铝铬渣对用后镁铬砖制备镁铬浇注料性能的影响

为实现用后镁铬砖的综合利用,本文以用后镁铬砖回收料为主要原料制备镁铬质耐火浇注料,研究了铁合金厂铝铬渣对用后镁铬砖制备镁铬质耐火浇注料体积密度、显气孔率、常温耐压强度、热震稳定性及抗渣性的影响.结果表明:铝铬渣对用后镁铬砖制备镁铬浇注料具有一定的促烧结作用,随着铝铬渣加入量增加,烧后试样常温耐压强度增大.随着浇注料结构中原位尖晶石量增加,试样显气孔率增大,体积密度减小.当铝铬渣加入量为10％时,试样的热震稳定性最好,热震前后试样的常温耐压强度保持率为93.8％,试样具有较好抗渣侵蚀性能,侵蚀层结构稳定均匀.     

水泥回转窑用镁尖晶石耐火材料

本文论述了第二代镁尖晶石耐火材料的研制成果。查明，利用水镁石可以生产出优质合成尖晶石和方镁石。含有这些组份的新研制的镁尖晶石耐火材料的物理陶瓷性能指标优超于目前俄罗斯在回转窑中所采用的镁铬质耐火材料的同类指标。     

钢包渣线用镁锆铬质无炭浇注料的研制

精炼钢包渣线使用含炭耐火材料存在着使钢水增碳的问题 ,需要研制抗渣侵蚀和渗透能力较强的无炭钢包渣线材料。以轻烧氧化镁和锆英石为原料 ,采用湿法共磨工艺 ,合成了镁锆质熟料 ,并以此合成料为主要原料 ,加入工业Cr2 O3细粉、锆英石细粉及硅微粉等研制了无炭的镁锆铬质钢包浇注料。实验证明 ,制得的镁锆铬质浇注料高温强度较高 ,高温收缩率较小 ,抗渣侵蚀和渗透能力较强。     

镁尖晶石砖添加TiO2的效果

1 前言 作为精炼钢包用耐火材料是以镁铬质耐火材料为代表。近年来,由于镁铬质砖的废弃处理很困难,因此在这种情况下,对镁尖晶石砖的关注目益提高,它在实际精炼钢包中的使用量也正不断增加。但另一方面,尖晶石砖的性能尚不如镁铬质砖那样令人满意,目前正在对其进行改进。 2 以往制品的损毁机理     

镁碳砖替代VOD钢包用的镁铬砖

由于六价铬的化合物污染环境,镁铬质耐火材料在全世界的应用受到限制。因此,研制了特种镁碳砖。在生产低碳的超低不锈钢时,这种镁碳砖能替代容量为４０ｔＶＯＤ钢包渣线部位用的镁铬砖,钢包的使用寿命得到提高而没有对钢的质量产生任何影响。     

澳斯麦特炉用镁铬和铝铬砖抗侵蚀性能对比

为延长澳斯麦特炉炉衬用耐火材料的服役寿命,对其所用镁铬和铝铬质耐火材料的主要损毁机理进行了分析.通过对现役镁铬和铝铬质砖进行物理化学性能检测,结合热力学模拟,对比了镁铬和铝铬质耐火材料抗热应力破坏,抗Cu/Cu2 S和FeO/SiO2渣的渗透侵蚀能力.研究表明:镁铬和铝铬质耐火材料均有较高的常温及高温强度,抗机械冲刷性能良好;镁铬质耐火材料抗Cu/Cu2 S侵蚀性能要优于铝铬系耐火材料,但抗FeO/SiO2渣的性能相比较差.铝铬砖可以替代镁铬砖在澳斯麦特炉上应用,并取得良好的使用效果.     

玻璃熔窑用现代耐火材料

当今Veitsch-Radex-Didier集团公司用于玻璃工业耐火材料的生产、集中在下同国家的几十个生产厂。在德国、奥地利、西班牙、英国、法国主要生产硅质、高铝质、镁质、镁铬质、方镁石质、刚玉质、粘土质、轻质制品以及各种类型的高温隔热材料、耐火混凝土等:在意大利(Refel公司)生产熔注斜锆石刚玉质制品;在美国和加拿大(Nalko公司)生产含锆制品。     

耐火材料中的六价铬

生态安全是对任何工艺过程和耐火材料的主要要求之一。主要氧化物生态安全的评价列于表1。 就生态学而言,最为有害的是含铬耐火材料,处于第二位的是硅质耐火材料,处于第3位的是焦油白云石耐火材料。它们的极限容许浓度为2mg/m~3(3级危害度)。 目前,耐火材料工业生产各种成分的含铬耐火材料:镁铬质、铬镁质、电熔铬尖晶石质、镁橄榄石铬质、铬镁橄榄石质、莫来石铬质、铬莫来石质、铬质和铬酸质耐火材料。为     

V_2O_5对玻璃熔窑蓄热室镁铬质格子砖的侵蚀

通过对玻璃熔窑蓄热室格子体使用后损毁状况的观察,对格子砖的原砖和残砖的分析,并结合部分模拟试验进行研究的结果,指明了当熔制玻璃采用重油作燃料时,燃油灰分中的V_2O_5对镁铬质格子砖有助熔作用,可促进镁铬质格子砖中的方镁石和尖晶石晶粒长大并导致格子砖裂隙的形成和扩展,也促进硅酸盐相镁橄榄石化,对格子砖表层的高熔点晶相的漂浮也有影响。同时指明V_2O_5对镁铬质格子砖的侵蚀主要是通过砖内的硅酸盐相进行的。欲提高镁铬质格子砖的耐侵蚀性,在降低其气孔率的同时,必须尽可能地降低硅酸盐含量。     

新型耐火泥浆的设计

介绍了20世纪80～90年代耐火泥浆的标准化情况以及存在的主要问题。以对耐火泥浆的性能要求为出发点,从耐火泥浆的化学组成、物理性能、使用性能和施工性能等方面阐述了新型耐火泥浆的性能设计。在设计耐火泥浆的化学组成时,从耐火砖的化学组成、砌体的工作环境以及添加剂的种类和数量对其耐火性能的影响三方面考虑。要使耐火泥浆在高温状态下达到规定的使用效果,就要以化学性能为基础,以施工性能为保障,以高温物理性能为目的,设计出具有最佳综合性能的新型耐火泥浆。同时还阐述了新型耐火泥浆的生产工艺设计、工艺流程和生产方法,包括耐火粉料的制备、添加剂的制备和成品的制备。     

Effects of Chrome Oxide Concentrate Powder on Properties of Magnesia Composite Materials

The magnesia composite materials were prepared using fused magnesia,used magnesia chrome bricks, magnesium aluminate spinel, alumina powder and chrome oxide powder as starting materials. In order to improve the performance of magnesia composite material,the influence of chrome oxide concentrate powder on the properties of magnesia composite material was researched. The apparent porosity,bulk density,cold crushing strength,linear expansion and thermal shock resistance of the specimens were determined. The results show that adding chrome oxide concentrate promotes the formation of the composite phases of three kinds of spinel,which is beneficial to the thermal shock resistance. The magnesia chrome spinel can not be formed at high temperatures theoretically,but can dissolve in the magnesia composite material. Comprehensively,the optimal addition of chrome oxide concentrate is 10. 0 mass% for the magnesia composite materials.     

水泥窑用高性能镁铬砖的研制及应用

分析了普通镁铬砖在水泥窑上使用存在的不足之处。在原来普通镁铬砖工艺基础上引入特制的合成料,使制品的性能得到改善。高性能镁格砖在水泥窑上使用,寿命远远超过普通镁铬砖。     

Corrosion Resistance Mechanism of Magnesia Zirconia Brick to RH Furnace Slag

Magnesia zirconia brick containing 11 wt% zirconia was prepared with magnesia and monoclinic zirconia as starting materials in order to replace the chrome-containing materials for RH furnace.The corrosion resistance of magnesia zirconia brick and fused rebonded magnesia chrome brick (short for magnesia chrome brick) to high and low basicity slag of RH furnace was comparatively researched by rotary slag method and their slag resistance mechanisms were analyzed.The results show that:(1) because the reaction l...     

Pollution of Chrome Bearing Materials and the Solutions

This paper summarizes the pollution, situation and solutions of chrome bearing materials used in high temperature industry. Hexavalent chromium compounds are readily soluble in water and associated with carcinogen. Therefore, serious environmental problems appeal for the study and application of chrome free materials. Chrome free products include: magnesia based materials, dolomite based materials, magnesia spinel materials, magnesia hercynite or magnesia galaxite materials and zirconia containing materials,and other substitutes. Although any product has its advantages and disadvantages, the trend to development of chrome free products is inevitable.     

TiO_2对镁铬砖抗渣蚀性的影响

利用XRD分析和光学显微镜等测试手段 ,研究了添加TiO2 对镁铬砖抗渣蚀性的影响。结果表明 :炉渣中的CaO能分解镁铬砖中的二次尖晶石而使镁铬砖损毁 ,但加入TiO2 后 ,TiO2 能优先于尖晶石中的Cr2 O3与渣中CaO反应 ,生成高熔点的CaTiO3,从而抑制CaO对砖中镁铬尖晶石的分解 ,提高了镁铬砖的抗高钙渣渣蚀能力     

Three bond modes of basic refractories used for Ruhrstahl Heraeus degassing process

Magnesia–spinel brick and unburnt periclase–spinel–Al brick are being employed as a substitution of traditional magnesia–chrome brick in the chromium-free campaign of lining materials in Ruhrstahl Heraeus (RH) degasser. These three materials are investigated, in terms of physical properties, corrosion resistance and flexibility by wedge splitting test. Tracking their physical alterations and chemical reactions through burning or heating, three bond modes are discovered. Magnesia–chrome brick is subject to a series of phase transformation with rising temperature to yield a liquid envelop around chromite-ore particles, to further form porous rim while liquid is gradually absorbed by surrounding magnesia and eventually to precipitate secondary chromite spinel lied between magnesia particles by thoroughly dissociating chrome ore. The precipitated chromite spinel functions as the featured bond that enhances hot strength and corrosion resistance to slag, and additionally liquid coexistence improves the flexibility. The direct bond mode of magnesia particles in magnesia–spinel brick endures slag penetration by immanent character of MgO. Spinel incorporation in magnesia effectively improves thermal shock resistance. Due to minor negative value of permanent linear change after reheating, further sintering (densifying) in using at high temperature would bring a risk of loosening and open joints of magnesia–spinel lining. While used in RH degasser, unburnt periclase–spinel–Al bricks undergo a miraculous process of metallic Al melting, gaseous AlN and AlON formation, MgAlON whiskers germination combined with gaseous Mg reduced, and micron-size whisker network bond domination in their matrix. Such a whisker-network bond renders the material a successful eco-friendly alternative to magnesia–chrome refractory.     

Slag Resistance of Refractories for Direct Reduction of Laterite Nickel Ores in Rotary Kilns

Aiming at prolonging the service life of refractories for direct reduction of laterite nickel ores in rotary kilns, the slag resistance of ten materials(corundum bricks, chrome corundum bricks, silicon nitride bonded silicon carbide bricks, high alumina silicon carbide bricks, high alumina bricks, magnesia chrome bricks, magnesium aluminate spinel bricks, spinel chrome corundum bricks, chrome corundum castables and magnesia alumina chrome composite spinel bricks) was evaluated by rotary slag tests, which simulate the service conditions in rotary kilns. The corroded residual bricks were analyzed by SEM and EDS. The results show that the magnesia alumina chrome composite spinel brick possesses the advantages of magnesium aluminate spinel bricks and chrome corundum bricks; MgO-rich spinel can absorb the penetrated ferric oxide, and forms a dense zeylanite layer, which prevents the penetration of the molten laterite nickel ores; therefore, it is an ideal lining of rotary kilns for direct reduction of laterite nickel ores.     

合理选择和使用耐火砖消除铬对环境的危害

水泥窑用镁铬砖的残砖中铬含量较高，对环境危害大。为降低铬盐对环境的危害，牡丹江新材料科技股份有限公司在水泥窑上进行了使用低铬砖和无铬砖的试验。试验表明，加锆改性尖晶石砖的使用情况较直接结合镁铬砖差，而加铬方镁石复合尖晶石砖(LYC砖)的使用效果好于直接结合镁铬砖。LYC砖不仅铬含量低，对环境的危害小，且其使用寿命是普通镁铬砖的5倍，是直接结合镁铬砖的1．72倍。使用LYC砖对提高窑运转率，降低生产成本有利。     

Improvement of Durability of Purging Plugs Using MgO Micropowder for Refining Ladles

To modulate the matrix of purging plugs, MgO micropowder was introduced as a replacement to magnesia powder in alumina–magnesia castables, and the effect of MgO micropowder on the properties of alumina–magnesia castables and the possibility of developing chrome‐free castables were investigated. Experimental results showed that the introduction of MgO micropowder resulted in an improvement in the volume stability, strength, and thermal shock resistance of alumina–magnesia castables due to its high surface energy and small particle size. However, excessive amounts of MgO micropowder led to a lower densification, and there was a slight degradation in the performance of the alumina–magnesia castables. The slag resistance of the prepared alumina–magnesia castables was significantly better than that of the alumina–chrome castables. Microstructure and energy spectrum analysis showed that the formation of a solidified reaction layer, mainly consisting of spinel and CaAl₁₂O₁₉, was the major cause of the observed difference in slag resistance. In addition, the alumina–magnesia castables had a lower linear thermal expansion coefficient than that of the alumina–chrome castables at each experimental temperature, which effectively decreased the thermal stress during its service period, thus exhibiting good thermal shock resistance.     

闪速炉用镁铬砖的研制与应用

简要介绍了闪速炉用耐火材料国产化工作的现状 ,阐述了闪速炉用镁铬砖的研制、使用和损毁情况。认为现在完全可以实现闪速炉用耐火材料的国产化