Rationale on composition of slags in oxygen steelmaking processes

Abstract

A study of plant analytical data on slags for the BOS and OBM processes revealed consistent interrelations between the concentrations of FeO, CaO, and SiO₂ in the slag at the end of the oxygen blow. Over a wide composition range, the amounts of CaO and SiO₂ decrease with increasing FeO, slag basicity increases with increasing FeO, and the amount of MgO decreases with increasing slag basicity. At all levels of lime and silica contents, the amount of FeO in the slag varies by 5–6% between the low and high contents. Consequently, the slag/ metal distribution ratios (%P)/[%P] and (%S)/[%S] as functions of basic and/or acidic oxide contents are within a composition range bordered by the equilibrium curves for the low and high FeO contents.     

氧气底吹熔炼氧枪浅析

系统地论述了氧气底吹熔炼氧枪的结构、工作原理、设计计算方法、材质及蚀损机理．指出了延长氧枪使用寿命的措施。     

氧气底吹熔炼氧枪浅析

系统地论述了氧气底吹熔炼氧枪的结构、工作原理、设计计算方法、材质及蚀损机理,指出了延长氧枪使用寿命的措施。     

Mathematical model for nitrogen control in oxygen steelmaking

A mathematical model was developed to quantify the effects of different operational parameters on the nitrogen content of steel produced during oxygen steelmaking. The model predicts nitrogen removal by the CO produced during decarburization and how the final nitrogen content is affected by different process variables. These variables include the type of coolants used (scrap, direct reduced iron (DRI), etc.), the sulfur content of the metal, combined gas blowing practices, and the nitrogen content in the hot metal, scrap and oxygen blown. The model is a mixed control model that incorporates mass transfer and chemical kinetics. It requires a single parameter that reflects the surface area and mass-transfer coefficient that is determined from the rate of decarburization. The model also computes the rate of decarburization and the change in surface active elements, such as sulfur and oxygen, that affect the rate of the nitrogen reaction. Nitrogenization of steel in the converter is also predicted with the model. The computed results are in good agreement with plant data and observations.     

Energetics of steelmaking processes

The basic energy indices of steelmaking processes, namely, the consumption of energy carriers, the total energy intensity, the full energy efficiency of a process, and the amount carbon dioxide released in atmosphere, are considered. The energy, ecology, and economic efficiencies of the processes are quantitatively analyzed for various alternative energy carriers during steelmaking in an ASF. The problem of sustainable development of an object in the environment is analyzed in relation to its main three parameters, namely, economics, energetics, and ecology.     

底吹熔池炼铜技术的应用

介绍了底吹熔池炼铜技术的特点、处理复杂金精矿的效果以及在越南、东营、牟平的应用情况.     

氧气底吹炉处理高铜铅精矿的生产实践

分析铅精矿含铜高对铅冶炼工艺过程的影响,叙述了氧气底吹炉处理高铜低品住硫化铅精矿的生产实践.     

基于FOA-GRNN模型的转炉炼钢终点预报

目前广泛采用的RBF神经网络具有训练时间长与训练困难等缺陷.本研究结合实际生产数据,建立了FOA-GRNN神经网络预报模型,并对转炉终点温度与碳质量分数进行预报.结果表明:与RBF神经网络相比,FOA-GRNN神经网络可以有效提高命中率并满足实际生产要求.当碳质量分数绝对误差小于±0. 03%时,FOA-GRNN神经网络预报命中率可由91%提高至94%;当温度绝对误差小于±15℃时,预报命中率可由89%提高至97%.同时,FOA-GRNN神经网络训练时间在RBF神经网络基础上分别降低了42. 22%与37. 08%,预报结果与实测值的均方差也有一定的降低,故可为现场生产提供重要的参考.     

A solid electrolyte oxygen sensor for steelmaking slags of the basic oxygen converter

Oxygen pressure in the slag phase is an important parameter in steelmaking processes. Consequently, an in situ solid electrolyte oxygen sensor for the steelmaking slags was developed in the present work. EMF measurements, optical examination, and EPMA analysis of cross sections of the electrolyte tubes used in laboratory experiments indicated that magnesia-stabilized zirconia was suitable for this purpose. The oxygen sensor was also tested on slags of a 100,000 kg LD converter at the end of the normal blowing operation. The stable oxygen pressure in the slag was successfully obtained by the simultaneous measurements of EMF and temperature. By using the oxygen sensor, a simple empirical relation was obtained between the oxygen pressure and ratio of ferric to the total iron ion content in the slag. Also, the oxygen pressure in the LD converter slag was found an order of magnitude higher than that in the metal at the end of the normal blowing operation.     

氧气底吹炉熔炼一次粗铅的能耗分析

氧气底吹熔炼-鼓风炉还原炼铅法是由我国自行开发的具有国际先进水平的炼铅新工艺。它与传统炼铅工艺最大的不同之处在于它采用氧气底吹炉熔炼一次粗铅过程取代了传统的烧结过程。文章利用系统节能理论中常用的投入产出模型对该生产过程的能耗进行分析,提出了降低吨铅能耗的方法。     

General heat balance for oxygen steelmaking

Energy balances are a general fundamental approach for analyzing the heat requirements for metallurgical processes.The formulation of heat balance equations was...     

复吹转炉炼钢过程脱碳模型

通过分析复吹转炉脱碳过程的冶金机理,应用冶金热力学、动力学和传输理论,建立描述转炉脱碳过程的动力学模型,确定了模型的有关参数.模型的关键在于正确计算并比较钢液中[C]和[O]的传质速度,找到转炉冶炼脱碳过程的限制环节,并通过一系列热力学计算得到进入钢液的氧在各元素间的分配比例,从而得到转炉中脱碳反应的速度方程.将模型应用于本钢150 t转炉冶炼过程,模型在不同时刻的计算结果与现场实测值吻合较好.     

Nozzle design in impinging jet steelmaking processes

A criterion to determine throat diameter of a supersonic nozzle is determined from conservation equations of flow of gases and applied successfully to nozzles used in impinging jet steelmaking processes. Influence of surroundings on the nozzle design is evaluated in terms of the force coefficient. It is suggested that a supersonic nozzle design delivering gas at exit pressures slightly greater than the surrounding pressure or overdriving a correctly designed nozzle is beneficial under the conditions of impinging jet steelmaking practice.     

Sulphur removal in ironmaking and oxygen steelmaking

Sulphur removal in the ironmaking and oxygen steelmaking process is reviewed. A sulphur balance is made for the steelmaking process of Tata Steel IJmuiden, the Netherlands. There are four stages where sulphur can be removed: in the blast furnace (BF), during hot metal (HM) pretreatment, in the converter and during the secondary metallurgy (SM) treatment. For sulphur removal a low oxygen activity and a basic slag are required. In the BF typically 90% of the sulphur is removed; still, the HM contains about 0.03% of sulphur. Different HM desulphurisation processes are used worldwide. With co-injection or the Kanbara reactor, sulphur concentrations below 0.001% are reached. Basic slag helps desulphurisation in the converter. However, sulphur increase is not uncommon in the converter due to high oxygen activity and sulphur input via scrap and additions. For low sulphur concentrations SM desulphurisation, with a decreased oxygen activity and a basic slag, is always required.     

A Mossbauer study of electric steelmaking basic slags

Mössbauer measurements have been made on powder samples of basic slags from a steelmaking electric furnace. The samples were taken during oxygen blowing. A prevalence is found of divalent iron in “mixed oxidrd form and in the silicate phase. The ability of Mössbauer spectroscopy to characterize such heterogeneous materials and to correlate the distribution of ferrous ions between the oxide and the silicate with the composition of the slags is demonstrated.     

A review of phosphorus partition relations for use in basic oxygen steelmaking

Phosphorus removal in basic oxygen steelmaking is a significant problem for integrated steelmakers. Phosphorus removal is required due to its deleterious effect on the mechanical properties of steel. However, this is progressively becoming more difficult due to the increasing phosphorus content of many iron ores. Many studies have investigated dephosphorisation and published empirical phosphorus partition (L_P) equations for a range of conditions. The structure of these equations has been used to develop a new partition relation that allows the effect of minor slag constituents such as TiO₂, Al₂O₃ and V₂O₅ on steel dephosphorisation to be tested. Al₂O₃ was found to have a weak negative effect on the measured L_P, except at the lower oxygen potential range tested, where a positive correlation was observed. Increasing TiO₂ and V₂O₅ contents were found to decrease the measured L_P; however, these correlations became less prevalent at the higher oxygen potential ranges tested.     

含铌铁水底吹氧气脱碳保铌的研究

通过中频炉底吹氧气冶炼含铌铁水,在1 350、1 475、1 515℃,加入Si O2-Ca O-Ca F2造渣剂或在无渣条件下研究了铁水中碳、硅和铌的氧化规律。结果表明,底吹氧气在1 350℃时加入碱性造渣剂或不加造渣剂时铁水中硅的氧化率为97%,碳的氧化率为20%,而在1 475℃吹炼时硅的氧化率为15%,碳的氧化率为84%;铁水中硅的质量分数下降到0.1%,铌含量不变;在1 515℃,加入酸性Si O2-Ca O-Ca F2造渣剂高温底吹氧气冶炼时铁水中的碳质量分数下降至0.66%,实现了脱碳保铌。