Phosphatic fertilizers, manufacture

The basic raw materials used by the phosphorus chemicals, phosphates, and phosphate fertilizer manufacturing industry are mined phosphate rock and phosphoric acid produced by the wet process. 

The sources and characteristics of wastewater streams from the various subcategories in phosphate and phosphate fertilizer manufacturing, as well as some of the possibilities for... 

In planning resource-based industries in remote regions, where transport of low-value byproducts can be costly. An important case in Australia is sulfur dioxide emissions capture from metallurgical smelters to make sulfuric acid. Sulfuric acid can be used for phosphate fertilizer manufacture, but depends on availability of phosphate rock deposit, natural gas supply (for ammonia production), and infrastructure for transporting the fertilizer to markets. 

Potts Klett - a phosphate fertilizer manufacturer, near Camden, founded by Robert Barnhill Potts (1816 - 1865) and Frederick Klett (1827 - 1869). 

Since the beginning of the new millennium, China has been the largest importing coimtiy of sulfur in the world, mainly for phosphate fertilizer manufacture. 

Sulfur is a component of black gunpowder, and is used in the vulcanization of natural rubber and a fungicide. It is also used extensively in making phosphatic fertilizers. A tremendous tonnage is used to produce sulfuric acid, the most important manufactured chemical. 

Modem commercial wet-acid purification processes (see Fig. 4) are based on solvents such as C to Cg alcohols, ethers, ketones, amines, and phosphate esters (10—12). Organic-phase extraction of phosphoric acid is accompHshed in one or more extraction columns or, less frequently, in a series of countercurrent mixer—settlers. Generally, 60—75% of the feed acid P2 s content is extracted into the organic phase as H PO. The residual phosphoric acid phase (raffinate), containing 25—40% of the original P2O5 value, is typically used for fertilizer manufacture such as triple superphosphate. For this reason, wet-acid purification units are almost always located within or next to fertilizer complexes. 

An alternative route of manufacture is from siUcon tetrafluoride that is generated ia large quantities as a by-product of the production of phosphate fertilizers. The reaction is... 

Sulfuric acid is the most important sulfur-containing intermediate product. More than 85% of the sulfur consumed in the world is either converted to sulfuric acid or produced direcdy as such (see Sulfuric acid and sulfur trioxide). Worldwide, well over half of the sulfuric acid is used in the manufacture of phosphatic fertilizers and ammonium sulfate for fertilizers. The sulfur source may be voluntary elemental, such as from the Frasch process recovered elemental from natural gas or petroleum or sulfur dioxide from smelter operations. 

The movement of fluoride through the atmosphere and into a food chain illustrates an air-water interaction at the local scale (<100 km) (3). Industrial sources of fluoride include phosphate fertilizer, aluminum, and glass manufacturing plants. Domestic livestock in the vicinity of substantial fluoride sources are exposed to fluoride by ingestion of forage crops. Fluoride released into the air by industry is deposited and accumulated in vegetation. Its concentration is sufficient to cause damage to the teeth and bone structure of the animals that consume the crops. 

Phosphate fertilizer complexes often have sulfuric and phosphoric acid production facilities. Sulfuric acid is produced by burning molten sulfur in air to produce sulfur dioxide, which is then catalytically converted to sulfur trioxide for absorption in oleum. Sulfur dioxide can also be produced by roasting pyrite ore. Phosphoric acid is manufactured by adding sulfuric acid to phosphate rock. The... 

The oxoacids and oxoanions of phosphorus are among the most heavily manufactured chemicals. Phosphate fertilizer production consumes two-thirds of all the sulfuric acid produced in the United States. 

Ca5 (P04)3 F( ) + 5 H2 S04(cz - 3 H3 P04(t2 ) + 5 CaS04( ) + HF(ts The dilute phosphoric acid obtained from this process is concentrated by evaporation. It is usually dark green or brown because of the presence of many metal ion impurities in the phosphate rock. However, this impure acid is suitable for the manufacture of phosphate fertilizers, which consumes almost 90% of phosphoric acid production. 

In the fertilizer manufacturing scheme, the wet process phosphoric acid most commonly ensues from dissolution of sedimentary phosphate rock in sulfuric acid. Such acid solution contains around 1 g 1 1 uranium which is recovered as the byproduct. This task is accomplished by three well-proven extraction processes, some salient details of which are presented in Table 5.10. 

The transfer of trace elements in phosphate rocks to P fertilizers is dependent upon the manufacturing processes. Triple superphosphate fertilizer contains 60-70% of the Cd present in phosphate rocks (Wakefield, 1980). The transfer coefficients may be similar for most other elements and heavy metals even though there are little data on the transfer of other elements from phosphate rocks to P fertilizers. In general, based on some long-term (> 50 years) soil fertility experiments in the U.S., annual Cd rates from the application of phosphate fertilizers are estimated to range from 0.3 to 1.2 g per ha. The addition of Cd to soils as a contaminant from P fertilizers... 

Phosphate conversion coatings, 18 829 Phosphated flour, 26 283 Phosphate drilling mud thinners, 9 16t Phosphate ester additives, 11 500 Phosphate esters, manufacture of, 19 51 Phosphate fertilizers, 11 111, 117-122, 125, 127 23 590... 

Phosphoric acid, H3PO4, is one of the world s most important industrial chemicals. It is mainly used to manufacture phosphate fertilizers. It is also the ingredient that gives cola drinks their tart, biting taste. Calculate the pH, [H2PO4-], and [HP04 ] of a 3.5 mol/L aqueous solution of phosphoric acid. 

Most elemental ph osphorus is used to manufacture phosphoric acid, a solid that is used to produce triple-phosphate fertilizers. Some soils require large amounts of phosphorus to produce a viable crop. 

The phosphate manufacturing and phosphate fertilizer industry includes the production of elemental phosphorus, various phosphorus-derived chemicals, phosphate fertilizer chemicals, and other nonfertilizer phosphate chemicals [1-30], Chemicals that are derived from phosphorus include phosphoric acid (dry process), phosphorus pentoxide, phosphorus penta-sulfide, phosphoms trichloride, phosphorus oxychloride, sodium tripolyphosphate, and calcium phosphates [8]. The nonfertilizer phosphate production part of the industry includes defluori-nated phosphate rock, defluorinated phosphoric acid, and sodium phosphate salts. The phosphate fertilizer segment of the industry produces the primary phosphorus nutrient source for the agricultural industry and for other applications of chemical fertilization. Many of these fertilizer products are toxic to aquatic life at certain levels of concentration, and many are also hazardous to human life and health when contact is made in a concentrated form. 

The phosphate fertilizer industry is defined as eight separate processes phosphate rock grinding, wet process phosphoric acid, phosphoric acid concentration, phosphoric acid clarification, normal superphosphate, triple superphosphate, ammonium phosphate, and sulfuric acid. Practically all phosphate manufacturers combine the various effluents into a large recycle water system. It is only when the quantity of recycle water increases beyond the capacity to contain it that effluent treatment is necessary. 

As previously mentioned, fertilizer manufacturing may create problems within all environmental media, that is, air pollution, water pollution, and solid wastes disposal difficulties. In particular, the liquid waste effluents generated from phosphate and mixed and blend fertilizer production streams originate from a variety of sources and may be summarized [17,27] as follows (a) ammonia-bearing wastes from ammonia production (b) ammonium salts such as... 

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