Calcium Silicate Slags - Properties of Quenched and Unquenched Slags and Effects of Their Admixtures with Phosphatic Fertilizers

Macintire, W. H.; Hardin, L. J.; Oldham, F. D.

doi:10.1021/ie50313a015

Cited by 9 publications

(14 citation statements)

References 5 publications

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“…Considered in connection with the data of Tables III and IV that show the extent and effect of removals of phosphatic components from basic fertilizers, the results of Table VII indicate that the analytical error attributable to formation of fluorapatite during ammonium citrate digestions is appreciable when the citrate is rendered alkaline by the dissolved mixtures of triand dibasic phosphates in the presence of fluorides, (17,20). Removal of basic phosphates by prior leaching with solvent tends to minimize the change in initial pH during the boiling digestion.…”

Section: Methodsmentioning

confidence: 95%

“…Both calcium sulfate and calcium fluoride decrease the solvent capacity of ammonium citrate for tricalcium phosphate (IS). Component calcium fluoride will also combine with tricalcium phosphate to form the less soluble fluorapatite during the official ammonium citrate digestion (17,20). The influence of the sulfate and of the fluoride upon the capacity of the solvent was therefore studied in the four systems of Table VII.…”

Section: Methodsmentioning

confidence: 99%

“…These practices have developed types of fertilizers (4, 24) that contain considerable quantities of dibasic phosphates (9,10,21,22) and variable amounts of tricalcium compounds that develop during processing and curing (11,IS,15,23). Moreover, engendered tricalcium phosphate and component fluorides react to form fluorapatite during both curing and analysis by the official method (17,20).…”

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confidence: 99%

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Direct Determination of Available P₂I₅ Content of Fertilizers

Macintire¹,

Shaw²,

Hardin³

1938

Ind. Eng. Chem. Anal. Ed.

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Section: Methodsmentioning

confidence: 95%

Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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Direct Determination of Available P₂I₅ Content of Fertilizers

Macintire¹,

Shaw²,

Hardin³

1938

Ind. Eng. Chem. Anal. Ed.

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“…Just as Ca3(PO4)2 will react with solution of CaF2 (24,25) to form by addition reaction the relatively insoluble fluorapatite and just as calcium hydroxyapatite will react with soluble fluorides to form by exchange reaction fluoroapatite 3Ca3(PO4) -CaF2 (26), so the possibility exists for similar addition or exchange reactions between the constituent ions and molecules of enamel and other ions, such as Pb, oxalate, SO4, etc. Such reactions might produce compounds less soluble than the original, such as a highly insoluble lead hydroxyapatite, the existence of which has already been shown (27).…”

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confidence: 99%

The Effects of Various Ions on Enamel Solubility

Buonocore

Bibby

1945

J Dent Res

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Several reports in the literature indicate that the solubility of enamel in acids can be changed by the action of various ions. Miller (1) using silver nitrate was unable to show retardation in enamel decalcification. The research work of Rickert (2) contradicted this and led him to believe that increased resistance to decalcification of silver nitrate-treated enamel was due to the clogging of tooth substance with reduced silver which prevented the penetration of acids. Hill and Arnold (3) studied the effects of silver nitrate on powdered enamel and found that after treatment, the solubility of enamel was significantly reduced. Difference in enamel solubility in acetate and maleate buffers was attributed by Benedict and Kanthak (4) to the formation of calcium maleate which acted as a protective coating over the enamel particles. Volker (5) and Bibby (6) investigated the effect of fluorides on enamel and concluded that the fluorine ion produced marked reduction in solubility. Because little or no consideration has been given to the effects of other ions on the solubility of enamel, it seemed to us worthwhile to investigate the matter.The choice of the ions used in the experiments was determined by a consideration of the mechanisms whereby the phenomenon of reduced solubility might occur. In order to better understand these, an examination of the chemical nature of enamel is necessary. This will be limited to facts relevant to the adequate understanding of certain assumptions which are made in this paper.Tooth enamel is a crystalline substance showing a characteristic x-ray diffraction pattern. Moreover, this pattern is practically identical with that given by bone, dentin and certain synthetic or natural inorganic materials, such as fluorapatite. On the basis of these x-ray findings these substances have been included in the general class of apatites. It should be remembered that this apatite classification refers only to a particular atomic pattern or arrangement in the crystal lattice and not to any constancy of chemical composition. For instance, McConnell (7,8) has pointed out that a large number of substitutions are possible in the general apatite pattern. If X10(ZO4)6. (F20H2C12) represents the general formula for the apatites, then X may be calcium, lead, manganese, potassium, strontium and cesium or in lesser amounts yttrium, lanthanum, titanium, iron, aluminum and magnesium; Z may be chromium, phosphorous, arsenic, vanadium, silicon, and carbon. Further evidence of the complex and variable nature of the apatites is obtained from the work of Eisenberger, Lehrman and Turner (9). In their critical review of the literature on the system

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“…Only the Wilson Dam slag mixture produced an increase in citrate insolubility not removable by immediate repetition of the ammonium citrate digestion of the residue from the first digestion. It has been pointed out (10,11,15) that single digestions of such mixtures of superphosphate and liming materials are inadequate to effect complete removal of the engendered basic phosphates. The solvent capacity of the citrate solution was reduced by the common-ion effect (2,4,15) and also by the decided alkalinity induced in the citrate solution by its solvent action upon unreacted fractions of the added calcic materials (10).…”

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confidence: 99%