Cupola silicon slag

Cupola silicon slag : cupola smelting technology is mainly used for casting molten iron at present. This technology uses pig iron as raw material, coke as fuel, limestone slag, air for combustion, and finally molten iron is smelted. The waste slag is discharged out of the oven, and dust and exhaust gas are discharged into the atmosphere.  This process method has the following defects: 1, need to consume a lot of coke, coke consumption 300kg per ton of casting.  2, produced a large amount of dust, soot and carbon dioxide and other exhaust gas into the atmosphere, serious air pollution;  The resulting waste contaminates soil and water.  3, must use pig iron as raw material, production cost is high.  4, the product quality is poor, rejection rate as high as 15%.  5, single variety, limited to the production of gray cast iron.  In view of the shortcomings of cupola smelting technology, some manufacturers begin to use cupola smelting with silicon slag, but pig iron is still used as raw material, and it can only be used for steelmaking.  

The method of casting molten iron with silicon slag and scrap iron in cupola can not only greatly reduce the production cost, but also produce high quality and do not pollute the environment.  The advantage of cupola silicon slag is that the waste iron scrap is installed in the furnace, and the carburizer is added in the furnace. 

The cupola silicon slag , ferrosilicon and ferromanganese are added in the intermediate frequency electric furnace 10-30 minutes before the hot iron is baked, so as to improve the silicon and manganese content in the cast iron.  Carbon equivalent, carbon content, silicon content and temperature of hot metal are detected when hot metal comes out of the oven.  Carburizer used coke dust.  The ratio of iron filings, ferrosilicon, silicon slag for cupola and ferromanganese is 1∶0.07∶ 0.2:0.04.  The invention has the following advantages and positive effects: 1. Because waste iron filings and cupola silicon slag are used as raw materials and coke foam is used as carburizer, the production cost of casting can be greatly reduced.  The cost per ton casting can be reduced by 20%.  2, no dust, no carbon dioxide and other waste gas in the production process, no slag, therefore, to protect the environment and the health of workers.  3. Energy consumption can be reduced by 38.7%.  4, high quality products, rejection rate can be reduced to 5%.  5, can produce nodular cast iron, cast steel and other products.  6, the process is simple.  Cupola with silicon slag and scrap iron casting method, the content of carbon is 2.7% of the waste iron scrap 100kg into the furnace, at the same time in the furnace to add carburizer (coke)0.14kg melting 60 minutes (the amount of carburizer and the amount of carbon content of waste iron scrap is inversely proportional). 

In order to improve the content of silicon and manganese in cast iron, add ferrosilicon, cupola silicon slag and ferromanganese in medium frequency electric furnace 15 minutes before molten iron comes out of the oven.  Hot iron out of the oven need to carry out the detection of carbon equivalent, carbon content, silicon content and hot iron temperature, carbon equivalent should be between 3.05% ~ 3.6%, carbon content between 3.0-3.5%, silicon content between 1.8-2.3%, hot iron temperature is 1500℃.