Effects of Pr(6)O(11) Addition on the Acid Resistance of Ceramic Proppant

This paper investigated the effect of Pr(6)O(11) addition on the acid resistance of ceramic proppant. Acid resistance of proppants can be improved by introducing Pr(6)O(11) into the Al(2)O(3)-CaO-MgO-SiO(2) (ACMS) system. To illustrate and explain the mechanism of acid resistance, the samples were characterized by different techniques, using X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The phase structure of the specimens was characterized by XRD and SEM-detected microstructures of the specimens. It was observed that with the increase of rare-earth oxide content, the acid solubility of the specimens decreased, and then increased when it reached the minimum value 0.45 wt %. The results of the research show that the improvement of acid resistance with rare-earth oxides was achieved by refining the grain size, strengthening the grain boundary, and turning Ca(2)Al(2)SiO(7), in which acid resistance is poor, into CaAl(12)O(19), which possesses better acid resistance, and then enhance the acid resistance of the proppants. Furthermore, Pr(6)O(11) can form a solid solution with Ca(2)Al(2)SiO(7) and CaAl(12)O(19). The acid resistance of CaAl(12)O(19) improves with the increase of solid solubility. In contrast, the acid resistance of Ca(2)Al(2)SiO(7) will decrease after Ca(2)Al(2)SiO(7) forms a solid solution with Pr(6)O(11).