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The coherent supersonic oxygen supplying technology is now widely adopted in EAF steelmaking process. However, there has been limited research on the impact characteristics of the coherent supersonic jet. In this work, integrating theoretical modelling and numerical simulations, a hybrid computing model was developed to predict the penetration depth of the coherent and conventional supersonic jet. The results show that the lance height has much significant influence on the jet penetration depth, and the penetration depth of the coherent supersonic jet is much larger than that of the conventional supersonic jet at the same lance height. The k value reflects the velocity attenuation of the main supersonic jet, which is a key parameter of the hybrid computing model. Finally, the hybrid computing model and its modified models can well predict the penetration depth of the coherent and conventional supersonic jet with the error being no more than 3.92 pct.

Ferronickel enrichment and extraction from nickel laterite ore were studied through reduction and magnetic separation. Reduction experiments were performed using hydrogen and carbon monoxide as reductants at different temperatures (700-1000°C). Magnetic separation of the reduced products was conducted using a SLon-100 cycle pulsating magnetic separator (1.2 T). Composition analysis indicates that the nickel laterite ore contains a total iron content of 22.50wt% and a total nickel content of 1.91wt%. Its mineral composition mainly consists of serpentine, hortonolite, and goethite. During the reduction process, the grade of nickel and iron in the products increases with increasing reduction temperature. Although a higher temperature is more favorable for reduction, the temperature exceeding 1000°C results in sintering of the products, preventing magnetic separation. After magnetic separation, the maximum total nickel and iron concentrations are 5.43wt% and 56.86wt%, and the corresponding recovery rates are 84.38% and 53.76%, respectively.

Pulsating bottom-blowing was proposed to strengthen the electric arc furnace (EAF) molten bath stirring. The fluid flow characteristics and stirring effects of different pulsating bottom-blowing modes on EAF molten bath were studied through water model experiments and numerical simulations. The mixing time was measured by water model experiments and the flow field characteristics of EAF molten bath were simulated by numerical simulations. Compared with conventional bottom-blowing, pulsating bottom-blowing can accelerate the fluid flow velocity and improve the stirring of molten bath. With pulsating bottom-blowing, the molten bath fluid flow field is more disorder, the fluid flow velocity increases and the dead zone volume decreases.Compared with EAF steelmaking with conventional bottom-blowing conditions, pulsating bottomblowing technology can improve the metallurgical effects and the molten steel quality in EAF steelmaking with lower FeO content of final slag, lower phosphorus content and carbon-oxygen equilibrium of final molten steel, and lower temperature deviation.