气泡浮上来，带出夹杂物 ——气泡去除夹杂物技术研究现状及发展（一） Bubbles float up and bring out inclusions: the research status and development of bubble removal technology（part I)）

日前，北京科技大学的刘建华、张杰、李康伟在《炼钢》2017年第2期上发表了《气泡去除夹杂物技术研究现状及发展趋势》。文章对钢包吹氩、钢包长水口吹氩等气泡去除夹杂物的去除效果和应用前景进行了比较分析，指出钢中生成小尺寸气泡对夹杂物去除效果优于大尺寸气泡。利用弥散微小气泡去除钢中夹杂物技术的开发越来越受到冶金工作者的重视，部分新技术已被开发并趋于成熟。  

A few days ago, Liu Jianhua, Zhang Jie and Li Kangwei of the University of Science and Technology Beijing published the "Research Status and Development Trend of Bubble Removal Inclusion Technology" in the second issue of "Steelmaking" in 2017. This paper compares and analyzes the removal effect and application prospect of bubble removal inclusions such as ladle argon blowing and ladle long nozzle argon blowing, and points out that the removal effect of small-size bubbles generated in steel is better than that of large-size bubbles. The development of the technology of removing inclusions in steel by dispersing microscopic bubbles has attracted more and more attention from metallurgists, and some new technologies have been developed and matured. 

　　气泡去除夹杂物机理

Mechanism of bubble removal of inclusions

　　据介绍，气泡去除夹杂物机理主要包含两方面：一是利用气泡粘附夹杂物上浮去除；二是气泡上浮过程中产生尾流，夹杂物卷入尾流中去除。

　According to reports, the mechanism of bubble removal of inclusions mainly includes two aspects: one is the use of bubble adhesion to remove inclusions; Second, wake flow is generated during the bubble floating process, and inclusions are swept into the wake to remove.

　　气泡粘附去除夹杂物。气泡粘附去除夹杂物主要利用气泡的浮选作用，整个过程主要分为6个阶段：一是气泡向夹杂物靠近，与夹杂物发生碰撞；二是气泡与夹杂物之间形成液膜；三是夹杂物颗粒在气泡表面滑移及振动；四是夹杂物与气泡间的液膜破裂并形成动态的三相接触团；五是气泡—夹杂物成为可以抵抗外压的稳定聚合体，夹杂物被气泡粘附；六是气泡—夹杂物聚合体的上浮。其中，气泡与夹杂物的碰撞和粘附是整个过程中重要的两个环节。气泡粘附夹杂物上浮有一定概率，即并非所有夹杂物都能通过气泡粘附的方式上浮去除。有研究表明：气泡尺寸越小，气泡与夹杂物粒子发生碰撞概率越大，夹杂物去除效果越好；夹杂物尺寸越小，粘附概率越大。

Air bubbles adhere to remove inclusions. The adhesion of bubbles to remove inclusions mainly uses the flotation of bubbles, and the whole process is mainly divided into six stages: first, the bubbles are close to the inclusions and collide with the inclusions; second, a liquid film is formed between bubbles and inclusions; the third is the slippage and vibration of inclusion particles on the surface of the bubble; Fourth, the liquid film between the inclusions and the bubbles ruptures and forms a dynamic three-phase contact group; Fifth, bubbles-inclusions become stable polymers that can resist external pressure, and inclusions are adhered by bubbles; Sixth, the floating of bubble-inclusion polymers. Among them, the collision and adhesion of bubbles and inclusions are two important links in the whole process. There is a certain probability that bubble adhesion inclusions will float, that is, not all inclusions can be removed by bubble adhesion. Some studies have shown that the smaller the bubble size, the greater the probability of collision between the bubble and the inclusion particles, and the better the inclusion removal effect. The smaller the size of the inclusion, the greater the probability of adhesion.

　　气泡尾流去除夹杂物。在钢液中，夹杂物除了被气泡粘附去除之外，还有可能被大气泡尾流捕捉去除。气泡尾流去除夹杂物的主要原理为气泡在上浮过程中，位于其尾部的液体会填补由于气泡脱离和上升所导致的空间，从而在气泡尾部形成回旋区，回旋区内的流体形成了气泡尾流。如果夹杂物位于该回旋区内或其附近区域中，就有可能被卷入回旋区随气泡一起上浮运动。气泡尾流去除夹杂物主要有3个步骤：夹杂物向气泡尾流区靠近，夹杂物进入气泡尾流区，夹杂物在气泡尾流区做循环流动并随气泡一起上浮。气泡能否产生明显尾流是尾流去除夹杂物的关键。有研究表明，直径1mm~5mm的气泡下部就会存在明显尾流。

Bubble wake removes inclusions. In molten steel, inclusions can be removed by large bubble wake trapping in addition to being removed by bubble adhesion. The main principle of bubble wake removal of inclusions is that during the bubble floating process, the liquid located at its tail will fill the space caused by the bubble detachment and rise, thus forming a whirlpool area at the tail of the bubble, and the fluid in the whirlwind area forms a bubble wake. If the inclusion is located in or near the maneuver zone, it is possible to be caught in the maneuver zone and float with the bubbles. There are three main steps to remove inclusions from bubble wake: the inclusions are close to the bubble wake area, the inclusions enter the bubble wake area, and the inclusions circulate in the bubble wake area and float up with the bubbles. Whether the bubbles can produce a significant wake is the key to wake removal of inclusions. Studies have shown that there will be obvious wake in the lower part of the bubble with a diameter of 1mm~5mm.

　虽然大气泡尾流捕捉是去除夹杂物的重要方式，但目前有关气泡尾流去除夹杂物的数学模型研究文献还未见报道，相关研究仍不成熟；并且夹杂物通过尾流去除时需要较大的气泡和通气量，较大的通气量可能造成钢液表面卷渣，造成钢液二次氧化。相较于气泡尾流去除夹杂物，气泡粘附碰撞夹杂物研究较为深入，弥散的微小气泡具有优异的捕捉和粘附夹杂物的效果已经成为共识，大部分气泡去除夹杂物技术的开发主要是根据气泡碰撞粘附夹杂物去除机理。基于此，刘建华等人认为，在将来的发展中，气泡尺寸小型化、分布弥散化是未来气泡冶金技术发展的方向。

Although large bubble wake capture is an important way to remove inclusions, the mathematical model research literature on the removal of inclusions from bubble wake has not been reported, and the relevant research is still immature. In addition, when the inclusions are removed through the wake flow, a large bubble and aeration volume are required, and a larger aeration may cause slag on the surface of the molten steel, resulting in secondary oxidation of the molten steel. Compared with the bubble wake to remove inclusions, the research on bubble adhesion and collision inclusions is more in-depth, and it has become a consensus that the diffuse microbubbles have excellent effect of capturing and adhering inclusions, and most of the bubble removal technologies are mainly based on the bubble collision adhesion inclusion removal mechanism. Based on this, Liu Jianhua and others believe that in the future development, the miniaturization of bubble size and the diffusion of distribution are the direction of the development of bubble metallurgy technology in the future.