What are the measures to prolong the service life of the anode baking furnace?

The operating conditions and service life of the anode baking furnace are related to the normal production of pre-baked anodes, anode quality and production costs, and have an important impact on the normal progress of the aluminum electrolysis process. It is very important to maintain good operating conditions of the roaster and extend its service life. Today, it is mainly about how to extend the life of the anode baking furnace several measures to make important instructions.

1. Control the quality of refractories
When the anode baking furnace is newly built or overhauled, the quality of the refractory materials used in the furnace must be strictly controlled. The first is to purchase refractory materials from a reputable refractory manufacturer; the second is to strictly implement the refractory standards for anode baking furnaces in the non-ferrous industry; the third is to entrust a qualified inspection unit to the industry standards after the refractory enters the factory. The items of the refractory are strictly tested one by one, especially the alumina content, apparent porosity, 0.2MPa load softening start temperature, normal temperature compressive strength, high temperature flexural strength and thermal shock resistance of refractory materials. In addition, in order to prevent the "reuse" of the waste fire wall bricks in the roasting furnace, the content of alkali metals Na and K in the refractory bricks should be regarded as a key inspection, analysis and control item. For refractory materials that are unqualified after testing, they should be resolutely returned, and refractory materials with hidden dangers should not be used in the furnace masonry.

2. Control the quality of furnace construction
Regardless of whether the carbon plant has the masonry capacity of the roaster or adopts a turnkey project, the masonry must be carried out in accordance with the established roaster masonry construction plan during the roaster's masonry process. When building the roaster, the carbon plant should assign experienced personnel with good on-site coordination capabilities to monitor the construction quality. If conditions permit, professional engineering supervisors can also be hired from professional institutions to supervise and inspect the construction quality. And carefully prepare supervision records. Especially for fire road walls, the size of brick joints and mortar saturation should be strictly controlled, no gaps should appear, and no mortar should be filled in the brick joints. In addition, during the masonry process, the sealing measures of the fire channel wall should be strictly controlled.

3. Control oven quality
Control the oven quality of the roaster from the following aspects:

1) After the furnace body is built, the production conditions are restricted because other equipment has not been installed. Especially in winter, the newly built roasting furnace should be insulated to ensure that the temperature of each furnace and material box is controlled at 5~10℃. Prevent the furnace chamber from freezing and cracking.

2) Choose a reasonable oven curve, especially at 300, 800 and 1150℃, which are critical stages that affect the performance of refractory materials, and must be properly controlled to ensure that the refractory performance is stable and its internal structure will not be damaged.

3) Strictly follow the predetermined heating curve of the oven to raise the temperature. When the actual temperature does not match the heating curve, the temperature deviation should be adjusted in the shortest possible time to meet the curve requirements.

4) After the oven procedure is completed, the furnace body is cooled in strict accordance with the cooling curve. When the temperature of the carbon block in the furnace is cooled to less than 200 ℃, the furnace can be discharged.

4. Control the quality of roaster operation
The operation quality of the roaster should be strengthened from the following aspects:

1) Improve the operating skills of the crane operator, master the accuracy of the position of the carbon block during the loading and unloading process, and avoid the anode carbon block colliding with the fire channel wall during the loading/unloading process. Mechanical damage caused by the wall; at the same time, the furnace surface commander should also strengthen the communication and coordination with the crane operator to avoid the collision of the anode carbon block with the fire channel wall due to command errors.

2) Regularly adjust the flame direction of the combustion system and implement the combustion flame reverse operation to avoid permanent deformation of the fire channel wall caused by the flame burning in the same direction for a long time. In anode baking production, due to the long-term use of fixed combustion methods and flame movement methods, the temperature of the fire channel, especially the locally excessively high temperature, also presents a fixed distribution. Long-term high-temperature burning and cyclic production often cause regular deformation and bending of end walls, regular depressions, convex hulls and aging deformation of the fire channel wall, resulting in a large number of flame negative pressure squeezing, narrowing of the material box and leakage of filling materials, etc. , Which seriously affects the service life of the roaster. Based on the partial modification of the roasting equipment, the flame direction of the roasting furnace is regularly adjusted to the direction opposite to the original operating direction, which can greatly reduce the occurrence of the above problems, thereby prolonging the service life of the roasting furnace, and There is no adverse effect on the quality of the roasted anode carbon block.

5. Control the content of alkali metal in the raw material of the pre-cultured anode
The alkali metals K and Na in the prebaked anode not only have great harm to the fire channel wall bricks, but also have a great influence on the CO? reactivity and air reactivity of the anode carbon block. The existence of Na makes the anode in the electrolysis process Increase in consumption. Therefore, it is necessary to control the content of alkali metal entering the anode baking furnace through various channels.

1) Control the alkali metal content in refractory materials. When the anode baking furnace is built, refractory bricks should be selected in strict accordance with the refractory standards of industrial furnaces and kilns stipulated by the industry. For the purchased refractory bricks, impurity content analysis and testing must be carried out to control the impurity content including alkali metals to a minimum.

2) Control the alkali metal content in the recovered residual electrode. Since the sodium in the anode baking furnace is mainly derived from recycled residual electrodes, the high sodium content from the residual electrodes plays a vital role in the corrosion of the fire channel wall tiles. Therefore, the cleaning of residual poles is an important way to control the sodium content in the fire wall refractory bricks. The use of manual cleaning often keeps a high content of sodium in the residual electrode; while the automatic cleaning machine for the residual electrode can reduce the sodium content in the residual electrode to (60~83)×10??, thereby greatly reducing the amount of sodium. The sodium content of the anode entering the baking furnace.

3) As the binder of the prebaked anode, the sodium content (3×10??~10×10??) in the "no-sodium low ash" coal pitch is much lower than the sodium content in the common coal pitch 0.0003%~ 0.1%), therefore, replacing the common coal tar pitch with "no sodium and low ash" coal tar pitch as the pre-baked anode binder can also reduce the sodium content that enters the fire channel wall bricks through the green anode to a certain extent.

6. Application of new materials and new technologies in anode baking furnace

1) When the anode baking furnace is built, low-creep mullite fire-path wall bricks are used to reduce the high-temperature creep rate of the fire-path wall bricks, increase the load softening point and thermal shock resistance, and prolong the service life of the baking furnace.

2) When the anode baking furnace is built, the new type HY-MAC fast heat conduction fire channel wall bricks are used to extend the service life of the baking furnace by improving the thermal conductivity, high temperature resistance and compressive strength of the fire channel wall bricks.

3) When the anode baking furnace is masonry, offline masonry technology is used to replace the existing furnace masonry technology. By increasing the natural drying period, it solves the problem of entering the system to heat up immediately after the building is completed without drying and strict oven management. Insufficient, improve the masonry quality and prolong the service life.

4) When the anode baking furnace is masonry, the lock-type breathable block fire channel wall is used to cancel the vertical joints in the conventional masonry fire channel wall, improve the integrity of the fire channel wall, and effectively delay the fire channel wall. Cracking time, thereby prolonging the service life of the roasting furnace.