Experimental Study on Deep Desulfurizer in LF Process

CaO-Al2O3-SiO2-CaF2-MgO was selected as the slag system for desulfurization in LF process.The reaction between steel and slag during desulfurization has been simulated by using Factsage software to study the influence of component on the sulfur distribution ratio.In order to research the influence of CaO content,aluminum powder content and its granularity on desulfurization,laboratory experiments have been carried out in a 200 kg inductive furnace.Results showed that the optimal composition of deep desulfurizer is wCaO=64% and aluminium powder 10% with a granularity of 30 μm.Industrial trials showed that the main composition range of final slag in LF process is wCaO=53.0%-57.0%,wAl2O3=23.4%-25.1%,wSiO2=8.1%-10.0%,and wCaF2=3.2%-4.7%.The sulfur mass percent in steel is lower than 0.0008% with a desulfurization rate above 89%.According to the result of industrial production,this desulfurizer could meet the production requirement for ultra-low sulfur steel,of which sulfur mass percent is under 0.0015%

Kinetics of hot metal desulfurization by bottom blowing magnesium vapor

To solve the technical problems of hot metal desulfurization by injecting magnesium particulate,a new idea of hot metal desulfurization by bottom-blowing magnesium vapor was put forward.The reaction mechanism of hot metal desulfurization with magnesium vapor injection was analyzed,and the kinetic model of the desulfurization rate during the process of hot metal desulfurization with magnesium vapor injection was established.The dimensionless equation of the gas–liquid mass transfer coefficient under the injection conditions was obtained by the dimensional analysis method.And the theoretical calculation results were in good agreement with the experimental measurements.The results show that the diameter of the bubbles and the viscosity of the melt significantly affect the desulfurization rate of hot metal injected with magnesium vapor.When the temperature is 1573 K and the gas flow rate is 3 L/min,the desulfurization rate can reach 79%and the utilization rate of magnesium can reach 83%.

Preparation of calcium ferrite by flue gas desulfurization gypsum

At present,the continuous accumulation of the flue gas desulfurization(FGD)gypsum in steel plants leads to the serious environmental issues and resource waste.To achieve green and sustainable development for the steel industry,it is significant to improve the usage of by-product gypsum.Employing the sintering FGD gypsum,ferric oxide,and graphite carbon as raw materials,the effects of the carbon content,reaction time,and molar ratio of CaO to Fe_(2)O_(3)on the desulfurization rate of gypsum were studied based on the orthogonal experiment.The results show that the order of the three influencing factors on the desulfurization rate of FGD gypsum is:molar ratio of CaO to Fe_(2)O_(3)>reaction time>carbon content.Under the optimal conditions of 20 wt.%carbon content,4 h reaction time,and 1:1 molar ratio of CaO to Fe_(2)O_(3),the desulfurization rate of desulfurization gypsum is 95.79%,and 97.57 wt.%of calcium ferrite appears in the solid product,which can be used as sintering additive to increase the economic benefits of enterprises and realize the green ecological development mode of internal generation and internal digestion of solid waste in iron and steel enterprises.