世界炼钢生产和镁质耐火材料的现状及其发展趋势

探讨了世界炼钢生产、有色冶金及水泥工业等用镁质耐火材料的现状及近10年来的发展趋势。按照资源保护性及符合环保要求的工艺开发了氧气转炉、炼钢电炉、炉外精炼装置、连铸装置、有色冶金及水泥工业用的新一代镁质耐火材料，从而保证了制品的竞争能力。     

钢铁工业用定型含碳镁质和白云石耐火材料

镁质和白云石-碳试块系由不同等级的死烧中国镁砂和埃及白云石加工而成的。作为碳源采用10％～20％片状石墨以及适宜数量的沥青，采用甲阶酚醛树腊作为含碳结合剂及金属Al作为抗氧化剂。加工出的试块其抗氧化性、致密参数和常温耐压强度与还原气氛下在1500℃烧成后的固相组成和显微结构有关。在200％热处理镁碳和白云石-碳试块后常温耐压强度达到最大值，在还原气氛中于1000％烧成届稍微降低。这和沥青，树脂成分聚合成细的空心的纤维有关，持续达到1500℃。增加片状石墨的含量，从10％到15％和20％，在还原气氛中于1500℃烧成后体积密度随显气孔率的增加而显著降低。     

钢铁工业用定型含碳镁质和白云石质耐火材料

由分级的中国死烧镁砂和埃及白云石制取镁碳和白云石碳团块。10%～20%片状石墨作为碳源,以及适量的沥青、酚醛树脂作为碳质结合剂,金属Al作为抗氧化剂,用来加工这些团块。团块的抗氧化性、致密性参数和常温耐压强度被用来评价在还原气氛中于1500℃烧成之后,与固相组成和显微结构的关系。指出镁碳和白云石碳团块在200℃热处理并在还原性气氛中于1000℃下轻微还原后,常温耐压强度最大。这与沥青的聚合作用/树脂成分进入细的空纤维有关,可持续达1500℃。增加片状石墨含量,从10%到15%～20%,可以看到在还原气氛中于1500℃下烧成之后,随显气孔率增加,体积密度降低。     

世界芳烃生产技术的发展趋势

分析了近年来国内外聚酯和对二甲苯的供需状况及未来需求发展趋势;介绍了当前芳烃主要生产技术,包括催化重整、芳烃抽提、甲苯歧化与烷基转移、二甲苯异构化和二甲苯分离等;指出了扩大芳烃原料来源、通过催化剂的改进提高甲苯歧化过程的对二甲苯选择性、提高C9及以上重芳烃处理能力、提高乙苯转化率等将是未来芳烃技术的主要发展方向。     

Clean Production of Steel and Refractories in China''''s Steel Industry

The paper describes the importance of clean produc-tion of steel and the relationships amongst sustaining devel-opment of steel industry, environment protection and therole of refractories in the clean production of steel. Themain achievements and main shortcomings in the cleanproduction of China's steel industry have been reviewed to-     

The "Direct Bond" in Magnesia Chromite and Magnesia Spinel Refractories

The microstructures of several commercial refractory bricks have been characterized using scanning and transmission electron microscopy. The "direct bond" is shown to be direct at the level of resolution attainable (∼0.3 nm), and a significant number of such direct contacts occur between non-silicate phases in the microstructures of magnesia-chromite bricks. However, attempts to examine the direct bond in magnesia-spinel bricks were unsuccessful due to nonuniform ion thinning of TEM specimens.     

Oxidation and Diffusion in Selected Pitch-Bonded Magnesia Refractories

A conventional and an improved (Mg-containing) BOF refractory, of commercial pitch-bonded magnesia type, were evaluated to determine their Mg diffusion and carbon oxidation characteristics. MgO dense-zone formation was characterized experimentally for various firing times at 1650°C, from which Mg diffusion coefficients in the range 1.4x10^-9 to 8.13x10^-10cm²/s were determined. The data indicate that the Mg diffusion in the system is of the extrinsic type, controlled by the impurities in the MgO, such as Al³⁺, Fe³⁺, and Cr³⁺. The effects of Mg vaporization and MgO condensation, preceding dense-zone formation, were observed to initiate at 1200°C. The dense-zone thickness and the amount of unoxidized carbon were greatest for the Mg-containing refractory.     

Domestic Refractory Production: State of the Art

Refractories and Industrial Ceramics -     

Thermal Evolution of Al-containing Magnesia Refractories for RH Snorkels

Resin-bonded, Al-containing magnesia refractories have been an alternative of rebonded fused-grains magchrome bricks to be used as inner lining in the snorkels and lower vessel of RH degassers, having the advantages of being chrome-free and energy-saving(without burning), with a comparable performance. Microstructural investigations indicate that metal Al powder remains independent in the matrix after heating at 700 ℃ and 900 ℃, and Al_4C_3, Al_2OC and Al_4O_4C crystalline whiskers start forming from 1 100 ℃. The whiskers grow and connect into a network matrix with increasing temperatures,remaining up to 1 600 ℃. Comparison of used bricks from different snorkels indicates a strong whisker networks formation in the brick achieving long service life and superior performance, which is attributed to flexible network structure of stable and interwoven whiskers. On contrary, there is a strongly-oxidized layer on the hot face and almost no whisker found anywhere in the brick with the short service life. It is vital to form the bonding phase of whiskers at high temperatures,generating overall properties of high hot strength, high erosion resistance and thermal shock resistance, which are essential in the working conditions of RH snorkels.     

State of the Art and Trends in the Development of Base Plate Materials for Aluminum Electrolysis Cells

The state of the art and trends in the production and application of barrier materials intended for preventing the infiltration of corrosive components (sodium, sodium fluoride, and molten aluminum) into the heat-insulating layer of refractories for the base plate of aluminum electrolysis cells are discussed. Results for different types of barrier materials tested for cryolitic stability are given; the granular composition and pore structure of some of them are studied. Strengths and weaknesses of the barrier materials are discussed.__________Translated from Novye Ogneupory, No. 2, pp. 16 – 22, February, 2005.     

Production Technology of Wear-Resistant Magnesian Refractories in the Context of Contemporary Trends in Developing Steel Production and Other Processes,Ecology, Resource Saving,and Computerization

The physicochemical principles of technology and wear-resistance of magnesian refractories are considered in relation to the problems of resource saving, sustainable development, and environmentally safe production. A new concept of resource saving in the framework of the composition-structure-properties-technology-design-service conditions-ecology-computerization system is proposed as the main line of research for the 21st century.     

Characterization of the Mechanical Behavior of Magnesia Spinel Refractories Using Image Correlation

The improvement in thermal shock resistance of refractory materials is among the crucial properties that interest researchers and industrials. The “flexibility” in terms of large strain‐to‐rupture is, up to now, an important parameter to develop such characteristic. This can be obtained by generating a network of microcracks within the microstructure of the material under mechanical solicitations. As an outcome, the mechanical behavior can vary from fragile to a large nonlinear one depending on the degree of microcracking present inside the material. In fact, this nonlinear behavior of ceramics related to their microstructure is behind the possibility to enhance the level of strain‐to‐rupture for a better accommodation to the high level of strain induced by thermal shock solicitations. This study is devoted to apply digital imaging correlation method to support mechanical behavior analysis for the evaluation of the thermal shock ability of refractory materials. In this paper, mechanical characterization of magnesia spinel materials has been carried out using different experimental tests. These nonlinear materials are characterized by a mechanical behavior strongly dependent on their microstructure.     

国外钢铁工业用耐火材料的发展状况

耐火材料的发展驱动力来自于钢铁等用户行业的发展及技术进步。分别从炼铁工业、炼钢工业、连铸生产、环境保护方面论述了国内外钢铁工业用耐火材料的近几年发展情况,指出了开发使用优质、高效、长寿、多功能的耐火材料,以降低单耗、减少污染,同时关注耐火材料的再循环利用。     

Highly Reactive Magnesia Production: Modeling and Experiment

Refractories and Industrial Ceramics - The thermodynamic equilibrium conditions of bicarbonate leaching were analyzed and used to develop a mathematical model for determining the parameters giving...     

Development Tendency of the Refractories for Iron ＆ Steel Industry in China

This paper introduces the developing tendency of refractories for iron and steel industry combined with the new metallurgical techniques applied in iron and steel industry in China. Refractories for blast furnace long service life, smelting reduction iron-making process, secondary refining metallurgies and clean steel making, near net shape continuous casting are described respectively. To meet the requirement of iron and steel industry, the high quality, multi-functions and environment-friendly refractories with long service llfe will be focused and developed in the future. In addition, high grade refractories in China have great developing space and potential market.     

Influence of Nano-Al_2O_3 on Properties of Magnesia Chrome Refractories

Magnesia chrome bricks were prepared with fused MgO-Cr2O3 synthesized material,fused magnesite and chrome ore as main starting materials. Nano-Al2O3 was added into refractories ( 2% ,4% and 6% in mass) substituting for Al2O3 micropowder. After mixing and shaping,the bricks were fired at 1 550 ℃ ,1 600 ℃ , 1 650 ℃ and 1 750 ℃ ,respectively. The microstruc-ture,sintering property,mechanical properties,thermal shock resistance and slag resistance of the specimens with the addition of nano-Al2O3 were investigated. The re-sults indicate that the performance of brick with 4 mass% of nano-Al2O3 is greatly improved after firing at 1 650 ℃ .     

2005年耐火材料工业状况及趋势

耐火材料工业,对世界商品生产工业(钢铁、水泥、玻璃、铝、铜、石油化工等)的发展起着关键作用,并扮演着重要角色。聚焦耐火材料工业,显示中国、美国和日本之间的耐火材料产量和产值显著不同。中国的耐火材料产量和产值快速增长,但美国和日本则呈下降趋势。最近几年,美国和日本几种砖的产量下降 (粘土、高铝和镁碳砖),而不定形耐火材料则持续占领市场,呈增长趋势。耐火材料工业持续地满足了并超过了用户的需求,并在不断地改进技术,但还有一些需重点关注的,如价格压力和复原价值。但是新情况产生新的机遇,所以耐火材料工业也将不断的寻找出路向前发展。     

A Review on Some Applications of Magnesia in Current China Refractories Industry

Being rich in the magnesite resource,China hasbecome the biggest magnesia-based products manufac-turer.With nearly300magnesite mines including somenewly built magnesite processing plants,China has to-tal output of over14million tons magnesite ore peryear,…