Analysis of Wet-Process Phosphoric Acid and By-Product Filter Cake by X-ray Spectrometry

1984 ◽  
Vol 28 ◽  
pp. 221-226
Author(s):  
Wendell D. Wilhide ◽  
Doris H. Ash
Keyword(s):  
Phosphoric Acid ◽  
Calcium Sulfate ◽  
Filter Cake ◽  
Lithium Carbonate ◽  
Chemical Analyses ◽  
Element Analysis ◽  
X Ray ◽  
Wet Process ◽  
Control Precision ◽  
Preparation Techniques

AbstractRapid X-ray fluorescence (XRF) analytical methods have been developed for analyzing wet-process phosphoric acid liquid samples and by-product calcium sulfate filter-cake solids. Liquid acid samples are neutralized by lithium carbonate and pressed-pellet, dry sample wafers are prepared for a nine-element analysis. Filter-cake solids are dehydrated to anhydrous calcium sulfate for a ten-element analysis. Hovel sample preparation techniques are described which permit maximum use of the automated XRF system for process control. Precision obtained for typical materials is compared with results of conventional chemical analyses.

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

2012 ◽  
Vol 14 (2) ◽  
pp. 80-87 ◽  
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.

Improving Gypsum Slurry Filtration in the Production of Phosphoric Acid by Adding Cationic Amphiphilic Copolymer

2012 ◽  
Vol 550-553 ◽  
pp. 919-926 ◽  
Author(s):  
Yong Liu ◽  
De Jun Fei ◽  
Ya Gu Dang ◽  
Jian Xun Wu ◽  
Guang Chao Du
Keyword(s):  
Phosphoric Acid ◽  
Filter Cake ◽  
Ph Value ◽  
Solid Content ◽  
Amphiphilic Copolymer ◽  
Polymerization Temperature ◽  
Wet Process ◽  
Optimum Synthesis ◽  
Cake Moisture ◽  
The Mean

A cationic amphiphilic copolymer was synthesized with acrylamide (AM), dimethyl diallyl ammonium chloride (DMDAAC), monomer B by solution copolymerization. Through the orthogonal test, the optimum synthesis condition was obtained as follow: the solid content of the polymerization system is 10%, the pH value is 4.0, the polymerization temperature is 60°C, the concentration of the initiator is 0.06%, and the monomer ratio of m (AM): m (DMDAAC): m (monomer B) is 70:10:20. The copolymer was used for the filtration aiding in the wet process phosphoric acid. The filtration rate of the gypsum slurry is increased by 4.8 times, and the filter cake moisture is reduced by 11.79%, with the addition of PADB. The mechanism of filtration aiding was also researched, which shows that PADB can change the mean diameter of crystals and agglomerate the tiny crystals; PADB can decrease the surface tension of the filter liquor and enhance the hydrophobicity of the gypsum.

Some Biomedical Applications of Charged-Particle-Induced X-Ray Fluorescence Analysis

1973 ◽  
Vol 17 ◽  
pp. 457-466
Author(s):  
J. L. Campbell ◽  
A. W. Herman ◽  
L. A. McNelles ◽  
B. H. Orr ◽  
R. A. Willoughby
Keyword(s):  
Trace Element ◽  
Trace Element Analysis ◽  
Fluorescence Analysis ◽  
Atomic Absorption Spectrophotometry ◽  
Element Analysis ◽  
X Ray ◽  
Analytical Technique ◽  
Lead And Zinc ◽  
Lead Zinc ◽  
Preparation Techniques

AbstractX-ray fluorescence induced by charged particles has been employed in trace element analysis of both animal and human blood, tissue and bone samples. Preparation techniques included microtome slicing and wet digestion in nitric acid, internal chemical standards being used in the latter case.Most of the specimens arose from a study of interactions between the toxic elements lead and zinc in growing foals; this was motivated by reports of sickness and death in foals raised near lead-zinc smelters. The cause of toxicity in animals from environmental pollution is often attributed to Single factors, whereas in reality interactions among many factors, including a variety of toxic and nutrient trace elements, should be considered.A variety of spectra are presented and elemental concentrations derived. Agreement between the X-ray data and atomic absorption spectrophotometry is encouraging. The results demonstrate the potential of particle-excited X-ray fluorescenee as a broad-range analytical technique for the study of trace element interactions.

Application and Mechanism Study of a Novel Copolymer for Filter Aids on Wet-Process Phosphoric Acid

2012 ◽  
Vol 557-559 ◽  
pp. 961-967 ◽  
Author(s):  
Guang Chao Du ◽  
De Jun Fei ◽  
Jian Xun Wu ◽  
Ya Gu Dang ◽  
Yong Liu ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Filter Cake ◽  
Average Pore Size ◽  
Average Diameter ◽  
Mechanism Study ◽  
Average Pore ◽  
Wet Process ◽  
Surface Contact Angle ◽  
Filter Aids ◽  
Action Modes

A novel copolymer PADA which has two functions of flocculation and surface activity was synthesized in aqueous solution. The copolymer was applied to filtration aiding on wet-process phosphoric acid (WPA). The results show that PADA can increase the filtration rate of the phosphoric acid slurry and decrease the moisture of the filter cake. The mechanism of filtration aiding was studied. PADA neutralizes the surface potential of the phosphogypsum and makes the microcrystal particles flocculate to conglobation, which indicate that electrostatic neutralization and flocculation might be the action modes in the process of filtration aiding. The shortest flocculation time and largest average diameter of floccules can be obtained with the addition of 10 ppm PADA. The average pore size and porosity of the filter cake are enlarged by 0.22 μm and 15.38% respectively with the addition of PADA. The surface contact angle of the phosphogypsum is increased by 3.4° with PADA presence.

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

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.

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

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

ChemInform Abstract: Purification of Wet-Process Phosphoric Acid. X-Ray Data of a New Phase, MgAlF5. 1.5 H2O.

1986 ◽  
Vol 17 (46) ◽  
Author(s):  
M. FEKI ◽  
M. CHAABOUNI ◽  
H. F. AYEDI ◽  
J.-C. HEUGHEBAERT ◽  
G. BONEL
Keyword(s):  
Phosphoric Acid ◽  
X Ray ◽  
Wet Process ◽  
New Phase
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