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利用氧气吹炼镍锍直接得金属镍,其关键在于去锍保镍。本文利用选择性氧化原理,提出氧化转化温度的概念。热力学分析指出,去硫保镍的条件是: 1、镍锍熔体用O_2开吹的温度必须超过该组成硫、镍氧化的转化温度;对含硅20-25％的镍硫,其开吹温度不能低于1350-1400℃。 2、随着熔体中硫含量的减少,相应地硫、镍氧化的转化温度随之增高。吹炼操作必须迅速进行,以保证熔池温度上升的速度永远高于转化温度增高的速度。 硫、镍氧化的转化温度可用一步法按下列反应 [S]+2NiO_((s))=2[Ni]+SO_2进行计算。 热力学分析又指出: 1.镍锍内含铜全部留在熔体之内,在吹炼过程中不被氧化。 2.镍锍中的铁最易被氧化,但当降低到0.8—1.0％后即不能被氧化而以残铁留在熔体之内。 3.镍铳含钴如小于1％也将留在熔体之内。 通过在卡尔多斜吹旋转炉进行的半工业吹炼实验,在采用上列热力学推论得出的去硫保镍条件下,硫能顺利地降到1—2％,充分地证明了理论成功地指导了实践,克服在初期探索性试验中遇到大量镍氧化的困难。在吹炼末期,由于熔体中硫的扩散速度减慢,熔池表面逐渐有NiO层累积。采用不吹氧空转还原,可进一步去硫而提高镍的回收率。镍的直接回收率大于90％,而总回收率大于95％。镍的主要损失来自高温下镍及其氧化物的挥发 熔
The use of oxygen blowing nickel matte directly nickel, the key is to desulfonium nickel. In this paper, using the principle of selective oxidation, proposed oxidation conversion temperature concept. Thermodynamic analysis pointed out that the conditions for nickel sulfide desulfurization is: 1, nickel matte blown with O 2 temperature must exceed the composition of sulfur, nickel oxidation conversion temperature; for silicon 20-25% of the sulfur, it blow The temperature can not be lower than 1350-1400 ℃. 2, with the reduction of sulfur content in the melt, correspondingly, the conversion temperature of sulfur and nickel oxidation increases accordingly. The blowing operation must be carried out quickly to ensure that the temperature of the bath rises faster than the temperature of the conversion. The conversion temperature of sulfur and nickel can be calculated by the following reaction [S] + 2NiO _ ((s)) = 2 [Ni] + SO_2 in one step. Thermodynamic analysis also pointed out: 1. Nickel matte copper all remain in the melt within the blowing process is not oxidized. Iron in nickel matte is the most susceptible to oxidation, but when it is reduced to 0.8 to 1.0%, it can not be oxidized and remains in the melt as residual iron. 3. Nickel 铳 containing cobalt, such as less than 1% will remain in the melt. Through the semi-industrial blowing experiment carried out in the Kaldor oblique rotary kiln, the sulfur energy can be smoothly reduced to 1-2% under the conditions of desulphurization and nickel-nickel based on the above deduction of thermodynamics, which fully proves that the theoretical successful Guided practice to overcome the difficulty of encountering large amounts of nickel oxidation in exploratory experiments in the early stages. At the end of the blowing, due to the slower diffusion of sulfur in the melt, a gradual NiO layer build-up on the bath surface. Adoption of no blowing oxygen reduction, further desulfurization and improve the nickel recovery. The direct nickel recovery is greater than 90%, while the total recovery is greater than 95%. The major loss of nickel comes from the volatilization of nickel and its oxides at high temperatures