Investigating the effects of sintering additives and heating regimes on the performances of glass–ceramic proppants derived from industrial wastes

Sintering mechanism diagram of glass–ceramic proppants. • Cylinder compressive strength of proppant increase 73.3% through the optimization of technology. • Addition of TiO 2 and Fe 2 O 3 prompt the transformation from crystals to amorphous at high temperature. • Formation of mullite and amorphous improve the cylinder compressive strength enhance of proppants. • Introducing additive sintering mechanism of the proppant was ecluciated in detail. This article aims to explore a simple and effective method of preparation industry solid waste based ceramic proppant and elucidate the sintering mechanism for prompting further study in the future. Glass-ceramic-based proppants were successfully fabricated using fly ash and kaolin, as main raw, matching other raws and additive such as TiO 2 and Fe 2 O 3, in lab. The results showed that the proppants had the optimum overall performances when the total content of SiO 2 and Al 2 O 3 was at 85 %, their molar ratio was 1, with a sintering temperature of 1250℃. The heating rate and the holding time were 2.5℃/min and 90 min, respectively, with the addition of 3 % TiO 2 and 5 % Fe 2 O 3 . The cylinder compressive strength of the samples increased 73.33 % by following step-by-step optimizations than origin sample. Furthermore, the sintering mechanism was elucidated and all possible chemical reaction were explored at the high temperature sintering process. The additives such as TiO 2 and Fe 2 O 3 prompt the crystal melting and amorphous as well as mullite formation, which made raw solid particle set change into a glass–ceramic-based whole body. New finding indicates the new phase formation and their content inside proppant body have an important contribution to the enhance of the cylinder compressive strength.