Phosphoric acid (H3PO4) is a mild mineral acid with a wide range of industrial, food, and maintenance applications. Unlike stronger mineral acids, phosphoric acid is relatively gentle on metals, making it the go-to choice for rust removal and metal conditioning.

Primary applications include rust removal and metal surface preparation (rust conversion), food and beverage acidulation (it is the acid in many soft drinks), fertilizer manufacturing, water treatment, and dental and pharmaceutical formulations. It is also used in semiconductor etching and as a flux in soldering. For a step-by-step walkthrough, see our complete guide on how to use phosphoric acid for rust removal.

Alliance Chemical supplies phosphoric acid in concentrations from dilute to 85%, in Technical, Food Grade, and ACS Reagent purity levels. Sizes range from quarts and gallons for shop and home use to drums and totes for manufacturing and agriculture operations. If you need help selecting the correct grade, our chemical grades guide explains the differences.

Every shipment includes a Safety Data Sheet (SDS) and Certificate of Analysis (COA). We offer same-day shipping on in-stock products, no minimum orders, and responsive customer support to help you find the right concentration and volume.