Vacuum Treatment for Simultaneous Desulphurization and Dephosphorization of Hot Metal and Molten Steel

The vacuum treatment for simultaneous desulphurization and dephosphorization of hot metal and molten steel with pre-melted CaO-based slag was carried out.For pre-treatment of hot metal,both desulphurization and dephosphorization are improved with the increase of CaO in slag,but deteriorated with the increase of CaF2 in slag.The average desulphurization and dephosphorization rate is 68.83 % and 78.46 %,respectively.For molten steel,the substitution of BaO for CaO in slag has minor effect on simultaneous desulphurization and dephosphorization.The desulphurization and dephosphorization rate is higher than 90% and 50% respectively with the lowest final sulfur and phosphorus mass percent being 0.001 2% and 0.010%,respectively.The overall effect of simultaneous desulphurization and dephosphorization of molten steel is better than that of hot metal.

A Straightforward Mathematical Model of Hot Metal Desulphurization

A straightforward kinetic model for the hot metal desulphurization process is presented. The model contains some of the most important parameters and variables that govern the process. The inputs, outputs and parameters of a desulphurization program employed at industry are discussed. The model is able to cope with different injection policies of desulphurizers such as mono- injection, co-injection or multi-injection. When compared to the rotary impeller method, results of this model shows that the weight of lime consumed in the lance injection method is lesser than that consumed in the rotary impeller method for the same conditions of the hot metal charge.

Desulfurizer desulphurization kinetics by the injection method

To obtain a better desulphurization effect in hot metal, suitable desulfurizers should be selected first according to thermodynamics. However, the effect of desulphurization is also strongly affected by kinetics. The conditions of different desulfurizers （Mg, CaC2, and lime） penetrating into hot metal, the rising up velocity in iron melt, residence time, and dissolving time are theoretically calculated and analyzed. The results are helpful to select the desulphurization process and equipment and to improve the desulphurization effect.

Desulphurization of Hot Metal and Ferronickel With Calcium Aluminate Fluxes

Traditionally, fluxes containing calcium fluoride and other additives are used for the treatment of hot metal and molten steel. Recently, magnesium powder or lime-Mg mixture is used more popularly in hot metal desulphurization. However, the use of calcium fluoride has been restricted due to environmental concerns, and the supply of magnesium is uncertain for the countries, which are short of magnesium resource. For those reasons, calcium aluminate fluxes are a possible alternative to replace slags containing calcium fluoride or magnesium. Calcium aluminate fluxes can be produced from three different raw materials: (1) high-quality bauxite, (2) residuals from aluminum dross treatment processes and (3) waste products from alumina production. Due to the limited amount and high cost associated with high-quality bauxite, the other two sources are preferred based on both economic and environmental considerations. The objective of this paper is to examine the use of waste slags and by-products from the aluminum industry as potential refining fluxes for the steel industry so that waste disposal from the aluminum industry can be reduced with economical and environmental benefits for both industrial sectors.

Simulation of Thermodynamics and Kinetics for KR Desulphurization

This paper seeks to optimize parameters, reduce the cost of desulphurization and the consumption of operation about KR pretreatment of hot metal at the Stainless Steel Company, Baosteel Group. Based on the theoretical analysis of physical chemistry in metallurgy, simulation experiments of the KR desulphurization of hot metal were conducted in a laboratory and the composition of the desulphurization was optimized, by means of chemical analysis, DSC, SEM and EDS. The water modeling displays the fluid flow characteristics of KR desulphurization. Combination of the techniques and production at the Stainless Steel Company, Baosteel Group, the optimized parameters of the process are put forward.

Al_2O_3-SiC-C Bricks for Hot Metal Pretreatment

1 Scope This standard specifies the classification, shape and dimensions, technical requirements, test methods, quality appraisal procedures, packing, marking, transportation, storage, and quality certificate of Al2O3- SiC - C bricks for hot metal pretreatment.

Al_2O_3-SiC-C Bricks for Hot Metal Pretreatment

1 Scope This standard specifies the classification, techni- cal requirements, test methods, inspection rules, packing, marking, transportation, storage and quality certificate of Al2O3- SiC - C bricks for hot metal pretreatment.

Physical Simulation of New Desulphurization Technology Using Pulsed and Rotary Stirring-Injection

The contrast experiment of different stirring modes,which includes a new type of stirring-injection with the method of pulse and rotation,and the initial one-way stirring method,is done through physical simulation in the laboratory.The stirring methods of pulse and rotation are of two kinds.One is pulsed and rotary stirrer with positive and opposite directions.The other is pulsed and rotary stirrer with rotation-stop-rotation.The results show that the stirring mode of pulse and rotation has better effects than the one-way stirring method.The specific effects are that the mixing time of the melting bath is apparently shortened,the number of grains involved in the liquid surface is increased,and the residence time of air bubble in water is doubled.

Wettability of Molten Steel/Na2O-Li2O-SiO2-B2O3 Slag System

The vacuum treatment for simultaneous desulphurization and dephosphorization of hot metal and molten steel with pre melted CaO based slag was carried out. For pre treatment of hot metal, both desulphurization and dephosphorization are improved with the increase of CaO in slag, but deteriorated with the increase of CaF 2 in slag. The average desulphurization and dephosphorization rate is 68 83 % and 78 46 %, respectively. For molten steel, the substitution of BaO for CaO in slag has minor effect on simultaneous desulphurization and dephosphorization. The desulphurization and dephosphorization rate is higher than 90 % and 50 % respectively with the lowest final sulfur and phosphorus mass percent being 0 001 2 % and 0 010 %, respectively. The overall effect of simultaneous desulphurization and dephosphorization of molten steel is better than that of hot metal.

Practice of Hot Metal Full Pretreatment and Less-slag Steelmaking in ShouGangJingTang

The hot metal full pretreatment and less-slag steelmaking process constituted a platform to produce clean steel with low cost and rapid pace and also realized a professional production line. The w[P] can be less than 0.030% at the end of De-P converter and 0.006% at the end of De-C converter. The w[N] in steel can be less than 15×10-6 at the stirring station. This production line can make clean steel steadily used for auto sheet or pipeline, for example X65 MS. The De-C slag was left in the converter for the next heat and recycled to De-P converter to reduce lime consumption, which has a great benefit for the cost saving.

HMPT-BOF工艺生产低硫钢的硫控制与回硫分析

对涟钢HMPT-BOF工艺生产低硫钢的过程硫控制效果进行了分析,寻找出了转炉钢水回硫的主要原因,提出了有效的改进措施,满足了"HMPT-BOF-RH-CSP"工艺生产低硫钢的需要。

Study on Kinetic Model for Dephosphorization of High-Phosphorus Hot Metal Pretreatment

Focused on the hot metal pretreatment process in the torpedo-car and based on the powder injection metallurgy principle, a kinetic model for dephosphorization of high-phosphorus hot metal pretreatment was developed. The validity of this model was verified by comparison between the experimental results in laboratory and the calculated results. The influences of dephosphorization capacity of molten slag and technological conditions on the dephosphorization efficiency were calculated by applying the model. The results show that lower temperatures are favorable to dephosphorization, CaO content in slag should be controlled at about 50%, suitable initial phosphorus content in the hot metal with higher phosphorus contents is about 0.35% by comprehensively considering various factors, slag systems of higher iron oxide content and higher basicity have higher capacity of dephosphorization.

HMPT-BOF-RH-CSP process for SPHE substrate of cold rolled deep drawing steel

Based on hot metal pretreatment (HMPT)-basic oxygen furnace (BOF)-Rheinstahl Heraeus (RH)-compact strip production (CSP) process, parameters controlling on cold rolling deep drawing substrate SPHE were investigated during smelting and rolling process by composition design and technology control. The influence of parameters on chemical compositions, mechanical properties and microstructure was revealed by scanning electron microscope (SEM). The results show that, 1) main chemical components in SPHE are w(C)≤40×10-6, w(Si)≤ 0.01%, w(S)≤0.009%, w(N)≤20×10-6, w(O)≤ 25×10-6; 2) main mechanical properties of the SPHE are δs=274 MPa, δb=334 MPa, A=48.9%; 3) main performances of deep drawing quality (DDQ) grade steel produced by SPHE are as follows, transversely δs=167 MPa, δb=298 MPa, n=0.219, r=2.46; vertically δs=166 MPa,δb=298 MPa, n=0.226, r=2.39; in 45° direction δs=171 MPa, δb=308 MPa, n=0.214, r=2.26; 4) microstructure of DDQ is ferrite, average grain size is Grade 7.5, and inclusion size is 3-10 μm.

Performance of Low Fluoride Dephosphorization Slag of Hot Metal

The purpose of the study is to decrease content of CaF2 in dephosphorization slag. The dephosphorization effects of CaF2 replaced by B2O3 were investigated. The dephosphorization experiments were carried out at 1 450 ℃ in air atmosphere. The results show that the melting points and dephosphorization ratios change little when CaF2 was replaced by B2O3. The dephosphorization ratios are all greater than 80% and melting points can meet the requirement of hot metal pretreatment. Because of the change of alkalinity caused by B2 03, the oxidation of slag increases with increasing of B2 Oa contents. It is beneficial to pre-dephosphorization. As a result, for decreasing its pollution, CaF2 can be replaced by B2Oa to dispose fluoride-free pre-dephosphorization slag.

硅钢铁水预处理脱硫工艺实践

结合脱硫理论和实际生产数据分析,对某厂硅钢铁水预处理脱硫进行了研究。结果表明,二次脱硫渣硫含量与前渣中的硫含量成正比、与前渣余量成反比、与一次脱硫渣余量成正比、与脱硫剂用量成反比。当脱硫剂总量一定时,二次脱硫渣中硫含量随着一次脱硫剂占比的增加呈先降后增的趋势,最佳一次脱硫剂占比为40%。铁水随着预处理前温度的升高,处理后的硫含量呈先降再升的趋势,最佳处理前温度为1370~1400℃。铁水通过3次扒渣,2次脱硫处理,硫的质量分数降至11.7×10^(-6),满足硅钢生产需求。

关于KR法铁水脱硫脱硫剂和投料方式的发展与探讨

介绍了铁水预处理的必要性及我国KR法铁水脱硫的发展过程,并对KR法铁水脱硫的脱硫剂发展进行阐述,提出脱硫剂未来研究方向和目标;同时对脱硫剂的投料方式进行对比,以便于更加清晰地进行投料方式的选择。

攀钢含钒钛铁水预处理工艺实践

就含钒钛铁水预处理工艺在攀钢投入使用的情况作了介绍。这种预处理工艺分两步 ,第一步是铁水脱硫 ,第二步为脱硫铁水提钒。三年的试验研究和生产实践表明 ,采用这种工艺可以把铁水 [S]由脱硫前的 0 .0 4%～0 .0 8%降低到 0 .0 2 %以下 ,甚至可以降低到 0 .0 1%以下。脱硫铁水经撇渣后 ,进行二次预处理 ,即转炉提钒。通过提钒 ,将铁水中的V提取进入钒渣 ,从而使铁水中 [V]由原来的 0 .32 %～ 0 .34%降低到 0 .0 2 8%以下 ,而钒渣中(V2 O5)达

钙基、镁基脱硫剂的脱硫极限

对喷吹各种钙基、镁基脱硫剂的铁水炉外脱硫体系进行了系统的热力学分析,并通过理论计算得到了各喷吹体系的脱硫极限。理论分析认为,各喷吹体系都有很强的脱硫能力,喷吹Mg CaO和Mg CaC2的铁水炉外脱硫体系具有相同的脱硫能力,其脱硫极限可达到10-7%。从技术经济性及工艺方面考虑,工业生产中喷吹Mg CaO进行铁水炉外脱硫更合理。

高流动性防潮石灰粉剂的研制及应用

采用特殊的石灰锻烧方法、高速粉碎技术以及特殊的物理纯化处理技术 ,研制出防潮性和流动性能好活性度高的新型石灰粉剂。其防潮性可达到冷水浸泡 6 0 min不吸潮溶解 ,储存期可达一年。氧化钙含量在92 %以上 ,活性指数可达 32 0 m L以上。比表面积 8～ 10 m2 /g。该粉剂在铁水预处理工业试验的结果表明 ,由于粉剂流动性好 ,可使石灰粉有效地穿透气液界面而进入铁水内部 ,大幅度提高了 Ca O的利用率。与镁粉同时喷吹 ,铁水硫含量可以从原始的 0 .0 47%降低到 0 .0 0 3%以下。处理后的平均硫含量为 0 .0 0 16 % ,平均脱硫率达 96 .5 %。