1. Impact of improving the life of the furnace lining on energy saving

The selection of furnace construction technology and furnace baking and sintering technology should ensure that a reasonable three-layer structure is obtained after the furnace lining is sintered, that is, the initial thickness of the sintering layer, semi-sintering layer and buffer layer is roughly 1/3 each. This is an indispensable condition for the furnace lining to have a long service life and ensure safe production. The longer the life of the furnace lining, the less power consumption of furnace construction per furnace.

(1) Change the operating conditions of the medium frequency induction furnace to improve the service life of the furnace lining and reduce losses and save energy. Because the furnace lining undergoes a crucible reaction at high temperature, that is, the silicon dioxide in the furnace lining is reduced by carbon in the molten iron and the furnace lining is corroded quickly, and different slags cause chemical reactions that corrode the furnace lining, the longer the residence time at high temperature intensifies the reaction and shortens the service life of the furnace lining. Therefore, increasing the configuration power of the medium frequency induction furnace and melting in a short time can effectively extend the service life of the furnace lining and thus save energy and reduce consumption.

(2) Select a neutral furnace lining. Research in recent years has shown that neutral furnace lining (high-aluminum refractory material) is widely used in the smelting of various ferrous metals and non-ferrous metals and their alloys, and is particularly suitable for the precision casting industry's requirements for a wide variety of products and high quality. It has high thermal resistance and high refractoriness, which can reach a maximum of more than 1800°C. The life of the furnace is greatly extended, the cost of maintenance and furnace construction is greatly reduced, and the harm of quartz sand dust to human health is eliminated. Based on an annual output of 380 tons of alloy steel, the use of neutral furnace lining can save more than 20,000 yuan in material and maintenance costs per year compared with acidic furnace lining.

2. Analysis of energy saving in smelting process

(1) Reasonable batching. Scientific management of furnace charge is of great significance to improving the production efficiency of medium frequency induction furnaces and reducing energy consumption. Try to avoid delaying the smelting time due to adjusting the composition, and prevent the scrapping of iron (steel) liquid due to unqualified composition, which increases material consumption and electricity consumption. The charge must be properly classified according to the chemical composition, impurity content and block size, cut large and long scrap steel, and package light and thin materials if possible to ensure smooth charging and reduce smelting. The size of the charge block should be adapted to the power frequency. The power frequency used in the induction furnace decreases with the increase of the furnace capacity. The induction current penetration depth and the geometric size of the metal charge are properly matched (when the metal charge diameter/induction current penetration depth/>10, the furnace electrical efficiency is the highest) to shorten the heating time, improve thermal efficiency and reduce power consumption. For example, the appropriate charge block size for Hz medium frequency power supply is 8 cm, and the appropriate charge block size for 1000Hz medium frequency power supply is 5.7 cm.

(2) Extend the continuous smelting time. The unit power consumption is closely related to the smelting method. Data show that, considering the energy loss required for melting and overheating of slag, the unit power consumption of an advanced medium-frequency induction furnace during cold start is 580KW·h/t, and the unit power consumption during hot furnace operation is 505-545KW·h/t. If continuous charging is performed, the unit power consumption is only 494KW·h/t. Therefore, if conditions permit, centralized continuous smelting should be arranged as much as possible, and the number of smelting furnaces should be increased as much as possible to extend the continuous smelting time, reduce the number of cold furnace smelting, and thus reduce power consumption.

(3) Reasonable smelting operation

First, scientific charging,

Second, adopt a reasonable power supply system.

Third, adopt reasonable furnace front operation technology, control the amount of subsequent charge added each time, observe and pound the charge frequently, and prevent the charge from "building a shed". In this smelting operation, the temperature is raised for a short time before pouring, while the molten iron is kept at a low temperature for the rest of the time, which can reduce the erosion of the furnace lining by the high-temperature molten iron, extend the service life of the furnace lining, and reduce power consumption.

Fourth, use reliable temperature control and measurement equipment.

Fifth, promote direct reading spectroscopy to shorten the time for casting composition inspection.

Sixth, strictly control the temperature of steel and iron liquid out of the furnace.

Seventh, timely and sufficient application of thermal insulation covering agent and slag remover. After the molten steel is transferred to the ladle, an appropriate amount of thermal insulation covering agent and slag remover should be applied immediately to reduce the heat loss of the molten steel during the calm pouring process, and the steel tapping temperature can be appropriately reduced to save electricity consumption.

(4) Strengthen the management and maintenance of smelting equipment to achieve the purpose of saving electricity and energy. Strengthen the management of smelting equipment, standardize the operating process requirements of furnace construction, furnace drying, sintering, smelting, etc. and the maintenance system of medium frequency power supply, effectively increase the furnace life, ensure the normal operation of the medium frequency power supply, and thus reduce the smelting power consumption.