A furnace chamber is formed in the converter so that magnesium can be used to process the cast iron melt. The size and shape of the furnace wall components of the converter have a decisive influence on the efficiency of processing the cast iron melt in the converter and the accuracy of obtaining the remaining magnesium content. In order to optimally control this influence, the length L of the furnace wall member is determined according to the formula L=600×T0.45×A, and its height H is determined according to the formula H=1.5L×A. Where A is a The coefficient, its value is between 0.5 and 1.5, and its specific value depends on the value of the weight content of sulfur between 0.01% and 0.15%. It also depends on the thickness of the refractory lining in the converter shaft at 40 The value between 150 mm and 150 mm.
First, the crude nickel iron is discharged from the submerged arc furnace into the molten iron ladle, where soda ash is added to the molten iron ladle at a ratio of 14kg per ton of nickel iron and the sulfur in the nickel iron can be reduced to 0.015～0.01. 08%. It is also possible to spray passivated magnesium particles into the ladle, which requires a special evaporator to spray the particulate magnesium into the ladle at a depth of about 1.5m. This process can reduce the sulfur content in the nickel and iron to less than 0.015% (more than 20 Chinese steel companies have introduced this process from Ukraine for use in blast furnace hot metal desulfurization).
After the slag on the desulfurized molten nickel is poured out, it is poured into an oxygen top-blown converter lined with acidic refractory materials. In the sour oxygen top-blowing converter, the silicon is oxidized by blowing oxygen, and the temperature of the molten pool rises rapidly at this time. In order to control the proper bath temperature, it is necessary to add metal waste generated during the production process or purchased nickel-containing waste into the furnace.
After the desiliconization process, the nickel-metal molten iron is then charged into an alkaline oxygen top-blown converter of the same tonnage, and the carbon, phosphorus and other impurities in the nickel-metal molten iron are removed by top-blowing oxygen. In order to make alkaline slag and cool down, limestone is added to the converter. When there is sufficient nickel-containing waste, lime can be used instead of limestone.
The impurity content in the ferronickel from the basic oxygen top-blowing converter has met the requirements of the commercial ferronickel standard, and the nickel content has increased to about 20%, which can be sold as commodity ferronickel.