Enhanced corrosion resistance by simultaneous refinement of pore structures and phase composition: A novel lightweight microporous alumina-rich spinel (Mg0.4Al2.4O4)

Abstract

A lightweight microporous alumina-rich spinel aggregate with a single phase (Mg0.4Al2.4O4) was prepared to fabricate lightweight refractories with guaranteed corrosion resistance. To explore the corrosion behaviour of slags with different compositions, four types of slags were tested and compared with commercial sintered alumina and lightweight corundum-spinel aggregates. The slag corrosion depth of the lightweight microporous alumina-rich spinel aggregates was significantly lower than that of the other two aggregates. The alumina aggregate formed a calcium aluminate isolation layer with a thickness of 100–150 µm at the interface. The lightweight corundum-spinel aggregate did not form any isolation layer; however, a 50 µm reaction layer, composing of spinel and calcium aluminate, exists between aggregate and slag. Nevertheless, at the contact interface between the lightweight microporous alumina-rich spinel aggregate and slag, a uniform isolation layer (approximately 50 µm thick) forms, preventing direct contact and ensuring excellent corrosion resistance.