Silicon-manganese alloy is an alloy composed of manganese, silicon, iron, and a small amount of carbon and other elements. It is a ferroalloy with wide application and large output. The ferro silico manganese manufacturers are mainly in the southwest of China, such as Yunnan, Guizhou, Guangxi, Hunan, and other places. ZXferroalloy mainly produces
The Production Process of Silicon Manganese 60/14
The raw materials for the production of silicomanganese alloys include manganese ore, manganese-rich slag, silica, coke, etc. Silicon-manganese alloys can be smelted in continuous operation in large, medium, and small submerged arc furnaces, all of which are produced by simultaneously reducing manganese oxide and silicon dioxide in manganese ore and silica with charcoal in submerged arc furnaces.
Manganese-silicon alloy is a compound deoxidizer commonly used in steelmaking, and also a reducing agent for the production of manganese metal by low-carbon ferromanganese and electrosilicothermal method. With the rapid development of my country’s iron and steel industry and the expansion of demand, the ferroalloy industry has achieved considerable development and progress. In 2018, my country’s silicon-manganese production reached 9.45 million tons, accounting for 30.3% of ferroalloy production, an increase of 1.43 times compared to 2017. The production capacity of silicomanganese is gradually transferred to Ningxia, Guangxi, Inner Mongolia, Guizhou, and other places, which are the main provinces to increase production. The production capacity under construction is also mainly concentrated in Yunnan, Inner Mongolia, Ningxia, Guizhou, Chongqing, and other places. Companies such as Anyang ZXferroalloy, Ningxia Shengyan, Wulanchabu Xufeng Xinchuang, and Huiyi Ferroalloy are among the top silicomanganese enterprises in terms of output.
In the context of advocating environmental protection and energy saving, silicon-manganese alloys need to use various control measures reasonably in the production process in order to achieve the goal of energy saving and consumption reduction. Because silicon-manganese alloy enterprises will discharge a large number of harmful gases such as smoke, dust, and sulfur dioxide to the outside during the production process, causing pollution to the atmosphere; producing volatile phenols, cyanide, ammonia nitrogen, and other substances that pollute water bodies, as well as dust, sludge, and waste residues and other solid pollutants. The environmental pollution caused by silicon-manganese alloy production requires enterprises to pay attention to energy-saving production, clean production, and better protect the environment.
Traditional Pollution Control Methods and Deficiencies in Silicomanganese Production
The traditional pollution control of silicomanganese production adopts the concept of terminal control, that is, after the pollution occurs, targeted measures are taken for air pollution, water pollution, or solid pollution. This control concept played an important role in the early pollution control of silicomanganese alloy production. However, with the improvement of production efficiency and the acceleration of industrialization in silicomanganese alloy enterprises, there are more and more shortcomings of this concept, such as investment The cost is getting bigger and bigger, the economic benefits are getting lower and lower, and the pollution control effect is getting worse and worse. From the perspective of technology, the traditional pollution control of silicomanganese production is mainly controlled by computer and slag retention methods. For example, the use of hollow electrode equipment improves the power consumption of the submerged arc furnace itself, which has the effect of saving energy and reducing consumption; Some DC submerged arc furnaces, low-voltage compensation, low-frequency power supply, and other technologies have also been applied to the production of silicon-manganese alloys, which have played a good role in protecting the environment and controlling pollution. However, the development of many technologies is not mature enough, and the effect in reducing costs and controlling pollution is not satisfactory.
Based on the disadvantages of the traditional pollution control of silicomanganese production, both the production practice field and the academic field have begun to pay attention to the use of skills and technologies in the production process and to achieve clean production from the goal of source control pollution.
Energy-saving Technology for Silicon-manganese Alloy Production
At present, there are many skills and technologies related to the production of silicon-manganese alloys. Some technologies started earlier because they are more mature, and some technologies are in the development stage. Silicon-manganese alloy production enterprises should make scientific choices in combination with their own economic strength and production scale.
(1) Hollow Electrode Technology
This technology appeared earlier and began to be used as early as the middle of the last century, but it was not until the end of the 20th century that it achieved obvious results in terms of energy saving in the production of silicon-manganese alloys. The principle of the hollow electrode technology is that the electrode is placed on the central tube, and the solid electrode is hollowed out to achieve free control in time. According to actual needs, an appropriate amount of powder and raw materials can be added to the furnace to save energy.
First of all, the use of hollow electrode technology can put the pulverized coal into the furnace for use, and the loss of the electrode in the reduction reaction is greatly reduced, which realizes electrode saving. The arc and resistance will increase due to the cooling of the arc body. The principle is that the feeding process of the hollow electrode is continuous, and the continuous material flow will cool the arc body when it passes through the bottom of the electrode. Therefore, high voltage and low current can be used in the production of silicon-manganese alloys to reduce electrode diameter and reduce electrode wear. Through the application of hollow electrode technology, enterprises can reduce the large number of motor shells and electrode paste, and at the same time, according to statistics, it can reduce electrode consumption by about 40%.
Secondly, adjust the insertion depth of the electrode to achieve the effect of saving materials. There is a certain proportional relationship between the reducing agent and the electrode insertion depth in the batch, and this ratio will directly affect the amount of material and electric energy. The hollow electrode is used to adjust the proportion of carbon content in the charge, and the depth of the electrode is adjusted to control it within a certain range, so as to achieve obvious energy-saving effects. In the production of silicon-manganese alloy enterprises, the use of hollow motor technology can save about
Save 15% of electric energy and 40% of electrode consumption, reduce the number of materials added, and save nearly 200 yuan per ton of iron cost.
(2) Smelting Cycle Control Technology
The smelting cycle control technology is to control the smelting cycle of the silicon-manganese alloy in the submerged arc furnace and extend the time appropriately, but not too long. By appropriately prolonging the smelting time and controlling the reduction period of the elements Mn and Si in the slag according to the capacity of the molten pool reaction zone in the furnace, the slag ratio is as low as possible. The silicon-manganese alloy submerged arc furnace implements a low slag ratio smelting operation, the active power, and temperature in the furnace are greatly increased, and the temperature conditions in the coke layer reaction zone in the furnace are more conducive to the reduction rate of Mn and Si, thus realizing the saving of electric energy.
The extension of the smelting time should be moderate, avoiding excessively long tapping temperatures, which will cause too much volatilization and loss of manganese in the alloy, and the recovery rate of Mn will be greatly reduced. If the smelting time is too long, there will be too much power loss due to the large amount of “slag” produced. Therefore, when silicon-manganese alloy enterprises use this technology, they must operate according to the actual conditions on site and control the extended time. According to experience, the smelting time of a small submerged arc furnace is about 5 hours, and the smelting time of a large submerged arc furnace is about 3.5 hours.
(3) DC Submerged Arc Furnace Technology
Modern DC electric furnace technology was first developed by ASEA Company. After years of development and use, it has achieved remarkable results in ferroalloy smelting, so it has been applied in production by some silicon-manganese alloy enterprises.
The advantages of a DC submerged arc furnace are less electrode consumption, stable arc, low noise, relatively concentrated power, and high production efficiency. Due to the uniform temperature distribution in the single-electrode DC submerged arc furnace, there will be no problem with hot and cold areas of the charge, so the power distribution is balanced, and the positions of the electrode column and the fume hood can be effectively divided. However, in practice, it is easily constrained by conditions such as DC power supply equipment, large-capacity transformers, and self-baking electrode diameters. Therefore, although the electrode distribution of the three-electrode DC submerged arc furnace has the situation of hot and cold areas of the charge, if we further develop and transform the technology of the three-phase electrode tributary furnace, it will well cater to the capacity of the submerged arc furnace in our country, and many The plant structure and three-phase motor equipment of silicon-manganese alloy enterprises are of great significance for silicon-manganese alloy enterprises to reduce production costs and improve process procedures and will help enterprises to realize the target of their skill.
(4) Operation Technology of Iron Retention Method
One of Japan’s silicon-manganese alloy production technologies is the iron-retaining method. This technology abandons the arc heat and replaces it with the resistance heat of slag to expand the reaction zone in the furnace. Through this principle, the reduction of power consumption, the recovery rate of silicon and manganese, and the goal of increasing production are realized. With the method of leaving iron, the temperature of the molten slag released during the tapping operation is easier to control, ensuring stability; at the same time, the energy conversion rate in the slag can be controlled, and the reaction zone is expanded, so the gas distribution is relatively uniform, which is conducive to the utilization of heat; the separation efficiency is high, and the separation of slag and alloy is more thorough. The smelting of silicon-manganese alloy and high-carbon ferromanganese can be operated by the iron retention method, and the relevant technical indicators can be greatly improved. At the same time, the production capacity of the electric furnace has also been guaranteed and improved.
(5) Low Voltage Compensation Technology
Since the 21st century, reactive low-voltage compensation equipment for submerged arc furnaces has been used in production practice and has been well received by enterprises. The problem of reactive power consumption such as load impedance, transformer, and short network is a common occurrence in the operation of manganese silicon furnaces. In order to solve these problems, it can be realized through low-voltage reactive power compensation technology. The application of low-voltage reactive power compensation technology can specifically compensate for the consumption of high-voltage lines, transformers, and short-circuit networks, thereby increasing power. Low-voltage reactive power compensation technology is more suitable for three-phase submerged arc furnaces. Through the increase of capacitance in each link, it can change the crucible AC problem in the furnace caused by the difference in electrode insertion depth, improve production, and ensure that the power factor of three-phase electrodes remains consistent ( greater than 0.9). Due to the application of low-voltage reactive power compensation technology, the balance of three-phase active power is ensured, the thermal center, power center, and furnace center of the electric furnace are integrated, and the crucible in the furnace can communicate and expand effectively to achieve uniform heat distribution and energy saving.
(6) Adjustment Technology of Coke Dosage and Particle Size Distribution
The coke layer is attached to the furnace, and its position is between the solid slag layer and the hydraulic smelting layer. The thickness and specific position of the coke layer have a great influence on the electrode. Therefore, it is very important to control the thickness of the coke layer, and the position of the working end of the electrode can be changed. and electrode operation stability. How to adjust the thickness of the coke layer? It is a very good technology to adjust the particle size and increase the coke dosage. Through the adjustment of the particle size, the depth of the electrode and the temperature of the molten pool can be controlled, and the power consumption and slag ratio can be reduced. Generally speaking, the particle size of coke in a large furnace is about 15-30mm, and the particle size of coke in a small furnace is about 10-20mm.
In addition, there are charge resistance technology, reasonable slag type technology, manganese-containing material grade technology and technology to reduce slag ratio, etc. The core concepts of these technologies are to reduce slag ratio, reduce slag viscosity, slag amount, increase furnace temperature, and improve the Manganese recovery rate, save electricity. In the process of application, silicon-manganese alloy production enterprises should make scientific choices according to the actual situation.
Conclusion
There are many energy-saving technologies that can be used in the production process of silicon-manganese alloys. Through the application of one or several energy-saving technologies, for silicon-manganese alloy production enterprises, it is possible to reduce electric energy and control pollution.
Target. In the future, the promotion of energy saving and consumption reduction, and clean production will be one of the inevitable trends in the development of the silicon-manganese alloy industry. Therefore, the industry has high energy consumption and high pollution, and there is a lot of room for control through various advanced technologies. Silicon-manganese alloy enterprises should formulate scientific production technology measures and plans in combination with their own reality, strengthen awareness of energy saving and consumption reduction, improve environmental protection and energy-saving awareness, constantly discover and improve existing problems in the production of silicon-manganese alloys, improve environmental benefits, social and economic benefits.