新型干法水泥窑高温带用无铬砖的研制及应用

<正>镁铬砖在水泥窑高温带使用后会产生致癌物质六价铬盐化合物,西方发达国家已限制或禁止镁铬砖在水泥窑上使用,国内由于没有合适的无铬砖替代镁铬砖,所以镁铬砖仍在国内水泥窑高温带大量使用     

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。     

白云石砖在窑外分解窑上的试用

白云石砖在窑外分解窑上的试用梁忠博辽宁省本溪水泥厂（１１７０１９）我厂３号窑为１２００ｔ／ｄΦ３．７ｍ×５３ｍ的窑外分解窑，窑内烧成带衬料长期使用普通烧结镁铬砖。由于镁铬砖在水泥窑内使用中砖内Ｃｒ２Ｏ３组分与窑气、窑料中的碱、硫等相结合，形成有毒的Ｃ...     

使用镁铬砖窑衬延长窑的运转周期

我厂从推广水泥回转窑烧成带镶砌镁铬砖开始,先是在5号窑上使用。由于在运输和保管上没有注意镁铬砖的防雨防潮;在镶砌上忽视质量赶进度;在设备上窑胴体水冷却门处漏水;在使用上抢着开窑也未重视保温、挂窑皮和保护窑皮。因此,影响了镁铬砖窑衬的使用寿命。通过一段时间的实践,初步掌握了烧成带正确使用镁铬砖的规律,并相继在五台窑上全面推广,使窑衬的使用寿命延长,窑的运转     

水泥回转窑用再循环利用镁铬砖

把使用过的镁铬砖加工成再生原料可以用于生产适合水泥回转窑低温部位使用的镁铬砖。这种再循环利用镁铬砖不仅具有与普通镁铬砖和镁尖晶石砖基本相同的特性，可以降低水泥的生产费用，而且减少对环境的污染。     

国产耐火材料在500O t/d水泥窑烧成带上的使用

在大型窑外分解窑上,国产镁铬砖可代替进口砖,使用周期可达1年,阐述了烧成带窑衬损坏的机理、选用依据、砌筑方法及操作手段.     

国产耐火材料在5000t／d水泥窑烧成带上的使用

在大型窑外分解窑上，国产镁铬砖可代替进口砖，使用周期可达1年，阐述了烧成带窑衬损坏的机理，选用依据、砌筑方法及操作手段。     

尖晶石砖在水泥窑的使用前景

随着水泥窑的大型化、高效化以及原材料燃料的多样化,窑衬的工作环境更加苛刻,对火砖的性能提出更高的要求。近来国内外作为大型水泥窑烧成带和过渡带的窑衬,主要使用高温烧成和超高温烧成镁铬砖、尖晶石砖和白云石砖。这三种碱性砖作为水泥窑衬已成为鼎足之势。现仅就尖晶石砖在水泥窑上的使用前景作简要分析。一、烧成带用砖的演变水泥窑烧成带是全窑的高温带,物料温度可达1400～1500℃,而气流温度还要比物料温度高许多。这是全窑的最关键部位,是窑衬使用条件最苛刻的地段。烧成带最初用的是烧粘土砖、Al_2O_3含量在30%～40%之间。随着水泥质     

白云石砖在水泥回转窑中的应用

由于水泥回转窑使用的镁铬砖容易产生有害的六价化合物，导致环境污染。因此，在水泥回转窑的烧成带，用无铬砖代替镁铬砖已成为一种发展趋势。     

白云石砖在水泥窑的使用

0 前言 目前,在水泥窑烧成带使用的碱性砖主要是镁铬砖、镁尖晶石砖和白云石砖。由于镁铬砖存在公害问题,故有被镁尖晶石砖和白云石砖所取代的趋势,水泥窑用碱性砖将实现无铬化。这里仅就白云石砖在水泥窑的使用问题略述如下,供参考。     

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.     

水泥工业用无铬碱性砖的发展情况

消除铬公害和在水泥窑内应用代用燃料促使白云石砖、尖晶石砖和镁锆砖组成的系列无铬碱性砖成功地替代着镁铬砖。当前无铬碱性砖还在不断开发和更新之中。     

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.     

水泥窑用镁铬砖中Cr6+化合物的化学性质和解毒

研究了K2CrO4的化学稳定性。K2CrO4中的Cr^6 不能或难于被乙醇、乙醛、柠檬酸、酒石酸、葡萄糖甚至草酸还原，仅发现FeSO4与MnSO4可将K2CrO4的Cr^6 转化成Cr^3 。镁铬残砖产生的Cr^6 物质很难在环境中被破坏，很多情况下将长期存在自然界中，持续性地危害人体的健康。因此，水泥窑应优先使用无铬耐火材料，如使用镁铬砖，须用FeSO4或MnSO4等方法将残砖解毒。     

新型镁铬质耐火泥浆的研制与使用

以废镁铬砖为主要原料 ,采用国产材料作结合剂研制了镁铬质耐火泥浆。研制的三种镁铬质耐火泥浆理化性能优良 ,施工作业性好 ,已成功应用于各种高温窑炉     

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     

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...     

The State—of—art of Magnesia—chrome Refractories for P—S Converter in China‘s Non—ferrous Industry

The state-of-art of magnesia-chrome refractories from direct-bonded magnesia chroma brick to fused-grain rebounded magnesia chrome brick for P-S converter is discribed.The Cr2O3 conternt of the brick is continually increased with the reduction of the impurity content of brick ,the pre-synthetic raw material is applied and the operating condition of conerter is optimized so that the service life of converter is largely enhanced.     

水泥回转窑烧成带用耐火材料的最新研究

对水泥回转窑烧成带用耐火材料的使用条件和要求进行了分析,并对近年来水泥窑用镁铬砖、镁尖晶石砖、镁钙锆砖的应用进行了探讨,指出所存在的缺点及改进措施。认为其发展方向为镁钙锆砖及尖晶石砖,并对其应用前景进行了展望,希望实现水泥回转窑的无铬化。