Effect of oxides composition on the mechanical properties of non‐sintered spherical filters from waste steel slag

Abstract

Non-sintered spherical filters (NSSFs) from the waste steel slag for bottom filtration process are regarded as promising materials for sustainable development with economical benefits due to saving natural resource pebbles. To further optimize the preparation process, the influence mechanism of the main oxides on characteristics are comprehensively examined in this work. CaO in the raw materials makes it easier to release active components from the resulting glass body structure, while the expansion stress of Ca(OH) 2 crystals precipitated under highly basic circumstances needs special consideration. SiO 2 can positively contribute to the properties due to its adequate participation in the hydration reaction and the micro-aggregate effect.Al 3+ tends to combine and form a stable tetrahedral structure, which is conducive to liquid viscosity and the hindrance of hydration reaction of the active substance.Under the 6% mass ratio of MgO, NSSFs exhibit relatively excellent in physical properties. Specifically, the stimulation and promotion effect of MgO on hydration reaction is superior to the negative effect of excessive product Mg(OH) 2 on expansion stress. Fe 2 O 3 particles convert the structure in NSSFs to a dense state by the filling effect and serving as nucleation sites to promote the formation of hydration products.