Superphosphate fertilizer triple

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... 

H3P04) and calcium sulfate (CaS04 2H20, also known as gypsum). The phosphoric acid is then processed with the phosphate rock to produce triple superphosphate fertilizer. Triple superphosphate has three times the concentration of phosphorus as superphosphate. Another fertilizer produced from sulfuric acid is ammonium sulfate, (NH4)2S04. Ammonium sulfate is produced by reacting ammonia and sulfuric acid. 

Calcium dihydrogen phosphate, which is used in the production of triple superphosphate fertilizers, can be formed from the reaction of apatite, Ca5(P04)3F, with phosphoric acid. How many grams of calcium dihydrogen phosphate can be formed from 6.78 g of Ca5(P04)3F ... 

The simplest method for producing sodium phosphates involves the neutralization of phosphoric acid with either sodium hydroxide or carbonate, but, unless some waste source of alkali is found, it may not be the most economical. For this reason other methods of producing sodium phosphates were investigated. The two most promising methods involve conversion of monocalcium phosphate (or normal or triple superphosphate fertilizer) to sodium phosphate by ion exchange, and neutralization of phosphoric acid with dilute sodium hydroxide produced electrolytically from brine. 

Garda, M. C., Vallejo, A., Garda, L, and Cartagena, M. C. (1997], Manufacture and evaluation of coated triple superphosphate fertilizers, IjjdJng QienL s., 36,869-873. 

Falls JH (1991) Comparison and review of three available P2OJ methods for diammonium phosphate and triple superphosphate. Fertilizer Research 28 239-249. 

The routes by which mineral phosphates are processed into finished fertilizers are outlined in Eigure 7. World and U.S. trends in the types of products produced are shown in Eigures 8 and 9, respectively. Most notable in both instances is the large, steady increase in the importance of monoammonium and diammonium phosphates as finished phosphate fertilizers at the expense of ordinary superphosphate, and to some extent at the expense of triple superphosphate. In the United States, about 65% of the total phosphate appHed is now in the form of granular ammonium phosphates, and additional amounts of ammonium phosphates are appHed as integral parts of granulated mixtures and fluid fertilizers. 

Fig. 8. World trends in types of phosphate fertilizers consumed, where (—) represents ammonium phosphates and multinutrient compounds (— normal superphosphate ( ), triple superphosphate and (— —), basic slag and raw rock.

Triple (Concentrated) Superphosphate. The first important use of phosphoric acid in fertilizer processing was in the production of triple superphosphate (TSP), sometimes called concentrated superphosphate. Basically, the production process for this material is the same as that for normal superphosphate, except that the reactants are phosphate rock and phosphoric acid instead of phosphate rock and sulfuric acid. The phosphoric acid, like sulfuric acid, solubilizes the rock and, in addition, contributes its own content of soluble phosphoms. The result is triple superphosphate of 45—47% P2 s content as compared to 16—20% P2 5 normal superphosphate. Although triple superphosphate has been known almost as long as normal superphosphate, it did not reach commercial importance until the late 1940s, when commercial supply of acid became available. 

Worldwide, triple superphosphate, over the period 1955 to 1980, maintained about a 15% share of the phosphate fertilizer market (Fig. 8). World consumption for the year ended June 30, 1991 (9) was equivalent to 3.6 x 10 t of P20, which was about 10% of world fertilizer P2O5 consumption. In the United States, consumption for the year ended June 30, 1990 (Fig. 7) was equivalent to about 240 x 10 t of P20, which represented only 6% of U.S. fertilizer P2O5 consumption. 

Since about 1968, triple superphosphate has been far outdistanced by diammonium phosphate as the principal phosphate fertilizer, both in the United States and worldwide. However, production of triple superphosphate is expected to persist at a moderate level for two reasons (/) at the location of a phosphoric acid—diammonium phosphate complex, production of triple superphosphate is a convenient way of using sludge acid that is too impure for diammonium phosphate production and (2) the absence of nitrogen in triple superphosphate makes it the preferred source of phosphoms for the no-nitrogen bulk-blend fertilizers that frequendy are prescribed for leguminous crops such as soy beans, alfalfa, and clover. 

Monoammonium Phosphate. Monoammonium phosphate [7722-76-1] (MAP), NH4H2PO4, has become second only to diammonium phosphate as a phosphate fertilizer material of trade. During the year ended June 30, 1990, monoammonium phosphate used ia the United States furnished 985 thousand t of P2O5 as compared to 1.5 million t furnished by diammonium phosphate and 240 thousand t by triple superphosphate (Fig. 7). Monoammonium phosphate furnished 25% of total P2O5 consumption. 

Some commonly used primary nutrient fertilizers are incidentally also rich sources of calcium. Ordinary superphosphate contains monocalcium phosphate and gypsum in amounts equivalent to all of the calcium originally present in the phosphate rock. Triple superphosphate contains soluble monocalcium phosphate equivalent to essentially all the P2 5 product. Other fertilizers rich in calcium are calcium nitrate [10124-37-5] calcium ammonium nitrate [39368-85-9] and calcium cyanamide [156-62-7]. The popular ammonium phosphate-based fertilizers are essentially devoid of calcium, but, in view of the natural calcium content of soils, this does not appear to be a problem. 

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. 

Phosphates. The primary constituent of phosphate rock is fluorapatite, Ca3FP2022- Industrial phosphates including phosphate fertilizers (qv), phosphoric acid, and calcium phosphates (11) (see Phosphoric acid and the phosphates) are obtained from the large deposits of fluorapatite found in Florida in the United States, and in Morocco. Because phosphate rock is too insoluble to be useful as a fertilizer, it is converted to superphosphate [12431 -88-8] Ca(H2P0 2 CaSO, by H2SO and to triple superphosphate [7758-23-8] by H PO (l )- Phosphoric acid may also be... 

Phosphate Fertilizer Industry Triple Superphosphate Plants... 

Phosphate Fertilizer Industry Granular Triple Superphosphate Storage Facilities Goal Preparation Plants Ferroalloy Production Facilities Steel Plants Electric Arc Furnaces Constructed after October 21, 1974, and on or before August 17,1983... 

A great many phosphates are used in commercial fertilizers. Perhaps the most important of these is calcium dihydrogen phosphate, Ca(H2P04)2. In relatively pure form, this compound is known as triple superphosphate of lime. A 1 -2 mol mixture of Ca(H2PC>4)2 and gypsum, CaS04 2HzO, is commonly referred to as superphosphate of lime. ... 

Solid phosphoric fertilizers are available as mono-ammonium phosphate, di-ammonium phosphate, triple superphosphate and single superphosphate additionally, high-grade liquid phosphoric acid is available. 

The phosphate concentration in the tailings is upgraded to a level adequate for commercial exploitation through removal of the nonphosphate sand particles by flotation [32], in which the silica solids are selectively coated with an amine and floated off following a slurry dewatering and sulfuric acid treatment step. The commercial quality, kiln-dried phosphate rock product is sold directly as fertilizer, processed to normal superphosphate or triple superphosphate, or burned in electric furnaces to produce elemental phosphorus or phosphoric acid, as described in Section 9.2. 

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. 

Triple Superphosphate is made by acidulating phosphate rock with phosphoric acid. The concentrated triple superphosphate produced is essentially monoealeium phosphate containing very little gypsum. The principle use of triple superphosphate is ill mixed fertilizers to make P >0< available in water-soluble form. 

Reaction of the phosphoric acid with more phosphate rock gives Ca(H2PC>4)2/ a water-soluble fertilizer known as triple superphosphate ... 

Fig. 24.11. Continuous system for manufacture of nongranular triple superphosphate. (Source Fertilizer Manual.)...

Fig. 24.12. Slurry process for the manufacture of granular triple superphosphate.

Standards of Performance for the Phosphate Fertilizer Industry Wet-Process Phosphoric Acid Plants Standards of Performance for the Phosphate Fertilizer Industry Superphosphoric Acid Plants Standards of Performance for the Phosphate Fertilizer Industry Diammonium Phosphate Plants Standards of Performance for the Phosphate Fertilizer Industry Triple Superphosphate Plants Standards of Performance for the Phosphate Fertilizer Industry Granular Triple Superphosphate Storage Facilities... 

Poorly crystalline or amorphous Phosphorite sediments made from the hard remains of marine organisms are the principal commercial source of phosphates, although Apatites are also mined. Treatment of phosphate minerals with sulfuric acid yields superphosphate fertilizer, a mixture of Ca(H2P04)2, H3PO4 and CaS04. Phosphoric acid treatment gives triple superphosphate , rich in Ca(H2P04)2. Other soluble fertilizers such as ammonium phosphates are obtained from these products. 

SAFETY PROFILE AlkaU metal phosphates are strong caustics and therefore powerful irritants. Superphosphate is Ca(H2P04)2/CaS04. Triple superphosphate contains P2O5. Both are used as fertilizers. Organophosphates are often highly toxic pesticides. For an example of organic phosphates, see PARATHION. See also individual phosphates. 

Plant tissues and soil samples from nine long-term (>50 years) soil fertility plots in the United States were analyzed for Ra by a Rn bubbler tube method and for U and Th by inductively coupled plasma (ICP) spectrophotometry. The triple superphosphate (TSP) used for these studies, made from Florida phosphate rock, had been applied at rates of about 30 kg P ha annually. Results showed that there were no differences in U, Ra, or Th concentrations in com (Zea mays L.) leaves or grain, soybean (Glycine max. L. Merr.) leaves or grain, or timothy (Phleum pratense L.) forage grown on non-fertilized or TSP-fertilized soil (Mortvedt and Sikora, 1992). 

Subpart W Standards of Performance for the Phosphate Fertilizer Industry Triple Superphosphate Plants... 

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