CGM Online

Application of High-standard Sealed Paste Electrode Paste in the Process of Smelting Nickel Pig Iron In China, laterite ore is a better technology choice for producing ferronickel (nickel pig iron) in a closed paste submerged arc furnace. At present, the most suitable process route is considered to be laterite ore-after drying, crushing and agglomeration-closed paste smelting in an electric furnace with coke and solvent-production of crude nickel pig iron-energy reduction of C, SI, S, P, etc. Impurities are refined in a converter to obtain nickel and iron granulation, or liquid iron can be directly smelted into stainless steel. The above-mentioned process of using laterite ore to directly process stainless steel products has been realized by enterprises such as Inner Mongolia Mingtuo Company and Guangxi Beihai De Nickel Industry. In terms of production process, resource conditions, product quality, etc., the process technology of pyro-electrode paste ferronickel smelting is varied.

Raw materials analysis and market conditions of nickel-iron submerged arc furnace using high-standard closed paste electrode paste The domestic nickel oxide ore resources are extremely limited. At present, the domestic laterite resources for the production of nickel pig iron and ferronickel with high-standard airtight electric furnaces come from South Pacific island countries such as Indonesia and the Philippines. Enterprises purchase nickel ore from the market according to suitable production processes and equipment conditions. Laterite Dewatering The purchased laterite ore usually contains about 33% of the physical water and crystal water. It is extremely uneconomical to directly charge nickel ore into a high-standard closed paste electric furnace to smelt ferronickel. Inefficient and useless to use large amounts of heat. At present, the domestic enterprises engaged in smelting ferronickel with electrode paste electric furnaces almost all dry laterite ore. It is more economical

Electrode paste is also called self-baking electrode. It relies on the heat in the submerged arc furnace to complete the roasting. Therefore, matching the consumption speed of the electrode with the roasting speed is the key to the use of electrode paste. Due to the development of submerged arc furnace technology, it is gradually becoming large With the development of the electrode in the sintering process from open furnace to closed furnace, the heat obtained by the electrode from the furnace is greatly reduced, which requires the improvement of the sintering performance of the electrode paste to make up for this deficiency. Hard fracture is caused by insufficient strength of the electrode paste after sintering; soft fracture is that the electrode sintering speed is not as fast as the consumption rate, and the lowering is too fast. The electrode is not completely sintered and cannot withstand the stretching and lateral impact of the lower part of the electrode, causing fracture. Thes

Raw material for preparing electrode paste The raw material for making electrode paste is composed of solid carbon material and binding material. The quality of the electrode paste is closely related to the raw material formula and preparation process. Solid materials include calcined anthracite, metallurgical coke, petroleum coke and graphite electrode scraps. Anthracite is dense and has a high carbon content, which can improve the thermal stability, conductivity and mechanical strength of the electrode; the binder of the electrode paste includes pitch and coal tar, and tar is added to adjust the softening point. The binder is decomposed during the sintering process of the electrode paste and the volatiles are discharged and then converted into coke, so that the electrode forms a hard whole. The formula of electrode paste should consider various factors such as the ratio of various aggregates, particle size composition, softening point of the binder, and the amount of addition. Cl

 According to the quality requirements, raw materials and process conditions of the products, the cathode carbon blocks in China are basically divided into three categories: ordinary cathode carbon block, semi graphite carbon block and graphite carbon block. Anthracite calcined at 1250 ~ 1350 ℃ is the main raw material of common cathode carbon block. The semi graphite carbon block can be divided into two types according to different production processes. One is to use high-quality high-temperature electric calcined anthracite, or to use more graphite fragments or even all graphite fragments as aggregate. The formed green products are only roasted (the roasting temperature does not exceed 1200 ℃) and no longer enter the graphitization furnace for heat treatment. This kind of carbon block is called semi graphite carbon block. The other uses more easily graphitized coke as aggregate, raw products are roasted and then put into graphitization furnace for heat treatment at 180

　　④Cause of equipment 　　The holding system is not insulated, causing the system components and the electrode barrel to be connected to the electrode barrel, causing paste leakage; the conductive clip and the electrode barrel are not in good contact (the conductive clip has insufficient clamping force or the contact surface is rough), causing the electrode barrel to heat up and burn through the electrode barrel and leak the paste. The small clamping force of the electrode holding system causes the electrode to slide down during the pressing and release process, which causes the electrode to flow paste or soft break accident; the welding seam is not strict during the manufacture of the electrode cylinder, and the welding seam has blisters during the butting, and the electrode paste leaks from it. 　　(2) Preventive measures and treatment methods for electrode leakage 　　①Strictly control the quality of the electrode paste, so that the index of the electrode paste matches the furn