Journal articles: 'Gafsa phosphate'

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Smida, Olfa, Radhia Souissi, Marzougui Salem, and Fouad Souissi. "Geochemical Assessment and Mobility of Undesired Elements in the Sludge of the Phosphate Industry of Gafsa-Metlaoui Basin, (Southern Tunisia)." Applied Sciences 11, no. 3 (January 25, 2021): 1075. http://dx.doi.org/10.3390/app11031075.

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The raw phosphates in the Gafsa-Metlaoui phosphate basin are valorized by wet processes that are performed in the laundries of the Gafsa Phosphates Company (CPG, Gafsa, Tunisia) to reach market grades (>28% P2O5). This enrichment process allows the increase of P2O5 content by the elimination of the coarse (>2 mm) and fine (<71 µm) fractions. Mineralogical analysis has shown that all the investigated materials (raw phosphate, marketable phosphate, coarse waste, and fine waste) from the laundries of M’Dhilla-Zone L and Redeyef are both composed of carbonate fluorapatite, carbonates, quartz, gypsum, clays, and clinoptilolite. Chemical analysis shows that Cr, Cd, Zn, Pb, and U are concentrated in the fine wastes and associated with the clay–phosphate fraction. The rare earth elements are more concentrated in both raw and marketable phosphates. Drilling and sludge-water analysis, along with leaching tests conducted on the fine wastes, showed that, due to phosphate industry, cadmium, fluorine, and sulfate contributing to the pollution of water resources in the region, pollution is more conspicuous at M’Dhilla.

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Rousselin, Mathieu. "A study in dispossession: the political ecology of phosphate in Tunisia." Journal of Political Ecology 25, no. 1 (February 13, 2018): 20. http://dx.doi.org/10.2458/v25i1.22006.

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This article seeks to evidence the social, environmental and political repercussions of phosphate extraction and transformation on two peripheral Tunisian cities (Gabes and Gafsa). After positing the difference between class environmentalism and political ecology, it addresses the harmful effects of phosphate transformation on the world's last coastal oasis and on various cities of the Gulf of Gabes. It then sheds light on the gross social, environmental and health inequalities brought about by phosphate extraction in the mining region of Gafsa. The confiscatory practices of the phosphate industry are subsequently linked with global production and distribution chains at the international level as well as with centralized and authoritarian forms of government at the national and local level. Dispossessed local communities have few alternatives other than violent protest movements and emigration towards urban centers of wealth. Using the recent experience in self-government in the Jemna palm grove, the article ends with a reflection on the possible forms of subaltern resistance to transnational extractivism and highlights the ambiguous role of the new "democratic state" as a power structure reproducing patterns of domination and repression inherited from the colonial period and cemented under the dictatorship of Ben Ali.Keywords: political ecology, transnational extractivism, phosphate, Tunisia.

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Boujlel, Haïfa, Ghassen Daldoul, Haïfa Tlil, Radhia Souissi, Noureddine Chebbi, Nabil Fattah, and Fouad Souissi. "The Beneficiation Processes of Low-Grade Sedimentary Phosphates of Tozeur-Nefta Deposit (Gafsa-Metlaoui Basin: South of Tunisia)." Minerals 9, no. 1 (December 20, 2018): 2. http://dx.doi.org/10.3390/min9010002.

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The enrichment of the low-grade-phosphate ore of the Tozeur-Nefta deposit was investigated using scrubbing-attrition, ball grinding and anionic/cationic reverse flotation in order to separate phosphate-rich particles from their gangue. The choice of the beneficiation process was based on the petrographic, mineralogical and chemical analyses. The petrographic and mineralogical studies have revealed the abundance of phosphatic (carbonate-fluorapatite-CFA) particles) coupled with carbonates (calcite, dolomite,) and silicates (quartz, illite, kaolonite) that constitute the (endo/exo) gangue of these ores. Chemical analysis has demonstrated that the raw phosphate sample contains low amounts of P2O5 (12.0%) and MgO (4.9%) and high amounts of CaO (40.7%) and SiO2 (20.5%). Microscopic observation/counting has shown that the release mesh occurs in the 71–315 μm size. Scrubbing-attrition, grinding and reverse flotation methods were applied to the +71μm fraction. Scrubbing-attrition tests of the 71–315 μm fraction have helped to improve the P2O5 grade to 15.5%. Ball-grinding tests were used to reduce the coarse fraction +315 μm. Grounded materials were sieved to 71–315 μm and combined with the scrubbed fraction in the flotation feed. Reverse-flotation tests of the phosphate-rich fraction (71–315 μm) have helped to improve the P2O5 grade to 27.1%, with a recovery rate of 92.4%.

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Corrêa, Rossini Mattos, Clístenes Williams Araújo do Nascimento, Silvana Keely de Sá Souza, Fernando José Freire, and Gleibson Barbosa da Silva. "Gafsa rock phosphate and triple superphosphate for dry matter production and P uptake by corn." Scientia Agricola 62, no. 2 (April 2005): 159–64. http://dx.doi.org/10.1590/s0103-90162005000200011.

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Crops in general make poor use of phosphorous fertilizer and, as a result, recommended rates and production costs are very high. Phosphorus can be made more readily available to plants by proper management of phosphate fertilization, selecting both, type of fertilizer and application method. This study was carried out to evaluate the efficiency of the natural Gafsa rock phosphate and the triple superphosphate on dry matter production and P uptake by corn plants cultivated in a greenhouse. Fertilizers were applied localized and broadcast/incorporated on to two soils with contrasting phosphorus capacity factors (PCF). Rock phosphate broadcast application was as efficient as triple superphosphate in increasing corn plant dry matter in the Tropudult, with lower PCF. This effect was not observed on the Haplustox, owing to the lower P solubility due to the higher Ca concentration in this soil. Triple superphosphate rates increased plant P uptake in both soils and for both application forms. Rock phosphate resulted in higher P-content in plants, but only for broadcast application on the Ultisol.

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Lefires, Houda, Hayet Medini, Adel Megriche, and Arbi Mgaidi. "Dissolution of Calcareous Phosphate Rock from Gafsa (Tunisia) Using Dilute Phosphoric Acid Solution." International Journal of Nonferrous Metallurgy 03, no. 01 (2014): 1–7. http://dx.doi.org/10.4236/ijnm.2014.31001.

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ROBINSON, J. S., and J. K. SYERS. "A critical evaluation of the factors influencing the dissolution of Gafsa phosphate rock." Journal of Soil Science 41, no. 4 (December 1990): 597–605. http://dx.doi.org/10.1111/j.1365-2389.1990.tb00229.x.

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Ettoumi, M., M. Jouini, C. M. Neculita, S. Bouhlel, L. Coudert, I. Haouech, and M. Benzaazoua. "Characterization of Kef Shfeir phosphate sludge (Gafsa, Tunisia) and optimization of its dewatering." Journal of Environmental Management 254 (January 2020): 109801. http://dx.doi.org/10.1016/j.jenvman.2019.109801.

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Knox, O. G. G., O. N. Achara, J. Parker, R. Alegria, R. L. Walker, A. C. Edwards, and C. A. Watson. "Investigating the Use of Silage Effluent to Improve Available Phosphorus from Gafsa Phosphate Rock." Communications in Soil Science and Plant Analysis 45, no. 3 (January 30, 2014): 332–46. http://dx.doi.org/10.1080/00103624.2013.857412.

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9

Di, HJ, LM Condron, AS Campbell, KM Goh, and IS Cornforth. "Causes for the reduced reactivity of phosphate rock residues in partially acidulated phosphate rocks." Soil Research 32, no. 1 (1994): 95. http://dx.doi.org/10.1071/sr9940095.

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The agronomic effectiveness of partially acidulated phosphate rock (PAPR) fertilizers depends on the proportion of water soluble P present and the long-term release of P from the unacidulated residual phosphate rock (water-insoluble residue) in the soil environment. The relative reactivity of water-insoluble residues in a range of partially acidulated phosphate rock (PAPR) fertilizers was assessed according to chemical solubility, and was found to be lower than the corresponding original PRs. Two causes were identified for the reduced formic acid solubility of water-insoluble residues: (i) some preferential dissolution of more reactive apatite components (i.e. higher carbonate substituted apatite) during partial acidulation as indicated by reductions in the molar apatite C:P ratio of the residual PRs compared with the corresponding original PRs, and (ii) acid-insoluble metal (Fe-Al-Mg)phosphate and/or fluoride complexes formed on the surface of residual PRs during partial acidulation with commercial-grade phosphoric acid, which were partially soluble in alkaline ammonium citrate. These two mechanisms accounted for most of the solubility differences observed for 'medium' reactive PRs (Khouribga, Arad), compared with only half for more reactive PRs (North Carolina, Gafsa). The conclusion from this study is that partial acidulation may not be an ideal method for the manufacture of fertilizers containing fast and slow release (i.e. PR) components, particularly when highly reactive PRs such as North Carolina are used.

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Ben Farhat, Mounira, Ameny Farhat, Wacim Bejar, Radhouan Kammoun, Kameleddine Bouchaala, Amin Fourati, Hani Antoun, Samir Bejar, and Hichem Chouayekh. "Characterization of the mineral phosphate solubilizing activity of Serratia marcescens CTM 50650 isolated from the phosphate mine of Gafsa." Archives of Microbiology 191, no. 11 (September 22, 2009): 815–24. http://dx.doi.org/10.1007/s00203-009-0513-8.

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11

Srarfi, Feyda, Raouen Rachdi, Karim Khela, and Najet Slim Shimi. "Emerging plant-based flocculation treatment of phosphate clay: case study from Metlaoui-Gafsa (southwest Tunisia)." Water Science and Technology 2017, no. 3 (May 31, 2018): 743–51. http://dx.doi.org/10.2166/wst.2018.241.

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Abstract The objective of this study was to investigate the ability of cactus Opuntia ficus-indica, used as a natural flocculant in the treatment of phosphate clay as an industrial wastewater. It is a new process that has proven very promising in the removal of high turbidity from industrial effluents. The volume of clear water recovered (supernatant) is one of the characteristic features which allow us to judge the effectiveness of this bioflocculant. The following of the settling velocity on the one hand and the analysis of supernatant and sludge on the other hand allow us to compare the cactus-based flocculant effectiveness with that of a chemical flocculant (CF) of anionic polyacrylamide nature. The optimum pH required for maximum settling velocity was found to be 12. Obtained results indicated that after 900 seconds of settling, the highest volume of clear supernatant was obtained with the natural flocculant (740 mL/L), against 666 mL/L obtained with CF. Several analyses on recovered clear water (pH, turbidity, Cu, Zn, Fe, Cd and Cr) and on dry sludge (P2O5, CaO, MgO, organic C, SiO2 and Cd) are highlighted.

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Gallala, Wissem, Fatma Herchi, Ilhem Ben Ali, Leila Abbassi, Mohamed Essghaier Gaied, and Mabrouk Montacer. "Beneficiation of Phosphate Solid Coarse Waste from Redayef (Gafsa Mining Basin) by Grinding and Flotation Techniques." Procedia Engineering 138 (2016): 85–94. http://dx.doi.org/10.1016/j.proeng.2016.02.065.

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13

Ankomah, A. B., F. Zapata, S. K. A. Danso, and H. Axmann. "Cowpea varietal differences in uptake of phosphorus from Gafsa phosphate rock in a low-P Ultisol." Fertilizer Research 41, no. 3 (1995): 219–25. http://dx.doi.org/10.1007/bf00748311.

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14

Pereira da Rosa, Diego, Marcio Carlos Navroski, Mariane De Oliveira Pereira, Geedre Adriano Borsoi, Bruno Nascimento, Ramon Silveira De Andrade, and Carolina Moraes. "Liming and Fertilization on the Growth of Eucalyptus benthamii and Eucalyptus dunnii in Brazil." International Journal of Forestry Research 2020 (October 30, 2020): 1–8. http://dx.doi.org/10.1155/2020/8850641.

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The use of mineral fertilizers has shown substantial productivity gains for the vast majority of Eucalyptus forests. The objective of the present work is to evaluate the response of Eucalyptus benthamii and Eucalyptus dunnii at 48 months of age, to different doses of limestone, soluble NPK, and natural phosphates. The experiment was conducted in a plantation located in South Brazil. The experimental design was a randomized block with three replications, and the treatments consisted of combinations of doses of natural phosphate (NP) (0, 400, 600, and 800 kg ha−1 of Gafsa reactive NP P2O5), limestone (0, 3, 5, 6, and 10 Mg ha−1 of dolomitic limestone), and mineral fertilizer–NPK (0, 100, 133, and 167 kg ha−1 of mixed mineral fertilizer 6-30-6). Height and diameter measurements were taken after 48 months. There was a positive response with the increase of NPK fertilizer dose, and the dose where the highest averages were obtained was 167 kg ha−1. The doses of NP had significant effects on the increase of the variables up to 600 kg ha−1, also the averages decreased with the increase of the dosage. For liming, positive results were observed from its absence to the maximum dose, justifying its use in minimum dose in order to supply the necessary amounts of Ca and Mg in the soil. The use of NPK, natural phosphate, and limestone is recommended, causing an increase in the growth of both species of Eucalyptus studied.

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Mendes, Alessandra Monteiro Salviano, Gustavo Pereira Duda, Clístenes Williams Araújo do Nascimento, and Michelangelo Oliveira Silva. "Bioavailability of cadmium and lead in a soil amended with phosphorus fertilizers." Scientia Agricola 63, no. 4 (August 2006): 328–32. http://dx.doi.org/10.1590/s0103-90162006000400003.

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Phosphorus fertilizers are essential to obtain high productivity, however, they contain heavy metals that can contaminate the soil and threat the health of animals and humans. The present study focused the determination of Cd and Pb concentrations in different phosphorus fertilizers as well as the absorption of these heavy metals by velvet green bean grown on soil amended with such fertilizers. The experiment was set up as a completely randomized design in a factorial scheme. The factors were four phosphorus sources (triple superphosphate-TS, Yorin thermophosphate-YT, Araxa rock phosphate-AP, and Gafsa rock phosphate-GP) applied at five rates (0, 92, 183, 275, and 366 kg ha-1 of P2O5). The data obtained were submitted to variance and regression analysis. Lead availability to velvet bean was not altered as a result of fertilizer application. On the other hand, Cd uptake was significantly increased with addition of the tested fertilizers. Such an increase was a function of the rate. The highest Cd contents in shoots was reached by YT and TS applications, whereas the lowest one resulted from rock phosphate treatments. All the phosphorus sources tested increased Cd uptake in the first harvest. For the second harvest, Cd content in the shoot was detected only in plants grown on TS and GP amended soils.

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Rodrigues, Marcio Neves, Regynaldo Arruda Sampaio, Geraldo Ribeiro Zuba Junio, and Agda Loureiro Gonçalves Oliveira. "NUTRIENTS AND HEAVY METALS IN MAIZE CROP FERTILIZED WITH ROCK PHOSPHATE AND BIOSOLID." REVISTA ENGENHARIA NA AGRICULTURA - REVENG 25, no. 1 (March 31, 2017): 50–62. http://dx.doi.org/10.13083/reveng.v25i1.685.

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This study aimed to evaluate effects of natural phosphate and sewage sludge compound fertilization in level of contents of heavy metals and nutrients in two consecutive cultivation of corn grain. The project was conducted in a Haplic Cambisol between April 10, 2009 and September 15, 2010. The treatments in factorial scale 2 x 4 meters corresponds to application on the first corn cultivation of 2 doses of rock Gafsa phosphate (0 and 90 kg ha-1 of P2O5) and 4 compound doses of sewage sludge (0, 25, 50 and 75 t ha-1, in dry specimen). The experiment followed random blocks design with three treatment repetitions. The fertilization with rock phosphate increased the levels of N, P, K and Mg only in the first corn grain cultivation and did not had influence on the levels of Zn, Cu, Ni, Pb, Cr and Cd in the two successive cultivations. The fertilization with sewage sludge compound increased the levels of N, P, K, Mg and Zn in the first corn grain cultivation and P and Zn for the second. In addition, the fertilization with sewage sludge did not had influence on levels of Ca, S, Cu, Ni and Pb in any corn cultivation. Independent of the effect of the treatments, only Pb showed concentration above of acceptable limits for nourishment.

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ROBINSON, J. S., and J. K. SYERS. "Effects of solution calcium concentration and calcium sink size on the dissolution of Gafsa phosphate rock in soils." Journal of Soil Science 42, no. 3 (September 1991): 389–97. http://dx.doi.org/10.1111/j.1365-2389.1991.tb00417.x.

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Slimene, Wejdene, Jamel Touir, Nabil Fatteh, Lotfi Khélil, Zied Saiid, and Miled Bouzid. "Study of the Upper Paleocene-Lower Ypresian phosphate succession in El Guettar out crop (Gafsa area, central Tunisia)." Journal of African Earth Sciences 177 (May 2021): 104125. http://dx.doi.org/10.1016/j.jafrearsci.2021.104125.

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Gikonyo, E., A. R. Zaharah, M. M. Hanafi, and R. Anuar. "Phosphorus Leaching in an Acid Tropical Soil “Recapitalized” with Phosphate Rock and Triple Superphosphate." Scientific World JOURNAL 10 (2010): 1498–508. http://dx.doi.org/10.1100/tsw.2010.156.

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With high rates of phosphorus applied to increase “capital P” as a stock for plant uptake over several years, the question of P leaching is inevitable. We conducted an intact soil column experiment in the field to evaluate P leached from soils treated with triple superphosphate (TSP) and Gafsa phosphate rock (GPR) at 300, 600, and 900 kg P ha-1with and without integration of cattle manure. The lysimeters, made from PVC tubes of 30-cm length, were inserted into the soil up to the 25-cm depth. The tubes were fitted with a resin bag containing a mixture of cation and anion exchange resin (50:50) at the lower end of the tube inserted into the soil. The tubes, arranged in a completely randomized design, were sampled randomly at 10-week intervals for 12 months. Phosphorus extractable from the top- and subsoil at the end of experiment and leached P were determined. More P was leached out from TSP (threefold) compared to GPR, and the amount of P leached increased with increasing rates of P fertilizer applied. Application of manure intensified the amounts of P leached from TSP, particularly at the 6-month sampling time. There was hardly any substantial P leached from the soil treated with GPR. Thus, for effective and efficient long-term P fertilizer management strategies, choosing the right P fertilizer source and monitoring P losses through leaching has to be done for enhanced fertilizer use efficiency and thus reducing P pollution of ground waters.

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Freitas, Irio Fernando de, Roberto Ferreira Novais, Ecila Mercês de Albuquerque Villani, and Sarah Vieira Novais. "Phosphorus extracted by ion exchange resins and mehlich-1 from oxisols (latosols) treated with different phosphorus rates and sources for varied soil-source contact periods." Revista Brasileira de Ciência do Solo 37, no. 3 (June 2013): 667–77. http://dx.doi.org/10.1590/s0100-06832013000300013.

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Despite the large number of studies addressing the quantification of phosphorus (P) availability by different extraction methods, many questions remain unanswered. The aim of this paper was to compare the effectiveness of the extractors Mehlich-1, Anionic Resin (AR) and Mixed Resin (MR), to determine the availability of P under different experimental conditions. The laboratory study was arranged in randomized blocks in a [(3 x 3 x 2) + 3] x 4 factorial design, with four replications, testing the response of three soils with different texture: a very clayey Red Latosol (LV), a sandy clay loam Red Yellow Latosol (LVA), and a sandy loam Yellow Latosol (LA), to three sources (triple superphosphate, reactive phosphate rock from Gafsa-Tunisia; and natural phosphate from Araxá-Minas Gerais) at two P rates (75 and 150 mg dm-3), plus three control treatments (each soil without P application) after four contact periods (15, 30, 60, and 120 days) of the P sources with soil. The soil acidity of LV and LVA was adjusted by raising base saturation to 60 % with the application of CaCO3 and MgCO3 at a 4:1 molar ratio (LA required no correction). These samples were maintained at field moisture capacity for 30 days. After the contact periods, the samples were collected to quantify the available P concentrations by the three extractants. In general, all three indicated that the available P-content in soils was reduced after longer contact periods with the P sources. Of the three sources, this reduction was most pronounced for triple superphosphate, intermediate for reactive phosphate, while Araxá phosphate was least sensitive to the effect of time. It was observed that AR extracted lower P levels from all three soils when the sources were phosphate rocks, while MR extracted values close to Mehlich-1 in LV (clay) and LVA (medium texture) for reactive phosphate. For Araxá phosphate, much higher P values were determined by Mehlich-1 than by the resins, because of the acidity of the extractor. For triple superphosphate, both resins extracted higher P levels than Mehlich-1, due to the consumption of this extractor, particularly when used for LV and LVA.

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Hilman, Yusdar, Mohamed Hanafi Musa, Anuar Abdul Rahim, Azizah Hashim, and Justina Sri Adiningsih. "CHARACTERISTICS OF PHOSPHATE ROCK MATERIALS FROM CHINA, INDONESIA AND TUNISIA AND THEIR DISSOLUTION IN INDONESIAN ACID SOILS." Indonesian Journal of Agricultural Science 7, no. 2 (October 25, 2016): 43. http://dx.doi.org/10.21082/ijas.v7n2.2006.43-50.

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Dissolution of phosphate rock (PR) in soils is a primary concern for P in the PR to be available for plant. The dissolution of three PR materials, China (CPR), Ciamis (IPR) and Gafsa (GPR), in eight acid Indonesian soils (pH in water 4.1-5.7) was tested in a closed incubation system. Experiment was conducted in Soil Chemical Laboratory, Universiti Putra Malaysia and Indonesian Center for Agricultural Land Resources Research and Development from January to April 2002. The dissolution was determined from the increase in either 0.5 M NaOH extractable P (∆P) or 1 M BaCl2-triethanolamine (TEA)-extractable Ca (∆Ca) in soils amended with PR compared with control soil. Dissolution of the IPR was the highest (30-100%) followed by GPR (17-69%) and then by CPR (20-54%). The maximum dissolution followed the order: Bogor Ultisols > Bogor Oxisols > Subang Inceptisols > Bogor Inceptisols > Sukabumi Oxisols > Lebak Ultisols > Sukabumi Inceptisols > Lampung Ultisols. PR dissolution indicated a positive correlation with P retention capacity. The results implied that the extent of PR dissolution for the three PR sources (China, Indonesia and Tunisia) increased with increasing P retention capacity of the soils. PR dissolution can be based on a calibration curve of ∆Ca meaning that if ∆P is high then the amount of PR dissolution measured by ∆Ca in PR materials is also high.

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Hilman, Yusdar, Mohamed Hanafi Musa, Anuar Abdul Rahim, Azizah Hashim, and Justina Sri Adiningsih. "CHARACTERISTICS OF PHOSPHATE ROCK MATERIALS FROM CHINA, INDONESIA AND TUNISIA AND THEIR DISSOLUTION IN INDONESIAN ACID SOILS." Indonesian Journal of Agricultural Science 7, no. 2 (October 25, 2016): 43. http://dx.doi.org/10.21082/ijas.v7n2.2006.p43-50.

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Dissolution of phosphate rock (PR) in soils is a primary concern for P in the PR to be available for plant. The dissolution of three PR materials, China (CPR), Ciamis (IPR) and Gafsa (GPR), in eight acid Indonesian soils (pH in water 4.1-5.7) was tested in a closed incubation system. Experiment was conducted in Soil Chemical Laboratory, Universiti Putra Malaysia and Indonesian Center for Agricultural Land Resources Research and Development from January to April 2002. The dissolution was determined from the increase in either 0.5 M NaOH extractable P (∆P) or 1 M BaCl2-triethanolamine (TEA)-extractable Ca (∆Ca) in soils amended with PR compared with control soil. Dissolution of the IPR was the highest (30-100%) followed by GPR (17-69%) and then by CPR (20-54%). The maximum dissolution followed the order: Bogor Ultisols > Bogor Oxisols > Subang Inceptisols > Bogor Inceptisols > Sukabumi Oxisols > Lebak Ultisols > Sukabumi Inceptisols > Lampung Ultisols. PR dissolution indicated a positive correlation with P retention capacity. The results implied that the extent of PR dissolution for the three PR sources (China, Indonesia and Tunisia) increased with increasing P retention capacity of the soils. PR dissolution can be based on a calibration curve of ∆Ca meaning that if ∆P is high then the amount of PR dissolution measured by ∆Ca in PR materials is also high.

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Sabbagh, Foued. "The Tunisian Economics’ Situations After the Revolution of Arab Spring 2011." Indian Journal of Economics and Finance 1, no. 2 (November 10, 2021): 1–6. http://dx.doi.org/10.35940/ijef.a2902.111221.

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The Tunisian economic facts after the so-called the Arab spring or social revolution have been marketed by numerous fluctuations and radical changes in the general situation of the management of the administrative affairs of the country. The most prominent of these facts, including the series of chaotic sit-ins and the political and security instability that has increased from 2011 to 2018, note in particular the emergence of the phenomenon of terrorism and assassinations. These negative results are too the expensive cost of the Tunisian national economy, which has been directed, affected by all vital sectors of the country’s economy, especially the tourism, trade and investment sectors. In addition, the increase in excessive wages during the first three years following the revolution and the increasing number of random sit-ins that led to the cessation of the production in the Gafsa phosphate mine and the failure to work for most of the public servants represented negative factors that led to a decline in productivity and an increase in the financial and trade deficit. Thus, the budget deficit and the accumulation of indebtedness represent the main obstacle to achieving social and economic stability.

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Bouchmila, Imen, Bochra Bejaoui Kefi, Radhia Souissi, and Mohieddine Abdellaoui. "Desorption of La3+ and Ce3+ from Treated ‘Chert’ a Siliceous Byproduct of the Phosphate Mining Industry of Gafsa-Metlaoui Basin (Southwestern Tunisia)." Chemistry Africa 2, no. 1 (October 4, 2018): 89–101. http://dx.doi.org/10.1007/s42250-018-0022-8.

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Gikonyo, E. W., A. R. Zaharah, M. M. Hanafi, and A. R. Anuar. "Degree of Phosphorus Saturation and Soil Phosphorus Thresholds in an Ultisol Amended with Triple Superphosphate and Phosphate Rocks." Scientific World JOURNAL 11 (2011): 1421–41. http://dx.doi.org/10.1100/tsw.2011.131.

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Soil phosphorus (P) release capability could be assessed through the degree of P saturation (DPS). Our main objective was to determine DPS and, hence, P threshold DPS values of an Ultisol treated with triple superphosphate (TSP), Gafsa phosphate rocks (GPR), or Christmas Island phosphate rocks (CIPR), plus or minus manure. P release was determined by the iron oxide—impregnated paper strip (strip P), while DPS was determined from ammonium oxalate—extractable aluminum (Al), iron (Fe), and P. Soils were sampled from a closed incubation study involving soils treated with TSP, GPR, and CIPR at 0–400 mg P kg-1, and a field study where soils were fertilized with the same P sources at 100–300 kg P ha-1plus or minus manure. The DPS was significantly influenced by P source x P rate, P source x manure (incubated soils), and by P source x P rate x time (field-sampled soils). Incubated soil results indicated that both initial P and total strip P were related to DPS by exponential functions: initial strip P = 1.38exp0.18DPS, R2= 0.82** and total strip P = 8.01exp0.13DPS, R2 = 0.65**. Initial strip P was linearly related to total P; total P = 2.45, initial P + 8.41, R2= 0.85**. The threshold DPS value established was about 22% (incubated soil). Field soils had lower DPS values <12% and strip P was related to initial DPS and average DPS in exponential functions: strip P = 2.6exp0.44DPS, R2= 0.77** and strip P = 1.1DPS2— 2.4DPS + 6.2, R2= 0.58**, respectively. The threshold values were both at ≈8% and P release was 11–14 mg P kg-1. Results are evident that DPS can be used to predict P release, but the threshold values are environmentally sensitive; hence, recommendations should be based on field trials.

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Bolan, NS, RE White, and MJ Hedley. "A review of the use of phosphate rocks as fertilizers for direct application in Australia and New Zealand." Australian Journal of Experimental Agriculture 30, no. 2 (1990): 297. http://dx.doi.org/10.1071/ea9900297.

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Field trials in New Zealand have shown that reactive phosphate rocks (RPRs) can be as effective as soluble P fertilisers, per kg of P applied, on permanent pastures that have a soil pH<6.0 (in water) and a mean annual rainfall >800 mm. Whereas RPRs such as North Carolina, Sechura, Gafsa and Chatham Rise have been evaluated on permanent pastures in New Zealand, most Australian field trials have examined unreactive PRs such as Christmas Island A and C grade, Nauru and Duchess, using annual plant species. Only in recent experiments has an RPR, North Carolina, been examined. Except on the highly leached sands in southern and south-western Australia, both reactive and unreactive PRs have shown a low effectiveness relative to superphosphate. In addition to chemical reactivity, other factors may contribute to the difference in the observed agronomic effectiveness of PRs in Australia and New Zealand. Generally, PRs have been evaluated on soils of lower pH, higher pH buffering capacity (as measured by titratable acidity) and higher P status in New Zealand than in Australia. Rainfall is more evenly distributed throughout the year on New Zealand pastures than in Australia where the soil surface dries out between rainfall events. Dry conditions reduce the rate at which soil acid diffuses to a PR granule and dissolution products diffuse away. Even when pH and soil moisture are favourable, the release of P from PR is slow and more suited to permanent pasture (i.e. the conditions usually used to evaluate PRs in New Zealand) than to the annual pastures or crops used in most Australian trials. Based on the criteria of soil pH<6.0 and mean annual rainfall >800 mm, it is estimated that the potentially suitable area for RPRs on pasture in New Zealand is about 8 million ha. Extending this analysis to Australia, but excluding the seasonal rainfall areas of northern and south-western Australia, the potentially suitable area is about 13 million ha. In New Zealand, many of the soils in the North and South Islands satisfy both the pH and rainfall criteria. However, suitable areas in Australia are confined mainly to the coastal and tableland areas of New South Wales and eastern Victoria, and within these areas the actual effectiveness of RPR will depend markedly on soil management and the distribution of annual rainfall. Further research on RPR use should be focused on these areas.

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Messadi, Abdel Majid, Besma Mardassi, Jamel Abdennaceur Ouali, and Jamel Touir. "Phosphate genesis and concentration a response to sea level fluctuation in shallow marine environments of the lower Eocene deposits in the southern Tethyan margin: case study of the Gafsa Basin, southern Tunisia." Carbonates and Evaporites 34, no. 4 (April 8, 2019): 1489–509. http://dx.doi.org/10.1007/s13146-019-00498-z.

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Salhi, Bilel, Mohsen Dhieb, and Yamna Djellouli. "L’évolution de l’occupation du sol et des inégalités environnementales dans la ville minière de Métlaoui par le biais d’un SIG-AMC." Revue Internationale de Géomatique 29, no. 3-4 (July 2019): 381–99. http://dx.doi.org/10.3166/rig.2020.00094.

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La ville de Métlaoui constitue le noyau urbain central du bassin minier de Gafsa (BMG) au sud-ouest de la Tunisie. À l’instar des autres villes du bassin, Métlaoui est traditionnellement caractérisée par la mono-activité industrielle d’enrichissement de phosphate ; elle observe par ailleurs une dichotomie spatiale entre « le village européen » relativement favorisé qui constitue le cœur de la ville et les cités périphériques ouvrières très déshéritées. Cette dichotomie ne semble pas faiblir aujourd’hui ; bien au contraire, la recherche montre aujourd’hui les prémices d’une accentuation des ségrégations socio-spatiales héritées de la période coloniale et postcoloniale, les vicissitudes environnementales accumulées confirmant ces prédispositions d’iniquité territoriale. La méthodologie de travail a utilisé, côté socio-spatial une documentation hétérogène et open source : photos aériennes et images Landsat multidates (1952, 1976, 1991 et 2019) et du PAU (1978, 1992 et 2008) et recensements, analyses diachroniques de l’occupation du sol, durant les dernières décades. Côté environnemental, nous avons procédé à des analyses chimiques effectuées sur la composition du sol urbain des différentes entités spatiales de Métlaoui choisies judicieusement, notamment en termes de contenance de métaux lourds et évaluation des risques encourus par ces entités en termes de distances aux principales sources de pollution et de gravité réelle selon les standards internationaux et leur distance par rapport aux différentes unités urbaines. Les objectifs de la recherche sont donc d’examiner l’occupation du sol urbain et son évolution récente par le biais d’un SIG-minier, d’une part ; d’étudier ensuite par le biais d’une analyse multicritères (AMC) utilisant la méthode « ordered weighted average » (OWA) certains aspects de la question environnementale, d’autre part. Le tout est intégré dans un SIG-AMC. Les résultats cartographiés à partir du SIG et de l’AMC fournissent un diagnostic territorialisé sur les inégalités territoriales et sur les risques sévères encourus par la ville. Les produits cartographiques peuvent aider les décideurs à prendre des solutions viables en termes de protection et remédier aux dangers encourus.

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Belayouni, Habib, Maurice Slansky, and Jean Trichet. "A study of the organic matter in Tunisian phosphates series: Relevance to phosphorite genesis in the Gafsa Basin (Tunisia)." Organic Geochemistry 15, no. 1 (January 1990): 47–72. http://dx.doi.org/10.1016/0146-6380(90)90184-2.

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"Application of phosphate water and slime in agriculture: investigation of the mobility of the pollutants using hydrologic modeling." Issue 2 13, no. 2 (April 30, 2013): 130–40. http://dx.doi.org/10.30955/gnj.000636.

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The use of phosphate slime or phosphate water in a Mediterranean region (Gafsa, Tunisia) was investigated through hydrologic modeling. The simulations were made using the Hydrus 1D software package for a typical soil in the area of Gafsa (Tunisia). Two main applications were examined: mixing the surface soil with the phosphate slime and irrigating with polluted (phosphate) water or irrigating only with phosphate water. The elements under study were Cd, Cr, Ni, and Sr. The results show that there is no significant risk of groundwater pollution with these elements if the phosphate slime or the phosphate water is used for agricultural purposes. The addition of slime in the upper soil layer retards the mobility of the pollutants. The results also show that the mobility of these elements is highly dependent on the applied irrigation dose. These pollutants need high amounts of water in order to reach great depths. This research was carried out in the framework of the EU project “Integrated water management of Mediterranean phosphate mining and local agricultural systems” (ELMAA).

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Coutinho Junqueira Franco, Henrique, Bernardo Melo Montes Nogueira Borges, Sergio Gustavo Quassi de Castro, Michele Xavier Vieira Megda, Marcio Mahmoud Megda, Alan L. Garside, and Edson Luiz Mendes Coutinho. "Phosphorus sources residual effects on Tifton 85 production and nutritive value cultivated in a tropical weathered soil1." Bioscience Journal 36, no. 3 (February 6, 2020). http://dx.doi.org/10.14393/bj-v36n3a2020-42626.

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Acid reactions and low available phosphorus in tropical soils limit forage yield. The aim was to evaluate soil chemical characteristics pH, P and Mg, forage nutritive values, critical soil and plant P levels and the residual effect of each source. The experiment was in a greenhouse with a Rhodic Haplustox, loam texture. Experimental design was a 5 x 4 factorial with five replicates which phosphate fertilizers were triple superphosphate, reactive rock phosphates Gafsa and Arad, and fused magnesium phosphate powder and coarse, applied at rates of 30, 60, 90 and 120 mg kg-1 P and a control treatment without P. The effectiveness of rock phosphates increased due to their residual effect. The coarse fused magnesium phosphate resulted in the lowest efficiency. The P critical level in soil and plant were 18 mg kg-1 and 2.4 g kg-1, respectively. The increase of phosphorus rates provided an increase in crude protein content.

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Marzougui, Sondes, Ali Sdiri, and Farhat Rekhiss. "Heavy metals’ mobility from phosphate washing effluents discharged in the Gafsa area (southwestern Tunisia)." Arabian Journal of Geosciences 9, no. 12 (August 2016). http://dx.doi.org/10.1007/s12517-016-2613-5.

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Mokni, Ines, Hatem Dhaouadi, Hatem Mhiri, and Philippe Bournot. "CFD Comparative Investigation of the Performances of Reverse Flow and Uni-Flow Hydrocyclones in the Enrichment of the Phosphate Pulp." International Journal of Chemical Reactor Engineering 7, no. 1 (November 28, 2009). http://dx.doi.org/10.2202/1542-6580.2142.

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This paper presents a CFD comparative investigation of two types of hydrocyclone: uni-flow and reverse flow hydrocyclones. The study is conducted by means of a Reynolds Averaged Navier-Stockes (RANS) simulation using the finite volume code Fluent. The fluid flow is described by the use of the Reynolds Stress Model, while the determination of particles flow and the air core formation are modeled by the mean of two multiphase models which are respectively the Stochastic Lagrangian model (DPM) and the Volume of Fluid Model (VOF). The flow features are examined in terms of pressure drop and separation efficiency in order to contribute to better performance. The validity of the proposed approach is verified by the good agreement between the predicted and the measured results which are given by the Company of Phosphate of Gafsa (CPG-Tunisia). This study proves that uniflow hydrocyclone is more energy efficient because of its lower pressure drop and its higher removal efficiency for small particles from their carrying fluid.

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Raja, Mohamed. "Chemical and Mineralogy Characteristics of Dust Collected Near the Phosphate Mining Basin of Gafsa (South-Western of Tunisia)." Journal of Environmental & Analytical Toxicology 04, no. 06 (2014). http://dx.doi.org/10.4172/2161-0525.1000234.

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Tijani, Amara, and Fakhfakh Hamadi. "Did Socially Responsible Investment Create the Added Value for the Company? A study Case in the Company of Phosphate of Gafsa." Journal of Organizational Management Studies, October 29, 2012, 1–13. http://dx.doi.org/10.5171/2012.362444.

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Mabrouk, Lotfi, Wafa Mabrouk, and Hedi Ben Mansour. "High leaf fluctuating asymmetry in two native plants growing in heavy metal-contaminated soil: the case of Metlaoui phosphate mining basin (Gafsa, Tunisia)." Environmental Monitoring and Assessment 192, no. 6 (June 2020). http://dx.doi.org/10.1007/s10661-020-08385-0.

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Journal articles on the topic 'Gafsa phosphate'

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