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Analysis of Slag Melting Process
As can be seen in Fig. 3, the law of basicity influence in the melting temperature of the slag is: With the CaO/SiO2 content increases from 1.05 to 1.25, the beginning of melting temperature and the completely melting temperature of the base slag show a certain degree of increase. When the beginning of the melting temperature improve 10.21 K, the final melting temperature increase 74.5 K. The reason is that it is easy to generate high melting point material such as dicalcium silicate, wollastonite, anorthite which caused the increase of melting temperature with the increase of CaO/SiO2.
After calculating the trace components effect on the melting temperature of molten slag, data can be seen in Table 3.
Fig. 3 Effect of CaO/SiO2 content on melting temperature of slag
Table 3 Melting temperature and complete melting temperature of slag
From the experiment, it can be seen that with the increase of CaO/SiO2, the melting temperature and the melting range of the experimental slag are gradually expanded. The range of difference slag beginning melting temperature was at 37.42 K and completely melting temperature range was at 171.92 K and the minimum melting interval of different calculation samples was 48.08 K and the maximum melting range reached 192.63 K. At the same time, when the content of Al2O3 increases and the content of SiO2 decreases, the melting temperature of slag system will increase, but the effect of the slag system will gradually decrease with the Al2O3 increasing. The main reason lies in that the consolidation reaction and the multiphase reaction occurred before the start of melting in the slag system are almost identical. However, in the complete melting, because of the difference of the material component, the CaO/SiO2 and Al2O3 content can increase so as to form a higher melting point, which leads to an increase in the final total melting temperature and a larger melting range. When analyzing the change of magnesium content, the change of the content of magnesium can adjust the melting point and melting zone of the slag system. The increase of the content of magnesium can improve the melting temperature of slag system and decrease the melting range. For the blast furnace smelting process, the size of softening-melting and dropping zone in the blast furnace can be controlled effectively by adjusting the content of MgO, which can achieve the purpose of strengthening smelting.
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