How to make phosphate fertilizer

Phosphate fertilizers play a crucial role in the world of agriculture by promoting healthy root development and improving the quality and yield of crops. Creating phosphate fertilizer is an industrial process that involves the extraction and processing of phosphate rock into a usable form for plants.

Overview of Phosphate Fertilizer

Importance of Phosphorus in Plant Growth

Phosphorus is one of the essential nutrients for plant growth, vital for energy transfer, photosynthesis, and nutrient movement within the plant. Phosphate fertilizers supply this critical element to the soil, compensating for the natural depletion of phosphorus over time.

Extraction of Phosphate Rock

Mining and Quarrying

The production of phosphate fertilizer begins with the mining or quarrying of phosphate rock, which is a sedimentary rock containing high concentrations of phosphate minerals.

Crushing and Grinding

Once extracted, the phosphate rock is crushed and ground to the desired particle size to facilitate the chemical reactions necessary for its conversion into a fertilizer.

Chemical Processing of Phosphate Rock

Sulfuric Acid Treatment: The Wet Acid Process

The most common method for processing phosphate rock is the wet acid process (WAP), where the ground phosphate rock is treated with sulfuric acid to produce phosphoric acid and gypsum (calcium sulfate dihydrate).

Phosphoric Acid Production

In this step, sulfuric acid is reacted with the phosphate rock, typically in a reactor, to produce phosphoric acid and gypsum as a byproduct.

Alternative Methods: The Dry Process

An alternative to the wet acid process is the dry process, which involves heating the phosphate rock in a furnace with silicon and coke. However, this process is less commonly used due to its higher energy consumption and lower efficiency.

Purification of Phosphoric Acid

Removing Impurities

The crude phosphoric acid obtained from the wet acid process contains impurities that must be removed to produce a fertilizer-grade product. This is done through a series of filtration, precipitation, and extraction steps.

Concentration of Phosphoric Acid

The purified acid may need to be concentrated to the desired strength for fertilizer production, which involves evaporation of excess water.

Conversion to Fertilizer Forms

Production of Monoammonium Phosphate (MAP) and Diammonium Phosphate (DAP)

The phosphoric acid is then reacted with ammonia to produce monoammonium phosphate (MAP) and diammonium phosphate (DAP), two of the most common types of phosphate fertilizers.


The resulting slurry from the reaction is then granulated, dried, and cooled to form the granular fertilizer product, which is easier to handle and apply. There are many types of granlators for your choice in SX.

Environmental Considerations

Gypsum Management

The gypsum byproduct from the wet acid process must be managed properly, as it can create environmental challenges if not handled and disposed of correctly.

Air and Water Pollution Control

Phosphate fertilizer production facilities are equipped with pollution control systems to minimize emissions to air and water.

Packaging and Distribution

Storage Requirements

The final product is stored in a way that protects it from moisture and other elements that could compromise its quality.

Transportation to Market

The fertilizer is then packaged and shipped to agricultural markets, where it is distributed and used by farmers to enrich their soils with phosphorus.


The production of phosphate fertilizer is a complex process that converts phosphate rock into a form that plants can absorb. It involves extraction, chemical reactions, purification, and granulation, resulting in products like MAP and DAP. With careful management, the process can be environmentally responsible, ensuring that farmers around the world have access to this critical nutrient for their crops.