Foaminess of Refining Slags System

The experiments on the foaminess of the CaO-MgO-Al2O3 -SiO2 -CaF2 refining slag system have been carried out. The obtained results are as followst (1) relative foaming height linearly increases with the increasing of the flowrate of blowing gas; (2) the proper content of MgO is about 11% when slag basicity B<2.5 and it should lower when slag basicity will be higher; (3) the better content of Al2O3, (MgO)+(Al2O3 ) is 15% and 20 % ～ 26 % respectively at the range of lower basicities; (4) the effect of slag basicity on the foaminess is complex and its optimizing vaiue is 1.9 at the specific contents of MgO, Al2O3 and CaF2.     

High‐temperature calorimetric study of oxide component dissolution in a CaO–MgO–Al2O3–SiO2 slag at 1450°C

Blast‐furnace slags are formed, as iron ore is reduced to metal, as a molten a mixture of refractory and not easily reducible oxides, largely silica, alumina, lime, and magnesia. Their relatively low silica content makes them basic and poor glass formers. Their thermodynamic properties, though important for modeling their formation and reactivity, as well as furnace heat balance, are poorly known. Solution calorimetry of small amounts of solid oxides in a molten oxide solvent at high temperature (up to about 1500°C) permits direct assessment of energetics of dissolution. The enthalpies of solution of slag forming oxides: CaO, SiO₂, Al₂O₃, MgO, and Fe₂O₃ in a simplified model slag of composition: CaO (45.9 mol%), SiO₂ (35.1 mol%), Al₂O₃ (8.3 mol%), MgO (10.7 mol%) were measured by high‐temperature drop solution calorimetry at 1450°C. For this slag composition, enthalpies of solution become more exothermic in the order: Fe₂O₃ (279.3 ± 20.8 kJ/mol), MgO (56.7 ± 9.1 kJ/mol), Al₂O, (41.6 ± 11.3 kJ/mol), CaO (?4.3 ± 2.3 kJ/mol), and SiO₂, (?20.4 ± 4.4 kJ/mol), reflecting the relatively basic character of this low‐silica melt. Within these fairly large experimental errors, characteristic of calorimetry at this high temperature, there is little or no discernible concentration dependence for these heats of solution. The trends seen for these five solutes parallel those seen for heats of solution of the same oxides in other melts at various temperatures, with changes in magnitude reflecting the differences in acid‐base character of the melts. The new data for quartz show systematic behavior which extends the range of basicity studied for the enthalpy of dissolution of silica. The results provide reliable data for future modeling of the thermal balance of steel‐making furnaces and geologic and ceramic systems.     

低碳镁炭砖及其研究进展

分别就导热性、抗热剥落性能、抗氧化性、抗渣侵蚀性能等几个方面综述了低碳镁炭砖的研究进展 ,并讨论了影响这些性能的一些因素。指出了低碳镁炭砖亟待解决的问题是提高其抗热剥落性 ,抑制碳的氧化 ,提高材料的抗渣侵蚀性。最后指出 ,镁炭砖今后的发展方向是低碳化及如何在降低碳含量的同时保持良好的抗热剥落性能     

Recovery of rare earth metals and precipitated silicon dioxide from phosphorus slag

This article presents the results of a study conducted to investigate the recovery of rare earth metals and precipitated silicon dioxide from phosphorus slag. To determine the possibility and completeness of the studied processes, thermodynamic data was obtained through the determination of the Gibbs energy and equilibrium constant of the reactions of calcium metasilicate with different reagents, namely sodium hydroxide and carbonate as well as nitric, hydrochloric, and sulphuric acids. This article also presents the results of studies on the treatment of phosphorus slags via hydrometallurgical methods using alkaline agents (sodium hydroxide and sodium carbonate) and nitric acid. The recovery of silicon in solution by the autoclave leaching of phosphorus slag using solutions of sodium hydroxide and sodium carbonate resulted in recovery efficiencies of 1.1% and 16.6%, respectively. The nitric acid treatment of phosphorus slag was studied, and the recovery efficiencies of various elements were the following: rare earth metals, 98.3–98.6%; aluminium, 96.5–98.6%; iron, 94.9–96.5%; and calcium, 99.1–99.5%. Nitric acid (46.5%) was selected as the phosphorus slag recovery agent. The cake produced after the nitric acid treatment of phosphorus slag was leached using two processes based on the use of a sodium hydroxide solution: (1) in a temperature-controlled cell under normal conditions and (2) in an autoclave. The process of leaching under normal conditions was determined to be the most effective process, resulting in an efficiency of silicon recovery into solution of 97.7%.     

以瓷石尾砂和千枚岩为主要原料试制低温快烧外墙砖

以瓷石尾砂和千枚岩为主要原料，外加红粘土及助熔剂原料，研制出一次低温快烧的外墙砖，烧成温度1110℃，周期60分钟，性能达到国标要求。     

Smelting Reduction Technologies for Direct Ironmaking

Smelting reduction is a term assigned to a group of upcoming ironmaking processes which aim at overcoming certain fundamental problems of the existing blast furnace route. These problems include dependence on large scale operation, reliance on coking coal and prepared raw materials as well as environmental pollution. A number of groups around the world, particularly in Europe, Japan, Australia, South Africa and the USA, are engaged in R & D investigations on several process concepts. Many such processes have been successfully tested in pilot/demonstration plant scale and a few of them have been commercialized. The information on smelting reduction, scattered in the literature, is still inadequate. In this paper, the authors have made on attempt to review the subject with emphasis on the current status of the process development, the process fundamentals and the critical factors which affect the production. Some of these factors are : the degree of post-combustion and pre-reduction, heat transfer, slag foaming and kinetics of slag reduction. Results of an investigation on slag reduction, which is an important step in smelting reduction, are discussed with particular emphasis on the reduction kinetics. It is shown that the reduction mechanism depends on the source of carbon.     

Separating titania from treated slag by gravity separation or flotation

1　ＩＮＴＲＯＤＵＣＴＩＯＮＣｈｉｎａｉｓａｔｉｔａｎｉｕｍｒｉｃｈｃｏｕｎｔｒｙ ,ｗｈｏｓｅ92 .4 %ｏｆｔｉｔａｎｉｕｍｒｅｓｏｕｒｃｅｉｓｖａｎａｄｉｕｍ ｔｉｔａｎｉｕｍｂｅａｒｉｎｇｍａｇｎｅｔｉｔｅ .Ａｂｏｕｔ 53%ｔｉｔａｎｉｕｍｗｅｒｅｉｎｉｒｏｎｃｏｎｃｅｎ ｔｒａｔｅａｆｔｅｒｍｉｎｅｒａｌｐｒｏｃｅｓｓｉｎｇ ,ｂｙｗｈｉｃｈｔｈｅｂｌａｓｔｆｕｒ ｎａｃｅｓｌａｇｃｏｎｔａｉｎｉｎｇａｂｏｕｔ 2 5%ＴｉＯ2 ｗｅｒｅ ｐｒｏ ｄｕｃｅｄ[1] .ＴｈｅｃｏｎｔｅｎｔｏｆＴｉＯ2 ｉｎｓｕｃｈｓ…     

钢渣吸附除磷机理研究

研究了氨离子和几种阴离子对钢渣吸附除磷效果的影响,探讨了钢渣吸附除磷的机理.结果表明,氨离子、氯离子和硝酸根离子对钢渣吸附除磷基本没有影响,而碳酸根和硫酸根使除磷效果显著降低,这是因为混合溶液中碳酸根、硫酸根和磷酸根之间互相竞争,争夺钢渣中的钙离子.进一步研究表明,饱和钢渣中Ca、Mg-P的质量分数为总磷的80%以上,而Ca-P是Ca、Mg-P的主要成分,因此,钢渣吸附除磷的主要机理是钢渣中溶出的钙离子与磷酸根离子结合形成沉淀.