Mining Phosphate to Produce Fertilizer.

Simply put, fertilizers are not a luxury, but an absolute necessity for meeting the needs of a growing world. This presentation explains how phosphate fertilizers are produced in Central Florida – which holds some of the world’s greatest reserves – and is regulated by approximately 12 permitting authorities.

Phosphate rock is 15-50 feet beneath the ground in a mixture of phosphate pebbles, sand and clay known as phosphate "matrix." The sandy layer above the matrix, called the overburden, is removed using electrically operated draglines. Draglines remove overburden, placing it in previously mined voids, and excavate the matrix, depositing it into a shallow slurry pit. High-pressure water guns turn the material into a watery slurry, and send it through pipelines to a beneficiation plant, where phosphate rock is physically separated from sand and clay in the matrix.

At the plant, slurry moves through washing stations and vibrating screens— physically separating clay, sand and pebble-sized particles. Separated phosphate pebbles move through dewatering tanks onto an inventory pile via conveyor belt. Clay particles are pumped through pipelines into clay settling areas.

The manufacturing process begins when the rock is finely ground to uniform size. Sulfuric acid is added to form phosphoric acid, which is concentrated through evaporation, reacted with ammonia, and granulated to produce two phosphate/nitrogen crop nutrients, diammonium phosphate (DAP) and monoammonium phosphate (MAP).

Once mining is completed, Florida requires effective, acre-for-acre methods of returning mined lands to productive uses for both wildlife and people.