Papers by Author: Yong Chen

Abstract: The V₂O₃ is used as raw material to smelt FeV80 alloy by means of electric aluminothermic process in the vanadium products factory of PanGang, resulting in serious corrosion of magnesia lining. In order to analyze the above issues, some lining samples were taken from the locations where the refractory contacts with molten slag after furnace cooling, and processed to conduct SEM analysis. The research results showed that the slag corrosion of magnesia lining proceeds mainly in form of dissolution, The solubility of MgO in molten slag increases from 3.3% to 41% with the increase of smelting temperature from 1900°C to 2200°C based on the phase diagram analysis. The corrosion rate of magnesia lining at temperature 2000°C, 2100°C, 2200°C are about 13, 22 and 33 times than that at temperature 1900°C, respectively. Therefore，to control the ferrovanadium processing temperature below 2000°C is conducive to prolong the service time of magnesia lining.

Abstract: Using ladle slag, ferrovanadium smelting slag as well as slagging materials as starting materials, the converter slags with SiO₂ contents of 11.3% to 2.6%, Al₂O₃ contents of 3.3% to 19.1% were prepared and some cylinder-shaped MgO-C samples were processed to fulfill slag sticking tests conducted at 1600°C in atmosphere furnace. The research results show that the amount of slag adhesion decreases with a reduction of SiO₂ content and an increase of Al₂O₃ content in slag, owing to larger viscosity and higher foam index of molten slag. To control the variations of SiO₂ and Al₂O₃ contents in converter slag is conducive to better slag splashing. Furthermore, the mechanism of SiO₂ and Al₂O3 contents of converter slag impacted on slag sticking to MgO-C brick has been further discussed.

Abstract: In the early stage of commissioning, in order to solve the problem of bad metallurgical effect and serious lining erosion during steelmaking, oxygen supply strength is improved and lance position is adjusted as well. In addition, technology of “remaining slag and charging dolomitic lime” is applied to reduce the erosion velocity of lining. Results show that metallurgical effect of BOF is better after oxygen supply strength is improved, and which ensure the high efficiency production and smooth operation of BOF.

Abstract: Steelmaking Plant of PZH Steel improves the hitting ratio of independent converter model, by optimizing the terminal controlling model of molten steel, stabilizing the charging load in BOF, accelerating the turnover rapid of ladle, improving the quality of semi-steel into the furnace and optimizing the management of production organization. So the ratio of the direct-tapping is improved and increases to more than 50% now from 25% on average in 2011.

Abstract: This paper firstly analyzed the desulfurization mechanism of magnesium compound desulfurizer and compound desulfurizer. It is thought that the compound desulfurizer which contains a certain amount of magnesium is better used than the one does not contain. There is also the statistical analysis about these two type desulfurizers in practical Producing. The practical application of contrast verifies the theoretical analysis.The magnesium compound desulfurizer has better performance used in the effect of desulfurization, the consumption of desulfurizer, iron loss, process-time, the loss of hot metal temperature and the lance life than compound desulfurizer.

Abstract: According to the test of reducing tapping temperature of BOF, factors affect the tapping temperature are studied and measures to reduce temperature drop during tapping are raised. Results show that the average tapping temperature during test is 1672°C, which is 13°C lower than mass production; and the tapping temperature more than 1690°C only account for 14.28%, which is twenty percentage points lower than before; temperature drops during tapping is decreased from 99.0°C to 93.64°C, which 5.36°C lower than before.

Abstract: To solve the problems appeared in the initial operation period of 200t BOF such as low heating velocity, high TFe content in final slag, severe lining erosion, etc, optimization of steelmaking process is carried out. Metallurgical effects are greatly improved after optimization: slag-forming time is shortened by 0.9min; oxygen consumption is lowered by 1.5 m3 per ton steel; carbon content of aimed molten iron is increased by 0.031% while oxygen activity of which is decreased by 206ppm. TFe content of BOF slag is reduced by 0.84% on average.

Abstract: Focus on such problems as low supplying capacity, short furnace life and poor smelting effect during extracting vanadium using combined blowing converter, the structure optimization of bottom blowing brick used to ventilating was studied, the system used to supplying gas was implemented, and the crafts of extracting vanadium with combined blowing technology was developed as well as the protecting technology of brick used to ventilating was applied. The results show that strength of gas supplying of BOF is increased to at least 0.10m3/ (min•t). The combined blowing lifetime is extended, especially reaches to 7455 heats. The proportion of multiple blowing is reached to 100%. The quality o f vanadium slag is improving obviously.

Abstract: The lance system is one of the important link of converter. Stable and secure of the system is a necessary condition for whole production system to function normally. The numerical simulation for a three-dimensional oxygen lance nozzle was carried out according to the fundamental parameters of PZH steel, the characteristics of the oxygen jet were analyzed and discussed. The oxygen lance nozzle with the optimum design has achieved good results in practice: the average formation time of early slag was reduced by 1 min and 23 seconds, the pure blowing time was reduced by 46 seconds, the oxygen consumption per ton steel decreased by 1.05 m³/t, the rate of dephosphorization was increased by 1.35%, the basicity of slag was reduced by 0.38, the phosphorus and sulfur distribution ratio between slag and liquid iron were also increased effectively.

Abstract: Because of disadvantages of converter steelmaking with semi-steel in Panzhihua Steel, such as slow-footed slag forming, low rate of dephosphorization, high rate of rephosphorization after converter smelting, studies on increasing dephosphorization rate have been carried out. These studies comprise the optimization of slagging process, oxygen supply, bottom argon supply, end-point control of converter smelting, and so on. With these countermeasures, the rate of dephosphorization has been increased obviously. The results show that the average rate of dephosphorization is above 90% with single-slag process during converter smelting. Otherwise, content of phosphorus at the end-point of converter smelting can be controlled below 0.007%, and rephosphorization rate after converter smelting can be controlled below 0.003%, which meets the requirement of [P]≤0.010% for steel products.