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用5■公斤批量熔体研究了从Al—Mg合金中除钠,使之降到1ppm水平。采用了不同的方法:用叶轮机械搅拌;叶轮搅拌+MgCl_2盐覆盖;叶轮搅拌+惰性气体(氩气)吹洗,同时用盐覆盖或不用盐覆盖;叶轮搅拌,惰性气体+2％Cl_2吹洗。叶轮有一个单一的气体入口与空心轴相通。本试验给出了Na-时间关系曲线,它是用Na+1/2Cl_2=NaCl反应的化学计算法简单确定的。其理由是气泡熔体的接触面积足够大。在各个试验中发现镁都没有明显的去掉。如果接触面积不够大,除钠应该是由熔体中质量迁移起支配作用。文中也处理了这种情况的动力学。根据各种实验室的试验确定了顶部表面的质量迁移系数。在除去溶解氧的水模型试验中,测定了叶轮不同转速和气体不同流量下的接触面积。这些结果与带有多孔装置的化学工程系统有比较好的一致性。然而,不知道这些结果能否满意地推广到工业规模的装置上。
The 5-kg bulk melt was used to study the removal of sodium from Al-Mg alloys to a level of 1 ppm. Different methods were used: mechanical agitation with impeller; impeller agitated with MgCl 2 salt; impeller agitated + inert gas (argon) purged with or without salt; impeller agitated, inert gas + 2% Cl 2 purge . The impeller has a single gas inlet communicating with the hollow shaft. This test gives the Na-time curve, which is simply determined using the stoichiometry of the Na + 1 / 2Cl 2 = NaCl reaction. The reason is that the bubble melt contact area is large enough. Magnesium was not significantly removed in all tests. If the contact area is not large enough, the removal of sodium should be dominated by the mass transfer in the melt. The article also deals with the dynamics of this situation. The mass transfer coefficient of the top surface was determined according to various laboratory tests. In the water model test to remove dissolved oxygen, the contact area of the impeller at different rotational speeds and different gas flow rates was measured. These results are in good agreement with chemical engineering systems with porous devices. However, it is not known whether these results can satisfactorily be extended to industrial-scale devices.