JPH0430455B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing ferronic acid using a blast furnace. (Prior art and its problems) Nickel raw material ore has a low grade of about 2% nickel, and a large amount of adhering water and crystallization water, about 30%, and usually requires preliminary treatment such as drying and pelletizing. Conventionally, nickel ore has been generally produced by reducing it in a kiln or shaft furnace and melting it in an electric furnace, and methods using blast furnaces have only been partially used. However, when a blast furnace is used, since there is a lot of water in the raw material of Ferronickel, a lot of fuel is consumed to evaporate the water, resulting in problems such as an increase in the coke ratio, an increase in the furnace top temperature, and a decrease in productivity. (Technical Problems to be Solved by the Invention) An object of the present invention is to provide a method for producing ferronic acid that can lower the coke ratio, lower the furnace top gas temperature, and improve productivity. (Means for Solving Technical Problems) The present invention provides a method for producing ferronic acid, which is characterized in that ferronic acid ore is inserted from the upper part of the furnace, hot air is blown from the tuyere, and preheated gas is blown from the shaft section in the middle of the furnace. It is. (Example) Examples of the present invention will be described below with reference to the drawings. As shown in Figure 1, nickel ore is sieved after drying, lump ore is directly inserted from the top of blast furnace 1, and fine ore is granulated and inserted into blast furnace 1 as green balls, or after granulation. Insert into blast furnace 1 as a cold bond. Limestone and coke are simultaneously inserted from the top of the furnace. Hot air is blown from tuyere 2. Furthermore, preheating gas is blown from the middle stage 3 of the furnace. Preheating gas is obtained by introducing a part of the furnace top gas into a burner and burning it, and its temperature is approximately 500℃.
℃~1300℃. Preheating gas is performed to help evaporate a large amount of water contained in the ore. Through such operations, reduction of ferronite ore progresses, and FeNi and slag are obtained at the bottom of the furnace. According to this method, since the preheating gas is blown from the middle stage of the furnace, the evaporation of a large amount of water contained in the ore can be promoted and the coke ratio can be reduced. In addition, productivity can be improved by reducing the amount of boiling gas, and the operation of producing ferronic acid using a blast furnace can be carried out stably. Next, the material and heat balance in the blast furnace operation of the present invention will be explained. Table 1 shows the calculation conditions.

[Table] The calculation results are shown in Figures 2 and 3. Figure 2 is a heat diagram. This figure shows that in the case of ferronic ore, the amount of slag is excessive (approximately 7000Kg/T), and the sensible heat taken out is large, but the latent heat of vaporization of ore moisture is very large, and the furnace is lower than the lower part of the furnace. There seems to be a lack of heat at the top, and the fuel ratio is high. Coke ratio CR 2500
When changing from Kg/T to 1500 Kg/T, in the case of the comparative example in which no preheating gas is blown, there is a lack of heat in the upper part of the furnace. However, in the method of the embodiment, since preheated gas at 1000°C is blown, the heat deficiency can be overcome even if the coke ratio is lowered to 1500 kg/T. Figure 3 shows the relationship between furnace top gas temperature and coke ratio. From this figure, it can be seen that when the coke ratio is lowered, the furnace top temperature drops significantly, making it necessary to blow preheating gas. Table 2 shows the main unit consumption items, heat balance, and gas amount.

【table】

[Table] *Excluding circulating gas From Table 2, if you try to fill the energy required for water evaporation with gas from the tuyere tip (comparison method), the required amount of boiling gas, that is, the fuel ratio FR will increase. As the fuel ratio FR increases, the exhaust gas latent heat increases and the required amount of heat increases. In this embodiment, the heat balance is satisfied by blowing in a large amount of gas at a low temperature level by blowing in preheated gas. That is, it can be seen that in the example, since the fuel ratio is low, the amount of boiling gas can be reduced. Since ferronite ore has a very large amount of slag and is close to the flattening limit, productivity can be increased by lowering the amount of slag gas. (Effects of the Invention) According to the present invention, since preheating gas is injected from the middle stage of the furnace, it helps the evaporation of moisture, reduces the coke ratio, lowers the furnace top gas temperature, and lowers the amount of boiling gas, thereby improving productivity. It is possible to improve the efficiency and stabilize operations.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a blast furnace operating method showing an embodiment of the present invention, Fig. 2 is a diagram showing the relationship between temperature and amount of heat, and Fig. 3 is a diagram showing the relationship between furnace top temperature and coke ratio. be. 1... Blast furnace, 2... Tuyere, 3... Middle stage of the furnace.

Claims (1)

[Claims] 1. A method for producing ferro-nickel, which comprises inserting nickel ore from the upper part of the furnace, blowing hot air through the tuyeres, and blowing preheated gas through the shaft section in the middle of the furnace.