Method for directional solidification extraction of ultra-high-purity aluminum under electromagnetic agitation

Abstract

The invention relates to metal purification, and particularly relates to a method for directional solidification extraction of ultra-high-purity aluminum under electromagnetic agitation. The method comprises the following steps: cleaning and baking the surface of to-be-purified refined aluminum, and then loading the to-be-purified refined aluminum into a totally closed furnace jacket with a high-purity graphite crucible to form a furnace pipe; arranging the furnace pipe into an electromagnetic agitation heating furnace; firstly, vacuumizing the furnace pipe by using a vacuum pump, and introducing argon into a standard atmospheric pressure value; heating the furnace pipe, and simultaneously moving an electromagnetic stirring device to the lower part of the furnace body; stirring molten aluminum which is firstly molten until the original aluminum is completely molten by matching with a heating system; pulling out the furnace pipe from an electromagnetic stirring furnace by using a lifting device at a constant speed, simultaneously moving the electromagnetic stirring device to the front edge of a solid-liquid interface of the molten aluminum; carrying out axial flow agitation on the molten aluminum at the front edge of the solid-liquid surface, and simultaneously cooling the furnace pipe part which is pulled out of the furnace body by using a cooling device arranged at the position of a fire hole; stopping crystallizing after 4-5 hours, wherein 2-3cm part of the upper end of the product aluminum ingot is cut off, the lower end is cut off by being15-20% of the original weight, and the remaining part is over 5N of product.

Description

technical field [0001] The invention belongs to the technical field of metal purification, and relates to a method for extracting ultra-high-purity aluminum by directional solidification under electromagnetic stirring. Background technique [0002] The extraction of ultra-high-purity aluminum by segregation method has been widely used in the prior art. Chinese patent document number CN101191160 records a "high-purity aluminum extraction device". The aluminum liquid is gradually solidified from top to bottom, but due to the limitation of heat dissipation conditions, the solidified aluminum ingot is still in a high temperature state, which leads to a decrease in the solidification speed of the aluminum liquid in the later stage, poor purification effect, and long production cycle; In the initial stage, the heat loss is mainly due to the convective heat transfer of the water cooling jacket. As the crucible rises, the height of the high-temperature aluminum ingot being pulled ou...

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Problems solved by technology

[0004] Further search found that Chinese Patent Document No. CN102277505 records a "directional solidification method for purifying high-purity aluminum and its smelting furnace". Multiple heating devices from top to bottom melt the aluminum ingot, and then use the cooling device at the bottom and the heating device of the furnace body to make the molten aluminum have a certain temperature gradient, so that it solidifies from bottom to top, while using mechanical devices or electromagnetic fields Stir the liquid at the front of the solid-liquid interface to achieve the purification effect. Although the structure of the invention is reasonable, it is easy to cause secondary pollution by using a mechanical device to stir the aluminum liquid. Stir to improve melting efficiency. In addition, there is no gas protection in the whole purification process, resulting in low purification efficiency

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