MAGNESIUM ALUMINUM SPINEL BRICK PREPARATION METHOD AND MAGNESIUM ALUMINUM SPINEL BRICK PREPARED USING SAME

摘要

The present invention provides a manufacturing method of a low heat-conducting magnesium-aluminium spinel brick and a low heat-conducting magnesium-aluminium spinel brick manufactured by employing the method, said magnesium-aluminium spinel brick includes a flame retardant coating and a thermal insulating layer, specific manufacturing steps are as follows: (1) preparation of flame retardant coating raw materials: contents of respective components are expressed in mass percent, sintered magnesia of granularity‰¤5mm 40%ˆ¼70%, fused magnesia of granularity‰¤3mm 10%ˆ¼40%, magnesium-aluminium spinel of granularity‰¤4mm 10%ˆ¼20%, 0%corundum‰¤10% of granularity‰¤2mm are evenly mixed to prepare flame retardant coating raw material mixed powder, then 1%ˆ¼5% naphthalene binder is additionally added by taking the flame retardant coating raw material mixed powder as a basis, flame retardant coating raw materials are prepared after evenly mixing; (2) preparation of thermal insulating layer raw materials: contents of respective components are expressed in mass percent, forsterite 40%ˆ¼60%, fayalite 10%ˆ¼40%, magnesia 10%ˆ¼50% are selected to be evenly mixed, 1%ˆ¼5% naphthalene binder is added by taking the mixed powder as a basis, they are moulded by a frictional press, dried at 110°Cˆ¼150°C, burned at a high temperature above 1000°C to obtain aggregate composite hortonolite raw materials; granularity‰¤5mm aggregate composite hortonolite is used as a single raw material, 1%ˆ¼5% naphthalene binder is additionally added, they are evenly mixed to prepare thermal insulating layer raw materials; (3) the above mentioned flame retardant coating raw material and thermal insulating layer raw material are spaced and loaded in a mold by using corrugated thin iron sheets, pressed into green bricks by a press machine, kept at a temperature of 110°C for 24 hours, dried, and burned into magnesium-aluminium spinel bricks at a temperature of 1550°Cˆ¼1750°C in a tunnel kiln; wherein the sequence of step (1) and step (2) may be inversed; this magnesium-aluminium spinel brick has a high pure magnesium-aluminium spinel material flame retardant coating and a magnesium-iron composite olivine material thermal insulating layer. By adjusting the formula of the thermal insulating layer, a low coefficient of thermal conductivity and consistency of linear expansivity of the flame retardant coating and the thermal insulating layer are guaranteed, the sintering temperature of the thermal insulating layer is increased and made match the flame retardant coating.