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By L. Telfer

Summary During Palaeozoic time, there were deposited in the Canadian Rockies four beds of phosphate rock, ranging in age from Mississippian to Jurassic. Two of these beds are of probable economic importance if some means of separating the phosphate from the gangue can be devised. All the more important beds of phosphate rock so far discovered are just behind the front ranges of the Rocky mountains, within fifty miles of the prairie lands of Alberta. Mining conditions are favourable, with an abundance of timber and ample power available. The phosphate beds are all of the sedimentary type, and they all occur, apparently, at the same stratigraphic horizons over a wide area. The conditions necessary for deposition evidently occurred at several different periods in geological time, and were widespread. The most important factor appears to have been the condition of the land surface surrounding the basin of de-position. Both oolitic and nodular phosphate were laid down under nearly similar conditions. Introduction Following the discovery of phosphate rock in Idaho and Montana, search was commenced in Canada to determine whether formations of similar age in the Canadian Rockies carried similar beds of phosphate. The most widespread search has been that undertaken by the mines department of the Consolidated Mining and Smelting Company of Canada. The following paper will discuss some of the results of this exploration.

Jan 1, 1933

By H. M. Woodrooffe

In the U.S.S.R. three of the world's major-known phosphate deposits are located. These have an estimated reserve of 2,600 million short tons of contained phosphorus. The best known lies in the "Khibiny Massif', an alkalaic rock formation some 600 square miles in area with mountain peaks rising to an altitude of 3300 ft above the surrounding terrain. Location and Climate The Khibiny Massif lies north of the Arctic Circle in the Kola Penin-sula, 100 miles south southeast of Murmansk, at a latitude of 67° 30' north and a longitude of 35° 30' east. It is serviced by rail from Murmansk and Leningrad (900 rail miles south). Figure 1. The phosphate operations are centered about the two cities of Apatity and Kirovsk. The former has a population of 35,000 and is on the Leningrad¬Murmansk railway. Kirovsk, 15 miles to the east, is now a city of 85,000. The region is at the limit of the tree line with most of the ground cover typical tundra. The mean annual temperature is -4°C and, in a normal year, precipitation occurs on 240 days. Because the temperature does not exceed freezing for 300 days each year, virtually all of the precipitation is snow. The two towns are nestled between mountains and, because of the weather, extensive avalanche control systems incorporating major engineering construction have been introduced to divert snow slides away from the populated areas. General Kirovsk was first settled in 1923 and the apatite occurrences were recognized shortly after. In 1933, the first concentrator for the recovery of the mineral was completed, producing in its first year of operation 170,000 tons of concentrate. With the growth and demand for phosphate in the U.S.S.R., a second concentrator was erected at Apatity. It calve on stream in 1963. Because of the severe climate, in the early days mining was limited to 85 days per year. With the introduction of new techniques and improved mining methods, the season has been extended to 115 days.

Jan 1, 1972

By H. M. Woodrooffe

Three of the world's largest phosphate deposits are located in the USSR. These have an estimated reserve of 2,600 million short tons of elemental phosphorus. The best known lies in the Khibiny Massif, an alkalaic rock formation some 600 square miles in area with mountain peaks rising to an altitude of 3300 ft above the surrounding terrain. The Khibiny Massif is north of the Arctic Circle in the Kola Peninsula at a latitude of 67° 30' north and a longitude of 35° 30' east. It is connected by rail to Murmansk, 100 miles northwest, and Leningrad, 900 rail miles south.

Jan 12, 1972

By Bruce Congleton

The Florida phosphate industry is a leader in environmental control, both in terms of dollars spent and significant achievements. For instance, since 1960 the phosphate industry has spent over $71 million for air pollution and control devices, including installation, research and development and maintenance. Water pollution control expenditures also total in the millions, with over $69 million spent in the same 10 year period. The industry also is a leader in water conservation measures, having spent nearly $ 18 million since 1966 for conservation devices. Since phosphate is mined by strip mining, land reclamation plays an important part in the environmental control picture. Here again, the phosphate industry has met the challenge with a voluntary program of reclamation which accounts for over 20,000 acres of land useable after mining has taken place. In terms of progress in environmental control, the industry has been able over the years to solve within the limits of technology the fluoride emission problems it once had, and is currently at work solving sulfur dioxide and particulate problems. In just the past year the industry also has been extremely successful in limiting phosphorus and nitrogen discharges into area streams. The industry continues to cooperate with state and local pollution control officials on matters of environmental control, and future plans include even closer cooperation and assistance, as well as increased expenditures.

Jan 1, 1972

By D. M. R. Sekhar

Certain types of rock phosphates of sedimentary origin are applied to acidic soils as fertilizer directly. Recent research in India showed that high grade rock phosphate in fine size when used as a mix with organic manure works as efficiently as di-ammonium phosphate (DAP) in alkaline soils. The rock phosphate from Jhamarkotra, India (sedimentary origin), Egypt (sedimentary origin) and South Africa (volcanic origin) showed good agronomic efficiency when used as Phosphate Rich Organic Manure (PROM). Further PROM shows equal residual effect. The results of efficiency of PROM made using two grades (+ 24% P2O5 and 34% P2O5) of rock phosphate mineral from Jordan show that low grade rock phosphate slimes are as effective as high grade phosphate concentrate when used in PROM. Also PROM is very effective in the saline soil of Eshidiya desert where DAP is not at all effective.

Jan 1, 2014

By Musa Karakus

The sedimentary iron ores of Alsace-Lorraine, France have very high phosphorous contents that average 0.7% and are as much as 2.19% P. Ores from the Tucquegnieux and Joeuf mines have been studied by cathodoluminescence microscopy, X-ray diffraction, scanning electron microscopy, and electron microprobe analysis in order to fully characterize the mineralogy, size, shape, and distribution of the deleterious phosphate grains. The phosphorous occurs as collophane, a carbonate fluorapatite, in ten morphological forms, most abundantly as microcoprolites, but also as intraclasts, concentric layers, and cortices in ooids, phosphate replaced ooids and bioclasts, phosphatiC shells, fossil infillings and internal molds, fish teeth, phosphatiC laminae, and cements between the goethite ooids. About 95% of the phosphate grains are sufficiently large that relatively fine grinding fol'lowed by reverse flotation would be expected to be effective in significantly diminishing the phosphorous content of the concentrates.

Jan 1, 1989

By R. D. Grove, M. F. Elliott, R. L. Weigel

The control of Florida phosphate flotation plants is largely based on the visual observations of experienced operators, both in recognizing good and bad froth conditions and in making judgments about the composition of feed, concentrate and tailing streams. Chemical analyses lag the process by at least two hours and therefore only assist in recalibrating the operators' vision when major deviations occur. An image analysis system has been developed by IMC Agrico Company (IMCA) to improve upon the accuracy and precision of the composition estimation process. It still relies upon the operator taking a representative sample, but provides a measurement in about 15 minutes after that sample is obtained. This paper describes the system and its use and presents comparative results for various process streams.

Jan 1, 1993

By R. D. Grove

The control of Florida phosphate flotation plants is largely based on the visual observations of experienced operators, both in recognizing good and bad froth conditions and in making judgments about the composition of feed, concentrate and tailing streams. Chemical analyses lag the process by at least two hours and therefore only assist in recalibrating the operators' vision when major deviations occur. An image analysis system has been developed by IMC Fertilizer to improve upon the accuracy and precision of the composition estimation process. It still relies upon the operator taking a representative sample, but provides a measurement in about 15 minutes after that sample is obtained. This paper describes the system and its use and presents comparative results for various process streams.

Jan 1, 1993

By Jamal Asfahani

Abstract - Natural gamma ray well logging, an effective tool in geophysical prospecting, is used to investigate the radioactive and phosphatic layers in the Khneifiss mine in Syria. The interpretation of the gamma ray measurements, using numerical methods of analysis developed previously and applied successfully in some phosphatic areas in Syria, make it possible to define precisely the phosphate thickness from place to place in the study area. This technique has been successfully applied while studying seven boreholes in the area. Sixty-three core samples from phosphatic layers in the boreholes have been analyzed, using gamma ray spectrometry for the determination of P2O5 , U, Th, and K. Good correlation between P2O5 content and U concentration has been found. The total count gamma logs correlate reasonably well with the U core analysis, suggesting that radioactive equilibrium exists in the U decay series. These gamma logs can be therefore used effectively to quantitatively map the distribution of P2O5 and U. The characteristics of both subsurface phosphatic sand and phosphatic rocks have been investigated and outlined using a statistical approach. The affinity of uranium to some trace elements such as V, Sr, Cu, and Ni has been verified using correlation matrices of these elements.

Jan 1, 2002

By Robert E. Hershey

The phosphate industry is the fourth-ranking mineral industry in Tennessee; it has an annual value of 13,000,000 and a yearly production of almost 2,000,000 tons of phosphate ore. Tennessee, at present, is second in rank of phosphate production in the United States. In accord with the importance of this mineral commodity, the Tennessee Division of Geology, is conducting a continuing study of the industry' and the raw s, materials upon which it is dependent. Of the three type's of phosphate found in Tennessee, the brown phosphate rock of the Bigby faces of the Bigby-Cannon limestone is by far the most extensive in occurrence and is the only type being mined at the present time. Because of the importance of the brown phosphate ores, our Division has mapped , in detail the outcrop pattern of the Bigby facies of the Bigby-Cannon limestone. The geologic mapping was done by Dr C. W. Wilson, Jr. and others under his super-vision and the geology plotted on 7 1/2-minute topographic maps, with scale of 1 to 24,000 or 1 inch equals 2,000 feet. These maps will be available for use in the near future and will be published later-with complete geologic coverage.

Jan 1, 1960

By Richard C. Mayberry

Phosphate reserves have been and still are a controversial subject. Some published estimates are particularly conservative and have caused concern in government and political circles that southeastern phosphates are a dwindling resource. "Ores and ore bodies" are a function of economics that relate to a time/demand factor. The history of phosphates and other mineral commodities is one of mineral deposits (resources) ever becoming ore (reserves) via a long term logic based on price, supply, and demand factors operating through time and improved technology. Projections indicate that southeastern phosphates are sufficient for several centuries of operations at present production rates.

Jan 1, 1981

By G. Donald Emigh

Nothing is more important to life-plant and animal-than phosphate. Its compounds are essential to the energy functions of all living systems and for the formation of bones and teeth. Animals get their phosphate from eating plants and other animals, or domestically from feed supplements. Plants get their phosphate from the soil. Man's most important use of phosphate is for fertilizer; however, he is also a heavy user of many industrial phosphate chemicals. Phosphate occurs in all igneous and sedimentary rocks, and in all fresh and saltwater. The average content in rocks is 0.1 to 0.2% P2O5, as documented recently by McKelvey (1973). About 200 minerals contain more than 1 % P,O,. However, the important one in igneous rocks is fluorapatite, (Ca,(PO,) ,F) containing about 42% P,O, and 3.8% F,; in sedimentary rocks the one important mineral is francolite, a carbonate fluorapatite containing up to 2% molecular CO,. Both are in the apatite family of minerals. The mineralogy of phosphate minerals was reviewed recently by Altschuler (1973). Although phosphate occurs in nearly all rocks, economic recovery is limited to deposits where natural concentration of the phosphate mineral has occurred. Occasionally natural concentration is great enough that the material can be used as mined; generally, however, the ore is low grade and must be concentrated.

Jan 1, 1975

By Chester A. Fulton

APATITE, the most abundant crystalline phosphate mineral, is found in igneous rocks and probably is the primary origin of all other phosphates, whether mineral or organic. Its chemical formula may be expressed as Ca5(Cl,F) (PO4) 3. The chlorine may be replaced almost entirely by the fluorine. It is found in large or small hexagonal prisms, usually of a vitreous luster and a green or red color, but also violet, white, or yellow. It is found largely as an accessory mineral in granitoid rocks. Its hardness is 4.5 to 5 and its specific gravity is about 3.2. There are many other phosphate minerals-for instance, amblygonite, autonite, collophane, lazulite, monazite, pyromorphite, torbenite, triphylite, turquoise, vivanite, wavellite-with base elements of calcium, magnesium, iron, aluminum, manganese, lead, cerium, lanthanum, lithium, or several of these in combination and with various amounts of water of crystallization. However, these phosphate minerals have but little value save as specimens for mineral collections, the exception perhaps being turquoise. While large deposits of igneous apatite are mined today for the production of fertilizers and chemicals, more than 90 pct of the world phosphate production is derived from secondary apatites, called phosphorites. These calcium (and magnesium, aluminum, and iron) phosphates have been formed in the alteration of sediments by solutions containing phosphoric acid. Such solutions have come from the weathering or leaching of igneous rocks containing apatite, bone deposits of prehistoric animals and marine life, or guano deposits (excreta of birds). These phosphorites are mostly alterations of phosphatic limestones that took place slowly over many years. Whether it is apatite or phosphorite that is being produced, it is known in the trade as "phosphate rock." The sedimentary phosphate deposits are of marine origin. Some, as laid down, were rich in phosphate or have become so by subsequent subaqueous action and have not been further enriched since emergence from the sea. Some were originally phosphatic limestones or marls from which calcium carbonate was dissolved away by waters containing carbon dioxide, in which calcium carbonate is much more soluble than

Jan 1, 1949

By Theodore M. Gurr, James J. Bartels

Phosphate produced fertilizers provide the phosphorous nutrients required by plant life to sustain significant growth, thus improving the production of food for the world's population. Phosphorous replenishment of soil currently can be obtained efficiently by no other means than by direct application of phosphate fertilizer to the soil. Phosphate products are also utilized in animal feeds, detergent, and various industrial processes. Thirty-three countries are presently mining phosphate rock for the production of fertilizers, and its process byproducts. The major phosphate rock producers are the United States, the former Soviet Union, Morocco, and China [(Table 1)]. Phosphate rock is generally defined as a rock material that contains phosphate minerals which are sufficient for commercial usage. Phosphate minerals are found in sedimentary igneous and metamorphic rocks. Economic resources of phosphates are primarily developed from sedimentary rock sources. The apatite mineral family comprises the majority of phosphate constituents from both sedimentary and igneous rocks. Igneous phosphate rocks are generally composed of fluroapatite whereas sedimentary rocks are generally composed of carbonate fluroapatite, or chlorapatite. Phosphate rock is mined by a multitude of processes, including surface and underground mining. The mined rock requires mechanical and chemical processing to liberate the phosphate for utilization as fertilizer. Approximately 85% of the world's phosphate production uses sulfuric acid, with the remaining processes utilizing nitric and phosphoric acids. Ammonia is also introduced in the manufacture of liquid fertilizer, ammonium phosphate and ammonium polyphosphate. GEOLOGY Mineralogy and Chemical Properties Phosphate most commonly is derived from the mineral apatite, which is chemically described as CA5(F,Cl,OH)(PO4)3. Apatite is also broken up into the composite apatite minerals which are fluroapatite Ca5F(PO4)3, chlorapatite Ca5Cl (PO4)3 and hydroxyl-apatite Ca5(OH)(PO4)3. Carbonate CO3 can substitute for PO, forming carbonate apatite, called francolite. The guano phosphate (bird excrement) mineralogy commonly occurs as brushite CaHP04.2H20, monetite CaHPO4, whitlockite Ca3(PO4), and dahlite Ca10(PO4)6(OH)2. Apatite minerals form from igneous sources where they are developed deep in the earth's crust; and the cooling processes are slow, producing long, hexagonal prismatic to tabular crystals. The termination of the crystal can be basal plans or pyramids. In some instances, the crystals are bipyramids. Faster cooling, or sedimentary derived apatites are more commonly cryptocrystalline. Collophane is a name given to cryptocrystalline apatite found in phosphate rock in fossil form. Apatite minerals are relatively soft and are used to describe the 5 hardness on the Mohs scale. Cleavage is poor and develops along the C(0001). The color of apatite minerals varies from colorless, to violet, and blue, but are predominantly green or brown; luster is vitreous to subresinous. Collophane's physical appearance is often opaline, dense, with colloform structure and sometimes concretionary, nodular or pulverulent. Phosphate Bearing Materials Origins Phosphate deposits of igneous and metamorphic origins have been well defined. Sedimentary origins have been defined, but with a greater degree of uncertainty. Research in the 1980s proved out some of these processes through studies of real time deposition in Chile, Peru, and Australia. Igneous intrusive alkali rock and associated contact metamorphic rocks, provide approximately 20% of the world's phosphate. Fluorine containing apatite minerals are the most common materials containing phosphorous. Fluorapatite occurs in most igneous rocks. Fluorapatite and fluorine hydroxylapatite, together with carbonate varieties of these, are important members of the group. Where an essentially pure chlorapatite, carbonate apatite, and hydroxylapatite are rare and restricted in occurrence, the fluorine containing types occur in most all igneous rocks as early formed accessory mineral, usually in microscopic crystals, and may occur as extremely large bodies as magmatic segregations from alkalic igneous rocks. Apatite is also found crystallized in pegmatitic faces of both acidic and basic types of igneous rocks. More specifically, apatite is associated with magnetite deposits, in hydrothermal veins, especially those formed at relatively high temperatures, and in veins of the Alpine type. Apatite is common in both regionally and contact metamorphosed rocks, especially in the crystalline limestones where it is associated with sphene, zircon, pyroxine amphibole, spinel vesuvianite, phlogopite, talc, chloride schists, and as a contact metamorphic mineral.

Jan 1, 1994

By James A. Barr

Phosphate rock is a natural rock containing one or more phosphate minerals usually calcium phosphate, of sufficient purity and quantity to permit its use, either directly or after beneficiation in the manufacture of commercial products.1 The principal minerals in phosphate rock have the apatite structure which may be represented by the type formula: Ca10(X2) (PO4)6 where X represents the hydroxyl group (OH), chlorine or fluorine, either singly or collectively. The calcium may be partly replaced by sodium, magnesium, and other positive ions such as manganese, strontium, lead, uranium, cerium, yttrium and other rare earths. The PO4 radical may be partly replaced by small quantities of UO4, AsO4, SiO4, CO3, SO4, or Vo4. A typical commercial rock is usually a calcium phosphate containing 3 to 4 pct fluorine, the major impurities being limonite or other iron oxides, clay, aluminum phosphates and silica as quartz sand. A little vanadium is present in most of the domestic rock deposits (except the Tennessee Brown Rock), according to Jacob, Hill, Marshall and Reynolds! A little uranium occurs in the Florida leached zone, as will be brought out later. The chemical analyses are reported as P205, or tricalcium phosphate Ca3(PO4)2, the latter often designated by the trade name BPL (bone phosphate of lime). Commercial analyses usually report iron and alumina as oxides, lime as CaO and silica or insoluble. Colony3 examined many samples of apatite, staffelite, dahlite and American phosphorites and concluded that all have identical X-ray diffraction patterns. The phosphates in the phosphate rock have very minute crystalline structures. The mineral apatite Ca3(F.Cl) (PO4) 3 is the principal primary source of the element phosphorus, and occurs widely distributed in igneous rocks but rarely in a minable mass. Only about 12 pct of the world production of phosphate rock comes from primary apatites; the remainder is derived from secondary phosphorites. These phosphorites have been formed by the alteration of sediments by solutions containing phosphoric acid. Such solutions have come from the weathering or leaching of igneous rock containing apatite, bone deposits of prehistoric animals, marine life or guano deposits. These phosphorites are mostly alterations of phosphatic limestones. The sedimentary phosphate deposits are of marine origin and may have been enriched by subsequent solution of the more soluble calcium carbonate by waters containing carbon dioxide, by physical concentration by wave action, and by redeposition of the dissolved phosphate ions. Uses of Phosphate Phosphorus is the spark of life and is the structure builder and one of the main elements of plant food (fertilizer). Without phosphorus, life cannot exist. A "complete" plant food[t] in addition to phosphorus compounds contains potash, which acts as a catalyst to convert nutrients to useful forms, nitrogen to supply the growth element and many minor elements. The cycle of supply of phosphorus is from the apatite to solution and soil, absorption of plant life, decay and return to the soil or by animal life feeding on the plants. With insufficient supply of phosphorus in vegetation, life is not prolific. If crops are removed from

Jan 1, 1960

By James A. Beck

Phosphorus is essential to all life processes and therefore to the existence of man. In this role, there are no substitutes for phosphorus. In a commercial sense, phosphorus and its compounds are important to our entire economy, both in agricultural and in nonagricultural applications. The world's phosphate requirements are met by mining phosphate rock. Two general types of phosphate ore deposits are commercially important-igneous and sedimentary. Igneous deposits generally are more difficult and more expensive to mine than sedimentary deposits and are of importance mainly in the USSR, North Vietnam, and South Africa. Approximately 15% of current world production comes from these deposits. Over 80% of world production is from the pellet sedimentary deposits of Florida, North Africa, and elsewhere. Guano, the second type of sedimentary deposit, is produced in South America but is declining in world importance. Production Production of phosphate rock was reported in 31 countries during 1972. However, about 80% of world output is produced in three countries: the United States, the USSR, and Morocco (Table 15.2A.1). Throughout the past 20 years, between 75% and 80% of world output has been produced by these three leading countries. Between 1948 and 1972 world production increased at an average rate of 10% per year, from 21.5 to 103.9 million tons. Growth was quite steady at 6% per year through 1963, but in the 5 years from 1963 to 1968 production increased 11 1/2% per year. Since 1968 production has increased about 91/2 % annually. Since 1948 several new phosphate mining ventures have been developed in Senegal, Togo, Israel, and North Vietnam. In the same period, only one important phosphate deposit, on Makatea Island, has been mined out and closed. A number of other phosphate mining ventures are in various stages of planning and development. The most important new venture in phosphate mining is in the Spanish Sahara. New mining capacity is expected also in Syria, and serious investigation is in progress in Peru, India, Turkey, and Australia. Major expansion of existing operations is expected in Morocco, Russia, Tunisia, Israel, and Jordan. Consumption Historical data on world consumption of phosphate rock are not available in detail, but world consumption of phosphate has closely paralleled world production in the past two decades. The United States is the world's largest user of phosphate rock, accounting for 30%

Jan 1, 1976

By T. M. “Mike” Gurr

"U. S. marketable phosphate rock production for the 2018 crop year (July 1, 2017 to June 30, 2018) showed an increase to 27.7 Mt (30.5 million st) from the 2017 crop year production of 27.1 Mt (29.8 million st), as reported to the U. S. Department of the Interior by the mining companies operating in the United States during crop year 2018 (Table 1). Domestic consumption decreased in the 2018 crop year to 23.9 Mt (26.3 million st), as compared to the 27.2 Mt (30 million st) consumed in crop year 2017. U.S. imports of phosphate rock increased to 3 Mt (3.3 million st) for the 2018 crop year from the 1.81 Mt (1.9 million st) for crop year 2017. Imports of phosphate rock were from Peru and Morocco. There was an increase of 2.85 Mt (3.1 million st) in producers’ stocks from 7.45 Mt (8.2 million st) in crop year 2017 to 10.3 Mt (11.3 million st) in crop year 2018 (Table I).For calendar year 2018, Florida and North Carolina phosphate rock production accounted for 75 percent of the total U.S. production, with the balance being produced in Idaho and Utah. The Florida and North Carolina percent of U.S. production is declining. U.S. production of 25.7 Mt (28.3 million st) in calendar year 2018 was produced by five companies at 10 mines in four states and accounted for approximately 9.6 percent of the world production of 267.7 Mt (295 million st) for calendar year 2018 (Table 2).In calendar year 2018, U.S. phosphate production decreased by 2.2 Mt (2.4 million st), while companies increased stocks of phosphate rock by 1.7 Mt (1.9 million st). The domestic production for calendar year 2018 of 25.7 Mt (28.3 million st) represents 78.4 percent of the domestic production capacity of 32.8 Mt (36.1 million st).At present, China reportedly produces more than 50 percent of the world’s phosphate rock. As a result of planned expansions, Morocco production has increased from 27 Mt (30 million st) in 2017 to 33 Mt/a (36 million stpy), which is approximately 12.3 percent of the world’s production, moving ahead of the U.S. production. In calendar year 2018, the U.S. phosphate rock production was 25.7 Mt (28.3 million st), which is less than 10 percent of the world’s production of phosphate rock (Fig. 1)."

Aug 1, 2019

By G. Donald Emigh

Nothing is more important to life-plant and animal-than phosphate. Its compounds are essential to the energy functions of all living systems and for the formation of bones and teeth. Animals get their phosphate from eating plants and other animals, or domestically from feed supplements. Plants get their phosphates from the soil. Man's most important use of phosphate is for fertilizer; approximately 95% of the world's phosphate rock production is consumed by fertilizers. Most of the balance is processed in electric furnaces into elemental phosphorus, the important raw material for making industrial phosphates. Recovery of uranium from phosphates has been possible but not widely used. However, recent significant developments have generated interest in such recovery in the US and elsewhere. Phosphate occurs in all igneous and sedimentary rocks, and in all fresh and salt water. However, economical recovery is limited to deposits where natural concentration of the phosphate mineral has occurred. Occasionally natural concentration is great enough that the material can be used as mined; generally, however, the ore is low grade_ and must be concentrated. Phosphate rock is produced in 31 countries. Fig. 1 shows the location of major phosphate rock producers as well as some of the known phosphate deposits not yet in production. In the last decade the world phosphate industry has experienced steady growth. World production rose from 98 Mt of phosphate rock in 1973 to 140 Mt in 1982. Fig. 2 shows the growth curve of rock production and graphically illustrates the almost straight-line rise since 1945 in both US and world production. Table 1 gives the breakdown, by countries, of world rock production, 1974 through 1979. Table 2 shows US rock production by producing areas. Definitions of Terms Used in the Phosphate Industry Phosphate Rock: Commonly called rock in sedimentary deposits and apatite in igneous deposits. Those expressions generally include any mined, or mined and beneficiated, fluorine-containing calcium phosphate used as the raw material for the next stage of manufacturing. The average phosphate content in rocks is 0.1 to 0.2% P2O5, as documented by McKelvey (1973). About 200 minerals contain more than 1 % P2O5. However, the important mineral in igneous rocks is fluorapatite, [Ca5 (PO4),3 F], containing about 42% P205 and 3.8% F2; in sedimentary rocks the important mineral is francolite, a carbonate fluorapatite containing up to 2% molecular CO2. Both are in the apatite family of minerals. Most phosphate rock, whether beneficiated or not, is a fine-grained material. The expression phosphate rock has no relation to its phosphate content. For example, phosphate rock from Idaho used in the production of phosphorus may contain about 24% P205, whereas rock from Morocco may contain 36.6% P2O5. Phosphorite: A deposit of phosphate directly or indirectly of sedimentary origin, which is of economic interest. Grade of Phosphate Rock: The calcium phosphate content of phosphate rock is expressed in different world areas by one of the following terms: BPL (bone phosphate of lime) TPL (triphosphate of lime) P2O5 (phosphorus pentoxide) P (phosphorus-not commonly used) An illustration of relationship is: 80% BPL = 80% TPL = 36.6% P5O2 = 16% P

Jan 1, 1983

By Immo H. Redeker, O. E. Pothier, E. W. Gieseke

Phosphate rock is the primary source of phosphorus, an element necessary to all forms of life--plant, animal, and human. While phosphorus finds many uses in everyday life, it is an irreplaceable ingredient in all complete plant foods. With the present need for intensive farming, the fertility of the soil can be maintained only by external additions supplied by mines or other sources. A major consideration in any mining operation is to establish the economic and ecological impact of the development on the local population as well as the national interest. The Commodity Data Summaries, as published by the U.S. Bureau of Mines (USBM), is a ready reference concerning the importance of phosphate to the national and local interest. The summary of domestic and world pro¬duction is given in Table 1. During 19722 the demand for marketable phosphate rock exceeded the supply in the United States and the rest of the world. Domestic and world reserves are more than adequate to meet furture demands. Phosphate rock prices firmed and export prices increased, reflecting the change from oversupply to a shortage of phosphatic fertilizers. Demand is expected to exceed supply through 1973. New fertilizer plant capacity planned for 1973-74 will increase the production of phosphate rock by more than 5 million tons in the United States. Morocco and Spanish Sahara are scheduled to increase their production to 18 and 3 million tpy, respectively, within 2 to 3 years. The domestic phosphate rock production for 1972 was 40.8 million tons and 1973 was 42.1 million tons.' Industry, with government-supported programs, will emphasize restoration of mined land and solution of the colloidal slime disposal problem in Florida. The foregoing information comes by courtesy of The Division of Nonmetallic Minerals of the U.S. Bureau of Mines, January 1973. The summary gives a great deal of information but does not give a complete picture. There are many supporting industries which contrib¬ute to the area in which the mines are located. The figures shown in Table 1 deal with concentrates. To produce such concentrates many more tons of waste overburden and ore must be moved. Because of the competitive nature of the phosphate rock industry, data on concentration ratios not only are difficult to obtain but also are not for publication by companies. The concentration ratios vary from one mine to the next in Florida as well as in Tennessee and the western United States. To produce 42.4 million tons of phos¬phate rock in the United States required moving about 350 to 400 million tons of material. Domestic Industry. In 1972 some 26 firms and the Tennessee Valley Authority produced phosphate rock, with several firms produc¬ing from more than one mine. The distribution of marketable phos¬phate rock production was: Florida and North Carolina 82%; Idaho, Montana, Utah, and Wyoming 13%; and Missouri and Tennessee 5%. The value of this production was $223 million. The principal consuming classifications were: agriculture 75%, soaps and detergents 5%, plating and polishing 3%, animal feed supplements 4%, and miscellaneous applications 13%. Over 5,000 firms processed end-prod¬ucts for agricultural purposes. Uses of Phosphate Rock. The tendency in the United States has been to produce more phosphoric acid by the wet process, while the production of electric furnace phosphorus, triple superphosphate, and ordinary superphosphate has been on the decline. Exports of phosphate rock have been on the increase for several years and in 1971 reached 33% of total production. However, export sales of phos¬phate rock are expected to decline in the years ahead, both in total tons of sales and in percentage of production as domestic sales increase (see Table 2). The description and chemistry involved in the production of phos¬phate fertilizers is too complicated to be presented here. The Waggaman13 book is a very thorough reference on the subject involv¬ing production, utilization, and chemistry. The various operations generally have chemical plants near the dry plants or ship to associated chemical plants for further processing. Wet rock, dry rock, and ground dry rock of various grades are sold. In addition various grades of calcined phosphate rock, including defluorinated phosphate rock for animal food supplements, are pro¬duced. Various grades of phosphoric acid, superphosphate, triple suerphosphate, as well as diammonium phosphate, are produced. These products are available from the various producing compa¬nies listed in the text. For prices and specifications the producing companies should be contacted.

Jan 1, 1985

By K. D. Jacob, W. L. Hill

THE bulk of natural phosphates is comprised of calcium phosphates, which are usually apatites;1 calcium aluminum phosphates such as pseudowavellite;2 and aluminum phosphates, which occur in extensive deposits, notably on Grand Connetable Island.3 Nearly all deposits of current commercial value are apatite, often with admixed material of other classes. In the trade coarsely crystalline material, mainly fluorapatite of igneous origin, moves as apatite, whereas the fine-grained material of sedimentary origin is marketed as phosphate rock. The latter classification includes the phosphate shales in western North America. Although several genetic varieties of phosphate rock are recognized,4 most known reserves are of marine origin. Calcium phosphate is concentrated from Florida land pebble and Florida hard rock deposits and from Tennessee brown rock deposits. Phosphate Rock as a Fluorine Carrier: More than two decades ago Reynolds and Jacob surveyed the fluorine content of commercial phosphate rock from various parts of the world.3,5 Later these samples were reanalyzed by a new and more reliable method of determining flourine.6,7 The revised results with interim additions of new samples, published a few years ago in a brief summary,' are shown in Figs. 1-3. Through the points representing the respective varieties of rock medial straight lines are drawn. In some instances the lines are well defined by the points; in others, where scattering renders the position of the best line uncertain, the greater weight is given points near the end of the covered range. Wherever distinct varieties are not recognized among regional deposits the custom is to identify the sample with the geographical location of the deposit.

Jan 10, 1954