Phosphatic limestone

Phosphatic limestone is usually a high calcium type that contains appreciable percentages (up to 5%) phosphoms. It originates from invertebrate marine organisms. 

Kalk. m. lime (equivalent, in old names of salts, to calcium as, phosphorsauerer Kalk, phosphate of lime, calcium phosphate) limestone (Old Chem.) cabc. —. tzender —, caustic lime, quicklime. — gelfischter —, slaked lime. — gebraonter —, quicklime. 

Phosphate treatment, in industrial water treatment, 26 132 Phosphatic limestone, 15 28 Phosphating, metal surface, 16 214-218 Phosphazenes, 19 55-57... 

France.—Phosphatic limestones are found in the Pas de Calais, Meuse and Somme regions, and the last-named deposits were among the earliest to be worked. Specimens have been found which contain up to 78 per cent, of calcium phosphate. Those from the Meuse and the Ardennes contain about 40 per cent. A limestone with less than 30 per cent, of calcium phosphate is hardly considered worth using for the manufacture of superphosphate. France also controls the output of North Africa. 

Typical contaminants of Florida phosphorites are the phosphates wavellite, crandallite, barbosalite, rockbridgeite, dufrenite and vivianite (Swanson and Legal, 1967). Other than phosphates are turgite (hydrated iron oxide), clayballs, chert and sandstone pebbles, and phosphatic limestone pebbles. 

Fig. 11.15 Vertical section of a Co-rich Mn crust from the flanks of a guyot on the Ogasawara Plateau N.W. Pacific (25°18.9 N, 143°54.8 E 1515 m) collected by dredge during a cruise of the GSJ with R.V. Hakurei-maru in 1986. The substrate (not clearly seen) is phosphatized limestone. The crust is more than 20 cm across, about 10 cm thick and has a knobby surface texture. Element contents are Mn 21.7%, Fe 18.9%, Co 0.81%, Ni 0.31%, Cu 0.04%, Pb 0.26% and Pt 0.29 ppm. The upper layer of the crust displays the highest Co content and the bottom layer the highest Pt (0.78 ppm). 6Mn02 is the principal mineral present with minor quartz and plagioclase. Photograph courtesy of A. Usui, GSJ.

Phosphatic limestone is derived from invertebrate marine creatures. It contains significant levels of phosphorous, typically up to 5%, (largely derived from fish bones). 

In some localities, apatite occurs as nodules on the sea bed, as phosphatic limestone, and in various other forms. These varieties are generally too dispersed or have such a low concentration of apatite that their commercial exploitation does not at present assume much importance. The extent of deep-sea bed apatite has been little explored and available information relates mostly to shallow offshore regions. These regions include Portugal, Morocco, South West Africa, Peru, Chile, southern California, eastern New Zealand, eastern China and eastern United States. Phosphorite is present in snbmerged monntains, mostly in the North Pacific [26-32]. 

Although sodium triphosphate can be used as a dispersing and deflocculating agent, the presence of more than about 0.5% P2O5 in the raw material input to a portland canent furnace (e.g. in some phosphatic limestones) will decrease the yield of the most cementitious component of the product, that is, 3CaO Si02 ( C3S ). 

Limestone, chalk, marl, phosphatic limestone, subordinate phosphate rock... 

Many agricultural processes such as control of fertilizers and pesticides are influenced by surface and sub-surface movement, percolation and infiltration of water. Stable activateable tracers, such as bromide, analyzed by NAA, have allowed the soil scientist to quantify the distribution of agricultural chemicals under a wide variety of environmental and land use influences. In one of the study on phosphate fertilizers in Egypt using NAA, Abdel-Haleem et al. (2001) have reported the presence of heavy metals Fe, Zn, Co, Cr, and Sc as well as rare earth elements La, Ce, Hf, Eu, Yb and Sm in the samples containing the phosphate fertilizer components (e.g., rock phosphate, limestone, and sulfur) from which fertilizer is produced as final output product. The measurement of Ca/Si concentration ratio in the concrete samples has been carried out using NAA with 5Ci Am-Be neutron source (Khelifi et al. 1999). 

Engineering as a science must balance sophisticated mathematical models with practical field experience. In this chapter, some specific cases of slurry pipelines will be examined for coal, iron sand, clay, phosphate, limestone, and other materials. The practical experience with these minerals in different forms, particles sizes, and volumetric concentrations is very useful for the design of new pipelines or the modification of existing systems. 

Minerals. Supplementation of macrominerals to mminants is sometimes necessary. Calcium and phosphoms are the minerals most often supplemented in mminant diets. One or both may be deficient, and the level of one affects the utilization of the other. Limestone, 36% calcium, is commonly used as a source of supplemental calcium. Dolomite, 22% calcium oyster sheUs, 35% calcium and gypsum, 29% calcium, are sources of calcium. Bone meal, 29% calcium, 14% phosphoms dicalcium phosphate, 25—28% calcium, 18—21% phosphoms and defluorinated rock phosphate, 32% calcium, 18% phosphoms, are sources of both calcium and phosphoms. Diammonium phosphate, 25% phosphoms phosphoric acid, 32% phosphoms sodium phosphate, 22% phosphoms and sodium tripolyphosphate, 31% phosphoms, are additional sources of phosphoms (5). 

Calcium. Calcium is the fifth most abundant element in the earth s cmst. There is no foreseeable lack of this resource as it is virtually unlimited. Primary sources of calcium are lime materials and gypsum, generally classified as soil amendments (see Calcium compounds). Among the more important calcium amendments are blast furnace slag, calcitic limestone, gypsum, hydrated lime, and precipitated lime. Fertilizers that carry calcium are calcium cyanamide, calcium nitrate, phosphate rock, and superphosphates. In addition, there are several organic carriers of calcium. Calcium is widely distributed in nature as calcium carbonate, chalk, marble, gypsum, fluorspar, phosphate rock, and other rocks and minerals. 

In the geochemistry of fluorine, the close match in the ionic radii of fluoride (0.136 nm), hydroxide (0.140 nm), and oxide ion (0.140 nm) allows a sequential replacement of oxygen by fluorine in a wide variety of minerals. This accounts for the wide dissemination of the element in nature. The ready formation of volatile silicon tetrafluoride, the pyrohydrolysis of fluorides to hydrogen fluoride, and the low solubility of calcium fluoride and of calcium fluorophosphates, have provided a geochemical cycle in which fluorine may be stripped from solution by limestone and by apatite to form the deposits of fluorspar and of phosphate rock (fluoroapatite [1306-01 -0]) approximately CaF2 3Ca2(P0 2 which ate the world s main resources of fluorine (1). 

Mineral Feed. Mineral feed supplements for domestic animals and fowl usually contain a pure form of pulverized limestone. In fact, some state laws require the supplement to be at least 35% available calcium. Other sources of calcium are bone meal and dicalcium phosphate. Use as mineral feed has been a steadily growing market for limestone. The material is ground to 90% minus 0.15 mm (100 mesh) or 80% minus 0.9074 mm (200 mesh), is low in silica, and has strict tolerances on arsenic and fluorine (see Feeds and feed additives). 

Miscellaneous. Both whiting and hydrated lime are used as diluents and carriers of pesticides, such as lime—sulfur sprays, Bordeaux, calcium arsenate, etc. The most widely used bleach and sterilizer, high test calcium hypochlorite, is made by interacting lime and chlorine (see Bleaching AGENTS). Calcium and magnesium salts, such as dicalcium phosphate, magnesium chloride, lithium salts, etc, are made directly from calcific and dolomitic lime and limestone. 

The western phosphates are sedimentary deposits in adjoining areas of Wyoming, Idaho, and Utah derived from a former inland sea. They consist of layers of limestone, phosphate, and chert, now budded and faulted so they are rarely horizontal. The phosphate ore is strip-mined using large earth-moving equipment such as shovels, scrappers, dump tmcks, and bulldozers to mine the overburden and phosphate ore. Mining ratios of overburden to metric ton of recovered ore are from 1—3 m /1 (2—4 yd /short ton). The typical mining practice is to remove ore and overburden from a pit in discrete layers (Lifts) of 10—20 m in depth. Overburden from the pit is back-hauled to a previously mined pit. Extensive land reclamation practices are later carried out to return the mine areas to natural states. 

Triboeleetrie Silica from limestone Florida pebble-phosphate flotation cone. Reduction of (piartz bv 80-90% Residual silica from pebble phosphate Tube t pe Tube t pe 80-100 70-90 -1.0 + 0.015 -1.0 + 0.10 20 10-15 1 1... 

Intermediate Hardness (4) Fluorite, soft phosphate, magnesite, limestone (5) apatite, hard phosphate, hard limestone, chromite, bauxite (6) feldspar, ilmenite, orthoclase, hornblendes. 

Calcium (sixth most abundant element) is found in limestone, CaC03, and gypsum, CaS04-2H20. Bones are made up of calcium phosphate, Ca PO. ... 

Of the principal minerals of Ca listed in Table 1, the most important ores are the various deposits of CaCOj, especially limestones, which occur as immense sedimentary beds over extensive parts of the earth s surface. Extraction of Ca from CaCOj is a simple and relatively inexpensive process. Although the other Ca-bearing minerals are rarely considered as potential Ca sources, they are widely distributed and extensively mined fluorite and apatite for their fluoride and phosphate content, gypsum and anhydrite for their use in construction. 

Many of the minerals that form the Earth s crust contain oxoanions. Examples of carbonates are CaC03 (limestone) and MgCa (003)3 (dolomite). Barite (BaS04) is a sulfate mineral. An important phosphate is Caj (P04)3 F (apatite). Two silicates are zircon (ZrSi04) and olivine (a mixture of MgSi04 and FeSi04). 

Krajewski, K. P. (1984). Early diagenetic phosphate cements in the albian condensed glauconitic limestone of the Tatra mountains. Western Carpathians. Chemical Abstracts, 10, 114382. 

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