric acid is generally easier to handle than hydrochloric or nitric acid at comparable concentrations.
Industrial Applications
Phosphoric acid at this concentration and grade serves a range of industrial processes:
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pH Adjustment (Water Treatment & Manufacturing) — Phosphoric acid is a triprotic acid, releasing hydrogen ions in three stages. That buffering behavior makes it useful for pH adjustment in cooling towers, boiler-water treatment, and process streams where a gradual, controllable pH drop is preferable to the sharp crash that a strong mineral acid can cause.
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Metal Cleaning & Rust Removal — At working dilutions, phosphoric acid dissolves iron oxide (rust) and light mill scale from steel and iron surfaces while leaving a thin iron-phosphate conversion layer that temporarily inhibits re-rusting. Plating shops, fabricators, and maintenance teams use it for surface preparation before painting, coating, or welding.
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Fertilizer Production — Phosphoric acid is the primary phosphorus source in the manufacture of phosphate fertilizers, including monoammonium phosphate (MAP) and diammonium phosphate (DAP). Blending operations start with concentrated acid and react it with ammonia or other bases.
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Chemical Synthesis — In pharmaceutical and specialty-chemical manufacturing, phosphoric acid serves as a proton donor, catalyst, or pH-control agent in reaction sequences. The ACS Grade designation is commonly specified for synthesis work where lot-to-lot consistency of the reagent matters to reproducibility.
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Food & Beverage Processing — Phosphoric acid functions as an acidity regulator in food systems. Note: if your process requires a food-grade or USP designation, confirm that the ACS Grade designation satisfies your facility's procurement and audit requirements, or consider the Food Grade alternative.
Handling & Storage
Signal word: Danger (per the product's GHS classification).
- H314: Causes severe skin burns and eye damage (per the product's GHS classification).
- H290: May be corrosive to metals (per the product's GHS classification).
Wear chemical-splash goggles, a face shield, and chemical-resistant gloves (butyl rubber or neoprene) when handling. Use a chemical-resistant apron or suit for transfer and drum-change operations where splashing is possible. Ensure adequate ventilation — while vapor pressure is low, prolonged exposure in enclosed spaces warrants mechanical exhaust.
Store in HDPE, polypropylene, or glass containers. Phosphoric acid will attack mild steel, aluminum, and most common metals over time. Keep containers sealed, upright, and in a cool, dry area away from strong bases, oxidizers, and reactive metals. The 85% solution can crystallize if stored below approximately 21 °C (70 °F); if crystals form, warm the container gently and agitate to re-dissolve before dispensing.
In the event of a spill, neutralize cautiously with soda ash or lime, then flush the area with water. Do not use metal scoops or shovels — use plastic or HDPE tools to avoid corrosion.
Hazmat & Shipping
Phosphoric Acid 85% ACS Grade ships as a regulated hazardous material under DOT:
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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)
All outbound shipments are placarded, packaged, and documented per DOT requirements. A hazmat-trained shipper prepares the shipping papers and applies the correct Class 8 corrosive labels before the package leaves our dock.
Documentation
A Safety Data Sheet (SDS) is included with every order, available in English, Spanish, French, and Japanese. A Technical Data Sheet (TDS) with product specifications is also available. Lot-specific Certificates of Analysis (COA) can be requested at the time of order to support your incoming-QC or audit documentation.
Why Buy from Alliance Chemical
This product is available to order in sixteen configurations — from single quarts for lab and bench work to 330-gallon totes for high-volume production — with full hazmat shipping documentation, SDS, and lot-specific COA available for every order. Alliance Chemical has operated as a hazmat chemical distributor from Taylor, Texas since 1998, serving over 50,000 industrial, municipal, and institutional customers. Shipping and handling guidance on this page has been reviewed by Andre Taki, DOT Hazmat Specialist.
