What Is Phosphoric Acid (H₃PO₄) and Why Is It Essential in Agriculture and Industry?

Technical Introduction

Phosphoric Acid (H₃PO₄) is a colorless, odorless, and non-volatile inorganic acid that plays a critical role in agriculture, food processing, and industrial manufacturing.
It is mainly produced through wet-process (from phosphate rock with sulfuric acid) or thermal-process (burning elemental phosphorus) methods.
Phosphoric acid serves as the primary raw material for phosphate fertilizers, which account for over 80% of its global consumption.

Applications

1. Agriculture & Fertilizer Production

• Phosphate Fertilizers: Key raw material for DAP, MAP, TSP, and NPK fertilizers.

• Foliar & Fertigation Use: Used in diluted form as a direct phosphorus source.

• Soil pH Control: Helps lower alkaline soil pH for better nutrient absorption.

2. Food & Beverages

• Food-Grade Acidulant: Used in carbonated drinks, fruit juices, and jams for tartness.

• Preservative Function: Inhibits microbial growth, extending product shelf life.

• Nutrient Supplement: Source of phosphorus in animal feed additives.

3. Industrial Uses

• Metal Treatment: Applied in rust removal, surface cleaning, and phosphating of steel.

• Detergents & Cleaners: Used in formulations to remove mineral deposits.

• Pharmaceuticals: Component in dental cements, antiseptics, and drug intermediates.

Advantages

• Multi-Purpose: Serves agriculture, food, and industrial sectors.

• Highly Reactive: Easily converted into valuable phosphate derivatives.

• Nutrient-Rich: Provides a concentrated source of phosphorus, an essential plant nutrient.

• Versatile Forms: Available as industrial-grade, food-grade, and fertilizer-grade.

Typical Parameters

FAQs

Q1: What is the main use of phosphoric acid?
A1: Over 80% is used in fertilizer production (MAP, DAP, TSP, NPK).

Q2: Is food-grade phosphoric acid safe?
A2: Yes, when used within regulatory limits, it is safe as a food additive and acidulant.

Q3: Can phosphoric acid be used directly as a fertilizer?
A3: Yes, in controlled applications through fertigation or foliar spraying, but usually it is processed into solid phosphate fertilizers.

Q4: What is the difference between wet-process and thermal-process phosphoric acid?
A4: Wet-process is used mainly for fertilizer-grade, while thermal-process produces high-purity food/pharma-grade acid.

Q5: How should phosphoric acid be stored?
A5: Store in plastic or acid-resistant containers, in a cool, ventilated area, away from alkalis and metals.