Manganese iron smelting furnace charcoal for heating and reducing agents, in a blast furnace manganese and iron oxides reduced to form ferromanganese alloy and slag, coal gas, is a series of complex physical and chemical processes. The rock phase analysis was carried out at different heights of the smelting ferromanganese blast furnace, and the viscosity and temperature of the slag were measured. The results of the determination were used to prepare the slag forming process of the ferromanganese blast furnace (Fig. 1). The figure shows that in the temperature range of 600~700 °C, the charge exists in a solid phase, where MnO 2 is reduced to Mn 3 O 4 , and the adsorbed water and the crystal water evaporate. The manganese ore partially enters the plastic state from 750 to 900 °C - ore is sintered, and new mineral phases such as 3CaO·SiO 2 , 2CaO·SiO 2 and 3CaO·2SiO 2 begin to appear. In the temperature range of 800~1000 °C, a liquid phase appears in addition to plasticity. Since the calcium manganese olivine (2CaO·SiO 2 , 2MnO·SiO 2 ) is present in the region to form a liquid phase, the gas permeability of the region is deteriorated. During this temperature range, the ore has softened and transformed into a plastic state and produced a liquid phase initial slag containing manganese. When the temperature is higher than 1100 ° C, the main part of the plastic body except the plastic phase is substantially similar to the upper region, and most of the lime is still a solid phase. In the belly region, due to the direct reduction of a large amount of manganese from the slag, the CaO content in the slag increases sharply, and the MnO content decreases accordingly. In the hearth, the slag finally absorbs the ash in the coke and the CaO, MgO, etc. in the flux to form the final slag. [next] Table 1  Relationship between CaO content and slag and molten iron temperature CaO content /% Hot metal temperature / °C Slag temperature / °C 28 1295 1350 35 1445 1480 39 1515 1587 CaO in the slag can improve the reduction condition of manganese silicate, replace MnO in manganese silicate, increase the concentration of free MnO in the slag, and facilitate the reduction of MnO. The relationship between CaO content and MnO content in slag is shown in Fig. 2. CaO in the slag can increase the temperature of the slag and molten iron, which is beneficial to the reduction of MnO. Table 1 shows the relationship between the CaO content and the temperature of the slag and molten iron. In production, the CaO content in the slag should not exceed the allowable range of blast furnace working conditions, and also has a certain relationship with the content of SiO 2 in the charge. The ratio of n(CaO)/n(SiO 2 ) is slag basicity and CaO content is too high. If the alkalinity of the slag is too high, the hearth will be blocked and the furnace condition will be unsatisfactory. The A1 2 O 3 in the slag also has an effect on the reduction of MnO, as shown in FIG. At the same alkalinity, the MnO content in the slag decreases as the amount of Al 2 O 3 increases. This is because the increase in the A1 2 O 3 content increases the melting point of the slag. The position where the initial slag is formed in the blast furnace is lowered, the preheating of the charge is sufficient, the heat introduced into the hearth is increased, and the reduction speed of MnO is accelerated to create conditions. However, if the content of A1 2 O 3 is too high, the viscosity of the slag will increase, and the reduction condition of MnO will be deteriorated. The blast furnace production practice proves that the content of A1 2 O 3 in the slag should be controlled at 10%~15%, and the highest should not exceed 20%. [next] Production practice shows that the radial distribution of CO 2 in the furnace gas of ferromanganese blast furnace is ideally controlled by a double-peak funnel-shaped curve, as shown in Fig. 4. With this kind of curve operation, the soft melting zone is inverted V type, the "air window" is large in area, and the gas is easy to pass, so that the blast furnace operation is antegrade. Pipe Chamfering Machine,Pipe Tube Chamfering Machine,Pipe Chamfer Machine,Tube Shaping Machine Zhangjiagang heshun machinery manufacturer co.,ltd. , https://www.hspipemachine.com
1. Reduction process of manganese in the blast furnace In the lower temperature region of the upper part of the blast furnace, the high-valent oxide of manganese is easily decomposed and gradually reduced to MnO, but since the manganese ore contains SiO 2 , the MnO does not reach the reduction temperature, ie Combined with SiO2 in the gangue (or in the fuel flux) to form manganese silicate into the slag, the reduction of manganese is actually carried out in the liquid slag. The manganese silicate in the slag is more stable than the free state MnO, making the reduction of manganese more difficult and requiring a higher temperature.
2. Formation of manganese iron slag and its effect on smelting 
During the formation of blast furnace ferromanganese slag, the components in the slag have different effects on smelting.
The suitable MgO in the slag can not only adjust the alkalinity of the slag, but also improve the fluidity of the slag, and create favorable conditions for the reduction of MnO, thereby promoting the improvement of various indexes of the blast furnace. According to domestic production practice, when n(CaO)/n(SiO 2 )=1.40~1.55, the MgO content in the slag increases by 1%, and the MnO content in the slag can be reduced by 0.5%~1%.
3. Formation and movement of gas flow in blast furnace The gas in the blast furnace is generated by coke combustion in the tuyere zone (2C+O 2 ===2CO). The gas distribution generated before the tuyere is called the initial distribution of gas. The distribution is determined by the arrangement of the tuyere, the number of tuyères, the diameter of the tuyere, the angle of the tuyere and the length of the furnace, the amount of wind and the temperature of the wind. The above factors are comprehensively reflected in the blast function. The blasting kinetic energy is high, the gas flow is concentrated to the center, the central airflow is developed, and the edge airflow is developed.
The second distribution of gas occurs in the soft zone in the middle of the blast furnace. The shape of the soft melt zone can be roughly classified into a V shape, an inverted V shape, and a W shape. The shape of the soft melt zone is related to the adjustment of the upper and lower parts of the blast furnace, the temperature distribution in the furnace, and the nature of the charge. The shape of the soft melt zone is different, and the flow direction after the gas passes is also different. According to the analysis of the CO 2 curve of the throat, there are mainly four types of gas flow distribution in the blast furnace.
(1) Edge development type - Gas passes mainly along the edge near the furnace wall.
(2) Bimodal type - Gas passes mainly through two paths, the edge and the center.
(3) Center development type - also called double-peak funnel type, gas is mainly passed by the central area.
(4) Flat type - the gas passes evenly along the cross section of the blast furnace.
The impact of the above four types of gas distribution on the blast furnace smelting process is shown in Table 2.