METHOD OF PRODUCING FUSED ALUMINIUM-MAGNESIUM SPINEL Russian patent published in 2024 - IPC C04B35/443 C04B35/653 

FIELD: various technological processes.

SUBSTANCE: invention relates to refractory industry and specifically to methods of producing fused materials based on aluminium-magnesia spinel MgAl₂O₄ for producing high-quality refractory materials. Method of producing fused aluminium-magnesia spinel involves preparation of charge and its melting. As raw materials of the charge there used is magnesite and boehmite, which are preliminarily subjected to isothermal holding at 1,200 °C for decomposition and removal of chemically bound water is mixed in stoichiometric ratio. Charge is granulated and melted in graphite melting chamber by plasma melting in turbulent mode of plasma jet outflow with plasma-forming gas flow rate of 2.5 g/s for formation of homogeneous melt. Then, plasmatron operation is switched to laminar mode of plasma jet outflow with flow rate of plasma-forming gas of 0.9 g/s, at which relaxation of melt to temperature (0.4-0.5)⋅T_m takes place to minimize residual stresses during melt crystallisation.

EFFECT: obtained aluminium-magnesium spinel is characterized by open porosity ≤ 5 % at true density of material 3,56 g/cm³ with element composition O = 42 wt.%, Mg = 16 wt.%, Al = 42 wt.%, where the surface of the product is prismatic crystals with a median size of 220 mcm, and the inner frame is a dense packing of octahedral crystals with a median size of 50 mcm.

1 cl, 1 dwg, 2 tbl, 1 ex