Energy Saving Analysis of Electromagnetic Stirrer in Aluminum Smelting

After the application of electromagnetic stirrers, the aluminum alloy production technical indicators have reached the domestic advanced level, saving energy, reducing costs, enhancing market competitiveness, and greatly improving its survivability. Some of the materials in the "Research on energy-saving technologies for aluminum alloy furnaces" are now extracted as follows:

The design report's advanced technology and equipment must be combined with a high-level rapid smelting process in order to obtain higher comprehensive technical and economic indicators. In the premise of ensuring the quality of the melt, try to increase the melting speed. From the viewpoint of energy conservation, all invalid heat losses increase with time. Therefore, shortening the operation time of each step of the metal melting can increase the productivity of the furnace, reduce the energy consumption, and have obvious economic benefits.

The heating and melting of the charge occupies about 70%-80% of the entire smelting time, which is the most energy-consuming process in aluminum smelting. The heat load should be increased to achieve forced melting to increase the melting capacity of the furnace. When melted, the temperature difference between the surface layer of the melt and the bottom of the melt is about 200°C. The unmelted temperature is at the bottom of the furnace. If the melt is not stirred, the melting time will be prolonged and the surface melt will burn. Therefore, the melt must be agitated to enhance convective heat transfer and to accelerate the melting of the furnace bottom charge. At the same time, the liquid surface temperature becomes lower, and the temperature difference between the high-temperature combustion gas increases, which is favorable for accelerating the exchange of heat. Practice has proved that after forced stirring, the temperature difference between the upper and lower sides of the melt decreases from 200° C. to about 10° C., and is the alloying element. Homogenization creates good dynamic conditions. Electromagnetic stirring can work with a small amount of melt, can increase the melting rate 10-45%, electromagnetic equipment is easy to automate, and can work according to a given procedure.

The bottom induction electromagnetic stirrer is a device that does not contact with the aluminum solution and stirs the aluminum liquid by electromagnetic force. This device can completely replace the external force stirring device such as artificial and mechanical, and basically realizes the closed door operation and can improve The overall homogeneity of the various types and gold shortens the melting time, reduces metal burnout, and improves the quality of the product.

The company uses a set of plate-type furnace bottom stirring device to stir the two stirring furnaces through the walking of the sensor, which greatly reduces the equipment cost.

Industrial Application Report Smelting Test Process Record Material Preparation According to calculations and raw material conditions, a total of 9946 kg of material is prepared. See Table 1 for the smelting process.

Table 1 Smelting Records (ZL102)

Step Time Furnace Operation 19:20 Furnace 750°C

29:20-9:40 Solid material plus cutting head 3252kg, adding aluminum ingot 3210kg, igniting two burners to start melting 310:20 start melt stop, adding 30kg covering agent, ignition, continue to melt 411:20 to melt all electromagnetic stirring 10 minutes 511:35 total melting temperature 695 °C, a ceasefire, ready to add the remaining part of the material 611:50 solid added to the remaining aluminum ingot 3295kg, adding 187kg of ZLD102 alloy, after the end of ignition melting.

712:20 All melted and electromagnetic stirring for 10 minutes 812:30 Total melting temperature measurement 736°C

912:45 Fully melted sampled and sent to analysis 1013:00 Fully melted, analyzed and purified. The slag 1113:20 was completely melted and started casting. The temperature in the casting furnace was 731°C.

Electromagnetic Stirrer Test The electromagnetic stirrer test is performed in a smelting furnace. The equipment runs well and the mixing force is adjusted in four stages. From visual inspection and sampling analysis, the stirring effect is very good. At the same time, the smelting time and burning loss can be significantly shortened. .

Stirring effect 1 Aluminum alloy quality The deviation of the liquid composition of the alloy is less than 0.3%, which improves the quality of the aluminum alloy. Table 2 is a sample analysis report of alloy composition.

Table 2 Sample analysis report of ZL102 alloy composition

Sample No. SiFeCuAl

111.50.48<0.005 Balance 211.60.47<0.005 Balance 311.40.47<0.005 Balance 411.40.49<0.005 Balance 511.30.48<0.005 Balance 611.50.46<0.005 Balance 711.40.49<0.005 Balance 811.30 .49<0.005 Balance 911.60.50<0.005 Balance 1011.40.48<0.005 Balance 1111.50.49<0.005 Balance 1211.50.48<0.005 Balance 2 Melt temperature difference is small Usually the upper heated melt is not stirred Under the circumstances, every 100 mm of melt depth, the temperature difference between up and down can reach 20°. After electromagnetic stirring for 15 minutes, the measured temperature difference is generally about 10°C. The measured conditions are as follows in Table 3:

Table 3 Electromagnetic stirring is not performed Melt surface and bottom temperature (°C)

Sample No. Surface Layer Lower Temperature Difference 1793687106

2805698107

380070298

4810695115

5806690116

Average 803694109

Table 4 Electromagnetic stirring for 15 minutes Melt surface and bottom temperature (°C)

Sample No. Surface Layer Lower Temperature Difference 175574510

27507446

37467433

47487453

57507446

Average 7507446

3 Non-polluting Melt Electromagnetic stirring is not non-contact stirring, so the mixing process will not cause pollution to the melt, which is of great significance for maintaining the original alloy composition and controlling the iron content.

4 Shorten the smelting time and improve the production capacity of the equipment. Because the electromagnetic stirrer can fully stir the melt, the melt temperature is uniform, the alloy composition can be well dispersed, and the mass transfer and heat transfer of the melt are promoted, and thus can be shortened. Melting time. The smelting of the ZL102 alloy with one pass of the component shortens the smelting time by more than 20%, and the production capacity of the equipment has been improved.

5 It can reduce energy consumption Different from the manual mixing method used in the past, since the use of electromagnetic stirring does not have to open the furnace door, it can reduce the heat loss. In addition, melting can be performed at a low temperature, so that the temperature of the gas in the furnace can be reduced, thereby reducing the heat loss of the exhaust gas and the heat loss through the furnace wall. In addition, since the melting time is shortened, and because the melt temperature is uniform, the melt temperature can be lowered by 50° C. during the smelting process, and energy consumption can be reduced by more than 20%.

6 can reduce the labor intensity of workers The electromagnetic stirrer is simple and easy to operate. When the furnace is running, there is no need to power off and open the furnace door. Workers' labor intensity and working environment are improved.

7 Fuel consumption and metal balance 9:20 Before the ignition, the number of fuel flow meters showed 237,589 litres, 13:20 showed 238,501 litres, and the first test shared 912 liters of heavy diesel oil, which was about 729.6kg. The average fuel consumption is 73.36kg/t-AL.

The various aluminum slags in the production process are measured as follows:

Product: 9459kg

Residual aluminum in the furnace (estimated): 400kg

Loss of aluminum: 87kg

Metal loss rate: 0.88%