Mixed fertilizers

These nitrogen solutions are used both for direct field appHcation and as a nitrogen ingredient in fluid mixed fertilizers. 

Essentially all the ammonium sulfate fertilizer used in the United States is by-product material. By-product from the acid scmbbing of coke oven gas is one source. A larger source is as by-product ammonium sulfate solution from the production of caprolactam (qv) and acrylonitrile, (qv) which are synthetic fiber intermediates. A third but lesser source is from the ammoniation of spent sulfuric acid from other processes. In the recovery of by-product crystals from each of these sources, the crystallization usually is carried out in steam-heated sa turator—crystallizers. Characteristically, crystallizer product is of a particle size about 90% finer than 16 mesh (ca 1 mm dia), which is too small for satisfactory dry blending with granular fertilizer materials. Crystals of this size are suitable, however, as a feed material to mixed fertilizer granulation plants, and this is the main fertilizer outlet for by-product ammonium sulfate. 

Fig. 16. Steam granulation process for production of granular mixed fertilizers from dry, pulverized feed materials (7). A granulator producing 12 t/h would...

Fig. 18. TVA-type cogranulation process with preneutralizer, as used for production of granular mixed fertilizers. Feed materials such as ammonium sulfate, ammonium nitrate, urea, superphosphates, sulfuric acid, and potash are used.

Fig. 20. U.S. market share for several types of mixed fertilizer, where (—) represents bulk blends (-) ammoniation—granulation and ( ) fluids.

Fig. 24. Routes of wet-process phosphoric acid into solution-type and suspension-type mixed fertilizer.

Nitrogen solutions consist of fertilizer product combinations, eg, ammonium nitrate —ammonia, urea—ammonium nitrate—ammonia, urea—ammonium nitrate, and urea—ammonia solutions. Mixed fertilizers cover a broad range and can be loosely defined as fertilizers which contain chemically mixed nitrogen, phosphoms, and potassium (N—P—K). Examples are ammonium phosphate—potash mixtures and ammonium phosphate nitrates. 

Low 500-20,000 2-4 Mixed fertilizers, phosphate ores, shales, urea Coal, charcoal, coke, lignite, animal feed, candy Phosphate ores, urea... 

Am POLLUTION FROM AGRO-INDUSTRY CHEMICALS Mixed Fertilizer Plants... 

Mixed fertilizers contain two or more of the elements nitrogen, phosphorus, and potassium (NPK), which are essential for good plant growth and high crop yields. This subsection briefly addresses the production of ammonium phosphates... 

Additional pollution control devices beyond the scrubbers, cyclones, and baghouses that are an integral part of the plant design and operations are generally not required for mixed fertilizer plants. 

Misch-barkeit, /. miscibility, -behaiter, m. mixing vessel (tank, drum, etc.), mixer, -be-stand, m. (Agric.) mixed stand, mixed crop, -bleichen, n. mixed bleaching, -bottich, m. mixing tub or trough, -diinger, m. mixed fertilizer compost, -element, n. mixed element (a mixture of isotopes). 

Mixed Fertilizer. The raw materials used to produce mixed fertilizers include inorganic acids, solutions, double nutrient fertilizers, and all types of straight fertilizers. The choice of raw materials depends on the specific nitrogen-phosphate-potassium (N-P-K) formulation to be produced and on the cost of the different materials from which they can be made. 

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