Purifying method for ultra-pure aluminum

Abstract

The invention relates to a purifying method for ultra-pure aluminum. The purifying method specifically comprises the following steps: injecting molten aluminum with purity being 4N6 into a cast iron crucible, and heating the molten aluminum by a heating wire on the outer wall of the cast iron crucible for preserving the temperature of the molten aluminum to be 680-700 DEG C; stretching seed crystals above the cast iron crucible into a position 2-3cm under the liquid level of the molten aluminum, and introducing cooling gas to the other ends of the seed crystals to cool and crystallize the molten aluminum; spirally rotating the seed crystals in the cast iron crucible, thereby enabling the molten aluminum to carry out rotary motion in the cast iron crucible; and after the crystallizing is ended, quickly pulling out the seed crystals with crystallized ingots, and finally enabling the crystal seeds and the formed crystallized ingots to be in shape of inverted mushroom. The purifying method has the advantages of greatly reducing the purifying cost, and greatly improving the purifying efficiency and the purifying purity, and is suitable for industrial production.

Description

technical field [0001] The invention relates to a method for purifying metal aluminum, in particular to a method for purifying ultra-high-purity aluminum. Background technique [0002] With the continuous progress and development of science and technology, ultra-high-purity aluminum (aluminum products with a purity of more than 5N are called ultra-high-purity) are widely used in electronics, aviation, navigation, chemical and defense industries, and their consumption is increasing year by year. However, there are very few domestic companies that can produce 5N5 ultra-high-purity aluminum to meet the needs of users, and there are only a handful of R&D units. Therefore, most of the ultra-high-purity aluminum required in China needs to be imported. How to solve the above problems is the top priority of domestic demand. [0003] Although some domestic enterprises are already in trial production or large-scale production of ultra-high-purity aluminum, there is a big gap compared ...

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Problems solved by technology

[0003] Although some domestic enterprises have been in trial production or large-scale production of ultra-high-purity aluminum, there is a big gap compared with similar foreign enterprises, and there are many deficiencies: 1. The equipment and process are relatively complicated, and it uses multi-disciplinary technology to make The investment cost is too large, and it is inconvenient to control; 2. The efficiency of impurity discharge is not ideal, and no qualified products can be produced; 3. The energy consumption is high, reaching more than 15000KWH/ton, which is contrary to the national energy saving and emission reduction policy. 4. Although the products are produced, the quality is still unstable, making it impossible for domestic users to use

[0004] After searching the literature of the prior art, it was found that Chinese Patent No. 200910045029.0 proposed a method for ultrasonic purification of high-purity aluminum. The method is specifically to melt the aluminum in the crucible after passing an inert protective gas into the heating furnace cavity; the aluminum liquid is heated to 660°C-750°C, insert the seed crystal under the liquid surface of the aluminum melt, turn on the ultrasonic generator, and the other end of the seed crystal is forced to cool by water cooling to ensure a temperature gradient of 100-300K/cm at the front of the interface; put the melt The temperature is controlled near the melting point. After the crystallization starts, slowly pull up the seed crystal or slowly pull down the crucible containing the aluminum melt, and control the crystallization speed at 5-25cm/h, and keep the pulling speed and crystallization speed consistent; control the ultrasonic The power is between 0.2kw-10kw, and the final formed aluminu

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