Design of an Aqueous Particle Sensor (APS) for Optimizing Inclusion Removal by Bubbles in Tundish Operations

Front Cover
McGill University Libraries, 2016
"Due to the increasingly stringent cleanliness requirements for final steel products, there has been growing interest in using micro gas bubble injection in the steelmaking tundish for the removal of inclusions with diameter smaller than 50[mu]m. However, several technological barriers prevent adoption of this technique in industry. These are related to the generation of micro bubbles, measurement of bubble size distributions, and optimization of bubble injection conditions. In the present study, a novel Aqueous Particle Sensor (APS) IV system was developed for in-situ, on-line detection of bubbles generated by a newly designed ladle shroud located at McGill Metal Processing Centre (MMPC). Measurement results from the sensor were validated against bubble size data collected through a high speed camera. The Aqueous Particle Sensor (APS) III system was also used experimentally under various gas injection conditions to optimize inclusion removal efficiency. Control variable and orthogonal experiments were designed to assess the dependence of the final steel cleanliness and bubble size on key experimental parameters. These were the air inlet flowrates, the distance from the injection port to the slide gate, and the number of injection ports. The investigation demonstrated that the APS system can be successfully used for micro-bubble detection. Through this novel sensor it was shown that multi-port injection using a small air inlet flowrate and a shorter distance from the slide gate can be used to promote the formation of small micro-bubbles. However, optimizing the gas injection flowrate for inclusion removal requires a compromise between reducing the bubble size and increasing the number of micro-bubbles."--

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