Aluminum-phosphate minerals

Calcined Aluminum Phosphate. Ores consisting mainly of hydrated aluminum phosphate minerals are useful for direct application after thermal treatment (calcination) at a controlled temperature. Calcination removes the combined water and destroys the crystallinity of the phosphate minerals, thereby improving the reactivity of the phosphate.3... 

Dissolved metals other than calcium have a minor effect on the distribution of phosphorus between the water column and sediment in this fluvial system. The two principal metals of potential interest, iron and aluminum, are present in Genesee River water almost entirely in the particulate phase ( ). Dissolved concentrations of these metals are below the detection limit (less than 50 ug/1). Iron and aluminum minimum detectable dissolved concentrations were used to estimate the saturation levels of the corresponding phosphate minerals. These calculations suggest that both iron and aluminum phosphate minerals are substantially below saturation levels. The solid surfaces exhibited by iron and aluminum hydrous oxides (as particulate material in the water column) undoubtedly serve as sites for phosphorus adsorption and incorporation in the fluvial system. Data presented for the oxalate extraction procedure in Table III demonstrate the importance of phosphorus binding by hydrous metal oxides. 

Recently occurrences of unusual aluminum phosphate minerals have been found with ash partings in coals (Triplehorn and Bohor, 1983). Since that report we have found a number of additional occurrences in Alaska and one in the appalachian area. These minerals were grouped by Palache (et. al., 1951) as the... 

Bleam,W.R, Pfeffer, P.E. and Frye, J.S. (1989) Psolid-state nuclear magnetic resonance spectroscopy of aluminum phosphate minerals. Physics and Chemistry of Minerals 16, 455M64. 

Iron and aluminum oxides present no special problem within the range of occurrence in commercial phosphate rocks these oxides usually are dissolved in nitric acid and reprecipitated during ammoniation as citrate-soluble phosphates, TVA tested leached-zone" Florida phosphate containing a high percentage of aluminum phosphate minerals in a special nitrophosphate process... 

TVA conducted experiments with Florida leached-zone ore, which also contains a high percentage of aluminum phosphate minerals-millisite, crandaDitej and wavelite. It was found that maximum P2O5 citrate solubility of 70%-79% was obtained by caldning at 500 -600 C. However, the leached zone material is low" grade and variable in composition and hence poorly suited for commercial use. 

Inorganic reactions in the soil interstitial waters also influence dissolved P concentrations. These reactions include the dissolution or precipitation of P-containing minerals or the adsorption and desorption of P onto and from mineral surfaces. As discussed above, the inorganic reactivity of phosphate is strongly dependent on pH. In alkaline systems, apatite solubility should limit groundwater phosphate whereas in acidic soils, aluminum phosphates should dominate. Adsorption of phosphate onto mineral surfaces, such as iron or aluminum oxyhydroxides and clays, is favored by low solution pH and may influence soil interstitial water concentrations. Phosphorus will be exchanged between organic materials, soil inter-... 

Very often, vaccines are formulated with certain substances to enhance the immune response. These substances are called adjuvants (from the Latin adju-vare, which means to help ). The most common adjuvants for human use are aluminum hydroxide, aluminum phosphate, and calcium phosphate. Other adjuvants being used include bacteria and cholesterol. Mineral oil emulsions are normally the adjuvants used in animal studies. The adjuvant known as Freund s complete adjuvant consists of killed tubercle bacilli in water-inmineral oil emulsion, and Freund s incomplete adjuvant is a water-in-oil emulsion. Both these adjuvants are effective in stimulating an immune response, but they cause unacceptable side effects in humans (see Table 4.2). 

Once mineral-bound aluminum is recovered from ores, it forms metal complexes or chelates. Examples of the different forms of aluminum include aluminum oxide, aluminum chlorhydrate, aluminum hydroxide, aluminum chloride, aluminum lactate, aluminum phosphate, and aluminum nitrate. The metal itself is also used. With the exception of aluminum phosphide, the anionic component does not appear to influence toxicity, although it does appear to influence bioavailability. Aluminum phosphide, which is used as a pesticide, is more dangerous than the other forms however, this is because of the evolution of phosphine gas (a potent respiratory tract and systemic toxin) rather than to the exposure to aluminum. 

Kirsner JB. 1942. The effect of calcium carbonate, aluminum phosphate, and aluminum hydroxide on mineral excretion in man. J Clin Invest 22 47-52. 

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. 

Although the title of this book, Perspectives in Molecular Sieve Science, avoids the zeolite definition controversy, a large majority of the research reported here centers on traditional zeolites. Only three of the 39 chapters comprising the book deal with materials that are clearly nonzeolitic Two cover clay-type derivatives, and one deals with carbon molecular sieves. Not surprisingly, interest in these materials lies in their possible use as catalysts. Only four chapters present work on mineral zeolites and three on aluminum phosphate-type molecular sieves. Two of those chapters are by workers from Union Carbide, the laboratory that did the pioneering work in this field. It is surprising that other workers have not submitted papers on the aluminum phosphates, but perhaps this situation indicates that although much activity may be underway, laboratories hesitate to publish until patent positions are established in this potentially lucrative area. Union Carbide s synthetic faujasites (zeolites X and Y) and zeolite A receive the most attention, while ZSM-5-class materials are accorded more attention than zeolite A alone. This reflects the important roles that zeolites X and Y and ZSM-5 materials have already played as catalysts. 

I.I.3.2. Phosphate minerals Dissolution equilibria for aluminum phosphate can be written as follows ... 

About 25 minerals are described as having a lithium content in excess of 2% lithium oxide (Li20) and are regarded as lithium ores. Among these, only four occur in suffi-dent quantities which justify mining and industrial production the lithium aluminum silicates spodumene and petalite, the mica material lepidolite, and the lithium aluminum phosphate amblygonite (Debe-ritz 1993, Wietelmann and Bauer 2003). 

Johan Z, Slansky E, Povondra P (1983) Vashegyite, a sheet aluminum phosphate new data. Can Mineral 21 489-498... 

The deactivated catalyst was studied by several methods scanning electron microscopy (SEM)-energy dispersive spectroscopy (EDS), infrared spectroscopy (IR), and by extracting water-insoluble phosphorus. The SEM-EDS studies gave no useful results. IR absorption was measured on samples that were mulled in mineral oil. Comparisons of IR spectra were made with samples of y -alumina and aluminum phosphate. Determination of total P in the deactivated sample, presumed to be present as water-insoluble aluminum phosphate, was made by standard wet chemical analysis dissolution in hot, dilute HCl followed by colorimetric determination of phosphate. ... 

Under oxidized conditions in mineral wetland soils, the coating of hydrated ferric oxides on silt or clay particles have occluded in them several forms of phosphate including ferric phosphate, aluminum phosphate, and calcium phosphate (Figure 9.32). As a result of anaerobic conditions, reduction of hydrated ferric oxide to more soluble ferrous hydroxide results in the release of these occluded phosphates. Calcium phosphate released in this manner is available to wetland plants, whereas the occluded ferric phosphate is probably not available to the plants until it has been reduced to more soluble ferrous phosphate. 

Under conditions near the surface of the earth, a wide spectrum of secondary minerals can form that may be common to both igneous and sedimentary phosphate rocks. These minerals include iron and aluminum phosphates, clays, and iron oxides. 

S.2.3 Aluminum and Iron Phosphates - A total P2O5 analysis of a potential ore is not a dependable criterion for evaluation of a phosphate deposit. With the weathering of apatitic phosphates and associated minerals, a suite of other secondary phosphate minerals may form (Table 5.7). These minerals are most com--monly-aluminurn and.irorhConteining phosphates. These minerals cannot be processed by the methods used to beneficiate apatitic calcium phosphates. Aluminum and iron phosphate minerals may form in both sedimentary and igneous deposits. 

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