Luoyang Judian Metal Hot Processing Equipment Co., LTD is mainly engaged in the manufacture of complete sets of equipment in the metal thermal processing industry and the integration of the entire production line.
There are several main reasons for adding salt when melting aluminum: I. Removing impurities
Adsorption: Salt can combine with impurities in the aluminum liquid in a molten state, such as some oxides, hydroxides, etc. These impurities will affect the quality and performance of aluminum, and the added salt can adsorb these impurities, causing them to aggregate and precipitate to the bottom of the aluminum liquid, making it easier to remove them later.
Forming slag phase: After the salt reacts with impurities, a slag phase with a lighter specific gravity will be formed, floating on the surface of the aluminum liquid, which can be easily skimmed off, thereby improving the purity of the aluminum liquid.
II. Covering protection
Prevent oxidation: Molten aluminum easily reacts with oxygen in the air to form aluminum oxide. After adding salt, a covering layer is formed on the surface of the aluminum liquid, which can prevent oxygen from contacting the aluminum liquid, reduce the occurrence of oxidation reactions, and thus reduce aluminum loss.
Reduce heat loss: This covering layer can also play a certain role in heat preservation, reduce the heat loss of the aluminum liquid, reduce energy consumption, keep the temperature of the aluminum liquid stable, and facilitate the smooth progress of the smelting process.
Improve fluidity
Reduce viscosity: Salt can interact with certain components in the aluminum liquid to reduce the viscosity of the aluminum liquid, making it easier to flow during casting or processing, thereby improving production efficiency and product quality.
Uniform composition: It helps to evenly distribute the components in the aluminum liquid and avoid component segregation.
(3) When does aluminum begin to melt?
The melting point of aluminum is 660.37℃. Aluminum begins to melt when it is heated to 660.37℃. In the actual melting process, the temperature at which melting begins may vary slightly due to factors such as the purity of the aluminum, the heating environment, and the heating speed. If there are impurities in the aluminum, the melting point will usually be lowered, and it may begin to melt at a temperature slightly lower than 660.37℃; if the heating speed is slow, it may take a temperature slightly higher than the melting point to clearly observe the aluminum melting.
(4) What are the three methods for melting aluminum?
The following are three common methods for smelting aluminum:
Reverberatory furnace smelting: This is a traditional smelting method that uses a reverberatory furnace to heat the aluminum raw material to a molten state. Reverberatory furnaces are usually made of refractory materials and use the heat generated by the combustion of fuel to melt aluminum. Generally, they can be divided into natural gas, oil, biomass fuel, etc. according to the type of fuel.
Induction smelting: The alternating magnetic field generated by the induction coil is used to generate an induced current in the metal, thereby heating the metal to melt. This method has a fast heating speed and high energy utilization rate, and is suitable for small-scale smelting.
Arc smelting: In an arc furnace, high temperatures are generated by arc discharge to melt aluminum. Arc smelting is usually used to produce high-purity aluminum or special alloys.
(5) How to effectively reduce burnout during aluminum smelting?
The following are some effective methods to reduce burnout during aluminum smelting:
I. Control the smelting temperature
Avoid excessive temperatures: Strictly control the smelting temperature and do not exceed the melting point of aluminum by too much. Excessive temperatures will accelerate the reaction of aluminum with oxygen in the air and increase burnout.
Use precise temperature measuring equipment: ensure accurate temperature measurement so that heating power can be adjusted in time to prevent excessive temperature fluctuations from causing increased burning.
Use protective atmosphere
Nitrogen or inert gas protection: nitrogen or inert gas (such as argon) is introduced into the melting furnace to form a protective atmosphere, isolate the air from the aluminum liquid, and reduce oxidation burning.
Control gas flow and pressure: ensure that the flow and pressure of the protective gas are appropriate to fully cover the surface of the aluminum liquid and play a protective role.
Add covering agent
Choose a suitable covering agent: use a special aluminum liquid covering agent, such as a mixture of chlorides, fluorides, etc., to form a dense covering layer on the surface of the aluminum liquid, prevent oxygen from entering the aluminum liquid, and reduce burning.
Use covering agent correctly: add covering agent according to the prescribed amount and method to ensure good covering effect.
Optimize smelting operation
Shorten smelting time: minimize the residence time of aluminum liquid at high temperature, speed up the connection between smelting and casting processes, and reduce the risk of burning.
Reduce the number of stirring times: Excessive stirring will increase the contact area between aluminum liquid and air, increasing the burning loss. Under the premise of ensuring uniform composition, try to reduce the number and intensity of stirring.
Prevent aluminum liquid from splashing: During the process of adding materials and stirring, be careful to avoid aluminum liquid splashing and reduce the burning loss caused by the increase in surface area.
V. Improve the quality of raw materials
Select high-purity raw materials: Aluminum raw materials with low impurity content have relatively less oxidation and burning loss during the smelting process. Try to choose high-purity aluminum ingots, waste materials, etc. as raw materials.
Control the quality of waste materials: Strictly screen and pre-treat the recycled waste materials to remove oil, moisture, impurities, etc. to reduce the burning loss during the smelting process.
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