Evaluation of Estonian phosphate rock by flotation

Minerals Engineering, 2014

The amenability of a low-grade Egyptian phosphorite to flotation for separation of both calcareous and siliceous gangue minerals by just pH control was investigated. The ore, assaying 19.39% P 2 O 5 , 16.1% L.O.I. and 12.41% A.I. is mainly composed of francolite and hydroxy apatite minerals consolidated into three different phosphatic varieties according to texture and origin, i.e. coarse phospho-chem, sharpedged phospho-clast and fine cementing phospho-mud. This was endorsed by microscopic investigation of thin sections. X-ray diffraction analysis of the ore sample showed that the main gangue minerals are calcite and quartz with minor dolomite and some gypsum.

Journal of African Earth Sciences, 2019

The chemical and mineralogical compositions of four layers (A 1 , A 2 , B and C) from the Sra Ouertane phosphorite deposit were studied. Chemical characterization of each sample, classified as five size fractions, reveals that the richest samples in P 2 O 5 are the fine fractions 40 µm ˂f SR ˂ 125 µm of the layers A 2 and C with a P 2 O 5 content of 17%. Mineralogical characterizations of the samples were undertaken by X-Ray diffraction revealed that the main minerals are carbonates, carbonate fluorapatite and quartz. The highest REEs+Y+Sc concentration values were recorded for Y in all samples, followed by La and Ce. Higher concentration of REEs was found in layers A 2 and C which are the richest layer in P 2 O 5 indicating that REEs content has a close relationship with the P 2 O 5 concentration. However REEs concentrations are not equally distributed in the different size fractions, the maximum concentrations were found in fraction 40 µm ˂f SR ˂ 125 µm. Moreover, REEs in Sra Ouertane deposit have the highest values of all the Tunisian phosphorites. The present work contributes to a better understanding of the relation between the mineralogical and chemical composition (e.g. REEs, Cd, Th and U) in different layers and different size fractions of Sra Ouertane phosphorite.

2015

The critical role of rare earth elements (REEs), particularly heavy REEs (HREEs), in high-tech industries has created a surge in demand that is quickly outstripping known global supply and has triggered a worldwide scramble to discover new sources. The chemical analysis of 23 sedimentary phosphate deposits (phosphorites) in the United States demonstrates that they are significantly enriched in REEs. Leaching experiments using dilute H2SO4 and HCl, extracted nearly 100% of their total REE content and show that the extraction of REEs from phosphorites is not subject to the many technological and environmental challenges that vex the exploitation of many identified REE deposits. Our data suggest that phosphate rock currently mined in the United States has the potential to produce a significant proportion of the world's REE demand as a byproduct. Importantly, the size and concentration of HREEs in some unmined phosphorites dwarf the world's richest REE deposits. Secular variatio...

Technology audit and production reserves, 2024

Currently, the processing of beige and black phosphates only concerns the main sub-layers, while the other sublayers (lower and upper for beige phosphate and the upper for black phosphate) are considered waste rock and stored near the complex. Therefore, the object of this research is the use of mixtures of three beige phosphate sub-layers and two black phosphate sub-layers as a feed fraction for the calcination and reverses flotation processes. This research work aims to characterise and treat two types of phosphate: one beige with the sub-layers (main, lower and upper) and the other black with the sub-layers (main and upper) in order to have better recovery of P 2 O 5. The working methodology consists of a series of sample preparation operations and characterization of the two types of beige and black phosphate. This characterization includes a petrographic study, a granulochemical analysis, an X-ray diffraction (XRD), a scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), and an atomic adsorption spectrophotometry (SAA), an auto analyzer (AA), a Bernard calcimeter. These analyzes allow on the one hand to identify the mineral phases in quantitative and qualitative manner, and on the other hand to choose the process for treating phosphates from the Kef-Essenoun-Tebessa deposit. The combined method of treatment by calcination followed by reverse flotation gave satisfactory results. The P 2 O 5 content reaches 33.88 % for beige phosphate and 33.13 % for black phosphate. The stored waste rock represents a problem for the company; this waste rock contains fairly high levels of phosphate. The treatment of the mixture of the main sub-layers with these waste rocks makes it possible to obtain a better recovery of P 2 O 5 , a better economic profitability of the Djebel Onk mining complex and an environmental impact in the region.

Mining and Metallurgy Engineering Bor, 2014

This paper presents the importance of phosphate in the world, and the problems that arise in the process of preparing the low-grade phosphate ore for obtaining the phosphate concentrate using the flotation concentration. The apatite concentrates are obtained using the selective flotation from the silicate and oxide minerals while defining the process of selective flotation of apatite from carbonate deposits is the major problem worldwide. The experimental part of this paper presents the results of laboratory flotation tests of phosphate ore from the surface part of the location "Panjevica" of the deposit "Liina". The results have enabled definition of the flotation process in continuous conditions of work.

2019

The article analyzes the present state of the phosphate raw material base to meet Ukrainian chemical enterprises' needs. In Ukraine, a number of complex apatite and phosphorite deposits have been explored. Their exploitation can lead to a complete supply of Ukrainian chemical enterprises with raw materials and can partly reduce the amount of expensive imported phosphate mineral fertilizers. At present, the following deposits, where apatite is connected with other useful components, are prepared for exploitation: Stremyhorod, Fedorivka, Novopoltavka, Kropyvna and others. The advantage of the development of these deposits is the possibility to extract apatite along with the production of rare earth concentrates, ilmenite, titanomagnetite, as well as feldspars, olivine, pyroxenes, mica and others which will significantly increase the profitability of the deposits development. The alternative to apatite-containing deposits in Ukraine can be sedimentary deposits of nodule, granular a...

Procedia Engineering, 2012

Trace elements in particles of the phosphate ore and their behaviour in the various mineralurgic modes of processing were studied to: (i) locate the importance of these contents according to granulometry, their association with the existing mineralogical species, and (ii) check if the enrichment operations applied are compatible with a kind of processing. We used several methods of preconditioned analyses to (i) define the optimal meshes of release of the phosphatic elements and gangue minerals, (ii) identify the raw material mineralogical phases, the major elements chemical composition, their distribution into particle-size classes, and their thermal behaviour. X-ray fluorescence and ICP-MS allowed to identify 30 REE and transition metals. We obtained significant differences in the particle shapes, especially the fine ones and in the mineralurgic modes of treatment used, where the floatation processing is prevailing. A close relation between trace elements and various minerals (apatite, dolomite and silicates), through operations of substitution, is evidenced.

Minerals

Estonian phosphorite ore contains trace amounts of rare earth elements (REEs), many other d-metals, and some radioactive elements. Rare earth elements, Mo, V, etc. might be economically exploitable, while some radioactive and toxic elements should be removed before any other downstream processing for environmental and nutritional safety reasons. All untreated hazardous elements remain in landfilled waste in much higher concentration than they occur naturally. To resolve this problem U, Th, and Tl were removed from phosphorite ore at first using liquid extraction. In the next step, REE were isolated from raffinate. Nitrated Aliquat 336 (A336[NO3]) and Bis(2-ethylhexyl) Phosphate (D2EHPA) were used in liquid extraction for comparison. An improved method for exclusive separation of radioactive elements and REEs from phosphorite ore in 2-steps has been developed, exploiting liquid extraction at different pH values.

2017

Two steps of reverse flotation of silicates with seawater using amidoamine as collector (107mg/L) at natural pH yielded a concentrate from Bayóvar phosphate ore with 30% of P2O5 grade and metallurgical recovery of 90%. Fundamental studies were performed with pure minerals (apatite/feldspar), salty water and flotation reagent system at pH 8. The formation of precipitates composed by amidoamine and anions from salty water explained the good selectivity. Contact angles were measured to calculate surface energy of solids and free energy of adhesion for apatite/amidoamine precipitate (-32.39mJ.m-2) and feldspar/amidoamine precipitate (-38.55mJ.m-2), indicating attraction between particles of apatite/precipitate and feldspar/precipitate, preferably for feldspar. Curves of interaction energy of apatite/ aminoamide precipitate and feldspar/ aminoamide precipitate versus distance between particles (1-20nm) were also built (using DLVO/X-DLVO theories). Hence, the contribution of Lifshitz-van der Waals is the most relevant energy comparing with electrostatic and acid-base. Besides, the interaction energy for feldspar/aminoamide precipitate presented higher magnitude than apatite/precipitate that could explain the selectivity of apatite/feldspar.

Arabian Journal of Geosciences, 2020

Moroccan high-grade phosphate has so far always been upgraded by reverse flotation. Within a major project to go back to the deposits considered as sterile or low grade, this preliminary study was conducted in a micro-flotation cell to find new routes for their beneficiation by direct flotation. Three collectors, alone and combined to modifiers, were evaluated for a potential direct flotation of apatite from calcite and quartz minerals. The obtained results demonstrated that sodium oleate (NaOl) and ATRAC 50S have an affinity toward both apatite and calcite, but not quartz. In the opposite, Phospholan PE 169 has an affinity toward the three minerals even when it is combined with depressants. NaOl and ATRAC 50S flotation selectivity of apatite can be improved by their combination at dosages of 5.56 to 3.7 mg/L sodium alginate or CMC at pH 9.5. Apatite recovery exceeded 95%, and calcite buoyancy decreased from about 50% to only 19.20% and 19.39% using sodium alginate and CMC as prior depressants, respectively. On the other hand, when ethylene glycol was added as a synergist with the collector ATRAC 50S and sodium alginate as a depressant, 78.10% apatite recovery was obtained with 23.78% and 1.47% for calcite and quartz, respectively. These results were correlated to adsorption tests, zeta potential measurements, and FTIR analysis. Keywords Low-grade phosphate ore. Direct flotation. Fluorapatite. Micro-flotation. Flotation kinetics phosphates make up the largest portion of the world phosphate reserves. These sedimentary Moroccan phosphate ores typically contain some form of francolite or collophane as predominant phosphate minerals (Kawatra and Carlson 2013), associated with gangue minerals including clays, silica, calcite, and dolomite. The run-of-mine phosphate ores are mostly of low grade which need processing to match the market requirements: P 2 O 5 content larger than 30%, CaO/P 2 O 5 ratio smaller than 1.6, and MgO content less than 1% (Gharabaghi et al. 2010). Considerable effort has been made during the last decades to develop improved beneficiation strategies to upgrade phosphate ores, particularly with carbonaceous gangues of sedimentary origin (Zidi et al. 2016; Ruan and Ruan 2019). Although flotation has seen the most research interest, a universal flotation process for the separation of carbonates from low-grade sedimentary phosphate ores has not yet been developed. Hence, special concern has been brought to direct flotation of sedimentary phosphate, in which phosphate is floated, whereas carbonate gangue is depressed, in alkaline conditions, involving the use of new selective reagents (collectors and depressants) as well as their synergistic combination.