Attack of Tunisian Phosphate Ore by a Mixture of Sulfuric and Phosphoric Acid: Thermochemical Study by Means of Differential Reaction Calorimetry

A mixture of phosphoric and sulfuric acid was used to investigate the dissolution kinetics of phosphate ore by Differential Reaction Calorimetry (DRC). The effect of the solid-to-iquid ratio, concentration, stirring speed, particle size and temperature of the reaction is examined. It was established that the dissolution rate increased with stirring speed and particle size. However, rising the olid-to-iquid ratio, temperature and concentration decreased the dissolution rate. It was determined that the dissolution rate fits in the first order of the pseudo-homogeneous reaction model. Two negative values of apparent activation energies were found in the range of 25 to 60?C. The experimental data were tested by graphical and statistical methods and it was found that the following models were best fitted for the experimental data and an empirical equation for the process was developed. -ln (1 ? x) = [2,2 E-09((S/L)0.75C -0.461G0.447(SS) 0.471exp (2671/T)]t. T? 40?C -ln (1 ? x) = [2,2 E-09((S/L)0.75C -0.461G0.447(SS) 0.471exp (6959/T)]t. T > 45?C

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The digestion of phosphate ore in phosphoric acid

Industrial & Engineering Chemistry Research ◽

10.1021/ie00072a020 ◽

1987 ◽

Vol 26 (12) ◽

pp. 2501-2505 ◽

Cited By ~ 32

Author(s):

Sietse Van der Sluis ◽

Yulia Meszaros ◽

Wim G. J. Marchee ◽

Hans A. Wesselingh ◽

Gerda M. Van Rosmalen

Keyword(s):

Phosphoric Acid ◽

Phosphate Ore

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Rare Earth Occurrences in Streams of Processing a Phosphate Ore

Minerals ◽

10.3390/min9050262 ◽

2019 ◽

Vol 9 (5) ◽

pp. 262 ◽

Cited By ~ 6

Author(s):

Xiaosheng Yang ◽

Hannu Tapani Makkonen ◽

Lassi Pakkanen

Keyword(s):

Rare Earth ◽

Sulfuric Acid ◽

Phosphoric Acid ◽

Rare Earth Elements ◽

Electron Probe Microanalysis ◽

Electron Probe ◽

Phosphate Ore ◽

Mineral Liberation ◽

Efficient Recovery ◽

Liberation Analysis

Rare earth elements (REEs) are defined as lanthanides with Y and Sc. Rare earth occurrences including the REE-bearing phases and their distributions, measured by rare earth oxides (REOs), in the streams of processing a phosphate ore were determined by using MLA, the mineral liberation analysis and EPMA, the electron probe microanalysis. The process includes an apatite ore beneficiation by flotation and further processing of the beneficiation concentrate with sulfuric acid. Twenty-six, sixty-two and twelve percent of the total REOs (TREO) contents from the ore end up in the products of beneficiation tailings, phosphogypsum (PG) and phosphoric acid, respectively. Apatite, allanite, monazite and pyrochlore are identified as REE-bearing minerals in the beneficiation process. In the beneficiation tailings, the REEs are mainly distributed in monazite (10.3% TREO), apatite (5.9% TREO), allanite (5.4% TREO) and pyrochlore (4.3% TREO). Gypsum, monazite, apatite and other REE-bearing phases were found to host REEs in the PG and the REEs distributions are 44.9% TREO in gypsum, 15.8% TREO in monazite, 0.6% TREO in apatite and 0.6% TREO in other REE-bearing phases. Perspectives on the efficient recovery of REEs from the beneficiation tailings and the PG are discussed.

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