Some comments on the structure of high angle grain boundaries

Abstract

Fluxing trials were conducted at Brunswick Smelting over a four-month period to determine the effect of slag composition on slag lead losses, blast furnace coke consumption and smelting rate. A computer program was developed to analyse the blast furnace operating data so that relationships between slag variables and lead loss could be examined. Microscopic studies were carried out on granulated slag samples obtained from the smelter to identify the forms of lead in slag and to relate these forms to the flux composition of the slag.

The results of this investigation indicate that low lead losses in slag can be achieved with good blast furnace throughput by maintaining a slag composition of 40–42 wt % iron and 0.85–0.90 lime-silica ratio. The benefits expected from operating at these levels are reduced fluxing costs, lower coke consumption and increased savings in lead recovery.     

冷热双混辊压法高炉熔渣破碎试验

围绕高炉熔渣余热回收设计开发了冷热双混辊压法高炉熔渣破碎装置,并以水淬高炉渣作为冷却介质,开展了高炉熔渣辊压破碎试验。试验研究了电机转速R、辊间距离L、冷却介质漏斗高度H等装置运行参数对处理后炉渣的厚度、温度以及玻璃化率的影响,获得最佳参数,为高炉熔渣余热回收及工业试验奠定基础。结果表明,在电机转速为9 r/min、辊间距离为2 mm、水淬渣漏斗高度为4 mm时,处理后的高炉渣呈现为厚度最小为1.26 mm的薄片。此时,炉渣温度为442 ℃,玻璃体化率达89.8%,可在保证高炉渣后续利用的同时,最大程度地提高余热回收温度。     

冷热双混辊压法高炉熔渣破碎试验

围绕高炉熔渣余热回收设计开发了冷热双混辊压法高炉熔渣破碎装置,并以水淬高炉渣作为冷却介质,开展了高炉熔渣辊压破碎试验。试验研究了电机转速R、辊间距离L、冷却介质漏斗高度H等装置运行参数对处理后炉渣的厚度、温度以及玻璃化率的影响,获得最佳参数,为高炉熔渣余热回收及工业试验奠定基础。结果表明,在电机转速为9 r/min、辊间距离为2 mm、水淬渣漏斗高度为4 mm时,处理后的高炉渣呈现为厚度最小为1.26 mm的薄片。此时,炉渣温度为442 ℃,玻璃体化率达89.8%,可在保证高炉渣后续利用的同时,最大程度地提高余热回收温度。     

高炉渣中非晶态定量方法的比较分析

 利用观察法、岩相法和X射线衍射法定量分析了某钢厂高炉渣中非晶态含量,得到该高炉渣中非晶态含量大于95%的结论。三种方法中,观察法最简单,但易受人主观因素影响;岩相法需要一定的经验来判断;利用X射线衍射法可以较客观定量高炉渣中非晶态含量。     

Simulation of the mass and heat transfer in a three-electrode round impoverishment furnace

A thermophysical model is developed for a three-electrode round impoverishment furnace operating with electrodes immersed in a slag melt in order to predict the operation of the impoverishment furnaces located at the Nadezhdinsk metallurgical works of the Noril’sk Nikel integrated works and to optimize their energy-technical conditions. This model provides reliable information on the temperature field in the slag bath of a furnace depending on the furnace operating schedule, the velocity and character of motion of a slag melt, the heat release in different regions of the slag melt, and (hence) the heat load applied to furnace elements. The results of calculation by this model were used to make recommendations for improving the designs of the furnaces operating at the Noril’sk Nikel integrated works and for changing their operating conditions.     

铜闪速吹炼渣型的控制实践

采用铜悬浮吹炼炉生产时的棒渣样状态与化验结果相结合的方式探讨铜闪速吹炼渣型的控制手段。实践经验表明:吹炼渣型异常时,最直接最快速的表现形式即是棒渣样状态,通过棒渣样状态和化验数据的关联性可做前馈控制,避免因化验的延时性造成炉况继续恶化,再根据化验结果精准调节,可快速调整闪速吹炼渣型。     

萤石对改善高炉高铝渣性能的影响

高炉生产实践表明,炉渣w（Al2O3）超过16%会对炉况稳定顺行产生较大影响,甚至引起高炉失常。在w（Al2O3）为17%、18%、19%、20%、21%的炉渣中添加0%、2%、4%、6%、8%、10%的w（CaF2）,测定了炉渣黏度的变化。研究表明,炉渣中w（Al2O3）在17%～18%,起降低黏度作用的w（CaF2）最低为2%。最后介绍了某高炉加萤石处理炉况失常的情况。     

侧吹熔炼处置锌冶炼渣炉渣组成对导热性及析出物相的影响

侧吹熔炼炉采用水冷挂渣炉壁时,高导热系数炉渣可在炉衬表面形成稳定渣皮,保护并延长炉衬的使用寿命。针对铁矾渣和铅银渣处理用FeO-CaO-SiO₂-PbO-ZnO五元渣系,采用稳态平板法对炉渣渣皮的导热系数进行了测定,并通过扫描电镜对固态渣皮进行微观结构分析,以探究炉渣组分改变对渣皮导热系数及结晶矿相的影响。结果表明,增加CaO和SiO₂都会使渣皮导热系数增大,其中添加CaO对渣型影响最显著。优化渣型的导热系数从原渣的7.62 W/(m·K)增大到了17.94 W/(m·K),提高了135%。在冷凝过程中,高温析出的物相为黄长石,其熔点、黏度相较于原渣也有显著降低。调整后的渣型更容易形成稳定的渣皮,有利于水冷挂渣护炉。     

康斯迪电弧炉连续炼钢技术

康斯迪技术采用泡沫渣埋弧冶炼，留钢留渣操作，用钢水直接加热炉料，连续运行，同时对预热炉料后的烟气进行处理。采用康斯迪工艺可以减少设备配置，节约投资，提高生产率，大幅度降低２生产成本，且该工艺适应的炉料范围较广，是一种适于在我国推广应用的电炉炼钢技术。     

提钒转炉溅渣护炉试验研究

溅渣是提高转炉炉龄最有效的技术,但由于钒渣与钢渣成分差异较大,溅渣护炉技术尚未在提钒转炉上得到应用.为解决提钒转炉炉衬侵蚀严重的问题,对改性钒渣溅渣进行了研究.结果表明,通过改性可以达到调整钒渣状态的目的.改性后的钒渣具有良好的溅渣性能,溅渣后炉厚增加10 mm以上.改性钒渣中w(CaO)可控制在3％ 以下,对钒渣和半...     

Experimental study on slag splashing with modified vanadium slag

Slag splashing is the most effective technology to improve the furnace campaign of converter; however, due to the great difference of composition between the vanadium slag and the steel slag, the technology has not been applied in the vanadium extraction converter. To solve the serious problem of lining erosion in the vanadium extraction converter, in this paper, slag splashing with modified vanadium slag was studied. The results showed that the purpose of adjusting the state of vanadium slag can be achieved through the modification. The modified slag had good slag splashing performance. After slag splashing, the thickness of the furnace was increased by more than 10?mm. The content of CaO in the modified vanadium slag can be controlled less than 3%, and the quality of vanadium slag and semi-steel was not obviously affected. The metallic iron content in the slag was greatly reduced, which was beneficial to reduce the iron loss in the vanadium extraction process.     

粉末压片制样-X射线荧光光谱法测定炉渣中9种组分

快速准确地测定炉渣中多种组分含量,既是冶炼生产工艺的要求,也是环境保护和冶金废弃物综合利用的要求。实验采用聚酯(PET)薄膜包裹粉末压片法制样,选取与待测样品粒度一致的炉渣标准样品与高纯物质按照不同的比例,配制成各组分含量从低到高具有一定梯度炉渣校准样品,对其拟合校准曲线,建立了X射线荧光光谱法(XRF)同时测定高炉渣、转炉渣、电炉渣或平炉渣中SiO₂、TFe、Al₂O₃、CaO、MgO、TiO₂、S、P₂O₅、TMn含量的快速分析方法。PET薄膜包裹压片制样,减少了粉尘污染,把对仪器损坏的几率降到了最低,而且可以防止压片暴露在空气中,增加压片保存时间。通过调整仪器分析参数,控制试样在粒度大小方面一致以及采用OXSAS软件自带的TL+方程同时进行谱线重叠干扰校正和基体效应校正,有效地克服了炉渣复杂体系中各元素谱线干扰与基体效应,实现了粉末压片制样-X射线荧光光谱法对炉渣各组分的测定。按照实验方法对高炉渣样品进行精密度试验,结果的相对标准偏差(RSD,n=10)为0.16%～2.1%。采用实验方法对高炉渣、转炉渣、电炉渣或平炉渣标准样品和实际样品进行测定,结果与认证值或熔融法测定值相吻合。     

高炉渣对钢渣改性的物理化学基础研究

钢渣用作建筑材料时,由于其中含有大量游离氧化钙(f-CaO),稳定性较差,通常需要改性钢渣以提高其稳定性、胶凝性. 在对钢渣、高炉渣进行化学成分和矿物组成分析的基础上,对高炉渣改性钢渣的可能性进行了热力学计算,结果表明高炉渣中的SiO₂与钢渣中f-CaO反应,生成胶凝相,同时降低了钢渣中的f-CaO含量. 本文通过研究热态高炉渣改性钢渣,结合X射线衍射、拉曼光谱、扫描电镜及能谱分析等研究方法,对改性钢渣的矿物成分、f-CaO含量、黏度变化等进行了分析. 研究发现随着热态高炉渣配比量的增加,改性渣黏度缓慢增加,改性钢渣中f-CaO、RO相含量降低,改性渣的胶凝性能提高. 在1550℃下,钢渣中添加10%高炉渣时,改性渣中2CaO·SiO₂(C₂S)、3CaO·SiO₂(C₃S)含量显著提高,f-CaO质量分数降至1.64%,稳定性大大提高,符合建材化使用要求. 此外,进一步使用焦炭还原改性渣中的铁,轻松实现了渣铁分离,提高改性渣的易磨性.      

高炉熔渣直接调质改性制备矿棉纤维中试实践

 高炉熔渣从渣沟经分流后直接进入补热电炉中,同步加入硅质料等作为调质改性剂,并用补热电炉对调质改性后的熔渣进行熔化和补热,控制熔渣的出口温度为1 400～1 500 ℃,熔渣的黏度适宜,流动性好,满足制备矿棉纤维的要求。熔渣经高速离心法离心成纤后加工成集防火、绝热和吸音为一体的矿棉纤维产品,纤维的平均渣球质量分数4.7 %,纤维平均直径5.5 μm,含水率0.2%,均满足国家标准的要求,产品能耗和成本较传统的冲天炉工艺下降40%～60%。高炉熔渣直接调质改性制备矿棉纤维的新工艺解决了高炉熔渣高附加值直接利用的技术难题,为高炉熔渣资源化高附加值利用拓展了新的方向。     

铜冶炼炉渣综合利用技术的研究与探讨

铜冶炼渣具有硬度大、密度大、夹杂冰铜块的特点,综合回收难度大,生产成本高。为回收炉渣中铜、铁资源,主流选矿工艺为半自磨+球磨+浮选+磁选,可获得合格的铜精矿和多种用途的铁精矿产品。其指标的高低与炉渣冷却方式、碎磨方式、选矿工艺等密切相关,我国尾渣品位已经降至0.35%以下,比国外尾渣品位降低0.05个百分点以上。     

提高烟化炉处理铅锌冶炼渣能力的实践

某铅锌冶炼厂通过烟化炉处理铅锌冶炼渣回收有价金属,由于烟化炉采用的钢制冷却水套使用寿命短,导致作业率偏低。同时,由于烟化炉冶炼渣的SiO₂含量高,烟化炉经常出现炉渣流动性恶化而影响作业率。随着该冶炼厂渣物料产量的增加,烟化炉能力不足的问题逐渐凸显,急需提升作业率和炉床能力。通过系统研究,对烟化炉的工艺和设备进行优化改造,烟化炉的实际作业率从改造前的85.01%提高到96.48%,床能力提高3.9 t/(m²·d),达到21～22 t/(m²·d)。     

高Al2O3炉渣对高炉生产的影响

高炉炉渣中Al2O3含量偏高易造成炉渣粘度增高,流动性变差,引起炉墙粘结与炉缸堆积,直接影响高炉炉况。对此应制定科学的操作方法与操作方针,适当提高炉温水平,降低炉渣碱度,使炉渣保持良好的流动性与稳定性,下部调剂应提高鼓风动能,进一步活跃炉缸,同时要加强人炉原料管理,减少入炉粉末,采用强度和高温冶金性能好的焦炭,才能保证炉况顺行,取得良好的冶炼指标。     

Use of Banded Hematite Quartzite (BHQ) in Blast Furnace for Partial Replacement of Quartzite

Hot metal produced through blast furnace (BF) route is still the most preferred route in majority of the steel industries. In the blast furnace operation, quartzite is used as flux to adjust the desired slag chemistry and basicity (B2 of 1–1.08) to achieve optimum slag properties such as low liquidus temperature, high Sulphur carrying capacity and low viscosity. This paper describes the investigations carried out at JSW Steel Ltd to identify alternate sources of silica other than quartzite for use as flux in BF to maintain the desired slag chemistry for smooth operation and cost reduction. Banded hematite quartzite (BHQ) ore available in Karnataka region contains 28–33% Fe, 45–46% silica, 1.3–1.5% alumina and is found suitable for use as partial replacement for quartzite in blast furnaces. Mineralogy and phase analysis of BHQ reveals alternate bands of hematite and silica whereas in lump ore, hematite and silica are uniformly distributed. This phase distribution and reducibility index of BHQ (~66%) affect the softening start temperature by forming fayalite (2FeO·SiO₂) as primary slag. Fines generations are found to be comparatively higher (from 6.3 to 6.4%) but in acceptable range. The Fe content in the BHQ also contributes to the overall Fe input to the furnace favoring an option to reduce the equivalent amount of iron bearing materials in the charge. Plant trials at JSW steel blast furnace #4, indicate an improvement in overall operational performance resulting in increased Fe input per charge, reduction in slag rate by 8 kg/thm due to low alumina input and easier achievement of final slag chemistry.     

Operation at High Pellet Ratio and Without External Slag Formers – Trials in an Experimental Blast Furnace

Blast furnaces that operate with pellets and sinter normally use high basicity sinter and acid pellets to balance the slag chemistry. When external additives are used, irregular slag formation occurs due to their uneven distribution in the burden. If basic sinter is used together with a large amount of acid pellets, all additives are incorporated in the iron bearing materials with an improved burden mixture as a consequence. During a campaign in the LKAB Experimental Blast Furnace, pellets and sinter were operated at an ultra low slag volume. A high amount of pellets was balanced with high basicity sinter. An improved blast furnace operation is shown when operating at ultra low slag volume and without external slag formers. During the test period, the blast furnace operation was smooth and stable, and the reductant rate was decreased.     

粉末压片制样-X射线荧光光谱法测定炉渣中氟钾钠硫

炉渣中的氟、钾、钠、硫可以用于润滑,防止钢水与壁黏连,也可以用来调节熔点以及判定缺陷来源。实验利用转炉渣、高炉渣、电炉渣的标准样品和准确定值的炉渣生产试样绘制校准曲线,从而建立了粉末压片制样-X射线荧光光谱法(XRF)测定炉渣中氟、钾、钠、硫的分析方法。通过试验确定制样条件为:试样研磨过200目(74 μm)筛,压片机的压力为20 MPa,保压时间为30 s。按照实验方法,对1个炉渣试样压片11次测量,各元素测定结果的相对标准偏差(RSD)为0.17%～3.4%;正确度验证结果表明,实验方法的检测结果与其他分析方法(高频燃烧红外吸收法、电感耦合等离子体原子发射光谱法以及离子选择电位法)的检测结果一致,可以满足炉前分析量大、分析速度快的要求。