Potash contains potassium (K), one of three primary macronutrients required for plant growth. The other two are nitrogen (N) and phosphorus (P). These elements are often combined and distributed as NPK formula fertilizer. Any natural or manufactured material that contains at least 5% of one or more of these three macronutrients can be considered a fertilizer.
Commercial fertilizers containing nitrogen, phosphorus or potassium can improve plant yield by 40% to 60%. There are several sources that provide nutrients to plants; the two most important are organic manure and mineral fertilizers. When manure and crop residues are used, mineral fertilizers supply the remaining nutrient balance needed for good crop yields. In most parts of the world, the balance supplied by mineral fertilizers is substantial.
78% of the earth's atmosphere is nitrogen. However, the nitrogen we breathe is in a chemically inert form that plants (except legumes) cannot use. Large amounts of energy are required to convert this nitrogen to a form that can be used by plants. The most important nitrogen-based fertilizers are urea and ammonium nitrate. The production of ammonia from atmospheric nitrogen was made possible in the early 20th century by the development of the Haber-Bosch process. In this process, hydrogen is obtained from natural gas by a catalytic process. In some countries, though far less commonly, coal is used as the source of hydrogen through a process called coal gasification. The final stage involves the production of ammonia using an iron catalyst promoted with potassium oxide, calcium oxide, and aluminum oxide. This is done at a pressure of 200 atmospheres and at temperatures between 300 degrees centigrade and 550 degrees centigrade.
Phosphorus is mined from naturally occurring mineral deposits of phosphate rock formed in the sediments of ancient seas. Phosphate rock is the raw material used in the manufacture of most commercial phosphate fertilizers. However, due to the low availability of phosphorus, high transport costs, and low crop responses, very little rock phosphate is currently used in agriculture. Phosphate rock processing consists of the separation of phosphate from the mix of sand, clay and phosphate that makes up the matrix layer.
The potassium used in fertilizers is found in a salt form called potash. Potash deposits are derived from evaporated sea water and are found in sediment beds in only a few places in the world. Canada, Germany and Russia have large deposits of sylvite, also known as muriate of potash (MOP). Typically, sylvite is extracted using electrically-operated mining machines and conveyed to the surface to be 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 for blending. The Ochoa mine and mill will produce a premium potassium product, sulfate of potash (SOP) using a revolutionary process that was developed in the first half of the 20th century and forgotten. read more +