Quantitative X-Ray Diffraction Analysis of Calcium Sulfates and Quartz in Wet-Process Phosphoric Acid Filter Cakes

Advances in X-ray Analysis ◽

10.1154/s0376030800010284 ◽

1985 ◽

Vol 29 ◽

pp. 211-216

Author(s):

Kjell R. Waerstad

Keyword(s):

Phosphoric Acid ◽

Rapid Determination ◽

Diffraction Method ◽

Adhesive Tape ◽

X Ray Diffraction ◽

Synthetic Sample ◽

X Ray ◽

Wet Process ◽

A New Technique ◽

Filter Cakes

AbstractA quantitative X-ray diffraction method has been developed for rapid determination of the crystalline phases present in by-product filter cakes from wet-process phosphoric acid manufacture. A new technique to reduce preferred orientation of the crystallites by removing the top layer of the X-ray samples with adhesive tape is described, statistical analysis of synthetic sample mixtures of CaS04.2H2O, CaSO4 · 0.5H20, CaSo4, and α-Si02 indicates that the calcium sulfate phases present in typical filter cakes can be determined with an accuracy of about 3% at the 95% confidence level; quartz can be determined at about 14%. The method has been applied to the analysis of 10 filter-cake samples from an experimental hemihydrate plant. The results are in good agreement with data from X-ray fluorescence and chemical analyses

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Studies on the transformation of calcium sulphate dihydrate to hemihydrate in the wet process phosphoric acid production

Polish Journal of Chemical Technology ◽

10.2478/v10026-012-0075-4 ◽

2012 ◽

Vol 14 (2) ◽

pp. 80-87 ◽

Cited By ~ 1

Author(s):

Barbara Grzmil ◽

Bogumił Kic ◽

Olga Żurek ◽

Konrad Kubiak

Keyword(s):

Phase Composition ◽

Phosphoric Acid ◽

Diffraction Analysis ◽

Acid Production ◽

Phosphate Rock ◽

Calcium Sulphate ◽

Industrial Plant ◽

X Ray Diffraction ◽

X Ray ◽

Wet Process

Studies on the transformation of calcium sulphate dihydrate to hemihydrate in the wet process phosphoric acid production The influence of the process temperature from 85°C to 95°C, the content of phosphates and sulphates in the wet process phosphoric acid (about 22-36 wt% P2O5 and about 2-9 wt% SO42-) and the addition of αCaSO4·0.5H2O crystallization nuclei (from 10% to 50% in relation to CaSO4·2H2O) on the transformation of calcium sulphate dihydrate to hemihydrate has been determined. The wet process phosphoric acid and phosphogypsum from the industrial plant was utilized. They were produced by reacting sulphuric acid with phosphate rock (Tunisia) in the DH-process. The X-ray diffraction analysis was used to determine the phase composition and fractions of various forms of calcium sulphates in the samples and the degree of conversion of CaSO4·2H2O to αCaSO4·0.5H2O and CaSO4. It was found that the transformation of CaSO4·2H2O to αCaSO4·0.5H2O should be carried out in the presence of αCaSO4·0.5H2O crystallization nuclei as an additive (in the amount of 20% in relation to CaSO4·2H2O), at temperatures 90±2°C, in the wet process phosphoric acid containing the sulphates and phosphates in the range of 4±1 wt% and 27±1 wt%, respectively.

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High Temperature X-ray Diffraction Studies of the Defluorination Reactions of Chukhrovite, Falphite and Ralstonite

Advances in X-ray Analysis ◽

10.1154/s0376030800014178 ◽

1984 ◽

Vol 28 ◽

pp. 339-343

Author(s):

Robert L. Wilson ◽

Jacob Mu ◽

James L. Bradford

Keyword(s):

Phosphoric Acid ◽

Phosphate Rock ◽

Fluoride Ion ◽

Lower Grade ◽

X Ray Diffraction ◽

High Concentration ◽

X Ray ◽

Wet Process ◽

New Process ◽

Metallic Impurities

Current commercial processes for the production of wet-process phosphoric acid involve the dissolution of phosphate rock and separation of insoluble solids by filtration. Calcium is removed by the addition of H2SO4, to precipitate CaSO4•2H2O. Other metallic impurities are removed by extraction or precipitation.In a new process. Lower grade phosphate ore can be digested with recycled phosphoric acid. If the raw acid contains a fairly high concentration of Mg, it may be enriched in fluoride ion.

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An X-ray diffraction method for semiquantitative mineralogical analysis of Chilean nitrate ore

Open-File Report ◽

10.3133/ofr94240 ◽

1994 ◽

Cited By ~ 3

Author(s):

J.C. Jackson ◽

G.E. Ericksen

Keyword(s):

Diffraction Method ◽

X Ray Diffraction ◽

Mineralogical Analysis ◽

X Ray

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A new technique for the study of phase transitions by means of energy dispersive x-ray diffraction. Application to polymeric samples

Journal of Macromolecular Science Part B ◽

10.1080/00222349608212381 ◽

1996 ◽

Vol 35 (2) ◽

pp. 199-213 ◽

Cited By ~ 28

Author(s):

V. Rossi Albertini ◽

L. Bencivenni ◽

R. Caminiti ◽

F. Cilloco ◽

C. Sadun

Keyword(s):

Phase Transitions ◽

Energy Dispersive ◽

New Technique ◽

X Ray Diffraction ◽

X Ray ◽

A New Technique ◽

Polymeric Samples

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Growth of sillenite Bi12FeO20 single crystals: structural, thermal, optical, photocatalytic features and first principle calculations

Scientific Reports ◽

10.1038/s41598-020-78598-3 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Durga Sankar Vavilapalli ◽

Ambrose A. Melvin ◽

F. Bellarmine ◽

Ramanjaneyulu Mannam ◽

Srihari Velaga ◽

...

Keyword(s):

Single Crystal ◽

Single Crystals ◽

Photoelectron Spectroscopy ◽

Diffraction Method ◽

Lattice Parameter ◽

First Principle ◽

X Ray Diffraction ◽

X Ray ◽

First Principle Calculations ◽

Photodegradation Efficiency

AbstractIdeal sillenite type Bi12FeO20 (BFO) micron sized single crystals have been successfully grown via inexpensive hydrothermal method. The refined single crystal X-ray diffraction data reveals cubic Bi12FeO20 structure with single crystal parameters. Occurrence of rare Fe4+ state is identified via X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The lattice parameter (a) and corresponding molar volume (Vm) of Bi12FeO20 have been measured in the temperature range of 30–700 °C by the X-ray diffraction method. The thermal expansion coefficient (α) 3.93 × 10–5 K−1 was calculated from the measured values of the parameters. Electronic structure and density of states are investigated by first principle calculations. Photoelectrochemical measurements on single crystals with bandgap of 2 eV reveal significant photo response. The photoactivity of as grown crystals were further investigated by degrading organic effluents such as Methylene blue (MB) and Congo red (CR) under natural sunlight. BFO showed photodegradation efficiency about 74.23% and 32.10% for degrading MB and CR respectively. Interesting morphology and microstructure of pointed spearhead like BFO crystals provide a new insight in designing and synthesizing multifunctional single crystals.

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Study of Corrosion Resistance and Degradation Mechanisms in LiTiO2-Li2TiO3 Ceramic

Crystals ◽

10.3390/cryst11070753 ◽

2021 ◽

Vol 11 (7) ◽

pp. 753

Author(s):

Dmitriy Shlimas ◽

Artem L. Kozlovskiy ◽

Maxim Zdorovets

Keyword(s):

Degradation Mechanism ◽

Diffraction Method ◽

Large Mass ◽

Time Frame ◽

X Ray Diffraction ◽

Acidic Media ◽

X Ray ◽

Mass Losses ◽

The Stability ◽

Thermal Sintering

The interest in lithium-containing ceramics is due to their huge potential as blanket materials for thermonuclear reactors for the accumulation of tritium. However, an important factor in their use is the preservation of the stability of their strength and structural properties when under the influence of external factors that determine the time frame of their operation. This paper presents the results of a study that investigated the influence of the LiTiO2 phase on the increasing resistance to degradation and corrosion of Li2TiO3 ceramic when exposed to aggressive acidic media. Using the X-ray diffraction method, it was found that an increase in the concentration of LiClO4·3H2O during synthesis leads to the formation of a cubic LiTiO2 phase in the structure as a result of thermal sintering of the samples. During corrosion tests, it was found that the presence of the LiTiO2 phase leads to a decrease in the degradation rate in acidic media by 20–70%, depending on the concentration of the phase. At the same time, and in contrast to the samples of Li2TiO3 ceramics, for which the mechanisms of degradation during a long stay in aggressive media are accompanied by large mass losses, for the samples containing the LiTiO2 phase, the main degradation mechanism is pitting corrosion with the formation of pitting inclusions.

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