The furnace body consists of refractory masonry, steel structure and foundation raft.
The hearth and foundation are supported by the base helium to form the top structure.
Since the bottom temperature of the smelting furnace is higher than the bottom temperature of the smelting reverberatory furnace, in order to protect the bottom of the furnace, the refractory brick masonry is composed of a furnace bottom, a furnace wall and a furnace roof.
The bottom structure of the smelting electric furnace is a brick inverted arch bottom, the number of inverted arch bricks is 2 to 3 layers, and the total thickness of the bottom of the furnace is generally 1250 to 1300 mm. From bottom to top, bottom steel plate (40mm), refractory material (95~150mm), clay brick (230~300mm), magnesia brick (760mm), no refractory material injection, direct clay brick (500mm)) Made of (760 mm) with built-in inverted arched bottom.
In the production practice, it was found that the structure of the furnace is not good, and its main disadvantages are:
(1) The lower part of the bottom of the furnace is made into an inverted arch-shaped integral refractory castable base layer. The height on both sides is higher, and the thickness of the middle bottom and middle part is only 150-200mm. The overall base of different thicknesses and thicknesses can withstand 1000~2000t. The weight of the furnace body is not suitable for different thermal expansion and uneven subsidence, resulting in the rupture of the base of the refractory castable, resulting in leakage of the furnace body;
(2) The joint between the side wall of the furnace and the bottom of the furnace is a straight seam, and cracks in the steel strip often occur in the production, resulting in leakage of the furnace.
After the furnace bottom structure was improved, the refractory clay bricks were used to form the inverted arch pedestal instead of the original refractory casting pedestal, and the intersection of the inverted arch and furnace conditions was replaced by the wrong workbench. Replace the original straight seam. In addition, the wet laid clay bricks must be dried to build the inverted bricks of the magnesia bricks; if the clay bricks are baked with the magnesia bricks, the upper layer of magnesia bricks will be pulverized due to the rising moisture of the base layer.
(2) furnace wall
The height of the electric furnace wall used for smelting copper concentrate or copper-nickel concentrate is less than 8.7 m. The inner wall of the main wall of the side wall and the slag line are made of magnesia brick. The inner wall and all outer walls above the slag line are made of clay bricks. Side wall thickness: 690mm magnesia brick, 114mm clay brick. End wall thickness: 920mm magnesia brick, 114mm clay brick. The large rectangular electric furnace shell adopts a split plate (the thickness of the steel plate is 20~40mm), and the skeleton is used for fixing the masonry. In recent years, some large electric furnaces have been used to increase the service life of slag line linings, and water jacketed sheets have been used as hoarding sheets. The function of the water-cooled furnace wall.
(3) the top of the furnace
When the electric furnace is subjected to the smelting operation, the electrode is immersed in the slag, and the slag is heated by electric current, and the slag is used as a heat source for melting. Therefore, only a small amount of reaction gas and water vapor are precipitated from the melt. In addition, the surface of the slag is mostly covered by the charge, so the temperature at the top of the furnace does not exceed 600 ° C during the smelting. The roof built with clay bricks is in very good condition.
The roof is usually made of clay bricks. The thickness of the large electric furnace is usually 300-400 mm. Sometimes, in order to reduce heat loss, a layer of insulating bricks is built on top of the stove. The top of the furnace is about 5.3~6.2m; the thickness of the small electric furnace is 230mm. If a large hole is left in the top of the furnace, the surrounding area is cast into a unit by using a refractory castable. There are also prefabricated refractory cast roofs made of refractory castable or embedded with water-cooled copper tubing which provides better integrity and tightness than brick roofing.