Structure and Properties of Phosphate-Based Geopolymer Synthesized with the Spent Fluid Catalytic-Cracking (SFCC) Catalyst.

Qian Wan,Yimin Zhang,Ruobing Zhang

doi:10.3390/gels8020130

Qian Wan, Yimin Zhang + Show 1 more

Open Access

https://doi.org/10.3390/gels8020130

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Abstract

As a common industrial by-product, the spend fluid catalytic-cracking (SFCC) catalyst was used to prepare phosphate-based geopolymer for the first time. The structure and property of geopolymer with phosphoric acid concentration ranging from 6 to 14 mol/L was characterized by compressive strength measurements, X-ray powder diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and 27Al and 29Si nuclear magnetic resonance (NMR). A stable binder was formed with the compressive strength in the range of 9.8 to 30.2 MPa when the acid concentration was between 6 and 12 mol/L. The higher concentration of acid can promote the dissolution of raw materials and formation of geopolymer gels. The coordination of silicon and aluminum in geopolymer gel synthesized with the SFCC catalyst and metakaolin is similar. Compared with the geopolymer with metakaolin, which forms more Si-O-Al bonds, in the networks of geopolymer with the SFCC catalyst, more Si(Al)-O-P bonds were formed. These results indicate that the SFCC catalyst can be an excellent raw material for the synthesis of phosphate-based geopolymer.

Highlights

Geopolymer is considered to be a green building material that can replace Portland cement and attract increasing attention [1]
The highest strength was not higher than 4 MPa. These studies have shown that the spend fluid catalytic-cracking (SFCC) catalyst can completely or partially replace raw materials to prepare alkali-activated geopolymers; when it is completely used as a raw material, the compressive strength of the product is low and some highly active raw materials need to be added as additives to prepare geopolymers with satisfactory strength
With the acid concentration decreasing from. This suggests that the SFCC catalyst can be an excellent raw material for the preparation phosphate-based geopolymer

Summary

Introduction

Geopolymer is considered to be a green building material that can replace Portland cement and attract increasing attention [1] It is synthesized through activating the aluminosilicate source such as metakaolin with an activator solution [2]. The highest strength was not higher than 4 MPa. For the final product, the highest strength was not higher than 4 MPa These studies have shown that the SFCC catalyst can completely or partially replace raw materials to prepare alkali-activated geopolymers; when it is completely used as a raw material, the compressive strength of the product is low and some highly active raw materials (metakaolin or rice husk ash) need to be added as additives to prepare geopolymers with satisfactory strength. This study expands the possibilities for raw materials for the synthesis of phosphate-based geopolymer and gives a further understanding about the effect of raw materials on the structure of geopolymer

Materials

Synthesis of Geopolymer

Characterization

Results

Conclusions