With the rapid development of China’s stainless steel industry, the disadvantage of China’s poor nickel resources has been further exposed. China’s booming stainless steel industry must face these two issues directly:
First, the pricing power of the nickel market is not in China, and domestic spot nickel prices basically follow the fluctuations of LME nickel;
Second, the gradual decrease in global nickel sulfide mineral resources and the increase in mining difficulty will inevitably push up the production cost of electrolytic nickel, and the cost of stainless steel smelting will inevitably rise.
Ferronickel originally appeared as a substitute for electrolytic nickel. After experiencing the “baptism” of the 2008 financial turmoil, in the face of the continued development of China’s stainless steel industry and the sharp decline in global nickel sulfide resources, there is no doubt that ferronickel It is ushering in an opportunity to grow from a purely electrolytic nickel substitute to a leveraged commodity that checks and balances the price of nickel.
However, China’s ferronickel industry is also facing the following problems.
First, the laterite nickel ore used in the production of ferronickel in China mainly relies on imports. As the price of non-ferrous metals continues to rise, many mining countries have successively introduced policies such as restricting the export of raw ore or increasing export tariffs on raw ore in order to share the high profits brought by high prices. And related laws, such as Indonesia, Congo, Mongolia, etc. Since nickel ore is the most upstream of the entire nickel industry chain, no resource control power means no pricing power. This is a threat to the entire nickel industry in China and the downstream nickel application industries including stainless steel. Therefore, the “going out” strategy is implemented. , Forming strategic partnerships with major international nickel ore suppliers and actively investing in local nickel mining has become the only way for China to reduce risks.
Second, the main equipment for ferronickel smelting in China are blast furnaces and submerged electric furnaces. According to the detailed rules of the “Iron and Steel Industry Adjustment and Revitalization Plan” issued by the State Council and the “Notice of the State Council on Further Strengthening the Elimination of Backward Production Capacity” on April 7 this year, The blast furnace capacity of 300 cubic meters and below will be phased out by the end of 10, and iron blast furnaces of 400 cubic meters and below will be phased out before the end of 2011. According to this website, the main furnace capacity of China’s nickel-iron smelting blast furnace is 128 cubic meters. Mostly, very few of them reach more than 300 cubic meters. Once the State Council’s policy on eliminating outdated production capacity can be thoroughly implemented, the impact on China’s ferronickel industry, especially blast furnace ferronickel, will undoubtedly be huge, and it will also have a significant impact on the stainless steel industry. However, due to the low smelting efficiency of small blast furnaces, high pollution and energy consumption, and backward smelting processes, from the perspective of the healthy development of the industry itself, the survival of the fittest is an inevitable survival rule. With the country’s determination to eliminate outdated production capacity and transform the mode of economic development The implementation of step by step, the new pattern of China’s ferronickel production may also be born from this.
Converter effect
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 component 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.
Because sulfur can be removed in a converter, ladle desulfurization and acid converter desiliconization can be combined in one converter. The first converter was an acid converter, which was transformed into a basic converter for top-bottom combined blowing. Through bottom blowing of argon (nitrogen), desiliconization and desulfurization in a reducing atmosphere can be achieved in this converter.
The molten nickel and iron from the first converter enters the second converter for dephosphorization. During the smelting process, limestone must be added to the furnace to ensure a suitable smelting temperature. Qualified nickel and iron smelted in this converter are sent to the foundry to be cast into blocks with a nickel content of 20%.
Electricity consumption accounts for 30% to 33% of the total cost of ferronickel. The power consumption per ton of commercial ferronickel is related to the nickel content of the ore. When the nickel content of the ore is 1.5%, the power consumption is about 600kWh/t dry ore. When the nickel content of the ore is 2.5%, the power consumption per ton of ferronickel drops to 400kWh.
The consumption of nickel oxide ore containing 1.5% to 2.0% nickel purchased abroad is roughly 12t/t ferronickel. The reducing agent (pulverized coal of anthracite) accounts for about 8% of the ore; the weight of various fuels is 50kg/t ferronickel; oxygen 80m3/t ferronickel; lime 5kg/t ore before roasting.
The high-standard sealed electrode paste produced by Rongxin Carbon is a special electrode paste product for nickel-iron submerged arc furnace. High-standard sealed electrode paste has the characteristics of low ash content, low resistance and high strength. It is a product widely used by many nickel-iron alloy factories in Inner Mongolia and Indonesia.