- PROCESS FOR RECOVERING PHOSPHORIC ACID FROM SOLID PHOSPHORUS SOURCES
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The invention pertains to a process for preparing phosphoric acid from a solid phosphorus-containing material, comprising the steps of: - reacting a solid phosphorus-containing material with strong acid in an amount of 1.0-15 mole acid, calculated as protons, per mole of phosphorus (calculated as P) in the solid phosphorus-containing material in a monophasic reaction medium comprising an organic solvent, to form a solution of phosphoric acid in organic solvent and remaining solid material, - separating the solution of phosphoric acid in organic solvent from the remaining solid material. It has been found that phosphoric acid can be recovered from a solid phosphorus-containing material in high purity and efficiency via a solid-state rearrangement/elution process. The process according to the invention does not require the use of the large amounts of water required by the conventional dissolution/extraction processes known in the art. The solution of phosphoric acid in organic solvent can be used as a starting material for further processes.
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Page/Page column 12
(2020/09/08)
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- A study of thermal behavior of cesium phosphate
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Cesium phosphates with different Cs/P molar ratios were prepared by a solution evaporation method. X-ray powder diffraction, thermogravimetric, and differential thermal analyses were performed in order to reveal the chemical transformation and phase compositions which take place during the heating of the mixtures Cs2CO3/(NH4)2HPO4 and CsNO3/(NH4)2HPO4 as well as individual compound. The effects of the Cs/P molar ratio, Cs source and treatment temperature on thermal behavior of the cesium phosphates were investigated. The results showed that different reactions take place with molar ratio from 1/2 to 3/1. Meanwhile, the thermostability of Cs2CO3 and CsNO3 intimately affects the phase composition and phase transition during heating process. However, for all the Cs–P oxides samples, the crystallinity was decreased differently after higher temperature treatment.
- Zhang, Guoliang,Peng, Zhijian,Li, Chunshan
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p. 1063 - 1070
(2016/07/06)
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- Method for preparing hydroxylamine
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A method for preparing hydroxylamine is provided that includes the steps of (i) pretreating an acidic buffer solution; and (ii) reducing nitrate ions in the acidic buffer solution with hydrogen to give hydroxylamine in the presence of catalysts, wherein the pretreatment is performed by adding a precipitant represented by formula (I) to the acidic buffer solution, [in-line-formulae][(A)aM(CN)6.xH2O]??(I) [/in-line-formulae] allowing the metal impurities in the acidic buffer solution to react with the precipitant to form metal complex, and then to remove the metal complex. The metal complex is formed and separated by pretreating the acidic buffer solution with a specific precipitant without adjusting pH and changing the composition of the acidic buffer solution prior to hydroxylamine synthesis, thus enhancing the selectivity of the hydroxylamine production.
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Page/Page column 2-6
(2008/06/13)
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- Slow and controlled-release polymeric fertilizer with multiple nutrients, preparing process for the same and the use method of the same
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This invention relates to a slow and controlled-release polymeric fertilizer with multiple nutrients having the following general formula: wherein n, m and M are defined in the description. The polymeric fertilizer of this invention is an environment-friendly slow and controlled-release fertilizer. Its slow and controlled release action lies in self-degradation and hydrolysis. This invention also relates to the preparing process for the fertilizer and the use method of the fertilizer in agriculture.
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Page/Page column 3
(2009/11/22)
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- Solid-Phase Interaction of Fluorapatite with Ammonium Hydrogen Difluoride
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A solid-phase interaction of fluorapatite with ammonium difluoride was studied in the temperature range 25-900°C. At room temperature, calcium fluoride and ammonium dihydrogen phosphate or isostructural ammonium florophosphate were formed as the result of grinding a mixture of theinitial components. Above 200°C, the reaction was accompanied by the formation of a volatile phosphor compound. At the final stage of th e process (above 500°C), glassy ammonium hydrogen ultrafluorophosphate of nonstoichiometric composition was formed, which again yielded fluorapatite upon reaction with calcium fluoride.
- Laptash, N. M.,Kaidalova, T. A.
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p. 535 - 537
(2008/10/08)
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- Development and application of chromatographic methods of studying the kinetics of the formation of ammonium phosphates
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By studying the formation kinetics of ammonium phosphates we have demonstrated the advantages of chromatographic methods in studies of complex multi-stage processes involving changes in the stage of aggregation with time and temperature.
- Borisova, S. I.,Berezkina, L. G.,Mel'nikov, S. E.,Brodskii, A. A.
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p. 895 - 897
(2007/10/02)
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- FORMATION OF INSOLUBLE COMPOUNDS IN AMMONIUM POLYPHOSPHATE MADE FROM WET-PROCESS PHOSPHORIC ACID.
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A study was made of the influence of pH on formation of insoluble compounds in solid APP (Ammonium Polyphosphate). Orthophosphoric acid made by the wet process (WOPA) from Karatau phosphorites of the composition (mass %): P//2O//5//t//o//t equals 23. 1, R//2O//3 equals 2. 9, Fe//2O//3 equals 0. 96, F equals 0. 79, SO//3 equals 2. 5, MgO equals 1. 8 was used in the experiments. It is shown that the production of APP by evaporation and dehydration of ammonium phosphate slurries of various pH values is accompanied by retrogradation of the available and water-soluble form of P//2O//5, which intensifies with increase of pH. This investigation led to the development of a process for production of solid APP from unevaporated orthophosphoric acid obtained from Karatau phosphorites, with insignificant retrogradation of available P//2O//5.
- Gavrilov,Zhdanov,Leneva,Dubinin,Pachina,Kalinina
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p. 1339 - 1342
(2008/10/08)
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