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Basically, solubility of apatite is governed by two factors: crystallity and composition. High-crystalline apatite shows more limited solubility than low-crystalline apatite. As stated, apatite formed by the hardening reaction of calcium phosphate is low-crystalline apatite, compared with the sintered apatite which shows high crystallinity.
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As a rule, the process begins with the extraction of phosphate ore from underground deposits or quarries. This process generates large amounts of waste in …
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The transformation of ACP to apatite is a process that is common in both synthetic and biological systems. This is expected since apatite is the most thermodynamically stable CaP phase under physiological conditions. ... The step growth mechanism, of amorphous calcium phosphate to apatite as described here, could also …
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Apatite crystals are a favorite among collectors with their stubby, terminated, hexagonal prisms, glassy transparency, and soft, yellow-to-greenish-yellow or blue mineral colors.These beautiful crystals rank high on blue gems and minerals lists.Much is mined in Mexico.. However, most of the apatite in the Earth's crust occurs not as macrocrystals, …
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The plasma-treated samples were alternately dipped in alcoholic calcium and phosphate ion solutions three times to deposit apatite precursors onto their surfaces. The surface-modified samples formed a dense and uniform bonelike surface apatite layer after immersion for 24 h in a simulated body fluid with ion concentrations approximately equal ...
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These stones precipitate in alkaline urine (pH >7.2). Infectious stones are primarily composed of magnesium ammonium phosphate hexahydrate but may in addition contain calcium phosphate in the form of carbonate apatite. 2. Struvite stones are formed as a result of urinary tract infection with urease-producing bacteria.
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Relationships between geological phosphorite deposition and biological apatite nucleation have often been overlooked. However, similarities in biological apatite and phosphorite mineralogy suggest that their chemical formation mechanisms may be similar. This review serves to draw parallels between two newly described phosphorite …
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transformation process. Considering the importance of ACPs in bone apatite mineralisation, a generic mechanism is hypothesised for the in vivo ACP-apatite …
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Beneficiation of phosphate ores by flotation has been an important part of the concentration process since the 1920s at which time it became possible to recover those fine particles of apatite. Today, more than two-thirds of the phosphate ore produced in Florida and more than half of the world's marketable phosphate is upgraded by the ...
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Fluoride. Soi et al. have mentioned four mechanisms of action of fluoride. 15 Fluoride inhibits demineralization as the fluorapatite crystals, formed by reaction with enamel apatite crystals, are more resistant to acid attack compared to HAP crystals. Second, fluoride enhances remineralization as it speeds up the growth of the new fluorapatite crystals by …
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The ore contained apatite as a gangue mineral, and phosphate dissolution was 1.6% at most and typically below 1% over 24 hours of leaching in 1 mol/L total carbonate (with a bicarbonate/carbonate ratio ranging from 1 to 4, typically 2) solution between 50 and 90 °C, though this process does have the disadvantage of requiring …
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Bruce Fouke explores the biomineralization of calcium oxalate and apatite kidney stones and the opportunities that lie at the intersection of geology, biology and medicine; a transdisciplinary ...
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Based on the precipitation conditions in the nitrophosphate process, the obtained rare earth phosphate concentrate consists of about 7–15% total REE, 10–16% phosphorus, 4–10% calcium and 1–10% iron. ... Preparation of mixed REE phosphate concentrates. The apatite concentrate was first dried at 80 °C for 24 h and was then …
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This study aims to evaluate phosphate recovery and set aside TOC, OC, and IC in agricultural wastewater using electrocoagulation with helix electrode configuration. …
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The deposition of calcium phosphate (CaP) onto polymeric substrates was achieved through a coating process using SBF. Immersing a substrate in SBF allows for the formation of a layer of carbonated apatitic calcium phosphate coating, replicating …
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Our model is based on a collagen/apatite self-assembly process that combines the ability to mimic the in vivo extracellular fluid with three major features inherent to living bone tissue, that is ...
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Biological apatite is an inorganic calcium phosphate salt in apatite form and nano size with a biological derivation. It is also the main inorganic component of …
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The first commercial production of phosphate rock began in England in 1847. A wide variety of techniques and equipment is used to mine and process phosphate rocks in order to beneficiate low-grade ores and remove impurities. The eighth chapter of this book deals with mining and beneficiation of phosphate ore. The principle and …
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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.
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Apatite, Ca 5 (PO 4) 3 (F, Cl, OH), is a mineral that consists of calcium phosphate and varying amounts of fluoride, chloride, or hydroxide ions. The apatite obtained by LKAB is a fluorapatite that contains about 0.4 wt% of rare earth elements. The apatite can be processed by the nitrophosphate process to produce NPK fertilizer.
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Hydroxyapatite (HAp; Ca 10 (PO 4) 6 (OH) 2) is a form of calcium phosphate.It is the main inorganic mineral component of teeth and bones. HAp can be chemically synthesised as a biomaterial such as ...
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Synthetic-calcium-phosphate-apatite-based compounds are frequently encountered in the literature dealing with bone tissue engineering. ... In this view, pH monitoring could again be seen as relevant during the process. 2.1.4. Incomplete Reactions . Hydroxyapatite is a mineral phase that gathers a large number of ions.
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The formation process of apatite on both the immature and the mature biomimetic PCA powders as substrates consists of three steps, whose durations seem independent on their physicochemical features, under physiological conditions. ... Physico-chemical and thermochemical studies of the hydrolytic conversion of amorphous …
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Questions persist on mechanisms that control bone biomineralization processes 1.In particular, the nature and functions of the components involved in the formation and organization of apatite ...
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The overall aim is to control the selectivity and recovery of the process. The following review is an attempt to add to previous works gathering phosphate froth flotation data. In that sense, the relevant parameters of phosphate ores flotation are discussed while focusing on apatite, calcite, dolomite, and quartz as main constituent minerals.
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Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan, China; The phosphate ore flotation is achieved through the surface electrical behavior difference among apatite, dolomite and quartz, but it is usually affected by the dissolved ions from pulp, especially Ca 2+ and Mg …
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Mineralization of teeth and bone. Mineralization is a lifelong process, in which an inorganic substance precipitates onto an organic matrix. Normal biological processes include the formation of hard connective tissues, such as bone, dentin, and cementum, in which collagen fibrils form a scaffold for a highly organized arrangement of …
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For a fish body to completely mineralize into apatite, large amounts of phosphate must be present. ... leads to the inorganic precipitation of apatite. The efficiency of the process depends on the ...
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Illustration of apatite formation in two distinct contexts: (a) Homogeneous nucleation by precipitation, where an aqueous solution comprising phosphate ions are …
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In the nitrophosphate process of fertilizer production, rare earth elements (REE) can be recovered as a REE phosphate concentrate. In this process, after digestion of apatite in concentrated nitric acid, Ca(NO 3) 2.4H 2 O is first separated by cooling crystallization and then the REE are precipitated in phosphate form by a partial …
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