Continuous optimization of the structure and quality of fluorine-containing sinter minerals (2)

2. The influence of MgO on the performance of blast furnace slag The work done by the General Research Institute of Steel Research, Baotou Steel Research Institute, Wuhan Steel Institute and other units shows that the fluorine, potassium and sodium slag of Baotou Steel are characterized by low melting point, low viscosity and surface. Low tension and low specific heat are typical short slags. These characteristics are important factors for the often nodulation of Baotou Steel blast furnace. The slag is melted at a higher part, the viscosity is low, and the surface tension is low, so that the slag is easy to flow and soak the furnace material and the furnace wall after melting; the low heat capacity makes the slag change the temperature more than the ordinary slag under the same heat change; The short slag which is easy to melt and condense, the fluctuation of temperature makes it easier for the slag to coagulate and form nodules. In the test, it was found that MgO can change the short slag to the long slag within a certain range, and obviously increase the melting point, surface tension and mass heat capacity of the slag (see Figures 8 and 9), and also have a certain influence on the viscosity. It can be seen that MgO improves the slag fusible and condensable characteristics and improves the stability of the slag.
Several tests have shown that replacing part of CaO with MgO can improve the slag discharge capacity, especially the ability to eliminate K ₂ O, which is harmful to the blast furnace. Although the desulfurization capacity is reduced, the amplitude is relatively small. If the alkalinity and MgO amount of the slag are adjusted appropriately, it is possible to take both alkali and desulfurization into consideration. [next]
3. High alkalinity and high magnesium sinter industrial test In July and August of 1980, the researchers conducted industrial tests on four 75m ² sintering machines and two 1513m ² blast furnaces. For further research, they are still installed along the furnace body. The smelting test was carried out simultaneously on a 55 m ³ small blast furnace of a height sampling and measuring device. The main results are summarized below.
(1) High alkalinity high magnesium sintering industrial test results Due to the high melting point of magnesium oxide, the sintering process index is deteriorated.
(2) The permeability index of the blast furnace increases the small-grained portion of the high-alkalinity high-magnesium sinter (less than 20 mm) and the higher alkalinity sinter, but the low-temperature reduction pulverization rate decreases, and the V/ΔP of the blast furnace increases by about 6%. The small blast furnace load increased and the gas permeability index increased slightly.
(3) The blast furnace soft melt belt is moved down and the hearth is improved. The soft melt belt is moved down by about 1.6 m on the 55 m ³ blast furnace. The slag and iron temperature in the hearth are improved due to the prolonged heating time of the solid material. The problem of insufficient heat in the fluorine-containing ore smelting furnace. Since the reduction of the SiO ₂ reduction space above the tuyere reduces the [Si] in the pig iron, it is advantageous for improving the quality of the pig iron and reducing the coke ratio. The 1513m ³ blast furnace [Si] decreased from 0.84% ​​to 0.76%, [s] decreased from 0.04% to 0.035%, and the molten iron temperature increased by 25-30 ° C. Figure 10 shows the MgO content in the slag and the temperature of [Si] and molten iron. Statistical relationship.

(4) Improvement of alkali discharge capacity of slag slag 1513m ³ blast furnace base slag containing MgO4% ~ 5% and test period MgO 8% ~ 10% alkali, desulfurization capacity and The relationship between MgO content and MgO content is shown in Fig. 11. The calculation shows that 5% MgO replaces CaO, the slag alkali removal capacity is increased by 20%, the desulfurization capacity is only reduced by 6% to 7%, and the 55 ³ m blast furnace is on the 55 ³ m blast furnace. Similar results were obtained. According to the sampling analysis of the small blast furnace, the removal ability of the slag to K ₂ O is mainly improved. The K ₂ O removal rate in the slag is increased from 47.6% to 92% in the reference period, although the Na ₂ O is improved but the amplitude is not large.

InnoColor 1K Multi-Effect Colors

InnoColor Basecoat1K Multi-Effect Colors