Thermodynamics and Dynamics of Nitrogen Increasing in LF Refining Process

Nitrogen is one of harmful elements in liquid steel. Reducing nitrogen quantity is required for making high-grade steel. This paper analyzes the reaction mechanism of nitrogen increasing through the methods of metallurgical thermodynamics and dynamics. In liquid steel dissolved nitrogen and nitrides are the main forms of nitrogen. The factors of influence on nitrogen increasing are temperature, kinds and quantity of the alloying elements in the liquid steel, , the lifetime of foam in foam slag, the quantity of flow of argon and so on. Analytical results of metallurgical thermodynamics and dynamics are verified by measuring nitrogen content in the links of LF refining process of new developed area of Chongqing steel and iron Co.Ltd.

A Study of Porous Slag with Plasma Arc Melting

The slag from steel plants or incinerators was tried to be recycled and be reused as foam materials through plasma arc melting. The study was intended to investigate the making of foam slag with laboratory plasma melting facilities. The investigated materials consisted of different mixtures of Al2O3、SiO2 、FetO、CaO and Na2O, with the fluxes that were necessary to examine the capability of pore-formation in the solidified ingots. It has been found that the foam slag could be obtained with the proper compositions and conditions of arc heating. The dimensions and distributions of pores were studied and correlated with the temperatures and compositions of slag. The results showed that the sizes of pores inside the solidified ingots were in the range of 1~5 mm, and the thickness of slag was around 20 mm. As to the distributions of the pores in the ingots of slag, further improvement would be needed in the future.