Manganese-rich slag production method and process

At present, there are three methods for producing and smelting manganese- rich slag: blast furnace method, electric furnace method and converter method, wherein the blast furnace method and the electric furnace method are selective reduction, and the converter method is selective oxidation. The process is divided as follows:
(1) Production of manganese-rich slag and the blast furnace process generally similar to blast furnace pig iron, which scales the process shown in Figure 1.

The smelting of manganese-rich slag in blast furnace is the main method for enriching high-iron and high- phosphorus manganese-rich ore in high-iron and high- phosphorus treatment by fire method, and it is also a method applied at home and abroad. The basic principle is selective reduction (iron, phosphorus is reduced into pig iron, manganese high-valent oxide is reduced to low-oxide) and carbonate decomposition and crystallization water volatilization under high temperature, thereby achieving manganese enrichment. . The most critical of these is selective reduction.
Basically it is acceptable to charge (manganese ore and coke) from the roof into the furnace, hot air into the furnace from the lower drum, combustion of the coke, the coal gas generated _{(CO, CO 2, H 2} , N 2) Rise and release a lot of heat. In the blast furnace, a series of physical and chemical changes occur in the relative movement of gas rise and charge drop. The iron and phosphorus in the ore are reduced to form pig iron, and the high-valent oxide of manganese is reduced to a low-valent oxide, and then MnO and SiO _{2 in the} gangue form Mn ₂ SiO ₄ to enter the slag. After the gas escapes from the top of the furnace and is dedusted and purified, it is used as a hot blast stove or other fuel. The smelted slag iron is discharged through the iron mouth, and is separated in the iron mold and the slag tray after being separated in the furnace, or directly sent to the user.
(2) The electric furnace smelting manganese-rich slag mostly adopts a reduction electric furnace (mineral furnace), and the process flow is shown in Fig. 2.

The basic principle of smelting manganese-rich slag in electric furnace is consistent with smelting manganese-rich slag in blast furnace. The difference is that the heat source is different. The blast furnace smelting is the coke fuel combustion heat, while the electric furnace smelting is the electric energy heating. Adding a small amount of coke is only used as a reducing agent, adding a small amount of fluorite or silica as a flux, the electric furnace is not blasting, so the gas generation Less. [next]
The electric furnace smelting manganese-rich slag is to fill the furnace charge (manganese ore, coke, fluorite or silica) into the furnace from the top of the furnace, and then insert three electrodes into the furnace. The electric current is introduced into the furnace from the electrode, and the electric furnace relies on the generated arc. thermal and current charge is heated by the heat resistance when the metal and slag produced, the molten ore smelting. A series of physical and chemical reactions in the furnace smelting process are the same as those in the blast furnace. The metal and slag produced by smelting are collected at the bottom of the furnace and discharged regularly through the taphole. After the manganese slag and the molten iron flow out, they are separately ingots after being separated, and as the charge of the furnace is melted, the new charge is continuously added from the top of the furnace, and the smelting process is continuously performed.
(3) The manganese-rich slag of converter smelting adopts selective oxidation and low-temperature blowing, and the furnace temperature is controlled at 1350~1400°C. The converter process produces manganese-rich slag, which has not been adopted in China, and there are not many practical applications.
The basic principle of converter smelting manganese-rich slag is selective oxidation. According to the different oxidation properties of manganese, iron, phosphorus, silicon and other elements, the oxidation of phosphorus and iron is inhibited while ensuring sufficient oxidation of silicon and manganese. The smelting process of the manganese-rich slag in the converter is to use the mirror iron (low-grade ferromanganese) to blow oxygen in the converter, and add slag-forming flux to make the manganese in the molten iron preferentially and enriched in the slag in the form of MnO to form manganese-rich slag. Iron and phosphorus in molten iron are not oxidized or oxidized as much as possible, and do not enter or enter the slag to become semi-steel.
This section only discusses the blast furnace method and the electric furnace method which are used more. Table 1 lists the comparison of the basic characteristics of manganese-rich slag in electric furnace and smelting manganese-rich slag in blast furnace. The relevant indicators are compared in Table 2.

What method is used to smelt manganese-rich slag? First, we must look at the energy supply situation. Second, we must look at the quality requirements of manganese-rich slag. When the electric energy is rich and the product quality is high, the electric furnace method can be used. Otherwise, the blast furnace method is used.

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