With the rapid development of modern industries, various industrial sectors are booming continuously. Refractory bricks are widely known as core lining materials for high-temperature industrial furnaces. Strict technical requirements shall be followed during masonry construction. Before furnace bricklaying, the consistency and bonding performance of refractory mortar, including liquid dosage, shall be tested and verified in accordance with masonry design standards to meet construction requirements. The mortar bonding time shall be controlled within 1 to 1.5 minutes according to the overall dimensions of refractory products. Different types of refractory bricks shall be matched with corresponding refractory mortars for masonry.
Before construction, masonry personnel shall complete safety training. All construction equipment shall be fully prepared, and water and electricity supply shall be guaranteed on site. The construction shall be carried out in strict accordance with the following specifications:
(1) Before bricklaying, accurate measurement and elevation inspection shall be conducted per design requirements to verify the furnace center, structural dimensions and relative elevation of all masonry parts.
(2) Refractory brick masonry shall adopt staggered joint construction. All brick joints shall be fully filled with mortar, and all exposed surfaces shall be pointed. For dry masonry, gaps shall be filled with dry refractory powder unless otherwise specified in the design.
(3) On-site cutting or chiseling of bricks during masonry is prohibited. Brick alignment shall be completed only with wooden hammers or rubber hammers. No knocking or adjusting is allowed after the mortar initial sets.
(4) The processed surfaces of refractory bricks shall not face the furnace interior, flue channels or expansion joints.
(5) Broken or reworked bricks during laying shall be constructed with stepped joints.
(6) After on-site processing, the residual width of refractory bricks shall not be less than 1/2 of the original brick width, and the residual thickness shall not be less than two-thirds of the original brick thickness.
(7) Composite bricks shall be assembled and laid accordingly based on the furnace inner diameter and designed masonry elevation.
(8) Settlement joints shall be reserved between flues, chimneys and other building structures during chimney masonry. The settlement joints shall be well sealed to prevent air permeability and water penetration.
(9) For underground flue vaults, brick locking and arch closing can only be performed after backfilling and compaction of the surrounding wall soil.
(10) Both refractory masonry and thermal insulation masonry shall be protected from moisture throughout the whole process from construction to formal production operation.
Furnace bottoms are divided into dead bottoms and live bottoms. A dead bottom refers to the structure where the furnace bottom is laid first and the furnace wall is built subsequently, with the wall pressing on the bottom brickwork. A live bottom refers to the structure where the furnace wall is constructed first, followed by the furnace bottom masonry. Furnace bottom construction is critical. Tight bonding of bottom bricks must be ensured to avoid wear and other operational risks after furnace commissioning.
The upper brick layers of furnace bottoms, channels and flue bottoms are generally laid horizontally. For parts subjected to vertical scouring by molten metal, slag and high-temperature flue gas, the furnace bottom shall be constructed with arch structures according to production requirements. When masonry construction is interrupted, stepped back joints shall be reserved at the breaking section.
