利用矿热炉渣、矿渣、精炼渣制备复合水泥

为缓解矿渣等高活性混合材资源的紧张,通过对矿热炉渣、矿渣、精炼渣三种渣按照不同比例复掺进行了试验。试验表明,在加入激发剂后,当矿热炉渣掺量为25%、矿渣为5%、精炼渣为5%时,可配制达到PC42.5水泥;当矿热炉渣掺量为30%、矿渣为15%、精炼渣为5%时,仍可配制合格的PC32.5水泥。     

Magnetite powder and kaolinite derived from waste iron ore tailings for environmental applications

The present study demonstrated a feasible approach of utilizing waste iron ore tailings in synthesis of value added products for environmental applications. The ferric iron recovered from waste iron ore tailings via acid leaching followed by precipitation as ferric (hydr)oxide was used as feed stock to synthesis magnetite powder by its reductive-roasting with charcoal. Physicochemical characterizations revealed the formation of sufficiently pure magnetite powder with ferric (hydr)oxide to charcoal ratio 1:2 and calcined at 1200 °C for 4 h. The magnetic powder as such or coated with polyacrylic acid, was found efficient for removal of a model dye, methylene blue from its solution within 2 min. The acid insoluble residue, generated after iron recovery from iron ore tailings, was characterized as kaolinite. The residue with reasonably good surface area (119 m² g^− 1) was also found effective for adsorptive removal of dyes including methylene blue and can find large scale applications in wastewater treatment. Moreover the present study provided further inputs for possible alternative uses of waste iron ore tailings to partly reduce its associated disposal problems.     

硫酸铵熔融反应法从含钛高炉渣中回收钛

以承钢含钛高炉渣、(NH₄)₂SO₄和KHSO₄为主要原料,通过熔融反应法使其中的钛转化为易溶于水的形式,达到回收钛的目的。考察了(NH₄)₂SO₄加入量、KHSO₄加入量、加热温度和保温时间对钛回收率的影响。实验结果表明,反应温度和保温时间对钛回收率的影响较大。回收钛的最适条件为：含钛高炉渣与(NH₄)₂SO₄的质量比为1∶6,反应温度为350℃,保温时间为27 min,在此条件下钛的回收率为91.7%,硫酸铵中氮的挥发损失率为81.5%。回收钛后所得残渣主要含有大量硫酸钙、二氧化硅和少量钙钛矿、钙铝黄长石。     

Activation of blast furnace slag by a new method

Blast furnace slag is used as supplementary cementing material for the production of blended cement and slag cement. Its latently hydraulic properties can be activated by several methods. Most applications employ the use of high pH values in the pore solution (> 13.0) to accelerate the corrosion of the glass network of the slag.It is shown in this work that activation is also possible by lowering the pH to a range between 11.8 and 12.2 by the addition of calcium hydroxide and soluble calcium salts. Among the salts investigated in this study are calcium chloride, calcium bromide, calcium nitrate, calcium formate, and calcium acetate. Other salts can be used alternatively as long as they are able to increase the calcium ion concentration and thus reduce the pH in the pore solution via the calcium hydroxide equilibrium. Complex formation of organic anions with calcium ions in the pore solution is a serious handicap when using organic calcium salts.This concept was tested on a particular slag improving its early compressive strength. It was possible to increase the strength of mortar bars produced from the pure slag from 3 MPa to 25 MPa after seven days by adding calcium hydroxide, calcium carbonate and calcium acetate. The early strength of slag cement containing 80% slag was increased from 6 to 16 MPa after two days by adding calcium chloride. The final strength was increased from 36 to 53 MPa after 28 days (water/cement-ratio = 0.40, 20 °C).Analytical data is included to demonstrate that application of the aforementioned concept is able to increase heat liberation and degree of slag consumption.     

利用锰渣、矿渣、石灰石制备复合水泥

针对目前矿渣等高活性混合材资源的紧张,实验进行了锰渣、石灰石部分取代矿渣制备复合水泥的试验研究。研究表明,当石灰石粉掺量固定为10%时,相同水泥比例下,随着锰渣和矿渣比例的增加,胶砂试块3d强度增加,28d强度有所下降;当加入复合激发剂后复合混合材总掺量为60%,锰渣和矿渣质量比为4:1时,仍能配制合格的P.C32.5标号水泥。     

铁尾矿在新型干法水泥生产线上的应用

铁尾矿单独粉磨易磨性很差,作硅质原料配料时易磨性中等;制备的生料易烧性较好;实验证明采取适当的措施,预分解窑完全可用铁尾矿替代传统的硅质、铁质材料生产出质量较好的熟料,可以稳定生产普通52.5级等高标号水泥,并且可以大幅度降低原材料成本。使用时须注意:铁尾矿粉含水量大,应采取强制喂料保证下料顺畅;铁尾矿配料可能会有轻微结皮,预分解系统需加强防堵措施,多设空气炮,稳定煅烧制度;冬季生产用铁尾矿废石效果更佳。     

Preparation and properties of the glass-ceramics from low Ti-bearing blast furnace slag and waste glass

Ti-bearing blast furnace slag is a typical silicate material, which can be an important component for the preparation of silicate-based glass-ceramics. Quartz-based waste glass is commonly used as an additive to adjust the basicity of slag-based glass-ceramics. In this study, the quartz-based waste glasses were added to the Ti-bearing blast furnace slag to prepare the mixed solid waste glass-ceramics. The effects of waste glass content and heat treatment temperatures on the crystallization and performances of the prepared glass-ceramics were investigated. The results showed that as the waste glass content increased, the crystallization ability of the glass was weakened. Fassaite and nepheline were identified as the dominant crystalline phases in the prepared glass-ceramics and mainly featured a combination of both massive and dendritic forms. With increasing the heat treatment temperatures, the size of dendritic crystals first increased and then decreased. The optimal experimental conditions were identified as a waste glass content of 45%, a crystallization temperature of 900°C, and a nucleation temperature of 730°C. Under these conditions, the prepared glass-ceramics exhibited good crystalline phase distribution and excellent mechanical properties, including a Vickers hardness of 991.67 MPa and a flexural strength of 89.81 MPa. All the prepared solid waste-based glass-ceramics exhibited excellent chemical durabilities.     

含钛高炉渣制备SCR烟气脱硝催化剂

以含钛高炉渣为原料,稀硫酸为溶剂提取钛液,钛液经水解、高温焙烧后制得高比表面积的TiO₂,并以其为载体采用分步浸渍法制备了V₂O₅-WO₃/ TiO₂催化剂。优化了含钛高炉渣的酸解条件,对所得TiO₂进行了XRD、XRF、BET表征,用自制催化剂评价系统考察了所制备催化剂的脱硝性能及抗硫抗水性能。结果表明：H₂SO₄浓度40%、酸渣比1.5、酸解温度80℃、酸解时间3 h条件下,TiO₂浸出率可达90%,水解产物主要为锐钛型TiO₂,纯度达到74%,含有21.2%无定形SiO₂及少量其他杂质。SiO₂的存在提高了产物的比表面积、孔径,有利于活性组分的负载。以含钛高炉渣基TiO₂为原料制备的V₂O₅-WO₃/TiO₂脱硝催化剂相比于以商业TiO₂和TiOSO₄制备的催化剂,在250～450℃具有更高的催化活性,且在300℃具有较好的抗硫抗水性能。     

Preparation of TiC ceramics from hot Ti-bearing blast furnace slag: Carbothermal reduction,supergravity separation and spark plasma sintering

TiC ceramics, a kind of ultra-high temperature ceramics, are primarily prepared by the synthesized TiC powders from high purity metallic titanium or titania. In this work, a novel method for sustainable utilization of hot Ti-bearing blast furnace slag to prepare TiC ceramics was developed. Firstly, the Ti was efficiently transformed into the TiC in hot Ti-bearing blast furnace slag through carbothermal reduction. The high-purity TiC powders were fully recovered from molten carbonized Ti-bearing slag through supergravity separation, where the mass fraction and recovery ratio of Ti in TiC powders were up to 77.89 wt.% and 95.58 %. The TiC ceramics with a relative density of 98.23 % were prepared from the recovered TiC powders via spark plasma sintering method, which possess the favourable mechanical properties including Vickers hardness (Hv) of 23.3 ± 0.4 GPa, fracture toughness (K_IC) of 3.96 ± 0.24 MPa m^1/2 and flexural strength of 371.9 ± 15.4 MPa.     

硼铁矿高炉铁硼分离工艺试验研究

辽宁东部山区储有丰富的硼铁矿资源，由于矿物结构复杂，通过选矿只能得到含硼铁精矿和硼精矿。采用高炉法处理含硼铁精矿可使铁硼有效分离得到含硼生铁和富硼渣。硼精矿和富硼渣可代替面临枯竭的硼镁石作生产硼砂和硼酸的原料。     

Sulfur speciation in granulated blast furnace slag: An X-ray absorption spectroscopic investigation

Sulfur speciation in a granulated blast furnace slag (GGBFS) was analyzed by X-ray absorption near edge structure spectroscopy (XANES) before and after activation by saturated calcium hydroxide and five normal sodium hydroxide solutions. The solution to GGBFS ratio was 0.4.XANES showed that sulfur in GGBFS existed mostly as sulfides (frozen in calcium polyhedra) with a minor amount as sulfate. A slowly-cooled blast furnace slag, in contrast, had most of the sulfide transformed to sulfate. After activation of GGBFS, more sulfate formed and crystalline sulfide phases became more apparent. More slag reacted at lower pH than at higher pH.     

钢渣作水泥膨胀剂的初步研究

文章介绍了国内外膨胀的发展状况和钢渣利用情况,提出把钢渣掺入水泥中作膨胀的设想并进行了一系列实验。结果表明,用钢渣用膨胀剂,膨胀龄期较长,膨胀状况良好。水泥抗压强度随钢渣掺量的增加而有所降低,水泥安全性合格。     

高炉渣余热回收协同转化生物质制氢

高炉渣是钢铁生产过程的主要副产品,是一种多元金属熔体,具有大量显热并能促进焦油及甲烷等低分子碳氢化合物的催化转化。鉴于此本文提出通过干法离心粒化技术将液态炉渣制备成液-固过渡态的高温炉渣颗粒,作为生物质气化热载体,利用炉渣中多种金属矿物对大分子的解构、断键和分解的催化作用,提高气化反应的选择性,实现对炉渣显热的回收和转换,将低品位的液态炉渣余热转换成高品位的氢能。通过气化实验,对影响气化产物分布及气体组成的主要因素进行考察,结果表明：高炉渣在促进焦油分解和碳氢化合物重整方面表现出良好的催化性能,增加热载体炉渣颗粒温度,减小颗粒粒径能够减小炉渣表面积炭,降低气化产物中焦油产率和提升富氢气体品质,在最佳工况下（选用粒径小于2 mm,温度为1200℃的高炉渣颗粒作为热载体）,气化产物中焦油含量仅为2.52%,气体产率达到1.65 m³·kg^-1,富氢气体中H₂含量可达53.22%。     

攀钢高炉钛渣对出铁沟用耐火骨料侵蚀的相图热力学模拟分析

选取高炉出铁沟耐火材料常用的5种骨料(分别为棕刚玉、电熔刚玉、亚白刚玉、富铝尖晶石和特级矾土,粒度均为5～10 mm)和攀钢高炉钛渣(w(TiO2)=26%)作为研究对象,通过相图热力学计算和静态坩埚侵蚀试验对比研究,探讨了攀钢高炉钛渣条件下出铁沟耐火骨料的选择.热力学计算表明,电熔刚玉具有良好的抗钛渣侵蚀能力,而特级矾土骨料被侵蚀后形成的新渣相黏度高,有利于阻止渣对耐火材料的进一步渗透;而静态坩埚试验结果难以反映和判断材料高温下侵蚀的反应过程.因此,相图热力学计算技术可作为分析耐火材料侵蚀情况的可靠方法和手段.     

Tensile and fiber dispersion performance of ECC (engineered cementitious composites) produced with ground granulated blast furnace slag

An engineered cementitious composite (ECC) produced with ground granulated blast furnace slag was developed for the purpose of achieving moderately high composite strength while maintaining high ductility, represented by strain-hardening behavior in uniaxial tension. In the material development, single fiber pullout tests and matrix fracture tests were performed, followed by micromechanical analyses to properly select the range of mixture proportion. Subsequent direct tensile tests were employed to assess the strain-hardening behavior of the composite, which exhibited high ductility and strength with the addition of slag. High ductility is most likely due to enhanced workability and fiber dispersion performance which is attributed to the oxidized grain surface of slag, as verified by fiber dispersion tests. These results suggest that, within the limited slag dosage employed in the present study, the contribution of slag to fiber dispersion outweighs the side-effect of decreased potential for saturated multiple cracking, including a slight increase in matrix fracture toughness and fiber/matrix bond strength.     

Investigation of hydraulic activity of ground granulated blast furnace slag in concrete

Ground granulated blast furnace slag (GGBFS), a by-product of the steel manufacturing industry, being used as an effective partial cement replacement material, has already been proven to improve several performance characteristics of concrete. The reactivity of GGBFS has been found to depend on the properties of slag, which vary with the source of slag, type of raw material used, method and the rate of cooling. The present work aims at bringing out a novel relationship between the Hydraulic Index (HI) of slag at 7 and 28 days (HI7 and HI28) and the influencing properties of slag, namely, glass content, fineness and chemical composition by employing multiple regression analysis on 37 slag samples from various sources. HI7 and HI28, thus obtained, have been mapped onto a Slag Activity Index (SAI) plot, giving an indication of the ranges of strength of slag.     

Preparation of glass-ceramics with diopside as the main crystalline phase from low and medium titanium-bearing blast furnace slag

Because of the low content of TiO₂, the utilization of low and medium Ti-bearing blast furnace slag is a difficult problem. In this study, glass-ceramics with diopside as the main crystalline phase was made by using TiO₂ in the blast furnace slag as the nucleating agent and adding additional elements of TiO₂, Fe₂O₃ and Cr₂O_3. The effects of these three nucleating agents on the phase composition and structural properties of the prepared glass-ceramics were evaluated by DSC, XRD, and SEM to determine their optimal dosage. Research results show that the suitable mass percentages of the TiO₂, Fe₂O₃ and Cr₂O₃ crystal nucleation agents of the glass-ceramics are 7.69%, 0.96%, and 2.88%, respectively. The prepared glass-ceramics have excellent physical and chemical properties, e.g., a bending strength of 114.74 MPa, a bulk density of 2.77 g/cm³, a water absorption rate of 0, and a mass-loss rate of only 0.085%.     

熔盐高效分解含钛高炉渣制备纳米二氧化钛

采用熔盐法对含钛高炉渣进行高效分解并提取含钛组分,利用含钛滤液为原料制备了纳米二氧化钛粉体。对熔盐分解含钛高炉渣进行了热力学分析,并研究了碱渣比、熔盐反应温度及熔盐反应时间对钛组分浸出率的影响和pH及水解温度对二氧化钛产品纯度的影响。实验结果表明高炉钛渣在氢氧化钠熔盐中反应生成钛酸钠在热力学上是可行的。确定了最佳的碱渣比为3:1,最佳熔盐反应温度为500℃,最佳反应时间为3 h,在此条件下钛元素的浸出率为99.8%。得出较佳的水解pH范围为0.1～0.2,最佳水解温度为100℃。实验中制备的纳米二氧化钛粒子球形度好,粒度大小均匀且分散性好,颗粒直径为100 nm左右。     

含钛高炉渣的碳化产物对水泥砂浆强度及电阻率的影响

以攀枝花钢铁公司生产的高钛型高炉渣的碳化产物(碳化渣)取代标准砂为集料制备了水泥砂浆。采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对高钛型碳化渣进行了成分、物相和形貌表征;测试了不同碳化渣含量下水泥砂浆的抗压强度和电阻率,探讨了不同碳化渣取代量对水泥砂浆电阻率的影响机制。研究结果表明,含有碳化渣的水泥砂浆的强度满足建筑水泥砂浆的要求;在潮湿状态下,碳化渣的引入无法降低28 d龄期水泥砂浆的电阻率;在干燥状态下,当碳化渣的取代量达到60%以上时,水泥砂浆的电阻率可低于标准水泥砂浆,且最低可下降87.5%。高钛型碳化渣可作为导电集料的候选材料用于制备面向建筑加热采暖用的水泥基复合导电材料。     

Development of CaO-rich blast furnace slag containing fluorine mica-based glass ceramic coatings

In the present study, Blast Furnace Slag (BFS) waste was evaluated as a sustainable, cost-effective CaO, SiO₂, Al₂O₃ and MgO substitute for inorganic oxides for the production of frit, a raw material for glass ceramic production. Two different frits were prepared to compare a commercially available frit (F-STD) with frit produced using BFS waste (F-BFS). The samples were characterized by XRF, XRD, heating microscopy, dilatometry and TG-DTA to determine the chemical composition, phase formation and thermal properties. The frits were applied on steel using the electrostatic spray method and subsequently thermally treated at 830 °C for 4.5 min. The reference (GC-STD) and partially BFS-substituted glass ceramic (GC-BFS) coatings were examined by XRD, SEM-EDS and ICP-MS experiments. The main crystal phase for both samples was Ni-substituted fluorine mica (KLiNi₂Si₄O₁₀F₂). GC-BFS was slightly more amorphous (70%) than GC-STD (69.1%), which was correlated with the thermal properties of the BFS waste. Likewise, ICP-MS analysis after a boiling citric acid test (ISO 28706-1: 2008) revealed that the GC-BFS had relatively higher chemical resistance. The total release from the reference sample (GC-STD) was 23.556 mg/L, whereas the total release from the sustainably produced sample (GC-BFS) was 21.451 mg/L, which was consistent with the XRD results.