At present, the domestic control index for the compressive strength of electrode paste is more than 150 kg per square centimeter; The control index of resistance coefficient is less than 80 ohms square millimeter per meter; Ash content is less than 6%; Specific gravity greater than 1.35 g / cm2; The porosity is less than 27%; The current density is 6-9 A / cm2; The volatile control index is 12-16%.
However, these control indicators have not controlled the occurrence of electrode accidents in the production practice of small and medium-sized calcium carbide furnaces in the past decades. At present, the diameter of the electrode of the large closed calcium carbide furnace to be developed is relatively large, and the working length is relatively long. The tensile force generated by its own weight is larger, which requires high mechanical strength, and it also needs to re regulate the new compressive strength control index; Now energy conservation has become a national policy. The national standard for the energy consumption index of large closed calcium carbide furnace is quite strict, so the electrode paste should have a relatively small resistance coefficient to reduce the loss of electric energy. Therefore, the original control index of the electrode paste needs to be changed.
In addition, because the electrode of large closed calcium carbide furnace bears great impact of furnace charge collapse and furnace gas flash explosion in the production process, the index of flexural strength is used to regulate abroad, and its control index is more than 35 kg per square centimeter, while there is no control index in China. The electrode used in calcium carbide production is self-cultivation, which is made by using the heat generated in the production process to bond the solid raw materials of the electrode with the liquid raw materials, and then burn from bottom to top; In China, liquid raw materials are called volatile and regulated by 12-16%, while in foreign countries, volatile indicators are not regulated.