ZHENGSHAN TECHNOLOGY

In the process of smelting nickel iron in a blast furnace, electrode paste is one of the key materials, and its sintering quality directly affects the smelting efficiency and product quality. However, under burning of electrode paste is one of the common problems in the smelting process, which not only increases energy consumption but may also cause damage to equipment and affect production stability. This article will analyze the reasons for under burning of electrode paste in the process of smelting nickel iron in a submerged arc furnace from multiple aspects.

1、 Properties and formula of electrode paste

The sintering performance of electrode paste is closely related to its properties and formulation. The electrode paste is mainly composed of raw materials such as coal tar pitch and calcined petroleum coke, and its sintering process involves the volatilization, carbonization, and bonding of coal tar pitch with solid particles. If the formula of the electrode paste is improper, such as insufficient coal tar content or unreasonable particle ratio, it will lead to insufficient bonding force, making it difficult to form a dense structure during the sintering process, thereby affecting the strength of the electrode. In addition, if impurities or dust are mixed into the electrode paste, it will also reduce its sintering quality, leading to the occurrence of undercooking phenomenon.

2、 Baking conditions for electrode paste

The calcination of electrode paste is mainly completed by the heat inside the mineral thermal furnace, and its sintering speed is affected by various factors such as furnace temperature, thermal conductivity efficiency, and resistance heat. In a closed electric furnace, due to the reduction of radiant heat, electrode paste is mainly sintered through resistance heat. If the temperature distribution inside the furnace is uneven or the heating area of the electrode paste is insufficient, it will cause some electrode paste to not be fully sintered, resulting in under burning phenomenon. In addition, if the firing speed of the electrode paste is too fast or too slow, it may also lead to insufficient sintering and affect the quality of the electrode.

3、 Electrode operation and management

The operation and management of electrodes are also important factors affecting the sintering quality of electrode paste. During the smelting process, if the electrode is lowered too quickly or the load is not adjusted properly, the electrode paste inside the electrode shell may not be fully sintered and pressed, resulting in under burning phenomenon. In addition, the welding quality of the electrode shell, the performance of the electrode clamping equipment, and the stability of the pressing system all have an impact on the sintering of the electrode paste. If the electrode shell is not welded firmly or the clamping equipment fails, it will cause the electrode to slide down as a whole or the electrode core to fall, affecting the sintering quality of the electrode paste.

4、 Smelting process and furnace condition

The stability of smelting process and furnace conditions is also one of the reasons for the under burning of electrode paste. During the smelting process, if the furnace conditions fluctuate greatly, such as unstable temperature and large current fluctuations, it will affect the sintering quality of the electrode paste. In addition, if the ingredients in the furnace are uneven or there is too much carbonaceous reducing agent, it will cause the furnace bottom to rise, and the bottom of the electrode will be pushed by the conical surface, increasing the risk of electrode fracture and possibly affecting the sintering quality of the electrode paste.