Fertilizer is any natural or manufactured plant nutrient that contains at least 5% of one or more of the three primary nutrients – nitrogen (N), phosphorous (P), or potassium (K)
Industrially manufactured fertilizers are sometimes referred to as mineral fertilizers.
The two most important are organic manure and mineral fertilizers.
When manure and crop residues are used, mineral fertilizers supply the outstanding nutrient balance needed for good crop yields.
In most parts of the world, the balance to be supplied by mineral fertilizers is substantial.
Fertilizer production entails gathering raw materials from nature; treating them in order to purify them or increase their concentration; converting them into plant-available forms; and often combining them into products that contain more than one nutrient.
The main sources of manufactured fertilizers are Nitrogen, Phosphate, Potash and Sulfur.
Large amounts of energy are required to convert this nitrogen to a form that can be used by plants.
The production of ammonia from atmospheric nitrogen was made possible in the first part of the 20th century by the development of the Haber-Bosch process.
It remains the only chemical breakthrough recognized by Nobel prices for chemistry, awarded to Fritz Haber in 1918 and Carl Bosch in 1931.
The most important nitrogen-based fertilizers are urea and ammonium nitrate (ammonia)
Rock phosphate is the raw material used in the manufacture of most commercial phosphate fertilizers.
Ground rock phosphate was ounce applied directly to acid soils.
However, due to low availability of phosphorous, high transport costs, and low crop responses, very little rock phosphate is currently used in agriculture.
Phosphate rock processing consists in the separation of phosphate from the mix of sand, clay and phosphate that makes up the matrix layer.
Potash deposits occur in beds of sediment derived from evaporated sea water.
The largest deposit, in Saskatchewan, Canada is 2.7 to 23.5 meters (9 to 77.6 feet) thick and found at depths of 1000 to 10, 000 meters (3,200 to 10,000 feet).
Mining methods are used to extract potash at greater depths.
Conventional underground dry-shaft mining methods are used in mines as great as 1100 meters (3500 feet.).
The ore is extracted from potash deposits by electrically operated mining machines and conveyed to the surface, where it is crushed.
Using a flotation process, salt and clay particles are removed, the brine solution is dried, and the potash is sized by screening.
The resultant coarse grade product is then ready for distribution.
Fine particles remaining from the screening process are compacted into sheets that are crushed and screened to particle sizes suitable for blending.
Natural gas treatment is one of the main source of sulfur production.
All the following downstream operations will also require de-sulfurization units that will produce sulfur as a waste.
Oil cracking in the refinery produces also more and more sulfur with the implementation of the new environmental standards requested to use low sulfur gasoline or diesel.
The fertilizer industry helps ensure that farmers have the nutrients they need to grow enough crops to meet the world’s requirements for food, feed, fibre and energy.
All of these nutrients exist in nature, but the quantities are not sufficient to meet the needs of our growing, urbanized population.
The fertilizers may be mineral or organic, sourced from nitrogen, potash, phosphate or sulfur, they need at a certain point of transformation the support of chemical processes for optimal use.