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Reaction of chlorapatite, Ca5(PO4)3(Cl, F) with sodium carbonate and silica (1979)

Gunawardane, R. P. ; Glasser, F. P.

Springer

Journal of materials science 14 (1979), S. 2797-2810

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ISSN: 1573-4803

Source: Springer Online Journal Archives 1860-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: Abstract The conversion of insoluble phosphorous minerals such as apatite, Ca5(PO4)3(F, OH, Cl), to phases containing phosphorous in soluble form is an essential step in the production of fertilizer grade phosphates. Developing countries lack the capital-intensive industrial base necessary to create a phosphate industry. We examine a process suitable for use in Sri Lanka which uses mainly indigenous raw materials. In this process, a chlorine-rich apatite is fused with Na2CO3 and SiO2 at 900° C and 1300° C for 1 to 2 h to yield a product having 〉90% available phosphorous. Data necessary for the technological evaluation of the process are presented. Phase equilibria in the lime-rich portions of the system CaO-Na2O-P2O5-SiO2 have been studied. The section Ca3(PO4)2-Ca2SiO4-CaNaPO4 is shown to be a ternary system, and phase relations on the 1100° and 1300° C isothermal sections are presented. A reconnaisance of the system CaO-Ca3(PO4)2-Ca2SiO4-CaNaPO4 has been made. These data, combined with studies of the kinetics of the reaction, point to regions of composition and reaction conditions favouring high yields of available phosphorous.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00611458

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Crystal chemistry and synthesis of Ternary Silicates and Germanates containing alkali (Na+, K+) and alkaline earth (Ca2+, Sr2+, Ba2+) cations (1975)

Gunawardane, R. P. ; Glasser, F. P.

Weinheim : Wiley-Blackwell

Zeitschrift für anorganische Chemie 411 (1975), S. 163-172

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ISSN: 0044-2313

Keywords: Chemistry ; Inorganic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Description / Table of Contents: Darstellung und Kristallchemie der ternären Silicate und Germanate mit Alkali (Na+, K+)- und Erdalkali (Ca2+, Sr2+, Ba2+)-KationenDie Darstellung von neuen ternären Silicat- und Germanat-Phasen mit großen Alkali- und Erdalkalikationen wird beschrieben. Sie wurden durch Festkörperreaktion von Mischungen der Carbonate bzw. Oxalate mit SiO2 bzw. GeO2 oder durch Schmelzen und anschließende Rekristallisation des Glases erhalten.Vertreter der kubischen M4+M2+X3O9-Familie sind Na4CaSi3O9 und die isostrukturellen Verbindungen K4CaGe3O9, K4SrGe3O9, K4CaSi3O9 und K4SrSi3O9. K4BaSi3O9 ist pseudokubisch; die Symmetrie des Na4SrSi3O9 ist unbekannt. Zur rhomboedrischen M8+M2+X10O25-Familie gehören K8CaSi10O25, K8SrSi10O25 und K8BaSi10O25.Na2CaGe2O6 und Na2SrGe2O6 sind isostrukturell, aber strukturell nicht mit Na2BaSi2O6 verwandt. Na2Ba2Ge2O7 und Na2Ba2Si2O7 sind strukturell ähnlich.

Notes: The synthesis of new ternary silicate and germanate phases containing large alkali and alkaline-earth cations is described. They are made by solid-state reaction of mixtures of carbonates or oxalates with SiO2 or GeO2, or by fusion and subsequent recrystallization of the glass.Representatives of the cubic M4+M2+X3O9 family include Na4CaSi3O9 and the isostructural compounds K4CaGe3O9, K4SrGe3O9 and K4SrSi3O9. K4BaSi3O9 is pseudocubic: the symmetry of Na4SrSi3O9 is unknown. The rhombohedral M8+M2+X10O25 family includes K8CaSi10O25, K8SrSi10O25 and K8BaSi10O25.Na2CaGe2O6 and Na2SrGe2O6 are isostructural but both are structurally unrelated to Na2BaSi2O6. Na2Ba2Ge2O7 and Na2Ba2Si2O7 are structurally similar.

Additional Material: 2 Ill.