Expansion Joints for the Fertilizers Industry

Introduction

A fertilizer is a natural or artificial substance that contains chemical elements that enhance plant growth and productivity. Fertilizers improve the natural fertility of the soil or replace the chemical elements extracted from the soil by previous crops.

Fertilizers are generally composed of nitrogen, phosphorous and potassium compounds and contain trace elements that enhance plant growth.

The most important primary nutrient is Nitrogen and represents 57% of total consumption.
Phosphorous (phosphate) and potassium fertilizers are mainly applied to improve the quality of crops.

Since phosphate and potassium mineral deposits are only available in certain regions of the world, fertilizers of this type (phosphate and potassium) are supplied by a small number of major players in this industry, while nitrogen fertilizers are produced in many countries, given the wide availability of key raw materials: natural gas and air, necessary for its production on an industrial scale.

Primary fertilizers include substances derived from nitrogen, phosphorus and potassium. Several raw materials are used to produce these compounds. When using ammonia as a nitrogen source in a fertilizer, a synthetic production method, the use of natural gas and air is required. The phosphorus component is made from sulfur, coal, and phosphate rock. The source of potassium comes from potassium chloride, a main component of potash.

Nitrogen fertilizer. Ammonia is a nitrogen fertilizer component that can be synthesized from expensive raw materials. Since nitrogen constitutes an important part of the earth's atmosphere, a process was developed to produce ammonia from the air.

While ammonia itself is sometimes used as a fertilizer, it is often converted into other substances for ease of handling. Nitric acid is produced by first mixing ammonia and air in a tank. In the presence of a catalyst, a reaction occurs that converts ammonia to nitric oxide. Nitric oxide is further reacted in the presence of water to produce nitric acid.

Nitric acid and ammonia are used to produce ammonium nitrate. This material is a good fertilizer component because it has a high concentration of nitrogen. The two materials are mixed in a tank and a neutralization reaction occurs, producing ammonium nitrate. This material can then be stored until it is ready to be granulated and mixed with the other components of the fertilizer.

Phosphorus-based fertilizers. Phosphate is the natural source of phosphorus, an element that provides a quarter of all the nutrients that plants need for their growth and development.

To isolate phosphorus from rock phosphate, it is treated with sulfuric acid, producing phosphoric acid. Some of this material is further reacted with sulfuric acid and nitric acid to produce triple superphosphate, an excellent source of phosphorus in solid form.