Phosphorus Life Cycle: From Geological Genesis, Mine Cycle, Chemical Transformation, Use as Fertilizers, and Environmental Fate

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Environmental Mineralogy and Biogeochemistry".

Deadline for manuscript submissions: closed (30 June 2021) | Viewed by 54150

Special Issue Editors

Geology & Sustainable Mining Institute (GSMI), Mohammed VI Polytechnic University, Ben Guerir 43150, Morocco
Interests: environmental geochemistry and the mineralogical characterization of mine ores and waste; stabilization/solidification of contaminated soils and mine wastes
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Phosphate, especially the phosphorus form, is one of the most critical substances for human life. It is a nonsubstitutable element for agriculture and food industries serving the growing world population. Phosphates are exploited as sedimentary or magmatic deposits. Phosphate ores are highly heterogeneous from an orebody to another due to various phosphogenesis pathways. Consequently, characterization of phosphate deposits is crucial for the design of the most optimal extraction, beneficiation, and waste management practices. The characterization step must be multidisciplinary and might include analyzing various geomechanical, physical, chemical mineralogical, and environmental properties, which may allow developing a rational and global knowledge about the orebody. All these characteristics could be combined in one approach called geometallurgical models that are used during the entire mine life cycle. Phosphate minerals, namely apatite, are known for their ability to adsorb and/or substitute variable chemical species that could be added values or nondesirable elements. The most known chemical species having affinity to phosphorites are rare earth elements, uranium, and heavy metals. Thus, when phosphate ores are processed through a specific mineralurgical of metallurgical treatment flowsheets, these elements could follow different enrichment/exhaustion paths between phosphate products (concentrate, phosphoric acid, fertilizers, etc.) or within different wastes (waste rocks and tailing streams). In addition, the prediction of contamination speciation within waste rocks is a priority to preserve ecosystems where these wastes are deposited. However, recent trends in mining operation try to reduce the quantities of deposited waste rocks by incorporating circular economy (e.g., waste rock valorization, recoverable elements recovery such as rare earth elements) or at least decontaminating these wastes through reprocessing before the final deposition.

Insights related to the following aspects will be included in this Special Issue:

  • Phosphate deposit typology and ore characterization;
  • New phosphate extraction techniques;
  • Prediction of the contaminant potential of phosphate mine wastes;
  • Low-grade ores and waste beneficiation;
  • Mine waste reprocessing/decontamination;
  • Geo-environmental modeling of phosphate ore deposit;
  • Mine waste in situ reuse;
  • Mine waste valorization in civil engineering;
  • Mine resources life cycle analysis;
  • Phosphate mining and circular economy

Prof. Dr. Mostafa Benzaazoua
Prof. Dr. Yassine Taha
Dr. Abdellatif Elghali
Guest Editors

Manuscript Submission Information

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Keywords

  • phosphate extraction
  • beneficiation
  • rare earth elements
  • uranium
  • heavy metals
  • geomodeling
  • mine waste management and valorization
  • circular economy

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Published Papers (12 papers)

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Research

Jump to: Review

10 pages, 2182 KiB  
Article
Recycling of Spent Reverse Osmosis Membranes for Second Use in the Clarification of Wet-Process Phosphoric Acid
by Khaoula Khaless, Brahim Achiou, Rachid Boulif and Rachid Benhida
Minerals 2021, 11(6), 637; https://doi.org/10.3390/min11060637 - 16 Jun 2021
Cited by 10 | Viewed by 2621
Abstract
Various techniques have been used to “clean-up” wet-process phosphoric acid such as precipitation, flotation and adsorption. To address the potential of membrane processes in the phosphoric acid clarification process, this study explores the benefits of membrane techniques as a green separation technique for [...] Read more.
Various techniques have been used to “clean-up” wet-process phosphoric acid such as precipitation, flotation and adsorption. To address the potential of membrane processes in the phosphoric acid clarification process, this study explores the benefits of membrane techniques as a green separation technique for phosphoric acid clarification in an eco-efficient way through the use of recycling spent reverse osmosis membrane. Regenerated membrane was used to study the phosphoric acid clarification at a laboratory scale. They were immersed in an oxidizer for at most seven days. The samples were characterized systematically before immersion in an oxidant media. In this study, the potential to regenerate spent membranes and application of this media to clarify the 29% P2O5 phosphoric acid was demonstrated. This study shows, through experiments, that the reverse osmosis (RO) membranes could achieve a rejection of 70% and 61% for suspended solid and organic matter, respectively. These promising results will pave the way for implementation of these membranes in phosphoric acid treatment. Moreover, besides being economically advantageous, the use of the spent membrane is likely an environmentally friendly route (no waste, no organic solvent and effluent to be regenerated later on). Full article
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15 pages, 2789 KiB  
Article
Experimental and Numerical Investigations on Conductive Drying of Phosphate Washing Waste Clay
by Fatiha Berroug, Yassir Bellaziz, Naaila Ouazzani, Fatima Ait Nouh, Abdessamad Hejjaj, Lahcen Boukhattem, Ali Idlimam, Hamid El Mahmoudi and Laila Mandi
Minerals 2021, 11(5), 482; https://doi.org/10.3390/min11050482 - 30 Apr 2021
Cited by 1 | Viewed by 1918
Abstract
Morocco is the leading producer of phosphate and its derivatives in the world with a total production of 35 Mt. However, the extraction and the valorization of this mine generate huge quantities of phosphate washing waste clay (PHWWC) that constitute a main environmental [...] Read more.
Morocco is the leading producer of phosphate and its derivatives in the world with a total production of 35 Mt. However, the extraction and the valorization of this mine generate huge quantities of phosphate washing waste clay (PHWWC) that constitute a main environmental and economic concern. To facilitate this waste clay storage and handling, it is necessary to decrease its moisture content that represents 80% of PHWWC. The present paper is devoted to studying the conductive drying of PHWWC. Drying experiments were conducted in a laboratory pilot. Afterwards, the experiment results were implemented in a one-dimensional numerical model of heat and mass transfer in a porous media to identify the drying parameters and performances. It was found that most of the water contained in PHWWC is free water that is removed with a constant drying rate. The volume reduction with a marked cracks phenomenon attained 65% without any significant effect of drying temperature and sample thickness. The effective moisture diffusivity of the PHWWC for a conductive drying process is ranged between 10−9 and 1.1 × 10−8 m2·s−1. The thermal efficiency of the drying system is up to 86%. The results could be used for the purpose of design and scale-up of the industrial dryer based on laboratory-scale experiments. Full article
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10 pages, 14575 KiB  
Article
Mechanical Behavior of Hydroxyapatite-Chitosan Composite: Effect of Processing Parameters
by Hamid Ait Said, Hassan Noukrati, Hicham Ben Youcef, Ayoub Bayoussef, Hassane Oudadesse and Allal Barroug
Minerals 2021, 11(2), 213; https://doi.org/10.3390/min11020213 - 19 Feb 2021
Cited by 18 | Viewed by 3501
Abstract
Three-dimensional hydroxyapatite-chitosan (HA-CS) composites were formulated via solid-liquid technic and freeze-drying. The prepared composites had an apatitic nature, which was demonstrated by X-ray diffraction and Infrared spectroscopy analyses. The impact of the solid/liquid (S/L) ratio and the content and the molecular weight of [...] Read more.
Three-dimensional hydroxyapatite-chitosan (HA-CS) composites were formulated via solid-liquid technic and freeze-drying. The prepared composites had an apatitic nature, which was demonstrated by X-ray diffraction and Infrared spectroscopy analyses. The impact of the solid/liquid (S/L) ratio and the content and the molecular weight of the polymer on the composite mechanical strength was investigated. An increase in the S/L ratio from 0.5 to 1 resulted in an increase in the compressive strength for HA-CSL (CS low molecular weight: CSL) from 0.08 ± 0.02 to 1.95 ± 0.39 MPa and from 0.3 ± 0.06 to 2.40 ± 0.51 MPa for the HA-CSM (CS medium molecular weight: CSM). Moreover, the increase in the amount (1 to 5 wt%) and the molecular weight of the polymer increased the mechanical strength of the composite. The highest compressive strength value (up to 2.40 ± 0.51 MPa) was obtained for HA-CSM (5 wt% of CS) formulated at an S/L of 1. The dissolution tests of the HA-CS composites confirmed their cohesion and mechanical stability in an aqueous solution. Both polymer and apatite are assumed to work together, giving the synergism needed to make effective cylindrical composites, and could serve as a promising candidate for bone repair in the orthopedic field. Full article
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22 pages, 8859 KiB  
Article
Alkali-Hydrothermal Treatment of K-Rich Igneous Rocks for Their Direct Use as Potassic Fertilizers
by Aaron Mbissik, Abdellatif Elghali, Muhammad Ouabid, Otmane Raji, Jean-Louis Bodinier and Hicham El Messbahi
Minerals 2021, 11(2), 140; https://doi.org/10.3390/min11020140 - 30 Jan 2021
Cited by 6 | Viewed by 3452
Abstract
Due to the increasing demand for conventional sources of potassium (K) and their inaccessibility by African countries, K-rich igneous rocks are increasingly studied as potential alternative sources. In this study, six potassic igneous rocks (syenites and trachytes) from the Tamazeght, Jbel Boho, Ait [...] Read more.
Due to the increasing demand for conventional sources of potassium (K) and their inaccessibility by African countries, K-rich igneous rocks are increasingly studied as potential alternative sources. In this study, six potassic igneous rocks (syenites and trachytes) from the Tamazeght, Jbel Boho, Ait Saoun, and El Glo’a regions (Morocco) were sampled and characterized. Then they were hydrothermally treated to enhance their K release for potential use as potassic fertilizers. The raw materials are mainly formed by microcline (up to 74%), orthoclase (20–68%), albite (36–57%), biotite-muscovite (15–23%), and titanite, calcite, hematite, and apatite as accessory minerals. These samples were crushed and milled to reach a particle size <150 µm and mixed with 4 N NaOH solution in an autoclave. The liquid/solid (L/S) ratio was about 44 mL/50 g. The powders were allowed to react with the solution at 170 °C for 7 h. For all tests, NaOH reacted completely with the powders and no liquid was observed after the treatment. X-ray diffraction (XRD), thermal gravimetric analysis (TGA), infrared spectroscopy (IRTF), and scanning electron microscopy (SEM-EDS) were carried out on treated samples to characterize the mineralogical and structural changes due to the alkali-hydrothermal treatment. Indeed, the treated samples revealed the presence of sodic neoformed phases such as thermonatrite, sodalite, analcime, and cancrinite. The treated material was leached for a week using deionized water and the elements released were measured using inductively coupled plasma–atomic emission spectroscopy (ICP-AES). The hydrothermal process showed a strong effect on structure breakdown as well as on the release of K and other nutrients such as P, Fe, Si, Mg, and Ca. Therefore, the alkali-hydrothermal treatment allowed the release of 50.5 wt% K. Moreover, the release of Mg, Ca, Fe, P, K, and Si were significantly increased. Mg, Ca, Fe, P, K, and Si release within raw materials was about (0.5–3.6), (3.5–31.4), (0.01–0.4), (0.01–0.3), (20–55), and (4.6–8) mg/kg, respectively, whereas treated samples showed a higher release of these elements. Quantitatively, Mg, Ca, Fe, P, K, and Si releases were about (10–11.8), (60–70), (7–20), (1.2–15), (218–1278), and (1119–2759) mg/kg, respectively. Consequently, the treated igneous rocks (syenite and trachyte) could be directly used as potassic fertilizers that would also be a source of other nutrients. Full article
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13 pages, 2195 KiB  
Article
Development of in-House Industrial Fluosilicic Acid Certified Reference Material: Certification of H2SiF6 Mass Fraction
by Said Kounbach, Mokhtar Ben Embarek, Abdeljalil Chemaa, Rachid Boulif, Rachid Benhida and Redouane Beniazza
Minerals 2021, 11(1), 92; https://doi.org/10.3390/min11010092 - 19 Jan 2021
Cited by 3 | Viewed by 2572
Abstract
Fluosilicic acid is a by-product of the chemical phosphate industry, mainly during the manufacture of phosphoric acid and triple super phosphate (TSP). To ensure the accurate measurement of the H2SiF6 mass fraction in this by-product, method validation is required, which [...] Read more.
Fluosilicic acid is a by-product of the chemical phosphate industry, mainly during the manufacture of phosphoric acid and triple super phosphate (TSP). To ensure the accurate measurement of the H2SiF6 mass fraction in this by-product, method validation is required, which needs a certified reference material (CRM) with its traceability to the International System of Units (SI). This work describes the development of a certified reference material of fluosilicic acid, which is commercially unavailable. Details of all steps, such as sample preparation, homogeneity and stability studies, value assignment, establishment of metrological traceability, and uncertainty estimation of the certified reference material, are fully described. The H2SiF6 mass fraction in the CRM was quantified by two analytical methods, i.e., UV-VIS as a primary method of analysis and flame mode atomic absorption spectroscopy (AAS) as a second method. It is worth noting that the results obtained from each method were in good agreement. The CRM certified value and corresponding expanded uncertainty, obtained from the combined standard uncertainty multiplied by the coverage factor (k = 2), for a confidence interval of 95%, was (91.5 ± 11.7) g·kg−1. The shelf life of the developed CRM is determined to be 1 year, provided that storage conditions are ensured. The developed CRM can be applied to validate analytical methods, improve the accuracy of measurement data as well as to establish the meteorological traceability of analytical results. Full article
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15 pages, 1926 KiB  
Article
Wild Plants for the Phytostabilization of Phosphate Mine Waste in Semi-Arid Environments: A Field Experiment
by Hamza Zine, Sara Elgadi, Rachid Hakkou, Eleni G. Papazoglou, Laila Midhat and Ahmed Ouhammou
Minerals 2021, 11(1), 42; https://doi.org/10.3390/min11010042 - 31 Dec 2020
Cited by 17 | Viewed by 2593
Abstract
The management of mine waste has become an urgent issue, especially in semi-arid environments. In this context, and with an aim to inhibit the oxidation of the sulfide tailings of the abandoned mine of Kettara in Morocco, a store-and-release (SR) cover made of [...] Read more.
The management of mine waste has become an urgent issue, especially in semi-arid environments. In this context, and with an aim to inhibit the oxidation of the sulfide tailings of the abandoned mine of Kettara in Morocco, a store-and-release (SR) cover made of phosphate mine waste (PW) was implemented. In order to guarantee its long-term performance, phytostabilization by local wild plant species is currently the most effective and sustainable solution. This study aimed to assess the growth performance and phytostabilization efficiency of five local wild plant species to grow on the SR cover made of PW. A field experiment was conducted for two growing seasons (2018 and 2019), without amendments and with the minimum of human care. PW and the aboveground and belowground parts of the studied plant species were collected and analyzed for As, Cd, Cu, Ni, and Zn. The bioconcentration factor (BCF) and translocation factor (TF) were also calculated. Despite the hostile conditions of the mining environment, the five plant species showed promising growth performances as follows: Atriplex semibaccata > Vicia sativa > Launaea arborescens > Peganum harmala > Asparagus horridus. The five plants showed high accumulation capacity of the trace elements, with the highest concentrations in belowground tissue. Principal component analysis distinguished A. semibaccata as having a high concentration of Cu and As, while Asparagus horridus had higher concentrations of Cd and Zn. In contrast, P. harmala, V. sativa, and L. arborescens demonstrated affinity regarding Ni. According to the BCF (<1) and TF (<1), these plant species could be used as effective phytostabilizers of the studied trace elements. The present study showed that local wild plant species have a great potential for the phytostabilization of PW, and could ensure the long-term efficiency of SR cover. Full article
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15 pages, 6573 KiB  
Article
Phosphogypsum and Black Steel Slag as Additives for Ecological Bentonite-Based Materials: Microstructure and Characterization
by Achraf Harrou, El Khadir Gharibi, Yassine Taha, Nathalie Fagel and Meriam El Ouahabi
Minerals 2020, 10(12), 1067; https://doi.org/10.3390/min10121067 - 28 Nov 2020
Cited by 18 | Viewed by 2685
Abstract
The Black Steel slag (Ss) and phosphogypsum (PG) are industrial wastes produced in Morocco. In order to reduce these two wastes and to evaluate their pozzolanic reactivity in the presence of water, they were incorporated into bentonite (B) mixed with lime (L). The [...] Read more.
The Black Steel slag (Ss) and phosphogypsum (PG) are industrial wastes produced in Morocco. In order to reduce these two wastes and to evaluate their pozzolanic reactivity in the presence of water, they were incorporated into bentonite (B) mixed with lime (L). The studied mixtures (BLW, BL–PG–W and BL–PG–Ss–W) were analyzed by X-ray diffraction, Infrared spectroscopy, Raman spectroscopy and SEM/EDX analysis. Compressive strength tests were performed on hardened specimens. The results obtained show that the hydration kinetics of the B–L–W and B–L–PG–W mixtures are slow. The addition of PG to a bentonite––lime mixture induces the formation of new microstructures such as hydrated calcium silicate (C–S–H) and ettringite, which increases the compressive strength of the cementitious specimens. The addition of the Ss to a mixture composed of 8%PG and 8%L–B accelerates the kinetics of hydration and activates the pozzolanic reaction. The presence of C2S in the slag helps to increase the mechanical strength of the mixture B–L–PG–Ss. The compressive strength of the mixtures BL–W, BL–PG–W and BL–PG–Ss–W increases from 15 to 28 days of setting. After 28 days of setting, 8% of Sc added to the mixture 8% PG–8%L–B is responsible for an increase of the compressive strength to 0.6 MPa. Full article
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13 pages, 4746 KiB  
Article
Thermal Beneficiation of Sra Ouertane (Tunisia) Low-Grade Phosphate Rock
by Noureddine Abbes, Essaid Bilal, Ludwig Hermann, Gerald Steiner and Nils Haneklaus
Minerals 2020, 10(11), 937; https://doi.org/10.3390/min10110937 - 22 Oct 2020
Cited by 11 | Viewed by 4827
Abstract
Low-grade phosphate rock from Sra Ouertane (Tunisia) was beneficiated using a thermal treatment consisting of calcination, quenching, and disliming. Untreated phosphate rock samples (group 1), calcined phosphate rock samples (group 2), as well as calcined, quenched, and dislimed (group 3) phosphate rock samples, [...] Read more.
Low-grade phosphate rock from Sra Ouertane (Tunisia) was beneficiated using a thermal treatment consisting of calcination, quenching, and disliming. Untreated phosphate rock samples (group 1), calcined phosphate rock samples (group 2), as well as calcined, quenched, and dislimed (group 3) phosphate rock samples, were investigated using inductively-coupled plasma atomic emission spectroscopy (ICP-AES), inductively-coupled plasma mass spectrometry (ICP-MS), thermogravimetric analysis (TGA), and X-ray powder diffraction (XRD). Besides, the particle size distribution of the aforementioned three groups was determined. The proposed thermal treatment successfully increased the P2O5 content of the untreated phosphate rock from 20.01 wt% (group 1) to 24.24 wt% (group 2) after calcination and, finally, 27.24 wt% (group 3) after calcination, quenching, and disliming. It was further found that the concentration of relevant accompanying rare earth elements (Ce, La, Nd, Pr, Sm, and Y) was increased and that the concentration of Cd could be significantly reduced from 30 mg/kg to 14 mg/kg with the proposed treatment. The resulting phosphate concentrate showed relatively high concentrations in metal oxides: Ʃ MgO, Fe2O3, Al2O3 = 3.63 wt% and silica (9.81 wt%) so that it did not meet the merchant grade specifications of a minimum P2O5 content of 30 wt% yet. Removal of these elements could be achieved using additional appropriate separation techniques. Full article
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13 pages, 2861 KiB  
Article
Proposal for an Environmentally Sustainable Beneficiation Route for the Amphibolitic Itabirite from the Quadrilátero Ferrífero-Brazil
by Gizele Maria Campos Gonçalves and Rosa Malena Fernandes Lima
Minerals 2020, 10(10), 897; https://doi.org/10.3390/min10100897 - 10 Oct 2020
Cited by 4 | Viewed by 2012
Abstract
The high world demand for iron ores opposed to the rapid exhaustion of high-grade deposits from the main producing regions around the world has motivated the search and/or improvement of beneficiation routes, which enable the economic use of iron formations previously considered marginal [...] Read more.
The high world demand for iron ores opposed to the rapid exhaustion of high-grade deposits from the main producing regions around the world has motivated the search and/or improvement of beneficiation routes, which enable the economic use of iron formations previously considered marginal ores, which have the potential to considerably increase mineable reserves due to their large volume. In this study, a sample of amphibolitic itabirite from the eastern region of the Quadrilátero Ferrífero, Minas Gerais, Brazil was characterized, aiming at its use in the industrial pelletizing circuit. The main physical characteristics of this ore are moisture = 10% and specific weight = 3710 kg/m3. The ore has a high grade of loss on ignition—LOI (6.7%) and P (0.14%). Through X-ray diffractometry (XRD), optical microscopy and scanning electron microscope—SEM, the ore was found to consist of 64.5% goethite (amphibolitic, alveolar, massive and earthy); 6.8% hematite (martitic, granular and lamellar) and 0.9% magnetite. The main gangue mineral is quartz (25.5%). Based on the results of concentration tests (magnetic and flotation) performed with the studied sample, the magnetic concentration route of deslimed sample followed by the addition of slimes in magnetic concentrate can be incorporated into the pelletizing process. Full article
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Review

Jump to: Research

20 pages, 5142 KiB  
Review
Towards Zero Solid Waste in the Sedimentary Phosphate Industry: Challenges and Opportunities
by Yassine Taha, Abdellatif Elghali, Rachid Hakkou and Mostafa Benzaazoua
Minerals 2021, 11(11), 1250; https://doi.org/10.3390/min11111250 - 10 Nov 2021
Cited by 23 | Viewed by 4260
Abstract
The phosphate industry produces huge volumes of waste (hundred million tons per year). These wastes are generally surface landfilled, leading to significant environmental impacts and a large footprint. The current practices of phosphate waste management, the typology of the waste streams and their [...] Read more.
The phosphate industry produces huge volumes of waste (hundred million tons per year). These wastes are generally surface landfilled, leading to significant environmental impacts and a large footprint. The current practices of phosphate waste management, the typology of the waste streams and their characteristics, and finally their potential applications are reviewed. All the waste streams generated during the life cycle of phosphoric acid production going from the extraction of phosphate rock to its enrichment and transformation are considered. Great circularity opportunities have been identified and they aim (i) to recover the residual phosphorus and other critical minerals and metals, and (ii) to consider phosphate wastes as alternative resources in the civil engineering and building sectors. The purpose is to shift from linear thinking to circular thinking where synergy between different mining and other industries is highly encouraged. By doing so, opportunities to safeguard natural resources and to minimize the environmental and societal impacts are limitless. However, many challenges are still limiting this shift: economic and technical constraints, societal and policy-makers’ awareness, regulation harmonization and finally knowledge gaps. More efforts and investment in research and development are still required to reach the zero-waste target. Full article
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23 pages, 9051 KiB  
Review
Phosphate Rocks: A Review of Sedimentary and Igneous Occurrences in Morocco
by Radouan El Bamiki, Otmane Raji, Muhammad Ouabid, Abdellatif Elghali, Oussama Khadiri Yazami and Jean-Louis Bodinier
Minerals 2021, 11(10), 1137; https://doi.org/10.3390/min11101137 - 16 Oct 2021
Cited by 32 | Viewed by 13847
Abstract
Phosphate rocks are a vital resource for world food supply and security. They are the primary raw material for phosphoric acid and fertilizers used in agriculture, and are increasingly considered to be a potential source of rare earth elements. Phosphate rocks occur either [...] Read more.
Phosphate rocks are a vital resource for world food supply and security. They are the primary raw material for phosphoric acid and fertilizers used in agriculture, and are increasingly considered to be a potential source of rare earth elements. Phosphate rocks occur either as sedimentary deposits or igneous ores associated with alkaline rocks. In both cases, the genesis of high-grade phosphate rocks results from complex concentration mechanisms involving several (bio)geochemical processes. Some of these ore-forming processes remain poorly understood and subject to scientific debate. Morocco holds the world’s largest deposits of sedimentary phosphate rocks, and also possesses several alkaline complexes with the potential to bear igneous phosphate ores that are still largely underexplored. This paper summarizes the main geological features and driving processes of sedimentary and igneous phosphates, and discusses their global reserve/resource situation. It also provides a comprehensive review of the published data and information on Moroccan sedimentary and igneous phosphates. It reveals significant knowledge gaps and a lack of data, inter alia, regarding the geochemistry of phosphates and basin-scale correlations. Owing to the unique situation of Moroccan phosphates on the global market, they clearly deserve more thorough studies that may, in turn, help to constrain future resources and/or reserves, and answer outstanding questions on the genesis of phosphates. Full article
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20 pages, 1344 KiB  
Review
Review of the Main Factors Affecting the Flotation of Phosphate Ores
by Manar Derhy, Yassine Taha, Rachid Hakkou and Mostafa Benzaazoua
Minerals 2020, 10(12), 1109; https://doi.org/10.3390/min10121109 - 10 Dec 2020
Cited by 39 | Viewed by 8212
Abstract
The way to successfully upgrade a phosphate ore is based on the full understanding of its mineralogy, minerals surface properties, minerals distribution and liberation. The conception of a treatment process consists of choosing the proper operations with an adequate succession depending on the [...] Read more.
The way to successfully upgrade a phosphate ore is based on the full understanding of its mineralogy, minerals surface properties, minerals distribution and liberation. The conception of a treatment process consists of choosing the proper operations with an adequate succession depending on the ore properties. Usually, froth flotation takes place in phosphate enrichment processes, since it is cheap, convenient, and well developed. Nevertheless, it is a complex technique as it depends on the mineral’s superficial properties in aqueous solutions. Aspects such as wettability, surface charge, zeta potential, and the solubility of minerals play a basic role in defining the flotation conditions. These aspects range from the reagents type and dosage to the pH of the pulp. Other variables namely particles size, froth stability, and bubbles size play critical roles during the treatment, as well. The overall aim is to control the selectivity and recovery of the process. The following review is an attempt to add to previous works gathering phosphate froth flotation data. In that sense, the relevant parameters of phosphate ores flotation are discussed while focusing on apatite, calcite, dolomite, and quartz as main constituent minerals. Full article
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