Scrap steel shall not be added to the first two batches of charge, and 10~20% high-quality scrap steel can be added to the next batch as required. Once the charging into the furnace is started, the charging action must be continuous, fast and stable, and the furnace charge must be added to the set charge level of the cupola. The mass of each batch of metal charge for 10t/h gas-fired cupola is 1000kg, and each batch contains 18Kg dolomite, 20Kg limestone, 12Kg broken glass and 2-3 ceramic balls. The number of ceramic balls in each batch depends on the required molten iron temperature. Properly increasing the number of ceramic balls in the batch will gradually increase the thickness of the refractory cushion on the furnace grate, which is conducive to obtaining high temperature molten iron. In the charging process of cupola, it is particularly important and easy to be ignored that the charging surface in the charging bucket and the furnace should be as flat as possible to prevent the tilting of the charging surface, which will lead to uneven distribution of certain charging materials in the furnace, and the ceramic balls are easy to roll down along the inclined charging surface to one side of the furnace, resulting in uneven changes in the thickness of the grate cushion. In addition, the flux must be evenly distributed in the metal charge. Fully mix limestone, dolomite, broken glass, etc. with metal charge in advance, which is beneficial to produce slag with low melting point and good fluidity in the furnace, and ensure the normal melting of gas cupola. Uneven feeding will have adverse effects on the operation of the gas furnace. Continued feeding beyond the set material level will also cause damage to the operation of the gas furnace. If the material level in the furnace is below the set material level, the melting speed and melting efficiency of the gas cupola will be reduced. Before charging the cupola, first increase the combustion power from 40% to 70%, and then increase it to 85%. At the same time, set the volume fraction of oxygen added in the air, and turn the oxygen supply knob to the automatic position. When the burners burn stably, the charging can be started into the furnace. The charge added by the gas furnace shall be as lumpy as possible, uniform in composition, pure and free of mud and sand.
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