Recycling of marls from phosphate by-products to produce alkali-activated geopolymers
2021; Elsevier BV; Volume: 51; Linguagem: Inglês
10.1016/j.matpr.2021.03.206
ISSN2214-7853
AutoresSafaa Mabroum, Yassine Taha, Mostafa Benzaazoua, Rachid Hakkou,
Tópico(s)Recycling and utilization of industrial and municipal waste in materials production
ResumoDuring open-pit mining operations of phosphates, huge volume of rocks by products are accumulated and deposited in the mine site. The aim of this paper is to investigate the use of marls as an only aluminosilicate precursor to produce alkali-activated geopolymers. Marls from Moroccan phosphate basins are composed of carbonates, quartz and clays. Raw marl was dried, grinded and calcined at 750 °C. After the heat treatment, the calcined powder was activated using a strong alkali solution, which is a mixture of sodium hydroxide and sodium silicate with a ratio of 0.5. The physical and chemical properties of raw and calcined marls were analyzed using TGA, BET, Pycnometer, particle size analyzer, XRF, XRD, FTIR and SEM. Furthermore, elaborated geopolymers were characterized after 7 and 120 days of curing at ambient temperature using XRD, XRF, TGA, SEM and the mechanical behavior was tested by measuring the compressive strength. The results showed the formation of both; C-A-S-H (Calcium aluminum silicate hydrate) and N-A-S-H (Calcium aluminum silicate hydrate) gels with a compressive strength of 38 MPa confirming that marls from phosphate extraction by-products could be used as a source for the elaboration of geopolymers.
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