Purification method of ultra-pure aluminum

Abstract

The invention relates to a purification method of ultra-pure aluminum, comprising the following steps: cleaning and drying raw refined aluminum, wherein the purity of the selected refined aluminum is at least 4N6, Mg is less than 6ppm, Ti is less than 0.2ppm and Zr is less than 0.2ppm; loading the selected raw refined aluminum into a purification furnace, sealing and vacuumizing the furnace, and heating to 680-750 DEG C by using a gas furnace to melt the solid raw refined aluminum to form liquid; moving the purification furnace heated to 680-750 DEG C to a crystal growing furnace which is kept at 660 DEG C inside by a crystal growing furnace heater, rotating the aluminum liquid of the purification furnace in the crystal growing furnace heater, and enabling the aluminum liquid inside the purification furnace to self-keep the crystallization speed at 5-10 cm/h by controlling the heat dissipating capacity of the crystal growing furnace and finishing the crystallization after 4-6 hours; cooling the crystallized purification furnace, taking out a crystallization ingot, removing 25-35 percent relative to the mass of the crystallization from the tail part of the crystallization ingot and obtaining a first purified aluminum ingot; placing the first purified aluminum ingot into the purification furnace again, and repeating purification until the aluminum ingot reaching the required precision is obtained.

Description

technical field [0001] The invention relates to a method for purifying metal aluminum, in particular to a method for purifying ultrahigh-purity aluminum. Background technique [0002] With the continuous progress and development of science and technology, ultra-high-purity aluminum (aluminum products with a purity above 5N5 are called ultra-high-purity aluminum.) is widely used in the fields of electronics, aviation, navigation, chemical and national defense industries, and its consumption is increasing year by year. . But now there are very few domestic enterprises that can produce 5N5 ultra-high-purity aluminum that meet the needs of users, and there are only a handful of research and development units. Therefore, most of the ultra-high-purity aluminum needed in China needs to be imported. How to solve the above problems is a top priority for domestic demand. [0003] Although some domestic enterprises have been producing ultra-high-purity aluminum on a trial basis or on ...

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Problems solved by technology

[0004] The first is the equipment, the process is relatively complicated, and the use of multi-disciplinary technology makes the investment cost too high, and it is inconvenient to master and control; secondly, the efficiency of discharging impurities is not ideal, and no qualified products can be produced; the third is high energy consumption. , reaching more than 15,000KWH / ton, which is contrary to the national energy-saving and emission-reduction policy. Although it has been reduced, it is still about 10,000 degrees; Fourth, although the products are produced, the quality is still unstable, making it impossible for domestic users to use

[0005] Specifically, the existing conventional ultra-high-purity aluminum production heating is electromagnetic induction heating and stirring synchronously, using low voltage and high current, the power factor of electrical equipment is less than about 0.3, and it cannot be compensated by super large capacitors, which consumes a lot of power. Due to the melting of aluminum The latent heat is more than 400 times greater than the specific heat, so that more than 80% of the power consumption is used for melting aluminum

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