Adopts a high-sealing structure with a displacement chamber of internal and external sealing doors, ensuring that the oxygen content in the furnace remains unaffected during material loading and unloading. The chamber uses a corrosion-resistant heavy-duty material vaulted roof to facilitate exhaust gas discharge. Heating elements are protected by quartz tubes or corundum tubes to prevent corrosion from gummy atmospheres. Pre-firing and firing functions can operate independently or integrate debinding-sintering processes.