scholarly journals Dephosphorization in Double Slag Converter Steelmaking Process at Different Temperatures by Industrial Experiments

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1030
Author(s):  
Han Sun ◽  
Jian Yang ◽  
Xinwu Lu ◽  
Wanshan Liu ◽  
Gefan Ye ◽  
...  
Keyword(s):  
Dynamic Equilibrium ◽  
Converter Steelmaking ◽  
Steelmaking Process ◽  
Hot Metal ◽  
Experimental Conditions ◽  
Rich Phase ◽  
Temperature Range ◽  
Industrial Experiments ◽  
Dephosphorization Slag ◽  
Double Slag

In the present work, the effect of dephosphorization endpoint temperature on the dephosphorization of hot metal was studied for the double slag converter steelmaking process under the conditions of low temperature and low basicity by the industrial experiments. In the temperature range of 1350–1450 °C, with an increasing dephosphorization endpoint temperature, the dephosphorization ratio and phosphorus distribution ratio first increase and then decrease. The phosphorus content in hot metal first decreases and then increases at the end of dephosphorization. At the dephosphorization temperature range of 1385–1410 °C, the dephosphorization ratio is higher than 55%, the P2O5 content in the dephosphorization slag is 3.93–4.17%, the logLP value is 1.76–2.09, the value of PCOP-C of the selective oxidation reaction of carbon and phosphorus is 53–80 Pa, and the aFeO value is 0.284–0.312. The path of phosphorus in hot metal entering the P-rich phase of dephosphorization slag can be reasonably inferred as: hot metal → Fe-rich phase → P-rich phase. Under the present industrial experimental conditions, the dephosphorization and rephosphorization reactions are in dynamic equilibrium at 1413 °C. Considering the experimental results and thermodynamic calculation results of industrial experiments by the double slag dephosphorization process, the optimal temperature range for intermediate deslagging is about 1400–1420 °C.

scholarly journals New trends in basic oxygen furnace dephosphorization

2020 ◽  
Vol 56 (1) ◽  
pp. 1-10
Author(s):  
E. Keskinkilic
Keyword(s):  
Phosphorus Removal ◽  
Basic Oxygen Furnace ◽  
Converter Steelmaking ◽  
Hot Metal ◽  
Basic Oxygen ◽  
P Content ◽  
Low Phosphorus ◽  
Unique Method ◽  
Dephosphorization Slag ◽  
Double Slag

Except for special grades of steel where it is used as an alloying element, phosphorus is regarded as an impurity that must be removed. Considering the conventional integrated iron and steelmaking, there are primarily two processes for phosphorus removal. The first is a hot metal dephosphorization (DeP) process that is applied to a blast furnace for hot metal before the steelmaking process. The second is the basic oxygen furnace steelmaking (BOS), a unique method primarily used for steelmaking, with the exception of stainless steels. Hot metal phosphorus content has a direct impact on BOS. An increase of phosphorus in hot metal is mainly related to the use of high P2O5 containing iron ores. In the current literature review, new trends of phosphorus removal in converter steelmaking are outlined. The double-slag practice was reported to be successful when hot metal P content was larger than 0.100%. It was indicated that the tapping temperature was critical for the production of low-phosphorus grades for which maximum allowable P content was 0.007% and that high tapping temperatures should be avoided. The tap-to-tap time for the double-slag process was slightly longer than the conventional converter steelmaking. It was further reported that the double-slag practice would be more economical than an establishment of a separate hot metal dephosphorization unit, if low-phosphorus grades did not have a significant share in the product mix of a steelmaking company. Endpoint phosphorus prediction was one of the important recent trends of converter steelmaking. A mixed injection of CO2-O2 to a basic oxygen furnace was applied to enhance dephosphorization, and promising results were reported. Unfortunately, a successful process for recycling of BOS dephosphorization slag has not been reported yet.

scholarly journals Dephosphorization by Double-Slag Process in Converter Steelmaking

2018 ◽  
Vol 37 (7) ◽  
pp. 625-633
Author(s):  
Yang Wang ◽  
Shufeng Yang ◽  
Jingshe Li ◽  
Jie Feng ◽  
Feng Wang
Keyword(s):  
Production Efficiency ◽  
Smelting Process ◽  
Converter Steelmaking ◽  
Steelmaking Process ◽  
Key Factors ◽  
Iron Slag ◽  
Low Phosphorus ◽  
Dephosphorization Slag ◽  
Phosphorus Steel ◽  
Double Slag

AbstractThe double-slag converter steelmaking process can smelt low- and ultra-low-phosphorus steel and reduce lime and dolomite consumption and the amount of final slag simultaneously. Industrial steelmaking tests on a 150-metric ton converter at the Tangsteel Company were carried out to study this principle and its effect on the dephosphorization ratio and material consumption. The results showed that low-temperature stage could be used with a reduced amount of slag in the double-slag steelmaking process to achieve rapid and efficient dephosphorization. A low-basicity slag (~1.5–2.0) in the dephosphorization stage is required in double-slag process. The dephosphorization ratio reached a maximum of 71 % when the slag basicity was 1.7. The end-point phosphorus content after the smelting process was reduced from an average of 0.018 mass% to an average of 0.011 mass% and the dephosphorization efficiency increased by more than 6 %. The dephosphorization slag could be poured out rapidly when the FeO content was controlled at ~16–20 mass% in the double-slag smelting process. Based on key factors such as an efficient dephosphorization and a rapid iron–slag separation, the production efficiency was improved and the smelting cycle increased by only four minutes over the conventional process.

scholarly journals Effect of the Basicity on Mineralogical Phases and Micro-Structure of Dephosphorization Slag in the New Double Slag Converter Steelmaking Process

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1480
Author(s):  
Wenkui Yang ◽  
Jian Yang ◽  
Runhao Zhang ◽  
Han Sun ◽  
Yunlong Qiu
Keyword(s):  
Liquid Phase ◽  
X Ray Diffraction ◽  
Hot Metal ◽  
Experimental Conditions ◽  
Rich Phase ◽  
X Ray ◽  
Structure Unit ◽  
P Content ◽  
The Matrix ◽  
Dephosphorization Slag

In the present work, the effect of the basicity at the lower range from 0.98 to 2.13 on dephosphorization of hot metal at 1623 K was studied through high-temperature laboratorial experiments. With the increase of the basicity from 0.98 to 2.13, the P and C contents in hot metal rapidly decrease and increase at first, and then gradually decrease and increase, respectively. From the scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray diffraction (XRD) results, with the increase of the basicity, the phase containing the high P content changes from the matrix phase into the phosphorus (P)-rich phase. Under the present experimental conditions, the P-rich phase can only be precipitated from the liquid slag when the basicity is higher than 1.55, which is a benefit to the dephosphorization. As the Raman intensity of the P-O-Ca structure unit in the P-rich phase is significantly higher than that of the P-O-Si structure unit, most of the phosphorus in the P-rich phase exists in the P-O-Ca structure unit and a small amount of phosphorus exists in the P-O-Si structure unit. With the increase of the basicity of the dephosphorization slag, the activity coefficient of P2O5, γ(P2O5) , in the liquid phase decreases, while the basicity in the liquid phase increases.

Research on Using Limestone for Slagging during BOF Steelmaking Process

2013 ◽  
Vol 690-693 ◽  
pp. 237-245 ◽  
Author(s):  
Jia Feng ◽  
Hong Li ◽  
Chen Xiao Li ◽  
Wen Chen Song ◽  
Wu Nian ◽  
...  
Keyword(s):  
Low Temperature ◽  
High Speed ◽  
Early Stage ◽  
Converter Steelmaking ◽  
Steelmaking Process ◽  
Hot Metal ◽  
Primary Research ◽  
High Basicity ◽  
Unreacted Core ◽  
Unreacted Core Model

This paper introduced the primary research on the method of using limestone instead of lime for slagging during BOF steelmaking. The study showed that the heat is sufficient for limestone to completely replace lime on the condition that the ratio of hot metal to ferrous scrap is adjusted properly. According to thermodynamic calculations, the partial pressure of CO2 at the hot metal surface at the early stage of converter steelmaking is close to 0 and nearly all the CO2 can react with elements in hot metal, producing CO and reducing O2 consumption. Slag with high oxidizability, high basicity and relatively low temperature can be formed quickly by using limestone, which is advantageous for dephosphorization. Industrial tests showed the endpoint Lp rises with the proportion of lime replaced by limestone increasing. CO2 volume expands by 4000~30000 times when limestone is heated at extremely high speed in converter, resulting in the fragmentation of some parts of limestone and the increase of the contacting area of limestone and slag. The unreacted core model with surface exfoliated was introduced.

Two-converter steelmaking process for high silicon hot metal

2019 ◽  
Vol 47 (6) ◽  
pp. 704-711 ◽  
Author(s):  
Yuxiang Dai ◽  
Jing Li ◽  
Chengbin Shi ◽  
Wei Yan ◽  
Chunhui Zhang ◽  
...  
Keyword(s):  
Converter Steelmaking ◽  
Steelmaking Process ◽  
Hot Metal ◽  
High Silicon
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