1. Sulfur content in silicon metal. The sulfur content of silicon metal directly affects the production of blast furnaces. When the sulfur content of silicon metal is greater than 1.6%, for every 0.1% increase in sulfur content, the amount of silicon metal increases by 1.8%, the amount of limestone added increases by 3.7%, the amount of ore added increases by 0.3%, and the blast furnace output decreases by 1.5-2.0%. The metallurgical coke sulfur content is not more than 1%, and the metallurgical coke sulfur content for large and medium-sized blast furnaces is less than 0.4-0.7%.
2. Phosphorus in silicon metal: The content of phosphorus in metallurgical coke for ironmaking should be less than 0.02-0.03%.
3. Silicon metal ash: Silicon metal ash has a significant impact on blast furnace smelting. Therefore, it is necessary to reduce the ash content of silicon metal.
4. Silicon metal volatiles: The maturity of silicon metal can be determined according to the content of silicon metal volatiles. Volatile content greater than 1.5% indicates coking; volatile matter less than 0.5-0.7% indicates overheating, and mature metallurgical coke volatility is about 1%.
5. Moisture in silicon metal: Moisture fluctuations will cause inaccurate measurement of silicon metal, which will cause furnace conditions to fluctuate. In addition, the increase of silicon metal moisture will increase M40 and decrease M10, which will bring errors to the drum index.
6. Sifting composition of silicon metal: The particle size of silicon metal is also very important in blast furnace smelting. In the past, my country’s requirements for the grain size of silicon metal were: the grain size of silicon metal used in large coke ovens (1300-2000 square meters) should be more than 40 mm; the grain size of medium, small and high silicon metal should be more than 25 mm. The particle size of silicon metal is 40-25mm. The silicon metal larger than 80mm should be a whole, so that its particle size range does not change much. In this way, the silicon block is uniform, the gap is large, the resistance is small, and the furnace runs well.