Chemical behaviour of nitrogen in metallurgical slags

According to previous experimental work, nitride capacity C_N, in opposition to sulfide capacity C_S, decreases with increasing optical basicity of metallurgical slags. This tendency is also confirmed by the contradictory behaviour of the free energy changes of oxide-nitride and oxide-sulfide transformation reactions as a function of basicity. From the present metal-slag equilibrium studies, denitrogenation potentials P_N = %(N)/{%[N] · %[Al]} were obtained characterizing denitrogenation efficacy of slags at given compositions and temperatures. From these potentials, factors were derived which mark the effects of individual slag components. It was found that these factors feature the same basicity dependence as nitride capacities C_N and denitrogenation potentials P_N. The factors are increased, e.g., as less basic oxides are increasingly present in the slag phase in the order BaO → SrO → CaO → MgO.     

Processing of metallurgical slags

Magnitogorsk Metallurgical Combine. Translated from Metallurg, No. 10, p. 38, October, 1990.     

钢铁冶金渣的资源化利用

开展冶金渣资源化利用,对于减少冶金渣弃埋用占地和防止环境污染,促进我国钢铁工业的持续高效发展具有重要意义.通过对我国冶金渣资源化综合利用的现状、目前存在的主要问题以及未来发展趋势的分析,得出了在不断完善现有冶金渣资源化利用方法的同时,还应进一步研究和开发利用冶金渣生产具有高附加值制品的结论。     

The composition and temperature dependence of the sulfide capacity of metallurgical slags

The concept of optical basicity and its applicability as a means of correlating the available data on the sulfide capacity of metallurgical slags has been reviewed. An excellent correlation based on very extensive data at 1500 °C, which was discussed in a previous paper, is combined with good correlations based on considerably less data at 1550 °C and 1650 °C to quantify the effect of temperature on the sulfide capacity of slags. The combined effects of slag composition and temperature have been expressed in the equation, logC _s = [(22690 – 54640A)/7] + 43.6A − 25.2. Use of this equation permits the calculation of the sulfide capacity of a slag at any temperature between 1400 °C and 1700 °C simply from a knowledge of its chemical composition, and can be employed for virtually any oxide slag of interest in the field of iron and steelmaking. This, in turn, permits calculation of the equilibrium distribution of sulfur between this slag and iron or steel, provided that the oxygen potential is known or can be calculated from the degree of deoxidation applied.     

钢铁工业冶金渣的X射线荧光分析

本文将报道钢铁中矿渣的高性价比的X射线荧光分析（XRF）方法。与其他分析一样,矿渣分析对高炉或炼钢炉控制十分重要。由于X射线光学和仪器设计的重大进展,灵敏度和可靠性的提高满足了金属工业过程控制的需要。简单、结构紧凑并高性价比的波长色散X射线荧光光谱仪（WDXRF）目前很可能用于钢铁工业的常规分析。本文包括仪器的技术细节、与矿渣有关的应用数据以及简单的在线操作自动化方案等方面的内容。     

Kinetics of evolution of SO2 from hot metallurgical slags

The kinetics of the evolution of SO₂ gas from a liquid synthetic blast furnace -type slag (CaO-Al₂O₃-SiO₂) in an atmosphere of O₂ + Ar gas at a total pressure of 1 atm for 0.003 ≤ Po₂ ≤ 1.00 atm has been studied in the range 1360 to 1460°C. The process has been followed by collecting and analyzing the SO₂ as it forms, and also by observing the change in weight of the slag sample with time. The effect of slag composition has also been studied. For partial pressures of oxygen less than about 0.1 atm, the rate is very rapid and is controlled by transport in the gas phase. At greater values of Po₂, the rate is much slower and is controlled by a chemical process. In the high Po₂ region, the process is half-order with respect to the concentration of sulfur in the slag. This half-order dependence on sulfur concentration in the slag may be explained by an initial fast irreversible reaction to form two intermediate species which then decompose at equal rates to give the final products. Additions to the slag of iron or manganese oxides greatly accelerate the rate of evolution of SO₂ at Po₂ = 1.00 atm. This is interpreted to mean that a charge transfer process, possibly involving S^2- and O^2- ions, is rate-controlling at Po₂ = 1 atm. It is also apparent that Fe²⁺ and Fe³⁺ (or Mn²⁺ and Mn³⁺) ions can act as charge carriers. Some measurements with actual industrial blast furnace slags are also reported. Formerly Visiting Scientist, Massachusetts Institute of Technology     

Thermodynamics of nitrogen in Ca-CaF2 slags

Formerly with the Department of Metallurgical Engineering and Materials Science, Carnegie Mellon University.     

Measurement of the thermal diffusivity of liquid oxides and metallurgical slags

The methods of heat transfer in stagnant bodies of glass and slag are reviewed, and it is shown that the effective thermal diffusivity determines the rate at which heat is transferred in glasses similar in composition to metallurgical slags. A new experimental apparatus is also described for measuring the effective thermal diffusivity of these glasses. The results of experiments performed on glasses containing between 10.9 and 26.8 pct FeO, with lime/ silica ratios,B, of 1.0 and 1.5, and at temperatures ranging from the liquidus temperatures of the glasses to 1750 K are represented by A theoretical basis is used to develop the form of this relationship, and consequently, it should yield reasonable estimates for glasses of other composition and at other temperatures. H. Allan Fine and T. Engh were formerly Research Assistant and Visiting Scientist, respectively.     

Physicochemical properties and structure of titania-containing metallurgical slags:a review

The titanium industry can hardly bypass the titania-containing slags,and the slag physicochemical properties are essential in the metallurgical reactor design a...     

X射线荧光光谱法测定冶金渣料中主次成分

以L₂B₄O₇和LiBO₂ [m(L₂B₄O₇) ∶m(LiBO₂)=2∶1] 为熔剂,LiNO₃为氧化剂,LiBr为脱模剂,熔融法制备样品,建立了X射线荧光光谱对冶金渣料中的TFe、SiO₂、TCa、MgO、TiO_2、MnO、P₂O₅、Al₂O₃、K₂O和Na₂O的快速检测方法。采用高炉渣、转炉渣、电炉渣系列标样绘制校准曲线,并通过加入钾长石、钠长石等适宜标准样品进行曲线分析范围扩展,使曲线既可以用于高炉渣、转炉渣、电炉渣等炉渣类样品分析,也可用于保护渣样品的检测分析。试验对稀释比、熔样温度、保护渣试样预处理温度等主要条件进行了探讨。结果表明,当试样与熔剂质量比为1∶10和熔样温度为1 050 ℃(熔样前保护渣样品预处理温度以700 ℃为宜)时,所得试样在熔剂中分散度(浓度)适当,同时适用于中高、低含量组分的测定。对一标准样品进行10次测定,各组合测定结果的相对标准偏差为0.07%~1.9%。方法用于各类实际冶金渣料分析时,结果与其他分析方法相一致。     

Thermodynamics of nitrogen in CaO-TiO2-TiO1.5 slags

The nitride capacities in CaO-TiO₂-TiO_1.5 slags, and nitrogen distribution ratio between these slags and liquid Cu (L_N = (mass-% N)/[mass-% N]) were measured by a gas-slag-metal equilibration technique, using a Mo crucible in the temperature range of 1823 to 1923 K under controlled partial pressures of oxygen and nitrogen . The values for , (mass-% Ti³⁺)/(mass-% Ti⁴⁺) ratio, and solubility of TiN in CaO-TiO₂-TiO_1.5 slags were obtained as a function of slag composition (X_CaO = 0.24 ～ 0.39) and temperature. Activity coefficients of TiN were evaluated from the values for activity coefficients of Ti in liquid Cu which were calculated from the results of TiN saturation experiments.