Apatite ( Fig. 1.12) is a group of natural calcium mineral±fluorine and chlorine (Ca 5 (PO 4) 3 (F, Cl, OH)). The mineral primarily occurs as phosphate rock. The large apatite deposits are located in China, Canada, the United States, Europe, Russia, and India. Apatite is used as a source of phosphorus, phosphoric acid, and fertilizers.

RÉSUMÉ. Les apatites constituent les composants des dents et des os. Ils ont un intérêt industriel, car, en plus d'être transformés en engrais, ils sont biocompatibles pour les os …

Apatite is the generic name, which was first introduced by German geologist A.G. Werner. These minerals and their synthetic analogs represent a major class of ionic compounds and the most common crystalline form of calcium phosphates, which are of interest of many industrial branches and scientific disciplines. Since, apatite …

K. Ishikawa, ... K. Kawate, in Comprehensive Structural Integrity, 2003 9.05.6.3 Carbonate Apatite. Biological apatite —constituent of both tooth and bone—contains ∼3–5 wt.% of carbonate ion in its lattice sites for phosphate and hydroxyl ions (Elliot, 1994).Substitutions of carbonate ion for OH site and PO 4 site are defined as A-type and B-type, respectively.

Calcium phosphate apatites are inorganic compounds encountered in many different mineralized tissues. Bone mineral, for example, is constituted of nanocrystalline nonstoichiometric apatite, and the production of “analogs” through a variety of methods is frequently reported. In another context, the ability of solid surfaces …

Phosphatic rock (phosphorites) is a marine sedimentary rock that contains 18–40% P 2 O 5.When uranium occurs mainly in the oxidized (U 6+) state, it can be trapped within the phosphate ion, forming secondary uranium phosphate minerals and its decay products.The content of uranium may range between 70 and 200 ppm U (Jasinski …

L'apatite des phosphates sédimentaires est une carboapatite phosphocalcique. Pour ce genre de structure, il existe deux types de remplacement de PO 3− 4 par CO 2− 3: l'un correspond à PO 3− 4 (CO 2− 3, F −) avec un taux de substitution x, l'autre à PO 3− 4 (CO 2− 3, Ca 2+, F −) avec un taux de substitution y.La formule …

Phosphate (apatite) appearing as radial flowers (ARF) is the most abundant mineral in phosphorite with their sizes ranging 3–7 μm. The rays of ARF are made of a core of crystallized apatite and the skin of amorphous phosphate that cements the rays together (Fig.4e). These ARFs account for >50% of the mineral compositions of phosphorite.

Using a bone-mimetic, apatite-polymer nanocomposite, we have studied the initial crystallisation steps during the transformation of amorphous calcium phosphate to apatite.

Apatite is a mineral that is composed of calcium phosphate, with the chemical formula Ca5(PO4)3(OH,F,Cl). It is a member of the apatite group of minerals, which also includes hydroxylapatite and fluorapatite. Apatite is a relatively common mineral that can occur in a variety of colors, including yellow, green, blue, and purple.

Calcium phosphate apatites are inorganic compounds encountered in many different mineralized tissues. Bone mineral, for example, is constituted of nanocrystalline nonstoichiometric apatite, and …

La solution de calcium est versée dans la solution d'ions phosphate et carbonate. L'excès de ces ions permet de tamponner la solution à un pH physiologique sans addition d'éléments étrangers. Le premier précipité formé est une apatite …

La historia de los fosfatos de calcio en el campo de la medicina comienza en 1769, cuando se descubre la primera evidencia de su existencia en el tejido óseo. ... Apatite was the first calcium phosphate recognized as mineral specie. It was in 1786 when Abraham Gottlob, well-known as the father of German geology, discovered this mineral. …

Desorption and precipitation of phosphate along salinity gra-dients are influenced by redox potential (Eh) and pH (van Beusekom and de Jonge, 1997). Typically, Eh decreases and pH increases from land to the sea (Clarke, 1985; Huang and Morris, 2005; Sharp et al., 1982). Seawater inundation in-duces the Eh gradient by limiting oxygen diffusion ...

Ce sont de minéraux de structure hexagonale ou pseudo hexagonale-monoclinique, contenant des arséniates, des phosphates et de vanadates. Ce groupe se scinde en deux sous-groupes : celui de l'apatite et celui de la pyromorphite[4]. Groupe de l'apatite. ChlorapatiteCa5(PO4)3Cl. FluorapatiteCa5(PO4)3F.

apatite, any member of a series of phosphate minerals, the world's major source of phosphorus, found as variously coloured glassy crystals, masses, or nodules. If not for its softness (Mohs hardness 5, compared with the 7 …

They indicated that sulfuric acid produced from biological oxidation of elemental sulfur reacts with the apatite rock phosphate to produce in situ superphosphate in the soil. An acid pH is a necessary prerequisite for the dissolution of an essentially water-insoluble phosphate rock in soil (Robinson and Syers, 1990). ... Département de ...

Lamboy M (1987) Genèse de grains de phosphate à partir de debris de squelette d'échinodermes: les processus et leur signification. Bull Soc Géol Fr 111:759–768. Google Scholar Lehr JR, McClellan GH, Smith JR, Frazier AW (1968) Characterization of apatites in commercial phosphate rocks.

Characterization of the transformation from calcium-de ® cient apatite to b -tricalcium phosphate. 1 533–539. [Google Scholar] Gjerde C., Mustafa K., Hellem S., Rojewski M., Gjengedal H., Yassin M. A., et al. (2018). Cell therapy induced regeneration of severely atrophied mandibular bone in a clinical trial.

RÉSUMÉ. Les apatites constituent les composants des dents et des os. Ils ont un intérêt industriel, car, en plus d'être transformés en engrais, ils sont biocompatibles pour les os de synthèse ou le surfaçage de prothèses osseuses. Cet article présente les caractéristiques physico-chimiques des apatites, les ressources naturelles et ...

Aluminum phosphate reacted with CaO, forming Ca2P2O7 and Ca3(PO4)2 at 750-950°C. Reactions between iron phosphate and CaO occurred at lower temperatures, forming Ca(PO3)2 before reaching 850°C. Keywords: Apatite phosphorus; Non-apatite inorganic phosphorus; Sewage sludge ash; Thermogravimetric analysis–differential scanning …

Phosphate is added to drinking water in the UK to minimise the release of lead from lead water pipes. The phosphate encourages the formation of insoluble lead apatites on the walls of the pipe. Hydroxylpyromorphite Pb5(PO4)3OH is the lead apatite that is most …

Aqueous Sulfuric Acid Dissolution. The mechanism of phosphate leaching with aqueous sulfuric acid is fairly well understood. The reaction occurs in three steps: (1) Sulfuric acid dissociates forming H+ …

Phosphate, (MAP), NH4(H2PO4), Di-Ammonium Phosphate (DAP), (NH4)2HPO4, are produced by the reaction of ammonia on phosphoric acid solution. The slurry is then granulated at high temperature leading to the fertilizer product. Triple Super Phosphate (TSP) results from the reaction of ph osphoric acid on the phosphate ore.

Hydroxyapatite (HA) was prepared by stirring amorphous calcium phosphate (ACP), which contained occluded Cl− as a tracer ion, in distilled water buffered to pH 7.4 by tris-HCl at 25, 37, 60, 80 and 100°. HA made in this manner contained from less than 1% (25°) to 11% (100°) of the amount originally occluded in the precursor ACP. These results suggest …

Phosphate is central to the origin of life (1–4) because it is a key component of nucleotides, phospholipids, and metabolites such as adenosine triphosphate used in cellular replication, compartmentalization, and energy transfer, respectively ().A major issue for prebiotic chemistry is that phosphate combines with Ca 2+ down to micromolar levels to form …

Processus d'accumulation des phosphorites. (A) Le vannage in situ des péloïdes phosphatés par les courants de tempête produit un phosphate granulaire. (B) Le transport et le redépôt des ...

Lamboy M (1987) Genèse de grains de phosphate à partir de debris de squelette d'échinodermes: les processus et leur signification. Bull Soc Géol Fr 111:759–768. …

Apatite mineralization requires a sufficient concentration of phosphate, which may be released from the decaying animal, or concentrated in the surrounding sediment. Decay …

vations of intracellular, vesicle-enclosed calcium phosphate in de-veloping mouse bone (12), and suggests that an intracellular process may play a role in bone apatite formation. It is dif ficult to observe any such intracellular process, however, as conventional EM preparation techniques, such as glutaraldehyde fixation,