Über einige Verbindungen im System CaO‐P<sub>2</sub>O<sub>5</sub>und ihre Beziehungen zur Thomasschlacke

Dieckmann, T.-H.; Houdremont, Eduard

doi:10.1002/zaac.19211200113

Cited by 9 publications

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“…Only two secondary calcium phosphates have been accepted as unquestioned (4), the dihydrate and the anhydrous. Two others have been described, 3CaHP04-2H20 (17,22) and 4CaHP04 H20 (10). The three types of patterns found indicate the existence of three crystallographic entities.…”

Section: Secondary Calcium Phosphatesmentioning

confidence: 90%

Chemical and X-Ray Diffraction Studies of Calcium Phosphates

Hodge¹,

Lefevre²,

Bale³

1938

Ind. Eng. Chem. Anal. Ed.

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To test the consistency of the entire method, two mixtures were prepared from analyzed cracked gasolines, and the compositions of the mixtures were determined by experiment and found by calculation. A comparison of the results is given in Table V. TABLE v. COhfPARATIVE RESULTS Per Cent aaiiiiilc Paraffins Saphthenes .Iromatics OlefinsIn no case do the differences exceed 5 per cent; in most cases they are much lower. It is believed that this value represents also the limit of precision of the method. ConclusionIt is clear that the analytical method herein outlined is not rigorously accurate. Nevertheless, in the absence of a simple exact method, the rapidity and simplicity of the operations involved in the procedure, the fact that the errors for different samples tend in the same direction, and the adaptability of the method to the analysis of smaller amounts than can be used with other procedures, do much to recommend it as a routine method, especially for comparative purposes. As such, it should prove valuable until more exact methods are available. Literature Cited(1) Anon.,The constancy and punty of composition of various commercial primary, secondary, and tertiary calcium phosphates are estimated. Secondary calcium phosphates are of least variability; primary and tertiary of marked variability.Evidence of three crystalline forms each of unignited primary and secondary cal-ESPITE the profusion of papers on the chemistry of the D calcium phosphates, there are many fundamental points still obscure. As Drakunov (11) points out, the study of these important substances involves great experimental difficulties. Larson (20) reported the preparation and properties of primary, secondary, and tertiary calcium phosphates "in pure crystalline form." However, a number of recent investigations offer contradictory evidence especially on the nature of the tertiary calcium phosphates. The work reported herewith proposes to examine the commercially prepared primary, secondary, and tertiary calcium phosphates chemically and by x-ray diffraction studies in order (a) to estimate the constancy and purity of composition of the commercial products, and (b) to interpret the analyses in the light of recent findings on the nature of these compounds. I n the interpretations, no attempt will be made to review exhaustively even the recent literature, but only such experiments or hypotheses as seem pertinent will be included.The commercially prepared calcium phosphates used in this investigation have been obtained from eight different cium phosphates is found from x-ray studies,The commercial tertiary calcium phosphates are probably hydroxylapatite with more or less adsorbed phosphate ions resulting in empirical formulas approaching the theoretical value for Ca3Pz08. Secondary calcium phosphate may be admixed.companies-five in this country, two in Germany, and one in England. Two samples each (of different lot numbers) of the tertiary phosphates and one each of the secondary and primary phosphates were used. Analytical ProcedureIn each case...

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