Electrode paste is a crucial material used in smelting furnaces for the production of various metals and alloys. It serves as a conductive medium that helps to transfer electrical energy to the smelting charge, enabling the reduction and refining of the metal. The quality and properties of electrode paste play a significant role in determining the efficiency and productivity of the smelting process. Therefore, it is essential to understand the various factors that can influence the performance of electrode paste during calcination in smelting furnaces.
(1) Influence of the atmosphere in the baking system
During the baking process, due to the thermal decomposition and thermal polycondensation reaction of the binder in the raw product, a certain baking atmosphere is formed inside and around the raw product. The gas generated by the decomposition of the binder continuously passes through the interior of the product and the gap of the filler, and is discharged with the hot air flow into the flue, so that there is a
concentration gradient of the decomposed gas between the inner and outer layers of the product and the inner and outer layers of the filler, so that the gas continues to flow outward diffusion. If the concentration of decomposed gas in the filling material and the upper space of the furnace chamber is low, the decomposed gas will diffuse outward from the product at a high speed, which will promote the thermal decomposition reaction of the binder and reduce the coking amount of the binder accordingly. Conversely, if the decomposed gas discharge rate is slow, the amount of coke analysis will increase.
(2) The influence of pressure
When the baking system reaches 300~400°C, the decomposition of the binder and the polycondensation reaction proceed simultaneously. If the pressure of the system is increased at this time, it is beneficial to participate in the polycondensation reaction, which can not only increase the coke resolution, but also facilitate the formation of mesophase spheres . In the early stage of baking, increasing the pressure of the system can make the binder penetrate into the micropores and microcracks inside the aggregate, strengthen the bonding between aggregate particles, and further densify the product. Therefore, in the case of the same bulk density, the mechanical strength of the press-fired product is high, the compressive strength is 30% higher than that of the normal-pressure baked product, and the flexural strength is increased by about 40%.
(3) Influence of heating rate
The heating rate has a great influence on the coking amount of the binder and the density of the product. The heating rate before 400°C should not be too slow, otherwise it will prolong the coking time of the binder, which will increase the waste products with hard shell cracks. The cooling rate is generally faster than the heating rate, but it should not be too fast, otherwise the temperature gradient inside and outside the product will be too large, which will also cause the product to crack. Generally, the cooling rate is controlled below 50°C/h, and it can be allowed to cool naturally when it is below 800°C.
In conclusion, electrode paste is a critical material for smelting operations, enabling the transfer of electrical energy to smelting charges in furnaces. However, the baking of electrode paste can be affected by various factors, including raw material properties, furnace type, operating conditions, and smelting charge composition. By understanding and optimizing these factors, smelting operators can achieve optimal electrode paste performance and improve the efficiency, productivity, and quality of their smelting operations. So, if you want to stay ahead of the competition, pay attention to the factors that can affect electrode paste baking and keep your smelting operation running smoothly.
