Heated Blends of Phosphate Sludge: Thermal Transformation and Microstructure Characterization

  • Hajer BaccourEmail author
  • Samir Baklouti
Conference paper
Part of the Advances in Science, Technology & Innovation book series (ASTI)


The mining industry faces many environmental challenges resulting from the huge amounts of waste generated by mines such as phosphate sludge. This waste deposited in the mine site is a potential source of pollution. The aim of this study was to valorize Tunisian phosphates sludge in ceramic manufacturing. To this end, the microstructure of heated blends was characterized using X-ray diffraction (XRD), inductively coupled plasma and atomic emission spectrometry (ICP-AES), scanning electron microscope (SEM), thermal analyses (DTA-TG) and dilatometry. Their ceramic properties: shrinkage, water absorption, density and compressive strength were followed as a function of heating temperature and kaolin content. The DTA curve shows an exothermic peak at 900 °C, which corresponds to the neoformation of the gehlenite phase. Moreover, fluor-apatite phase remains stable up to about 1100 °C. Based on their mineralogical and ceramic properties, heated blends of phosphate sludge may be a used in the ceramic industry. The addition of kaolin at different proportions with phosphate sludge improved the performance of samples sintered at 1100 °C and proved that the content of phosphate sludge in the mixture remained limited to 30% wt against 70% wt of kaolin.


Ceramic Phosphate Sludge Dilatometry Pollution Kaolin 


  1. 1.
    Sis, H.: Reagents used in the flotation of phosphate ores: a critical review. Miner. Eng. 16, 577–585 (2003)CrossRefGoogle Scholar
  2. 2.
    González, C.: Microstructure and mineralogy of lightweight aggregates manufactured from mining and industrial wastes. Constr. Build. Mater. 25, 3591–3602 (2011)CrossRefGoogle Scholar
  3. 3.
    Loutou, M.: Heated blends of phosphate waste: microstructure characterization, effects of processing factors and use as a phosphorus source for alfalfa growth. J. Environ. Manag. 177, 169–176 (2016)CrossRefGoogle Scholar
  4. 4.
    Fakhfakh, E.: Effects of sand addition on production of lightweight aggregates from tunisian smectite-rich clayey rocks. Appl. Clay Sci. 35, 228–237 (2007)CrossRefGoogle Scholar
  5. 5.
    Loutou, M.: Phosphate sludge: thermal transformation and use as lightweight aggregate material. J. Environ. Manag. 130, 354–360 (2013)CrossRefGoogle Scholar
  6. 6.
    Rachid, H.: Valorization of phosphate waste rocks and sludge from the Moroccan phosphate mines: challenges and perspectives. Procedia Eng. 138, 110–118 (2016)CrossRefGoogle Scholar
  7. 7.
    Wissem, G.: Beneficiation of phosphate solid coarse waste from Redayef (Gafsa Mining Basin) by grinding and flotation techniques. Procedia Eng. 138, 85–94 (2016)CrossRefGoogle Scholar

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© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Laboratoire de Chimie IndustrielleEcole Nationale D’Ingénieurs de SfaxSfaxTunisia

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