CaO-MgO-FeO-Al_2O_3-SiO_2-P_2O_5渣系与碳饱和铁液间硫分配比的热力学模型

在富氧顶吹熔融还原冶炼高磷铁矿的工艺研究中,以共存理论为基础,结合全选主元松弛迭代法,利用VB 6.0计算了CaO-MgO-FeO-Al2O3-SiO2-P2O5渣系中结构单元或离子对的质量作用浓度,并建立了该渣系与碳饱和铁液间硫分配比的热力学模型,由该模型计算的硫分配比与工艺中实测的硫分配比吻合程度较好,说明利用共存理论所建立的脱硫模型能适用在熔融还原高效脱磷熔渣。     

Inconel 718高温合金电渣重熔热力学分析

基于离子-分子共存理论建立了计算电渣重熔Inconel 718高温合金过程中平衡Al和Ti含量的热力学模型.并讨论了Ca O-Si O₂-MgO-Fe O-Al₂O₃-Ti O₂-Ca F₂电渣重熔渣系成分变化时, 渣中各组元的活度、活度比值与炉渣成分的关系.与此同时, 研究了不同温度条件下, 镍基合金中平衡的Al和Ti含量与炉渣成分之间的关系.结果表明:冶炼温度升高时, 合金中平衡的Al含量随之升高, 而平衡Ti含量降低;渣中MgO和Ca F₂只起到调整炉渣物理化学性质的作用, 对控制镍基合金中Al和Ti元素烧损作用不大.     

Inconel718高温合金电渣重熔铝钛元素烧损热力学分析

 为了研究Inconel718高温合金电渣重熔过程中渣系各组元对合金中易氧化元素铝、钛的影响，以五元渣系CaF2-CaO-Al2O3-MgO-TiO2为基，通过分子与离子共存理论，根据渣金界面中各组元的平衡反应和物质守恒，建立了Inconel718高温合金电渣重熔过程中渣金界面铝、钛元素氧化反应的热力学模型。通过分析该模型并对模型结果进行渣金平衡验证试验，验证了模型的有效性。研究结果表明，渣中CaF2、MgO质量分数的变化对合金中铝、钛元素的影响很小；渣中Al2O3有烧钛增铝的作用，TiO2有烧铝增钛的作用，CaO能够抑制铝元素的烧损；能够有效减少Inconel718高温合金电渣重熔过程中铝、钛元素烧损的渣系配比为CaO质量分数为20%～25%、TiO2质量分数为4%～6%、MgO质量分数为1%～4%、CaF2质量分数为50%～60%、Al2O3质量分数为15%～20%。     

电渣重熔易切削钢中硫含量及夹杂物的控制

基于热力学分析了电渣重熔中渣系及冶炼工艺对易切削钢AS136的夹杂物及硫均匀性的控制研究.实验采用4 t的非保护气氛电渣炉, 分析了电渣锭中硫含量及夹杂物级别.实验结果发现:采用渣系S1 (质量分数为50%Ca F₂+30%Al₂O₃+20%Si O₂) 冶炼的电渣锭中硫质量分数为0.066%⁰.075%, 能够满足产品要求 (产品中要求硫质量分数在0.05%⁰.10%) , 但是B类和C类的夹杂物级别均达不到标准;在渣系S3 (质量分数为70%Ca F₂+28%Al₂O₃+2%MgO) 以及整个重熔中持续地加入质量分数4.5%镁砂的冶炼工艺下, 不仅可以使电渣锭中硫含量呈均匀分布, 同时还能够改善夹杂物的分布和大小.分析结果表明:随着电渣重熔初期渣温的升高以及渣中Si O₂质量分数的增加, 持续均匀地补加镁砂可以使得电渣锭中的硫沿轴向呈均匀分布.     

CaO-SiO2-MgO-Al2O3渣系渣铁间硫分配比热力学模型

 为了探明高炉渣系组成对高炉渣脱硫能力的影响,根据分子-离子共存理论,建立了CaO-SiO₂-MgO-Al₂O₃高炉渣系与铁液间硫分配比的热力学模型,利用试验测定值对其进行验证与修正,探究碱度R、w((MgO))/w((Al₂O₃))和w((Al₂O₃))对炉渣脱硫能力的影响。研究结果表明,修正后的CaO-SiO₂-MgO-Al₂O₃高炉渣系硫分配比(L_S)热力学模型能较好地预测熔渣的脱硫能力,修正后的相对误差为8%,较修正前的相对误差降低了11%;当w((MgO))/w((Al₂O₃))=0.25~0.45,w((Al₂O₃))=15%时,随着碱度R的增加,炉渣的脱硫能力(L_S)增大;当w((Al₂O₃))=15%,R=1.15~1.25时,随着w((MgO))/w((Al₂O₃))的增加,炉渣的脱硫能力(L_S)增大;当w((MgO))/w((Al₂O₃))=0.25~0.45,R=1.20时,随着w((Al₂O₃))的增加,炉渣的脱硫能力(L_S)减小,故高Al₂O₃条件下应适当增加炉渣中的w((MgO))/w((Al₂O₃))。     

高炉CaO-SiO2-Al2O3-MgO-TiO2渣与铁液间硫分配比的热力学模型

 炉渣离子与分子共存理论认为,CaO-SiO2-Al2O3-MgO-TiO2渣中结构单元或离子对的作用浓度能够像传统意义上的熔渣活度一样表征化学反应能力。通过建立1773K时高炉CaO-SiO2-Al2O3-MgO-TiO2渣中结构单元或离子对的作用浓度控制方程,运用Matlab进行求解,进而建立了该渣系计算渣铁间硫分配比的通用热力学模型。此外,该模型能够定量计算出CaO和MgO各自对渣铁间硫分配比的热力学贡献率。建立的模型的计算结果表明,当TiO2含量增加时渣铁间硫分配比及CaO的热力学贡献率逐渐降低,而MgO的贡献率逐渐上升。     

Activity Calculation Model for Ternary Slag System of Al2O3-BaO-B2O3

According to the ion and molecule coexistence theory, the activity model of Al₂O₃-BaO-B₂O₃ ternary slag system was established, and the influences of BaO/Al₂O₃ molar ratio, B₂O₃ mole fraction and temperature on the activity of the slag system were investigated. Finally, the equal activity curves were drawn with the model results. The results show that with the increase of BaO/Al₂O₃ ratio, the activity of Al₂O₃ is significantly reduced, the activity of BaO ? Al₂O₃ is increased obviously, and the activity of 2Al₂O₃ ? B₂O₃ is also decreased. With the increase of B₂O₃ mole fraction, the activity of BaO ? Al₂O₃ decreased significantly, while the activities of BaO ? 2B₂O₃ and 2Al₂O₃ ? B₂O₃ increased. In addition, the influence of temperature on the activities of different components is comparatively smaller than the influence of BaO/Al₂O₃ ratio and B₂O₃ mole fraction.     

A Thermodynamic Model for Prediction of Iron Oxide Activity in Some FeO‐Containing Slag Systems

A thermodynamic model for calculating the mass action concentrations of structural units in CaO–SiO₂–MgO–FeO–MnO–Al₂O₃–CaF₂ slags, i.e., the IMCT‐N_i model, has been developed based on the ion and molecule coexistence theory (IMCT). The calculated comprehensive mass action concentration of iron oxides $N_{{\rm Fe}_{t} {\rm O}} $ has been compared with the reported activity of iron oxide $a_{{\rm Fe}_{t} {\rm O}} $ in 14 FeO‐containing slag systems from literatures. The good agreement between the calculated $N_{{\rm Fe}_{t} {\rm O}} $ and reported $a_{{\rm Fe}_{t} {\rm O}} $ indicates that the developed IMCT‐N_i model can be successfully applied to predict the activity of iron oxide $a_{{\rm Fe}_{t} {\rm O}} $ as well as the slag oxidation ability of CaO–FeO (s1), SiO₂–FeO (s2), CaO–SiO₂–FeO (s3), CaO–FeO–Al₂O₃ (s4), SiO₂–MgO–FeO (s5), SiO₂–FeO–Al₂O₃ (s6), CaO–SiO₂–FeO–Al₂O₃ (s7), CaO–SiO₂–MgO–FeO–Al₂O₃ (s8), SiO₂–FeO–MnO (s9), SiO₂–FeO–MnO–Al₂O₃ (s10), FeO–MnO (s11), FeO–MnO–Al₂O₃ (s12), CaO–FeO–CaF₂ (s13), and CaO–SiO₂–FeO–CaF₂ slags (s14) in a temperature range of 1473–1973 K.     

基于共存理论的转炉脱磷热力学分析

为了定量研究温度、炉渣成分、钢液成分对转炉磷分配比和平衡磷含量的影响,基于共存理论建立转炉炼钢六元渣系的组元活度计算模型和磷分配比L_P计算模型,将磷分配比模型计算结果与转炉炼钢实测磷分配比进行对比,发现两者吻合较好。定量计算结果表明,当炉渣碱度为3.8时,钢液温度从1 640升到1 680 ℃,平衡磷质量分数从0.011 5%增加至0.019 8%。同时定量计算了炉渣碱度及氧化铁含量变化对平衡磷含量的影响,但实际炉渣控制需要考虑炉渣黏度、铁损及炉衬侵蚀。转炉吹炼终点钢中元素含量数量级较小,计算表明终点成分变化对磷活度系数的影响不大,各元素对脱磷的影响主要体现在冶炼初期和过程。     

A thermodynamic model for calculation of sulfur distribution ratio between CaO- SiO2- Al2O3- Na2O- TiO2- (MgO) slags and carbon saturated hot metal

The ion and molecule coexistence theory (IMCT) indicates that the mass action concentrations of structural units or ion couples in slags can represent the chemical reaction ability as the traditional slags activity.By establishing the mass action concentrations equations of structural units or ion couples in the CaO- SiO2- Al2O3- Na2O- TiO2- (MgO) slags, the mass action concentrations were solved by Matlab, so as to build a thermodynamic model for calculating the sulfur distribution ratio between slags and carbon saturated hot metal under 1450??.The calculated sulfur distribution ratio of model agrees well with the experimental sulfur distribution ratio, which can help to predict the sulfur distribution ratio between slags and carbon saturated hot metal.The thermodynamic model can quantitatively determine the respective sulfur distribution ratio of CaO, Na2O and total sulfur distribution ratio in slags.Through the calculated results, the influencing factors on total sulfur distribution ratio were analyzed. In addition, the model can quantitatively calculate the contribution of CaO and Na2O on total sulfur distribution ratio, and qualitatively describe their trend affected by other factors.     

基于IMCT理论的CaO-SiO2-MgO-Al2O3-Na2O渣系的脱硫热力学模型

 为了精确表征含Na2O渣系的脱硫能力，改善脱硫效果，基于熔渣离子与分子共存理论（IMCT）建立了CaO-SiO2-MgO-Al2O3-Na2O渣系结构单元的作用浓度计算模型和1 753 K时该渣系的脱硫热力学模型。并对渣系的总硫分配比及各自硫分配比的影响因素进行了讨论分析。理论结果表明，除LS， MgS外，随着Al2O3质量分数的增加，该渣系的脱硫能力明显下降，而MgO和Na2O质量分数的增加，对提高渣系的脱硫能力具有明显的促进作用。此外，少量的Na2O即可表现出很强的脱硫效果，这为含有Na2O的冶金二次资源在铁水脱硫过程中的应用以及铁水脱硫渣系的优化提供了必要的理论依据。     

Thermodynamic Model for Calculating Activity of Nitrogen and Boron in Fe-C-B-N Molten Metal

The solubility of nitrogen in Fe-C-B-N system was measured at 1 758 K, and the computational model on activity (action concentration) of nitrogen and boron was established based on phase diagram and the coexistence theory about metal melt structure model. Comparing the computed results with the experimental results, satisfactory conclusion can be obtained. The result shows that BN and B₄ C can exist in Fe-C-B-N molten metal at high temperature, which consequently restrains the nitrogen removal from the melt. However, B₄C content is extremely low. Before graphite is precipitated, the influence of carbon on activity of nitrogen in melt is higher in ternary system than in binary system; however, this effect is contrary to that after graphite is precipitated.     

电渣重熔中的脱氧热力学

 为了研究电渣重熔的脱氧制度,基于熔渣的离子分子共存理论,以模具钢和脱氧剂铝为研究对象,根据渣 金反应中各组元的质量守恒定律和热力学平衡定律,构建了电渣重熔中的脱氧热力学模型。模型结合试验得到了钢中各个合金元素的热力学平衡质量分数随脱氧剂铝添加量的变化关系,并依据模具钢的合金成分要求对脱氧剂铝的添加量进行了分析。结果表明,钢中硅、铝、锰和渣中氧化铝的平衡质量分数随着脱氧剂铝的增加呈升高的趋势,而渣中氧化硅、氧化铁、氧化锰呈降低趋势;考虑到模具钢中各个合金元素的成分要求,脱氧剂铝的添加量不宜超过1.7 kg/t(钢)。     

CaO基含V2O5及TiO2脱磷终渣磷酸盐赋存形式

以Ca O基含V₂O₅、Ti O₂脱磷终渣为研究对象, 采用共存理论建立磷富集程度R_ci-cj模型, 并与实际渣系的磷酸盐赋存形式进行对比研究.结果表明:随着碱度的增加, 3CaO·P₂O₅的质量作用浓度逐渐降低, 4CaO·P₂O₅的质量作用浓度逐渐增加, 而2CaO·Si O₂的质量作用浓度呈现出先增加后降低的趋势;C₃P+C₄P的富集可能性范围87%⁹4%, C₂S既是主要的硅酸钙化合物也是形成富磷产物必不可少的物质, 磷酸盐富集相中主要以C₂S-C₃P和C₂S-C₄P的形式存在于炉渣中, 结合扫描电镜 (SEM) 结果、X射线衍射 (XRD) 分析与假设, 计算可得深灰色富磷区域内的含P₂O₅固溶体为2CaO·Si O₂-3CaO·P₂O₅和2CaO·Si O₂-4CaO·P₂O₅, 此结果与理论计算相吻合.     

锰离子与草酸共存体系的毛细管电泳相互作用分析

以咪唑作为背景电解质 ,在 pH 5.0 1,运行电压为 2 0kV ,缓冲溶液组成为咪唑和乙酸盐的条件下 ,采用毛细管电泳间接紫外检测方法测定了缓冲溶液中加入不同浓度草酸后锰离子迁移时间。根据迁移时间的变化 ,并利用毛细管电泳相互作用方法中的峰漂移模型 ,求出了锰离子与草酸共存体系的表观结合常数 ,其结果与文献值较为符合。     

合金熔体结构和原子- 分子热力学模型

对金属熔体结构的研究证实熔体中存在短程有序结构,而含金属间化合物的合金熔体中发现了原子- 分子结合的团簇结构,即固态下的金属间化合物在熔体中并没有消失,而是以团簇结构（实际上就是液态的分子）存在,并与熔体中的自由原子存在化学平衡。从熔体结构出发,提出了适用于合金熔体的原子- 分子热力学模型。然后以Ca- Mg合金熔体为例,介绍了该模型的构建和求解方法,并计算了1010K下的Ca- Mg合金熔体中各物质的摩尔分数。最后,将计算得到的钙、镁摩尔分数与各自的实测活度值进行比较,发现两者吻合得较好。这从计算上证明了合金熔体中同时存在着金属原子和金属间化合物分子,两者处于动态化学平衡之中。且达到平衡时,金属原子的摩尔分数实际上就是各自的活度。因此,对于合金熔体而言,活度并不存在。     

A Thermodynamic Model for Representation Reaction Abilities of Structural Units in Full Composition Range of Fe–Si Binary Melts Based on the Atom–Molecule Coexistence Theory

A thermodynamic model for calculating the mass action concentrations of structural units in Fe–Si binary melts based on the atom–molecule coexistence theory, i.e., the AMCT–N_i model, has been developed and verified through comparing with the reported activities of both Si and Fe in the full composition range of Fe–Si binary melts at temperatures of 1693, 1773, 1873, and 1973 K from the literature. The calculated mass action concentration N_Si of free Si or N_Fe of free Fe in the full composition range of Fe–Si binary melts has a good 1:1 corresponding relationship with the reported activity a_R,Si of Si or a_R,Fe of Fe relative to pure liquid Si(l) or Fe(l) as standard state. The calculated mass action concentration N_Si of free Si has a good corresponding relationship with the calculated activity a_%,Si of Si referred to 1 mass% of Si as standard state as well as the calculated activity a_H,Si of Si relative to the hypothetical pure liquid Si(l) as standard state. The calculated activity a_%,Si or a_H,Si of Si is much greater than the calculated mass action concentration N_Si of free Si in Fe–Si binary melts. The reaction abilities of both Si and Fe show a competitive or coupling relationship in Fe–Si binary melts at the above‐mentioned four temperatures. The calculated mass action concentrations N_i of six structural units as Fe, Si, Fe₂Si, Fe₅Si₃, FeSi, and FeSi₂ cannot show the linear relationship with the calculated equilibrium mole numbers n_i in 100‐g Fe–Si binary melts simultaneously. A spindle‐type relationship between the calculated mass action concentration N_i and the calculated equilibrium mole number n_i of FeSi and FeSi₂ in Fe–Si binary melts has been found.