Study On Super Large Calcium Carbide Furnace Confined Paste

As a self-baking electrode for the submerged arc furnace, paste electrode is known as the heart of the furnace during the process of smelting. Generally, small submerged arc furnace is low on power, and most of the furnace have no lid (commonly known as open furnaces), using standardized electrode paste (open paste). High power submerged arc furnaces are equipped with lids, so it is called sealed furnaces, which demand closed pastes with high quality. Due to the progress of technology, submerged arc furnaces are experiencing upsizing and sealing transformation. Therefore, the heat obtained during the baking process is reduced to conductive heat. It makes the heat transferred from the furnace to the electrode decrease largely, thus requiring the improvement of the sintering property of the electrode paste. Because of the basic requirement of the electrode paste such as high speed of baking, low resistivity, high thermal conductivity, half-graphitized and low-ash anthracite is recommended to be the main raw material for electrode paste.The targeted customers of our company to sell the electrode paste are manufacturers of calcium carbide furnace. The customers’furnaces utilized18-25MVA before2010. However, after that the calcium carbide furnace of30MVA has been developed rapidly and the oringinal National Standardized No1electrode cannot meet the requirement any more. In this thesis, in order to meet our company demands, we successfully prepared a special closed paste outperforming the national standardized No1paste through a series of scientific methods.During the program, some achievements are made:1. The quality of electrically calcined anthracite of supplier "L" was confirmed the best of the five suppliers according to the site inspection and sample analysis. The physical and chemical indexes of electrically calcined anthracite for super-calcium carbide furnace were decided.2. The recipes were considered under the following factors:devices available, cost of raw materials, the utilization of the residual of other products and the possibility of industrialization. The optimized recipes were made through sample preparation.3. The industrial production was completed with228ton of qualified closed pastes, which possess higher quality than that of national standardized No1paste. 4. The paste went through a successful trial in the45MVA calcium carbide furnace and the ton-consumption is2.9kg lower than the counterparts in the market. Now the products are applied in many furnaces and have a good feedback.5. Taking advantage of the residual anode and machine powder as raw materials to produce confined paste can not only sharpen the cost but also maintain the properties of the products.