Valorization of phosphate by-products to produce acidic geopolymers Valorización de subproductos de minas de fosfato para producir geopolímeros ácidos.

The present study evaluates the possibility of using a by-product of phosphate mines, such as red clay, as a precursor for the elaboration of acid geopolymers, using HPO phosphoric acid (5M and 8M) as an activator. Considering the chemical composition of the clay, sodium aluminate (NaAlO) was added...

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Bibliographic Details
Authors: En-Naji, S., Chhaiba, Salma, Mabroum, S., Hakkou, R., García-Lodeiro, Inés
Format: article
Status:Published version
Publication Date:2024
Country:España
Institution:Consejo Superior de Investigaciones Científicas (CSIC)
Repository:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/384590
Online Access:http://hdl.handle.net/10261/384590
Access Level:Open access
Keyword:Geopolymers
Phosphate mining
Phosphoric acid
Red clay
Description
Summary:The present study evaluates the possibility of using a by-product of phosphate mines, such as red clay, as a precursor for the elaboration of acid geopolymers, using HPO phosphoric acid (5M and 8M) as an activator. Considering the chemical composition of the clay, sodium aluminate (NaAlO) was added as an aluminum corrector. To increase the reactivity of the precursor, the clay was thermally treated at 900°C for 2 hours. Pastes were prepared and characterized from the mechanical (compressive strengths), microstructural (BSEM/EDX and MIP), mineralogical (XRD and FTIR), and nanostructural (Al, Si and P MAS NMR) point of view. The results showed that the type of reaction products is highly dependent on the chemical composition of the precursor and the acidic conditions. In addition, the presence of sodium aluminate improves the mechanical strengths in systems activated with 8M HPO