Preliminary study on fully replacing bauxite with secondary aluminum ash in ceramsite proppants

Abstract

This study investigates using secondary aluminum ash, a solid waste, to fully replace bauxite as the main raw material, with kaolin as a binder to prepare ceramsite proppants. XRD analysis confirms that secondary aluminum ash can produce ceramsite proppants with corundum as the main phase. Increased aluminum ash content enhances corundum crystallization at 1270 °C. SEM images show that a 2:1 ratio of aluminum ash to kaolin at 1270 °C achieves optimal internal density due to block-shaped corundum enveloped by a glass phase. The corundum fills gaps between crystals during sintering, reducing internal pores, enhancing density, and improving strength (corundum is harder than mullite). This is supported by measurements of bulk density, apparent density, acid solubility, and crush rate. The prepared proppants have a bulk density of 1.1690 g/cm3 (10 %), slightly above the standard, likely due to impurities in the ash affecting hardness. This study provides a novel approach for the efficient utilization of secondary aluminum ash, while identifying research gaps related to its crush rate issues.

Keywords

• Secondary aluminum ash
• Solid waste
• Green technology
• Solid-state sintering
• Ceramsite proppant