Florida, phosphate deposits

Fig. 8.22 (a-b) Online breakdown spectra of apatite (a) and dolomite (b) which are the main minerals in Florida phosphate deposits... 

Zellars-Williams, Inc., Evaluation of the Phosphate Deposits of Florida Using The Minerals Availability System, Final Report submitted to the U.S. Department of the Interior Bureau of Mines, June 1978. 

The fluorine levels observed for modem materials were, in general, comparable with those observed in other work (7,8). Included are the data of JaflFee and Sherwood (9) for modern and fossil manatee rib specimens from Florida waters and land-pebble phosphate deposits, respectively. The modem specimen shows a somewhat higher fluoride level than generally observed for modem bone. Since this sample was taken from an articulated skeleton (USNM 228478), only a small sample was taken. It is possible that preparation of the skeleton for display or the small sample size reduced the representativeness of the measurement. 

Phosphate rock deposits contain uranium (U), radium (Ra), thorium (Th), and other radionuclides as contaminants. Uranium in phosphate rock deposits throughout the world range from 3 to 400 mg kg (Guimond, 1978). It has been estimated that 1000 kg of Florida phosphate rock contains about 100 pCi each of" U and Ra and 4 pCi of °Th (Menzel, 1968). Some of these elements are retained in the HjPO and the remainder are transferred to the by-products during fertilizer manufacture. For instance it is estimated that 60% of the radioactivity in mined Florida phosphate rock remains with slime and sand tailings during beneficiation (Guimond and Windham, 1975). 

Sedimentary phosphate ores, such as those found in Florida and Morocco, tend to have high concentrations of uranium, whereas the opposite occurs with magmatic ores, such as apatite from Kola. Typical activity concentrations of U are 1500 Bq kg in sedimentary phosphate deposits and 70 Bq kg in apatite. U is generally found in radioactive equilibrium with its decay products. The activity concentrations of Th... 

In Florida, fluoride and phosphate are chemically and industrially associated. Phosphate deposits in Florida occur as sedimentary phosphorite of Miocene age (10-15 million years old). The principal mineral is apatite, Ca5(P04)3F, containing about 4% fluorine. The deposits are centered in a 500-sq mile area around Bartow. Mining was initiated in 1890, and in 1972, Florida produced more than 30 million tons of phosphate valued at about 170 million. Florida supplies over three-fourths of United States needs and roughly one-third of the world needs (7). 

It is critical to separate dolomitic limestone impurities from apatite to utilize the South Florida Phosphate Rock deposits for fertilizer manufacturing. Conventional flotation scheme is not successful for separation of dolomite from Its mixture with apatite. Several processing methods utilizing both anionic and cationic collectors have been proposed to solve this problem, but they have yet to be tested on a commercial scale. 

Many important sedimentary phosphate deposits owe their present character to surface or near-surface processes. For instance, the Florida deposits have been reworked in the past under surface conditions. Several cycles of deposition and reworking have concentrated the phosphate, and weathering has removed most of the carbonates from the upper (near the surface) portions of the deposits. --------... 

The first American superphosphate plant opened in 1850 by William Davison and T.S. Chapell of Baltimore. Other early producers in this decade were Potts Klett and Moro Phillips of Philadelphia. The introduction of the phosphate fertilizer industry created the first significant sulfuric acid market in the U.S. This country would eventually dominate phosphate fertilizer production, thanks mainly to massive phosphate deposits in Florida, which were first mined in 1888. Now, in the early 21 century, the U.S. market for sulfuric acid in the phosphate fertilizer industry is over 25 million tonnes, representing over 8.0 million tonnes per year of sulfur. The largest producer of phosphate fertilizer in the world is Mosaic, formed from the merger of IMC Global and Cargill Crop Nutrition in October 2004 (see Table 2.5). 

Never found free in nature, it is widely distributed in combination with minerals. Phosphate rock, which contains the mineral apatite, an impure tri-calcium phosphate, is an important source of the element. Large deposits are found in Russia, in Morocco, and in Florida, Tennessee, Utah, Idaho, and elsewhere. 

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... 

In the United States, major deposits of phosphate rock are found in Florida, North Carolina, and Idaho. 

The phosphate rock deposits in the Florida region are in the form of small pebbles embedded in a matrix of phosphatic sands and clays [31]. These deposits are overlain with lime... 

The major sources of TT3PO4 traditionally have been mineral deposits of phosphate rock. Mining operations are extensive in a number of locations, including the United States (Florida), the Mediterranean area, and Russia, among others. The major constituent of most phosphate rocks is fluorapatite, 3Cai(P04)2 CaF>. The supply of high-grade phosphates,... 

It is an interesting fact that the two elements most necessary in the maintenance of soil fertility are the related elements nitrogen and phosphorus, which occupy adjacent positions in Group V of the periodic table. Phosphorus occurs in nature only in the combined form, chiefly as the mineral phosphorite [Ca3P04)2]. Impure calcium phosphate, known as phosphate rock, is mined extensively in Tennessee, Florida, Montana, and Idaho. Large deposits of this mineral are also found in Morocco and Tunisia in North Africa. 

Phosphate fertilizers. From the extensive phosphate rock deposits in Tennessee, South Carolina, Florida, Idaho, and Montana, approximately 3 million tons of ore are used annually in the manufacture of fertilizers. The chief phosphate present in this rock is the normal calcium salt [Ca3(P04)2]. Because of its insolubility, this compound is not very useful as a fertilizer. If a phosphorus compound is to provide phosphorus that can be assimilated by growing plants, the compound must be one that is appreciably soluble. 

United States.—The principal deposits are in South Carolina, Florida, Tennessee, Arkansas, Utah and Wyoming. The South Carolina deposits are of Miocene age and occur both as land and river rock. They contain 25 to 28 per cent, of phosphoric oxide and 35 to 42 per cent, of lime. They were the earliest to be exploited, namely, from 1868 onwards, and in 1893 they furnished about one-fifth of the world s supply. Since this date the production has declined, while that of Florida has greatly increased. In 1913 Florida and Tennessee together produced some 96 per cent, of the total output from the United States of America. The hard-rock deposits of Florida are of Tertiary age, and they run parallel to the coast for 144 miles. After concentration by mechanical means they contain usually from 77 to 79 per cent, of calcium phosphate (more rarely up to 82 per cent.) with 3 per cent, of oxides of iron and alumina, some calcium fluoride and other constituents, and 3 per cent, of moisture. The best grades of Tennessee rock were guaranteed to contain 72 per cent, of calcium phosphate, and 65 per cent, is common. The soft rock is a phosphatic clay. The river pebbles are dark grey to black and are very cheaply obtained by dredging. 

The major deposits of phosphate ores are in Florida in the United States, Kola in Russia, and Morocco [2,3]. They consist of minerals of calcium and aluminum phosphates [2]. These ores are processed to extract these minerals the most important among these minerals is calcium fluorophosphate (CaioF2(P04)6). Richness of phosphate in these rocks and the extracted products is measured in terms of P2O5 content in them. 

All commercially used phosphorous compounds are derived from phosphate rocks. Some deposits accumulated have billions of tons of phosphate, for example the Phos-poria deposit of the western USA and Morocco. Large deposits are also found in Australia, China, Florida, and the Kola Peninsula. The deposits of Christmas Island are of guano origin and are rapidly being depleted by over-use, though other reserves of phosphate ore should last for a thousand years. Globally, over 75 million tons of such rocks, containing about 15 million tons of P, are mined annually. About 95% of this output is destined directly for the food chain, with 90% as fertilizers and 4% in the form of different additives to livestock fodder (3.4%) or human foodstuffs (0.7%). About 4.5% of mined phosphorus is used... 

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