Baosteel's Slag Short Flow process for molten steelmaking slag treatment and its application

Baosteel＇ s Slag Short Flow（BSSF） is an innovative process for steelmaking slag treatment that was developed by Baosteel. The process principles, flow-chart, parameters and component systems of the BSSF for steelmaking slag treatment are presented. Characteristics of the finished BSSF slag are summarized by analyzing the slag＇ s physical and chemical performances. Several Utilization methods for the BSSF slag are given.

Boron removal from metallurgical silicon using CaO-SiO_2-CaF_2 slags

The removal of boron from metallurgical silicon in slag system of CaO-SiO2-10%CaF2 was investigated. The partition coefficient of boron （LB） between slag and silicon phase was studied under different conditions of slag basicity （CaO/SiO2 ratio）, temperature, mass ratio of slag to silicon and gas blowing. The results show that LB has a maximum value of 4.61 when the CaO/SiO2 mass ratio is around 2 at l 873 K. The logarithm of LB is linear to the reciprocal of temperatures in the range of 1 773-1 973 K. LB increases with the increase of mass ratio of slag to silicon, but it does not increase markedly when the ratio excesses 3. Gas blowing can sionificantlv increase the removal of boron, and LR increases with the increase of water vapor content.

Application of the BSSF molten steel slag processing technology in POSCO

This study describes an overview of the POSCO＇ s Baosteel＇ s short-flow （BSSF） slag processing project, including process flow, process set-up, equipment composition, auxiliary facilities and relevant parameters, as well as a brief description of its application after commissioning.

The development of slag processing technology and its impact on energy-saving and emission reduction in the metallurgical industry

This study provides an overview of the production and classification of metallurgical slag and its impact on energy-saving and emission reduction in the metallurgical industry and an analysis of the impact of key factors on slag processing technology, including a brief account of blast furnace（BF） slag processing and applications with a focus on the steel slag disposal processes and the features of some typical processes. In view of the characteristics of the basic oxygen furnace （BOF） slag and the technical difficulties faced by the traditional processes,it describes the principle,features and technical advantages of the Baosteel short-flow （BSSF） steel slag treatment process developed by Baosteel. The thinking and outlook on the direction of the development of the metallurgical slag processing process are stated.

Vacuum Treatment for Simultaneous Desulphurization and Dephosphorization of Hot Metal and Molten Steel

The vacuum treatment for simultaneous desulphurization and dephosphorization of hot metal and molten steel with pre-melted CaO-based slag was carried out.For pre-treatment of hot metal,both desulphurization and dephosphorization are improved with the increase of CaO in slag,but deteriorated with the increase of CaF2 in slag.The average desulphurization and dephosphorization rate is 68.83 % and 78.46 %,respectively.For molten steel,the substitution of BaO for CaO in slag has minor effect on simultaneous desulphurization and dephosphorization.The desulphurization and dephosphorization rate is higher than 90% and 50% respectively with the lowest final sulfur and phosphorus mass percent being 0.001 2% and 0.010%,respectively.The overall effect of simultaneous desulphurization and dephosphorization of molten steel is better than that of hot metal.

Methods for Improving Volume Stability of Steel Slag as Fine Aggregate

Suitable methods for enhancing the volume stability of steel slag utilized as fine aggregate were determined. The effects of steam treatment at 100 ℃ and autoclave treatment under 2.0 MPa on the soundness of steel slag sand were investigated by means of powder ratio, linear expansion, compressive and flexural strength. DTA, EDX, XRD and ethylene glycol methods were employed to analyze both the treated slags and susceptible expansion grains. Experimental results indicate that powder ratio, content of free lime and rate of linear expansion can express the improvement in volume stability of different treated methods. Steam treatment process cannot ultimately prevent specimens from cracking and decrease of strength, but mortar made from autoclave treated slag keeps integration subjected to hot water of 80℃ until 28 d and its strength do not show significant decrement. The hydration of over-burn free lime and periclase phase are the main cause for the disintegration or crack of untreated and steam treated steel slag＇s specimens. Autoclave treatment process is more effective than steam treatment process on enhancement of volume stability of steel slag.

Wettability of Molten Steel/Na2O-Li2O-SiO2-B2O3 Slag System

The vacuum treatment for simultaneous desulphurization and dephosphorization of hot metal and molten steel with pre melted CaO based slag was carried out. For pre treatment of hot metal, both desulphurization and dephosphorization are improved with the increase of CaO in slag, but deteriorated with the increase of CaF 2 in slag. The average desulphurization and dephosphorization rate is 68 83 % and 78 46 %, respectively. For molten steel, the substitution of BaO for CaO in slag has minor effect on simultaneous desulphurization and dephosphorization. The desulphurization and dephosphorization rate is higher than 90 % and 50 % respectively with the lowest final sulfur and phosphorus mass percent being 0 001 2 % and 0 010 %, respectively. The overall effect of simultaneous desulphurization and dephosphorization of molten steel is better than that of hot metal.

中国西南地区电解锰渣特性分析及影响因素研究

电解锰行业发展面临的困境之一是锰渣的处理处置方法。为探索绿色低碳的锰渣无害化处理技术,选取中国5家典型电解锰企业新、旧电解锰渣,通过其理化特性及浸出毒性分析,研究堆存条件、时间及工艺参数等因素对不同企业锰渣特性的影响。结果显示:不同企业的新、旧锰渣平均质量含水率相差最大时均达19%以上,浸出液pH值最高分别相差0.95、1.45,不同企业新鲜锰渣的SiO_(2)和Al_(2)O_(3)平均质量分数最大相差分别为43.18%、146.25%,且可溶性盐质量分数均超过10%,未达到填埋入场标准。锰渣中石膏和石英的质量分数随堆存条件和时间发生不同的变化。企业C在堆存过程中石膏和石英的质量分数在增加,而企业E锰渣中烧石膏质量分数在增加,石英质量分数在减少。历史锰渣浸出液中Mn^(2+)和氨氮(NH_(4)^(+)N)的质量浓度较高,分别超过GB/T 8978—1996一级排放标准限值的65.92~935.00倍和2.56~63.80倍,表明长期堆存的锰渣仍存在较大的环境污染风险。不同地区企业的锰渣应通过无害化处理与资源化利用来降低其环境污染风险,须根据化学成分、理化性质不同选择合适的资源化方式。

Study on the treatment and the utilization of the Baosteel casting residue and the new grid engineering technology

This study summarizes some serious disharmonious problems that ubiquitously exist in the casting residue recycling of steel plants, such as large land occupation, low operational efficiency, hidden hazards, huge resource and energy consumption, serious environmental pollution and so on. It analyzes the necessity of the on-line innovation and recycling based on the present situation of Baosteel. It states the innovation of the new grid technology and the achievements of its integrated application at Baosteel. It also summarizes and elaborates some green technology features of the treatment and the utilization of the Baosteel casting residue and the new grid technology, such as safety,energy-saving and environmental protection. In addition,it lays out the prospects for the development and application of the technology.

不同处理工艺下钢渣的铁相赋存状态及其对磁选粉收得率和尾渣胶凝活性的影响

钢渣中含有的金属铁及其氧化物是一种高附加值的可再生资源,同时钢渣又可以作为矿物掺合料用在建材行业中。钢渣经不同冷却处理工艺,物相发生演变,从而影响钢渣中铁的回收及尾渣的胶凝活性。为了提高钢渣中铁资源的回收和尾渣的有效利用,文中针对热泼、辊压破碎-有压热闷和辊压破碎-热泼3种不同处理工艺下的钢渣,利用岩相分析、X射线衍射分析仪(XRD)、扫描电子显微镜-能量色散谱仪(SEM-EDS)、化学物相选择溶解等手段对不同处理工艺下钢渣的铁相分布及富集状态进行研究,并测定其磁选粉收得率和铁品位,以及尾渣的胶凝活性。结果表明:热泼工艺下钢渣中金属铁更易富集沉积,铁相主要以FeO均匀分布在RO相和铁酸盐相中,相中Fe占比较少,磁选粉收得率较高,但铁品位较差,分别为32.22%和33.43%;辊压破碎-有压热闷渣中未见明显金属铁粒,但含铁相中Fe占比较多,磁选粉收得率低,但铁品位较高,分别为28.37%和37.12%;辊压破碎-热泼渣中,铁相主要以Fe2O3形式存在于铁酸钙相和硅酸盐相,相中Fe占比较多,且含有磁性铁Fe3O4,磁选粉收得率高,铁品位也高,分别为37.60%和39.69%。辊压破碎-有压热闷渣中C2S含量相对更多且发育较好,胶凝活性高,7d及28d活性指数分别为78%和92%;辊压破碎-热泼渣的7d活性指数较低,为66%,但28d活性指数增长到92%;热泼渣的胶凝活性居中。

响应曲面法优化二次镍渣微晶玻璃热处理制度

镍渣作为有色冶炼过程产生的冶金废渣,以堆存形式处理,环境影响突出,但含铁量高,是一种极具开发前景的二次利用资源。以二次镍渣为原料制备微晶玻璃,采用响应曲面法并结合Box-Behnke原理设计探讨了核化温度、核化时间、晶化温度、晶化时间及其交互作用对微晶玻璃抗折性能的影响,建立了抗折强度与各因子间的模型。通过模拟优化,确定了最佳热处理工艺参数:核化温度和晶化温度分别为845℃和955℃、核化时间和晶化时间均为80 min。采用最优工艺参数试验验证发现,微晶玻璃主晶相为铁硅灰石和钙长石,抗折强度均值达到126.78 MPa,与模型预测值偏差较小,表明该预测模型可靠有效及工艺优化合理可行。

煤气化渣气流分级提炭分质试验

煤气化渣提炭分质是实现其减量化、资源化、高值化利用的关键。基于此,提出研磨破碎-气流分级的干法提炭工艺,利用研磨使气化渣中炭灰结合物解离,再利用气流分级机内离心力和气体曳力作用,将解离所得的细颗粒进行高效分离。通过设计均匀试验并对各影响因素进行回归分析,获取优选试验条件并对该试验条件下的提炭效果进行验证。结果表明,气流分级提炭受多因素耦合作用影响,其中分级机频率和引风机频率是影响提炭效果的关键。均匀试验优选条件为分级机频率175 Hz、引风机频率5 Hz,喂料螺旋频率5 Hz,二次风口全开;该条件下所得富炭产品的收率为25.86%,烧失量49.76%,较原气化渣烧失量提高了26.91%,与试验预测值(49.64%)较一致,且试验效果明显优于未研磨破碎直接气流分级的气化渣。优选条件下气流分级得到的富炭产品的平均粒径(Dav)为5.95μm,满足橡胶补强填充料的粒度要求,其热值为16.73 MJ/kg,亦可作为细粉燃料等使用。同时,气流分级可实现较好的气化渣脱炭效果,所得脱炭渣烧失量低于10%,有利于其在建材等领域应用。研磨破碎-气流分级方法可实现气化渣的提炭分质,有利于其下游利用。

电石渣的资源化利用现状

阐述了电石渣综合利用的研究状况。传统资源化方式包括制备建筑材料和改善环境,如以电石渣制造水泥、地聚物以及其他建筑材料等;电石渣呈强碱性,可以处理酸性废水、废气,达到以废治废、保护环境的目的。总结了电石渣资源化在化学、冶金和碳捕集方面的新机遇。电石渣不仅是良好的钙基资源,也拥有良好的经济性,电石渣的资源化利用具有重要意义。

电炉钢渣处理技术现状及发展趋势

在电炉钢渣排放量日益增多的背景下,电炉钢渣处理技术十分必要。以北方某厂电炉渣成分为依据,分析了钢渣中游离氧化钙及氧化镁的数量。由于钢渣成分具有较强的波动性,电炉钢渣的再利用技术受到了一定限制,目前,电炉钢渣利用方向主要包括制备钢铁冶炼熔剂及冶炼原料、建材用料、生态治理改良剂及土壤肥料。电炉钢渣处理技术的最新研发方向以在线处理钢渣及余热回收为主,包括改性电炉钢渣处理工艺、锍相富集分离的渣铁热态分离回收工艺、钢渣与有色金属冶炼渣协同调质处理、流化床淬化的钢渣处理工艺、圆盘式电炉钢渣处理工艺及水平振动式有压热焖钢渣处理工艺,但钢渣显热回收技术仍需进一步开发,并将其应用于生产实践。

钢渣处理工艺与综合利用现状

综述了钢渣的来源、钢渣的化学成分、矿物组成、膨胀粉化和一些其它性质,并介绍了多种钢渣处理工艺。在此基础上,阐述了国内外转炉钢渣的研究现状和利用现状,并根据我国钢渣处理的不足之处,指出有压热闷钢渣处理新技术有望解决钢渣在安定性、易磨性等方面存在的问题。

钢渣陈化处理与钢渣沥青混凝土浸水稳定性研究

研究不同陈化时间对钢渣沥青混凝土长期浸水体积膨胀特性和力学性能衰减规律,并通过现场铺筑试验段进一步检验钢渣沥青混凝土的耐久性。结果表明:钢渣新渣安定性差,混渣严重,且白渣含量高。钢渣破碎后堆放陈化处理应不少于1年,其安定性可按压蒸粉化率≤5%控制。钢渣新渣应通过洒水保湿加速游离氧化钙消解,钢渣沥青混凝土体积稳定性应按60℃浸水7 d体积膨胀率≤1.5%控制。经过有效陈化处理后,钢渣集料体积膨胀对钢渣沥青混凝土长期水稳定性和使用性能影响较小,不会造成早期水损害和结构失稳问题。

不同晶化温度对硅锰渣铸石的内部温差、析晶和物理性能的影响规律

以硅锰渣为主要原料,采用熔渣冷却析晶一步法(铸石浇铸法),在800、900、1000和1050℃四个不同晶化温度,分别制备了规格为ϕ100 mm×20 mm的铸石样品CT-800、CT-900、CT-1000和CT-1050,通过构建实验装置,测试了熔渣在成型和热处理全过程中心与边缘温度变化规律,并结合X射线衍射(XRD)、差示扫描量热分析(DSC)、扫描电子显微镜和能谱(SEM–EDS)等手段,分析了不同晶化温度对铸石中心和边缘的温差、析晶与物理性能的影响规律.研究表明:以硅锰渣为主要原料在900~1050℃保温析晶可以制备出满足天然花岗岩建筑板材标准(GB/T18601—2009)的铸石,晶相为辉石、黄长石以及硫化锰.CT-1000和CT-1050铸石析出更多和更大尺寸的晶相,存在微观孔隙和宏观缩孔,降低了其力学性能.CT-900具有最佳性能,而CT-800以玻璃相为主,热处理后发生断裂.在本实验条件下,最大温差(32℃)发生在把熔渣倒入模具的凝固成型阶段,且晶化温度越低,温差越大.CT-1000和CT-1050析晶阶段存在的大量析晶放热导致温差二次增大,延长了中心和边缘温度一致的时间.硫化锰是高温熔融态下析出晶相,易于氧化分解,快速冷却的边缘存在更多硫化锰相.黄长石较辉石在更高的温度下析出,较高的晶化温度处理样品和相同晶化温度下样品的中心部分均存在相对更多的黄长石相.

基于风险管控的历史遗留硫磺冶炼废渣综合治理效果

为解决赤水河源头流域(云南段)历史遗留硫磺冶炼废渣40多年无序堆积导致流域水体持续酸化的污染问题,通过对“自然衰减”“异位修复”“风险管控”等治理途径分析,提出“风险管控+生态修复”模式开展了该区域内酸性废渣和废水的示范工程治理。在查明治理区域污染因子的基础上,采取“废渣防流失、复合阻隔控制、适生植物配比、污水收集处理和运行监测管理”的集成风险管控技术,分析工程实施前、实施中和实施后的固废属性,以及地表水、地下水和废渣渗滤液中污染因子的变化。结果表明:在投加0.35%~0.65%比例生石灰条件下,固废属性从第Ⅱ类一般工业固废改性为第Ⅰ类一般工业固废;工程完工时,地下水pH即可达标,硫酸盐超标倍数从最大5.3倍削减至1.2倍;工程实施3个月后,渗滤液pH稳定达标,硫酸盐超标倍数从最大3.2倍削减至1.7倍;工程实施7个月后地表水pH达标。基于风险管控的历史遗留硫磺冶炼废渣综合治理,能够满足管控目标,并初步完成了技术推广和应用。

拉林铁路弃渣场水土保持型生态恢复技术探讨

为研究高寒高海拔地区铁路建设项目弃渣场的生态恢复措施,该文以拉(拉萨)林(林芝)铁路工程为依托,结合青藏高原的地域条件探讨弃渣场的水土保持型生态恢复技术。研究得到以下结论,根据恢复区立地条件,系统阐明弃渣场的选址原则及水土保持型生态恢复理论;基于物种选择原则和防护措施设计建立适应于青藏高原地区的水土保持型生态恢复技术。研究成果可为该地区铁路工程建设项目的弃渣治理提供一定的借鉴意义。