Fertilisers
Granular urea
Granular urea is a solid nitrogen fertilizer product that normally contains46 percent nitrogen content. Produced from ammonia and carbon dioxide, it has the highest nitrogen content of any solid nitrogen fertilizer. Granular urea can be applied by itself, or it can be easily mixed with phosphate and/or potash fertilizers, often as part of a total NPK (nitrogen, phosphate, and potash) plant food mix. As a granular product, urea can be applied directly to the soil using conventional spreading equipment. It is the most common form of nitrogen fertilizer used around the world.
Granular urea is produced on a major scale in the Middle East, USA, North Africa and in China. The majority of urea capacity additions in recent years produce granular urea, as opposed to prilled urea. This includes the significant additions in North America, new capacity in Algeria, Nigeria and Malaysia.
Prilled urea
Prilled urea is the processed product resulting from the reaction of ammonia in an anhydrous manner with a pressure of 180 degrees.
It is a substance produced by protein metabolism and, in contrast to granulated urea, dissolves in water in a very short time due to its dissolvable nature.
It is a nitrogen fertilizer manufactured by the reaction of ammonia and carbon dioxide and thus, it is used largely in agriculture as a nitrogen rich fertilizer.
Prilling is a process by which solid particles are produced from molten urea. Molten urea is sprayed from the top of a prill tower. As the droplets fall through a countercurrent air flow, they cool and solidify into nearly spherical particles.
Ammonium nitrate
Ammonium nitrate is a chemical compound with the chemical formula NH4NO3. It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, although it does not form hydrates. It is predominantly used in agriculture as a high-nitrogen fertilizer.
Its other major use is as a component of explosive mixtures used in mining, quarrying, and civil construction. It is the major constituent of ANFO, a popular industrial explosive that accounts for 80% of explosives used in North America; similar formulations have been used in improvised explosive devices.
Many countries are phasing out its use in consumer applications due to concerns over its potential for misuse. Accidental ammonium nitrate explosions have killed thousands of people since the early 20th century. Global production was estimated at 21.6 million tonnes in 2017. By 2021, global production of ammonium nitrate was down to 16.7 million tonnes
UAN 32 % N
UAN is a solution of urea and ammonium nitrate in water used as a fertilizer. The combination of urea and ammonium nitrate has an extremely low critical relative humidity (18% at 30 °C) and can therefore only be used in liquid fertilizers. The most commonly used grade of these fertilizer solutions is UAN 32.0.0 (32%N) known as UN32 or UN-32, which consists of 45% ammonium nitrate, 35% urea, and only 20% water.
Super phosphates
Triple superphosphate is a component of fertilizer that primarily consists of monocalcium phosphate, Ca(H2PO4)2. Triple superphosphate is obtained by treating phosphate rock with phosphoric acid. Traditional routes for extraction of phosphate rock use sulfuric acid gives a single superphosphate, an approximate 1:1 mixture of Ca(H2PO4)2 and CaSO4 phosphogypsum). Double superphosphate refers to some average of triple- and single superphosphate, resulting from the extraction of phosphate rock with a mixture of phosphoric and sulfuric acids.
Many fertilizers are derived from triple superphosphate, e.g. by blending with ammonium sulfate and potassium chloride. Typical fertilizer-grade triple superphosphate contains 45% P2O5eq, single superphosphate 20% P2O5eq
NPK's
NPK fertilizer is a complex fertilizer comprised primarily of the three primary nutrients required for healthy plant growth. The agriculture industry relies heavily on the use of NPK fertilizer to meet global food supply and ensure healthy crops.
There are numerous building blocks of life that plants need for healthy and optimum growth. Without these nutrients, plants cannot grow to their full potential, will provide lower yields, and be more susceptible to disease.
The three most important nutrients, without any one of which plants could not survive, are referred to as the primary macronutrients: Nitrogen , Phosphorus , and Potassium .
Soils often lack these nutrients, either naturally, or as a result of over cultivation or other environmental factors. In cases where soils are lacking, nutrients must be put back into the soil in order to create the ideal environment for optimal plant growth.
Each of the primary nutrients is essential in plant nutrition, serving a critical role in the growth, development, and reproduction of the plant.
While NPK fertilizers are composed mainly of the three primary nutrients, flexibility in processing allows various other micronutrients to be incorporated into the blend. For example, NPKS has been gaining popularity in response to the sulfur deficient soils resulting from the Acid Rain Act.
Rock phosphates
Phosphorite, phosphate rock, or rock phosphate is a non-detrital sedimentary rock that contains high amounts of phosphate minerals. The phosphate content of phosphorite (or grade of phosphate rock) varies greatly, from 4% to 20% phosphorus pentoxide (P2O5). Marketed phosphate rock is enriched (“beneficiated”) to at least 28%, often more than 30% P2O5.
Approximately 90% of rock phosphate production is used for fertilizer and animal feed supplements and the balance for industrial chemicals. In addition to phosphate fertilizers for agriculture, phosphorus from rock phosphate is also used in animal feed supplements, food preservatives, baking flour, pharmaceuticals, anti-corrosion agents, cosmetics, fungicides, insecticides, detergents, ceramics, water treatment, and metallurgy.
For use in the chemical fertilizer industry, beneficiated rock phosphate must be concentrated to levels of at least 28% phosphorus pentoxide (P2O5), although most marketed grades of phosphate rock are 30% or more.
It must also have reasonable amounts of calcium carbonate (5%), and <4% combined iron and aluminum oxides.[citation needed] Worldwide, the resources of high-grade ore are declining, and the use of lower-grade ore may become more attractive.
Beneficiated rock phosphate is also marketed and accepted as an “organic” alternative to “chemical” phosphate fertilizer which has been further concentrated from it, because it is perceived as being more “natural”. According to a report for the FAO, it can be more sustainable to apply rock phosphate as a fertilizer in certain soil types and countries, although it has many drawbacks. According to the report it may have higher sustainability compared to more concentrated fertilizers because of reduced manufacturing costs and the possibility of local procurement of the refined ore.
Sulphur
Most of Sulphur-containing fertilizers materials generally could be classified into the following three main categories
First Sulphate-containing fertilizers provide most of the fertilizer Sulphur applied to soils. These materials have the advantages of supplying Sulphur primarily as a component of multi-nutrient fertilizers in a form, SO4-2, that is immediately available for plant uptake. The most readily available and popular sources are ammonium sulphate (AS), single superphosphate (SSP), potassium sulphate, and potassium and magnesium sulphate
Second Elemental Sulphur based fertilizers are the most concentrated Sulpher carrier. Modern technologies increased their use in direct applications or as additives to N-P-K fertilizers.
Third Liquid Sulphur Fertilizers Low water solubility hampers the use of several sulphate fertilizers, particularly in liquid formulations, which have gained importance.
