Cross-upgrading of biomass hydrothermal carbonization and pyrolysis for high quality blast furnace injection fuel production:Physicochemical characteristics and gasification kinetics analysis

The paper proposes a biomass cross-upgrading process that combines hydrothermal carbonization and pyrolysis to produce high-quality blast furnace injection fuel.The results showed that after upgrading,the volatile content of biochar ranged from 16.19%to 45.35%,and the alkali metal content,ash content,and specific surface area were significantly reduced.The optimal route for biochar pro-duction is hydrothermal carbonization-pyrolysis(P-HC),resulting in biochar with a higher calorific value,C=C structure,and increased graphitization degree.The apparent activation energy(E)of the sample ranges from 199.1 to 324.8 kJ/mol,with P-HC having an E of 277.8 kJ/mol,lower than that of raw biomass,primary biochar,and anthracite.This makes P-HC more suitable for blast furnace injection fuel.Additionally,the paper proposes a path for P-HC injection in blast furnaces and calculates potential environmental benefits.P-HC of-fers the highest potential for carbon emission reduction,capable of reducing emissions by 96.04 kg/t when replacing 40wt%coal injec-tion.

Micromorphology and safety properties of meager and meager-lean coal for blast furnace injection

Four types of meager and meager-lean coal and one type of high-quality anthracite were selected based on the safety requirements for blast furnace coal injection and domestic coal quality to conduct microstructure and component analyses.The analyses of the organic and inorganic macerals and the chemical compositions of the selected coal samples indicate that the four types of meager and meager-lean coal have low volatilization,low ash content,and low sulfur content;these qualities are suitable for blast furnace injection.Grindability test was conducted on the four types of meager and meager-lean coal and the anthracite mixed coal samples.Results indicate that the mixture of meager and meager-lean coal and anthracite is beneficial to improve the grindability of pulverized coal.The explosive tests reveal that the selected coal samples are non-explosive or weakly explosive.When the proportion of meager and meager-lean coal is less than 40wt%,the mixed coal powder would not explode during the blowing process.The minimum ignition temperature test determines that the minimum ignition temperatures of the four types of meager and meager-lean coal and anthracite are 326,313,310,315,and 393°C,respectively.This study provides a guiding research idea for the safety of meager and meager-lean coal used in blast furnace injection.

Physical Properties of Crushed Air-cooled Blast Furnace Slag and Numerical Representation of Its Morphology Characteristics

Physical properties and geometrical morphologies of crushed air-cooled blast furnace slag （SCR） and crushed limestone （LCR） were comparatively investigated. The shape, angularity, surface texture and internal pore structure of aggregate particles for different size and gradation were numerically represented by sphericity （ψ） and shape index （SI）, angularity number （AN）, index of aggregate particle shape and texture （IAPST）, porosity and pore size, respectively. The results show that SCR is a porous and rough aggregate. Apparent density, void, water absorption and smashing index of SCR are obviously higher than those of LCR with the same gradation, respectively. However, bulk density of SCR is lower than that of LCR with the same gradation. SI, AN, IAPST and porosity of SCR are obviously higher than those of LCR with the same gradation, respectively. The smaller particle size of SCR, the larger of its AN, IAPST and porosity.

Effect of Crushed Air-cooled Blast Furnace Slag on Mechanical Properties of Concrete

Morphology characteristics of mix aggregates with crushed air-cooled blast furnace slag（SCR） and crushed limestone（LCR） with 5-20 mm and 20-40 mm gradation were represented by numerical parameters including angularity number（AN） and index of aggregate particle shape and texture（IAPST）.The effect of mix aggregates containing SCR on compressive strength and splitting tensile strength of concrete was investigated.Fracture characteristics of concrete,interfacial structure between aggregates and matrix were analyzed.The experimental results show that porous and rough SCR increases contact area with matrix in concrete,concave holes and micro-pores on the surface of SCR are filled by mortar and hydrated cement paste,which may increase interlocking and mechanical bond between aggregate and matrix in concrete.SCR can be used to produce a high-strength concrete with better mechanical properties than corresponding concrete made with LCR.The increase of AN and IAPST of aggregate may enhance mechanical properties of concrete.

Non-water Injection Mix for Blast Furnace YB/T 4153-2006

1 Scope This standard specifies the classification, techni cal requirements, test methods, quality appraisal pro- cedures, packing, marking, transportation, storage, quality certificate, and construction manual of nonwater injection mix for blast furnace.

The future of blast furnace ironmaking—a Nordic perspective

The blast furnace is the oldest metallurgical process in commercial use.It has gone through great improvements during the last decades and new important modifications are still foreseen.The huge amount of coal and coke needed for reduction of iron ore is resulting in emissions of carbon dioxide that have to be strongly reduced to meet the requirement of minimizing the carbon footprint.All residuals from iron- and steelmaking also need to be taken care of to meet the requirement of zero waste.This paper deals with several potential improvements of the blast furnace process being developed in the LKAB Experimental Blast Furnace in Lulea, Sweden over the last decade,including operation at ultra low slag volume,injection of BF flue dust,injection of BOF slag,and the oxygen blast furnace.

Properties and Structural Optimization of Pulverized Coal for Blast Furnace Injection

The properties of mixed coals were studied on the basis of known various properties of the injecting coals in the treatise.The structure of the injecting coals was optimized and put into practical application.It was found that the ignition point was lowered with mixed coals,however,both combustibility and grindability were improved,and explosibility of the mixed coals were decreased as well.Hence,mixed coals injection not only can improve the amount of the injecting coals greatly,but also improve the economical and technical indexes of the blast furnace.

Properties and Mechanism on Flexural Fatigue of Polypropylene Fiber Reinforced Concrete Containing Slag

Properties and mechanism were investigated on flexural fatigue of concrete containing polypropylene fibers and ground granulated blast furnace slag（GGBFS）.Four polypropylene fibers’volume fractions and five slag proportions were considered.An experiment was conducted to obtain the fatigue lives at three stress levels in 20 Hz frequency and at a constant stress level of 0.59 in four frequency respectively.Mechanism and evaluation were investigated based on the experimental data.Fatigue life span models were established.The results show that the addition of polypropylene fibers improves the flexural fatigue cumulative strength and fatigue life span.It is proposed that the slag particles and hydrated products improve Interfacial Transition Zone（ITZ）structure and benefit flexural fatigue performance.A composite reinforce effect is found with the incorporation of slag and polypropylene fibers.The optimum mixture contents 55%slag with 0.6%polypropylene fiber for the cumulative fatigue stress.Fatigue properties are decreased as the stress level increasing,the higher frequency reduces the fatigue strength more than lower frequency at a constant stress level.

B_(2)O_(3)对含钛高炉渣熔体微观结构与输运性质的影响

为高效利用含钛高炉渣中钛元素,采用分子动力学模拟方法研究B_(2)O_(3)含量对CaO-SiO_(2)-B_(2)O_(3)-TiO_(2)系高炉渣微观结构和输运性质的影响。结果表明:B_(2)O_(3)的含量4%时,B—O、Si—O、Ti—O和Ca—O的键长分别为1.34、1.62、1.95和2.24A。渣中存在[SiO_(4)]四面体、[BO_(3)]三角体和[TiO_(6)]八面体稳定结构单元。体系中加入B_(2)O_(3)含量并不会改变O—Si—O、O—B—O和O—Ti—O键角分布情况。随着B_(2)O_(3)的加入,Si—O—Si和B—O—B键角分别从156.12°和148.43°增大到158.17°和157.08°,大部分Ti—O—Ti键角分布在100.48°,小部分Ti—O—Ti键角从140.17°减小到135.53°。随着B_(2)O_(3)含量的增加,B—O—M(Ca、Si、B和Ti)氧连接占比增多,熔体中高配位结构解聚为低配位结构,体系整体聚合度降低,各离子自扩散系数均增大,熔体黏度从0.183 Pa·s降低到0.140 Pa·s。

钛渣熔体结构及传输性质分子动力学模拟研究进展

高品位钛渣(TiO_(2)含量≥90%)的高效制备不仅是高品质钛产品生产的关键,而且已成为我国钛冶金行业发展的迫切需要。钛铁矿还原熔炼过程钛渣熔体传输性质的调控是实现高品位钛渣高效制备的关键。国内外学者采用分子动力学模拟的方法,开展钛渣熔体结构演变及传输性质的研究,取得了显著的进展,证实了分子动力学模拟的方法在钛渣熔体研究中的有效性。分子动力学模拟的方法在研究钛渣熔体结构和性质方面具有显著的优势,不但能考察钛渣熔体结构参数、传输性质及相关微观细节,而且不受试验条件(高温、高腐蚀性、高化学活性)的限制。通过分子动力学模拟能够获取钛渣熔体丰富的结构信息和重要的传输性质,避免了钛渣熔体结构及物理性质试验测试中存在的难题。最后,结合冶金熔体成分和结构的复杂性,总结存在的问题,对分子动力学模拟在熔体结构及传输性质研究中的应用进行了展望。

煤气化渣替代矿渣制备超硫酸盐水泥的可行性研究

煤气化渣(CGS)富含硅、铝元素,具备作为胶凝材料前体的潜力,但其颗粒形态粗糙,活性较低。为了解决CGS活性低、利用难等问题,利用CGS部分替代矿渣(BFS),探究CGS替代BFS制备超硫酸盐水泥(SSC)的技术可行性,并借助傅里叶红外光谱、X射线衍射仪、热重分析仪、扫描电子显微镜及能谱仪等微观测试技术对SSC水化产物的微观结构进行表征分析。结果表明,CGS作为制备SSC的原料,能提供初始水化所需要的硅、铝元素,驱动SSC发生水化反应。随着CGS掺量的增加,SSC胶砂的抗压强度呈逐渐减小趋势,而抗折强度受影响较小。CGS的最佳掺量为20%(质量分数),在此掺量下胶砂试样的28 d抗折强度最大,抗压强度也达到43.9 MPa。SSC的水化产物主要是水化硅酸钙、水化硫铝酸钙等凝胶。研究结果显示CGS部分替代BFS完全可用于制备SSC。

MgO对包钢高炉渣流变特性及熔化性影响的实验研究

基于包钢高炉炼铁生产原燃料条件,在实验室条件下以包钢4#高炉渣为基础,采用纯化学试剂配制渣样,在N_(2)气氛下分析了MgO对包钢高炉渣流变特性的影响。同时,探索了MgO对包钢高炉渣熔化性能和热焓的影响。结果表明,实验条件下,炉渣MgO含量由8.00%升高至13.00%,包钢高炉渣熔化性温度呈升高趋势,黏度和黏流活化能呈先降低后升高的趋势,炉渣流动性和热稳定性先变好后变差。另外,随炉渣MgO含量升高,包钢高炉渣熔化性能特征温度呈先降低后升高趋势,炉渣热焓呈升高趋势,表明炉渣在高炉炉缸蓄热能力增强。综合考虑实验研究结果、相关理论计算及包钢现有高炉炉渣MgO含量控制水平,建议包钢高炉渣MgO含量控制为10.00%。

Effects of MgO and TiO_2 on the viscous behaviors and phase compositions of titanium-bearing slag

The effects of MgO and TiO_2 on the viscosity, activation energy for viscous flow, and break-point temperature of titanium-bearing slag were studied. The correlation between viscosity and slag structure was analyzed by Fourier transform infrared（FTIR） spectroscopy. Subsequently, main phases in the slag and their content changes were investigated by X-ray diffraction and Factsage 6.4 software package. The results show that the viscosity decreases when the MgO content increases from 10.00wt% to 14.00wt%. Moreover, the break-point temperature increases, and the activation energy for viscous flow initially increases and subsequently decreases. In addition, with increasing TiO_2 content from 5.00wt% to 9.00wt%, the viscosity decreases, and the break-point temperature and activation energy for viscous flow initially decrease and subsequently increase. FTIR analyses reveal that the polymerization degree of complex viscous units in titanium-bearing slag decreases with increasing MgO and TiO_2 contents. The mechanism of viscosity variation was elucidated. The basic phase in experimental slags is melilite. Besides, as the MgO content increases, the amount of magnesia–alumina spinel in the slag increases. Similarly, the sum of pyroxene and perovskite phases in the slag increases with increasing TiO_2 content.

三元地质聚合物力学性能和微观结构研究

使用粉煤灰、矿粉和不锈钢渣粉制备三元地质聚合物,开展了原料配比、碱激发剂含量以及水玻璃模数对地质聚合物力学性能的影响,并利用SEM、EDS和XRD对试样进行了微观结构和物相成分分析。结果表明:在粉煤灰基础上,矿粉和不锈钢渣粉的添加降低了惰性晶体峰的强度,提高了试样的Si/Al,宏观表现为力学性能提高,当粉煤灰、矿粉和不锈钢渣粉占比为80%、60%、40%时,试样28 d抗压强度达到70.1 MPa;三元地质聚合物的抗压强度随着碱激发剂含量和模数的增加先提高后降低,同时抗压强度的提高会导致抗折强度降低试样变脆,且易出现收缩裂纹;与水泥相比,三元地质聚合物晶相主要为原料中未反应的惰性物质以及新生成的钠沸石和钙沸石,非晶相主要为C-S-H和N(C)-A-S-H共存产物。

再生粗骨料和高炉矿渣砂配合比对混凝土性能的影响分析

再生骨料混凝土造价相对低廉,环保性能优异,在各类建筑工程中具有广泛应用价值,但工程实践中由于其耐久性较低、强度水平较差,导致难以得到广泛应用。为解决这一问题,设计几种不同高炉矿渣砂和再生骨料配合比添加到混凝土中,设计实验探究各组混凝土性能差异,分析添加高炉矿渣砂、再生粗骨料的改性混凝土抗冻融性能、抗压强度性能和泌水性能差异。实验结果显示,使用高炉矿渣砂和再生粗骨料制备的混凝土相较普通混凝土而言,养护龄期为28 d时抗压强度已经十分接近,另外采用高炉矿渣砂替代50%天然骨料碎砂石和再生粗骨料制备所得混凝土抗冻融性能和泌水性能得到显著改善。

Evaluating Simultaneous Impact of Slag and Tire Rubber Powder on Mechanical Characteristics and Durability of Concrete

In this experimental study,the impact of Portland cement replacement by ground granulated blast furnace slag(GGBFS)and micronized rubber powder(MRP)on the compressive,flexural,tensile strengths,and rapid chloride migration test(RCMT)of concrete were assessed.In this study,samples with different binder content and water to binder ratios,including the MRP with the substitution levels of 0%,2.5%and 5%,and the GGBFS with the substitution ratios of 0%,20%and 40%by weight of Portland cement were made.According to the results,in the samples containing slag and rubber powder in the early ages,on average,a 12.2%decrease in the mechanical characteristics of concrete was observed,nonetheless with raising the age of the samples,the impact of slag on reducing the porosity of concrete lowered the negative impact of rubber powder.Regarding durability characteristics,the RCMT results of the samples were enhanced by using rubber powder because of its insulation impact.Moreover,adding slag into the MRP-included mixtures results in a 23%reduction in the migration rate of the chloride ion averagely.At last,four mathematical statements were derived for the mechanical and durability of concrete containing the MRP and GGBFS utilizing the genetic programming method.

MgO掺杂对高炉渣熔融调质钢渣物相组成及结构的影响

为了探明MgO掺杂对高炉渣熔融调质钢渣(混合渣)物相组成与结构的影响,采用X射线衍射仪和SEM-EDS扫描电镜对高温调质后混合渣物相组成及形貌进行了分析。结果表明,掺杂MgO能有效抑制MgFe_(2)O_(4)相和非胶凝性Ca_(2)Al_(2)SiO_(7)物相生成、促进MgFeAlO_(4)物相生成,提高混合渣熔点。MgO掺杂量2%的高温调质混合渣截面呈层状结构,内层MgFeAlO_(4)物相占比增加,孔洞均匀且细小;中间具有层状结构的MgFe_(2)O_(4)尖晶石包裹在MgFeAlO_(4)物相周围;外层Ca_(2)Al_(2)SiO_(7)物相孔洞均匀,致密度适中;此结构的混合渣是较好的重金属离子过滤材料。

碱活化钢渣-矿渣再生混凝土基本力学性能研究

以钢渣粉取代率、矿渣粉取代率和再生粗骨料取代率为变量,通过23组试验,对碱活化钢渣-矿渣再生混凝土的28 d立方体抗压强度、劈裂抗拉强度、轴心抗压强度和弹性模量进行测试。试验研究表明:碱活化钢渣-矿渣再生混凝土力学性能的变化规律与碱活化钢渣-矿渣天然骨料混凝土相似;当钢渣粉取代率在30%以下时,对碱活化钢渣-矿渣再生混凝土的各力学性能均有积极作用,最佳取代率为10%;矿渣粉取代率的增加对混凝土力学性能的增长是明显有利的;再生粗骨料对混凝土各力学性能起负面作用,影响程度随取代率的增加而增大。当钢渣粉用作胶凝材料时,可与矿渣粉复合,加入适量的碱性激发剂,配制出力学性能优良的混凝土。

Performance of Bacillus tropicus on Mechanical,Durable and Crack Remediation Properties in Sustainable Vermiculite Concrete

Sustainable cement-based concrete materials are primarily used for construction,among which vermiculite as lightweight fine aggregate gains more future development prospect.First,a bacterial solution was sprayed over vermiculite and wrapped using calcium sulphoaluminate(CSA)cement to replace with fine aggregate in concrete.Secondly,based on a preliminary test on compressive strength results,10%of Ground Granulated Blast Furnace Slag(GGBS)and a healing solution proportion of 9:1 was selected for preparing self-healing concrete.The fine aggregate was replaced in concrete using vermiculite in 0%,5%,10%and 15%and the findings suggest that bacterial vermiculite replacement should be at most 5%to achieve better results in strength and durable properties.The strength enhancement observed for compressive strength,strength regain,split tensile strength,flexural strength,and ultrasonic pulse velocity were 29.22%,45.5%,34.02%,28.03%and 41.4%respectively.Surface crack healing at 7,14 and 28 days of BIVC was 38.23%,58.82%and 79.41%,which is 3–4%lower than internal crack healing.Microstructural analysis by Scanning Electron Microscopy(SEM),X-Ray Diffractometer(XRD),and Energy Dispersive Spectroscopy(EDS)reveals the existence of calcite,and it was formed due to the bio-mineral action of bacteria with available nutrients in sustainable concrete.

高炉混合喷吹上湾高钙烟煤的性能研究

通过上湾矿烟煤和目标高炉常用煤种的混煤搭配实验,系统研究了不同方案下混煤的着火点、爆炸性、燃烧性和灰熔特性,实验结果表明:当上湾烟煤含量配比为40%时,上湾烟煤与ES无烟煤的混煤着火点最低,为370.8℃,并且没有爆炸性;上湾烟煤+ES无烟煤在混煤挥发分为18.6%时,混煤燃烧性最好;当上湾烟煤配比超过30%后,混煤软化温度会明显下降。