优质镁钙砖在AOD精炼炉上的应用

目前 ,AOD炉用耐火材料大体分为镁铬砖、镁白云石砖(镁钙砖 )及白云石砖 3种。欧洲的AOD炉衬普遍采用煅烧白云石砖 ,日本的AOD炉大多数仍采用MgO -Cr2 O3 砖 ,也有的采用综合砌筑 :风眼区 10层以下使用MgO -Cr2 O3 砖 ,前墙、炉底及其他部位使用MgO -CaO砖。太钢 18tAOD炉建成初期 ,炉衬全部使用镁铬砖。随着镁钙质材料的开发 ,在风眼区以外的部位逐步推广使用镁钙砖 ,风眼区一直使用电熔半再结合镁铬砖。这样的材料选择和综合砌筑方法一直延续到2 0 0 0年。随着AOD的扩容改造和单渣法精炼工艺的推行 ,MgO -Cr2 O3 砖区的侵蚀…     

AOD炉用耐火材料的改进

1 前言 在日本大同钢铁公司涩川厂,为了降低AOD炉用耐火材料费用,从1998年以后逐步扩大了白云石砖的使用范围。与以往使用的镁铬砖相比,白云石砖的单位价格低,但问题是使用次数较少。迄今为止,AOD炉已从2座增加到3座,取得了筑炉-操作-拆除的周转平衡,可100％使用白云石砖。     

中国产白云石砖

1前言用于不锈钢精炼的AOD炉及VOD炉,其内衬是使用高温下抗侵蚀性优良的烧成镁铬砖和烧成白云石砖。烧成白云石砖以前一直是在品川耐火材料公司神奈川县的相模工厂和冈山工厂生产,后来在1995年关闭了相模工厂,     

转炉炉衬用镁质大砖的生产与应用

采用优质电熔高钙低硅镁砂 ,添加复合外加剂 ,用复合有机结合剂结合 ,制成了镁质大砖。介绍了该大砖的整体吊装法和炉帽外装法两种砌筑工艺。与普通镁碳砖相比 ,使用镁质大砖可以极大地减轻工人的劳动强度 ,缩短筑炉时间 ,保证炉役后期炉膛的规则性 ,有利于提高转炉炉龄 ,提高炉子作业率 ,降低生产成本     

硫化碱转炉衬砖推广应用会在安徽萧县召开

目前我国硫化碱生产主要采用煤粉还原芒硝的方法。大部分生产厂采用短转炉生产,炉衬使用一般粘土耐火砖时,仅一个月左右的时间就必须停产修炉,因而炉龄直接影响到产品产量、原料消耗和生产成本。大连染料厂为了提高炉龄,经过几年探索,研究了高铝质耐火砖用作转炉衬砖可以使炉龄从900炉次提高到3046炉次,连续生产六个月不修炉。每台炉一年可节约修炉费用62,000余元,增加产值30多万元,经济效     

AOD炉衬MgO-CaO砖的侵蚀机理

采用光学显微镜(OM)、扫描电镜(SEM)和能谱仪(EDAX)对AOD炉用镁钙砖的残砖进行了分析,探讨了炉衬镁钙砖的侵蚀机理。结果表明:AOD炉衬镁钙砖的蚀损主要是由硅酸盐液相的溶解和渗透引起的;在残砖反应带和原砖带之间形成的平行于工作面的横断裂纹,是加速镁钙砖损毁的重要因素。     

提高普通电弧炉寿命的途径

安阳钢铁集团公司第一炼钢厂有两座普通电弧炉,1997年以前电炉炉衬均采用焦油镁砖砌筑。炉衬损坏之后,采用人工投补镁砂的办法修补。但人工投补存在镁砂分布不均匀、与炉衬粘结不牢、易剥落等缺点,同时还增加了成本。另外,炉底大砖在炉龄达到40炉之后,炉底工作层易出现吹坑、漂砖现象,处理吹坑一次需要10ｍｉｎ左右,且维持炉次有限,还存在穿炉、漏炉等恶性事故隐患。为了提高炉龄,在电炉炉体上采用了综合砌炉、综合护炉及改善操作工艺等措施,取得了明显的效果,炉龄已突破100炉。1　综合砌炉由于炉墙部位不与钢水直接接触,炉墙仍采用焦油镁砖…     

电熔白云石在耐火材料应用中的性能研究

3.2 不烧砖 以电熔白云石为原料采用传统工艺生产沥青结合白云石和白云石碳砖的方法,用来生产低温处理白云石砖。 由于电熔材料的密度高,用该料制成的砖的一些物理性能超过了采用死烧材料制造砖,见表5(仅包括一些有明显差异的数据)。沥     

镁钙系耐火材料在炉外精炼炉上的应用

综述了镁钙砂、烧成镁钙砖和不烧镁钙碳砖等镁钙系耐火材料的发展现状、生产工艺及性能,介绍了镁钙系材料在AOD炉、VOD炉、LF-VD炉、GOR炉等炉外精炼炉上的应用情况。     

镁碳砖MT-14A在GOR转炉炉底的应用研究

对镁碳砖MT-14A在65t GOR转炉炉底的使用情况进行了论述,并对寿命较低的炉底砖进行取样分析。研究表明,1 000mm长镁碳砖最高使用炉龄为62次,平均炉龄50次左右;800mm长镁碳砖最高使用炉龄为41次,平均炉龄不足30次。镁碳砖MT-14A在使用过程中出现了断砖现象,不是最理想的GOR炉底材料。其损毁机理是热冲击损伤及工作面电熔镁熔损和脱碳反应。     

优质电熔镁白云石砂的生产及应用

以太铜大关山矿特级白云石为主要原料，配入４０％辽南一级镁石，用直接电熔法熔炼的电熔镁白云石砂纯度高、密度大、抗水化性强、微观结构好．以此种电熔砂为原料生产的无水树脂结合的全电熔镁白云石（炭）砖，在ＬＤ转炉和ＡＯＤ精炼炉应用取得了较好的使用结果。     

精炼低碳超低碳钢用优质烧成镁白云石砖的研制与应用

采用BS55镁钙砂和大结晶电熔镁砂为原料,以石蜡和烯烃为复合结合剂制取的烧成镁白云石砖,具有优良的抗渣性和热震稳定性,在AOD精炼钢包中使用,其寿命已打破世界最高纪录。     

Corrosion Mechanism of MgO-CaO Brick for AOD Furnace

In recent years burnt MgO-CaO brick have a-chieved a good application in AOD furnace[1].Thiswork analyzed the microstructure of residual MgO-CaObricks after being used in AOD furnace and discussedthe corrosion mechanism,which provides a theoreticalfoundat…     

高聚合沥青结合镁钙炭砖的生产与使用

研制了抗水化、高聚合改性沥青结合、常温成型的镁钙炭砖，于长钢ＡＯＤ精炼炉内使用，取得了较好的应用效果。介绍了该镁钙炭砖的生产工艺、性能和使用     

氧化锆对碱性耐火材料使用性能的影响

在高纯镁砂中引入适量ＺｒＯ２制取的ＡＯＤ炉用风眼砖，可显著提高制品的机热震性和抗侵蚀性能。     

树脂结合白云石砖生产经验简介

白云石砖是一种优质、环保、资源广泛的新兴耐火材料。主要有高温烧结和低温结合两种,而树脂结合白云石砖在国内生产单位很少。本文主要介绍某公司生产树脂结合白云石砖的一些生产经验、工艺和常见问题等以交流提高。     

AOD炉用耐火材料的选择与应用

介绍了AOD炉的基本原理 ,炉衬损毁的主要原因及选材要点 ,同时对AOD炉常用的镁铬系和镁钙系材料的性能进行了比较 ,并且提出了提高AOD炉炉衬寿命的措施。     

THE MAKING OF DOLOMITE BRICK AND A STUDY OF THEIR PROPERTIES1

This investigation deals with the making and the properties of dolomite brick. A thorough review of the literature shows that there are many improvements possible in the making of dolomite brick and some of the principal faults are pointed out. In this investigation it was shown that 200-mesh dolomite mixtures of a composition 9–0–6M (9% Fe₂O₃–0% Al₂O₃–6% SiO₂–85% dolomite); 6–3–6M (6% Fe₂O₃–3% Al₂)₃–6% SiO₂–85% dolomite); and 2–4–4M (2% Fe₂O³–4% Al₂O₃–4% SiO₂–90% dolomite) can, if calcined to cone 20 down, be made into better brick than any previously described. The advantages of this higher fired material are (1) it has been more completely shrunk than that fired at lower temperatures and therefore does not shrink as much when refired in the form of brick, (2) in the use of aqueous binders less trouble is encountered due to slaking than with the lower fired material. In a continuation of the binder studies a thorough investigation was made of molasses, tar, epsom salts, water and carbonated water. No conditions were found where water, carbonated water, bindex or epsom salts, could be satisfactorily used. Using 20-mesh (2–4–4M) calcine and 15 and 20% of molasses as a binder it was found that the brick always squatted considerably at about cone 15 down. This was shown to be inherent in the material itself and not due to a migration of any part of the material or a softening of the molasses. The most successful brick were made using 20-mesh D9-0-6M composition (9% Fe₂O₃–0% Al₂O₃–6% SiO₂–85% dolomite 200-mesh calcined to cone 20 down), plus 13% of a one to three dextrin-water mixture as binder, and 20-mesh S6–3–6M (6% Fe₂O₃–3% Al₂O₃–6% SiO₂–85% dolomite 200-mesh calcined to cone 20 down), plus 12% of a 5% solution of sodium silicate and in each case fired to cones 16 to 18 down. These brick are dense, well shaped and refractory. Cone fusion temperatures of calcines 9–0–6M, 6–3–6M and 2–4–4M were made in an especially constructed oxyacetylene furnace. The results of the tests show that the above compositions have cone fusion temperatures above cone 40 (2010°C) down. In connection with this work it was also shown that an electric induction furnace, where graphite is used as the resistor, is not reliable for cone fusion tests due to the strong reducing atmosphere. In a load test on brick D9–0–6M and S6–3–6M it was found that when they are heated to 1350°C and held at 1350°C for one hour under a load of twenty-five pounds per square inch they show only a small compression. Brick D9–0–6M shows a compression of 3% while S6–3–6M shows a compression of 0.9% neither brick showing any tendency to crack or squat. In a spalling test these brick (D9–0–6M and S6–3–6M) were shown to possess the characteristic fault of magnesite in that they do not withstand sudden heat change without spalling. On heating one hour a t 1350°C and then exposing to room temperature they crack badly. The use of less flux was unsuccessful as the material thus prepared shows strong hydration which is fatal in that it causes the material to disintegrate. Dolomite compositions 9-0-6M, 6-3-6M and 2 4 4-M, flux violently with silica and fire brick but are inactive toward magnesia and chrome brick. It is, however, possible to burn the dolomite on fire clay brick if a thick layer of magnesia brick grog is used. Since it is necessary to grind the dead-burned dolomite before it can be made up into brick i t is necessary to know the relative tendency toward slaking of the various size particles. It was found that the finer the calcined dolomite is ground the more rapidly the slaking takes place and that it is in some cases very appreciable for 20-mesh material as used in making brick.     

Multi-impregnating pitch-bonded Egyptian dolomite refractory brick for application in ladle furnaces

A method of preparation of multi-impregnated pitch-bonded Egyptian dolomite refractory brick for ladle furnace is described. Brick samples were prepared from blend of calcined dolomite mineral and coal tar pitch. The blend was hot mixed and pressed under a compression force up to 151 MPa. Green bricks were baked for 2 h at temperatures up to 1000 °C. Voids in the baked bodies were filled with carbon by multiple impregnations using low-softening point coal tar pitch. Each impregnation step (30 min) was followed by calcination at 1000 °C. Brick samples containing 8–12 wt.% coal tar pitch binder and pressed under 108–151 MPa acquired quantify crushing strength. However, multi-impregnating favored the mechanical strength of the baked brick samples and improved their hydration resistance (>45 days). Dolomite brick samples containing 10 wt.% coal tar pitch and pressed at 108 MPa gave high hydration resistance (more than 60 days in normal condition) compared to the hydration resistance of the commercial bricks (30 days). The prepared brick samples have acceptable density, chemical stability, outstanding resistance and good mechanical properties would meet the requirements of Ladle furnace (LF) for steel making industry. In addition, estimation of production cost of the brick indicates it is competitive with the market price based on durability and service life time aspects.