up21 - 4.2 Manufacture of Ammonia 4.2.1 Introduction Ammonia is one of the most highly produced inorganic chemicals in the world because of its

up21 - 4.2 Manufacture of Ammonia 4.2.1 Introduction...

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4.2. Manufacture of Ammonia 4.2.1. Introduction. Ammonia is one of the most highly produced inorganic chemicals in the world because of its widespread application. Synthetic ammonia is produced from the reaction between nitrogen and hydrogen. Before synthetic nitrogen fixation was discovered, manures, ammonium sulfate (a by-product from the coking of coal), Chilean saltpetre, and later, ammonia recovered from coke manufacture were some of the important sources of fixed nitrogen. During the first decade of the twentieth century, the worldwide demand for nitrogen-based fertilizers far exceeded the existent supply. 4.2.2. Uses of ammonia Ammonia is the basis from which virtually all nitrogen-containing products are derived. The main uses of ammonia include the manufacture of: Fertilizers ((ammonium sulfate, diammonium phosphate, urea) Nitric acid Explosives Fibres, synthetic rubber, plastics such as nylon and other polyamides Refrigeration for making ice, large scale refrigeration plants, air-conditioning units in buildings and plants Pharmaceuticals (sulfonamide, vitamins, etc.) Pulp and paper Extractive metallurgy Cleaning solutions 4.1.3. Raw Materials The raw materials used to manufacture ammonia are air, water and, hydrocarbons. Coal can also be used in place of hydrocarbons but the process is complex and expensive. 4.2.4. Nitrogen fixation
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For a long time, commercial development of nitrogen fixation ammonia process had proved elusive. Old methods used to produce ammonia included dry distillation of nitrogenous vegetable and animal waste products. Here, nitrous acid and nitrites were reduced with hydrogen according to the following equation: N 2 O + 4H 2 = 2NH 3 + H 2 O
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