Iron ore tailings used for the preparation of cementitious material by compound thermal activation

In the background of little reuse and large stockpile for iron ore railings, iron ore tailing from Chinese Tonghua were used as raw material to prepare cementitious materials. Cementitious properties of the iron ore tailings activated by compound thermal ac-tivation were studied. Testing methods, such as XRD, TG-DTA, and IR were used for researching the phase and structure variety of the iron ore tailings in the process of compound thermal activation. The results reveal that a new cementitious material that contains 30wt% of the iron ore tailings can be obtained by compounded thermal activation, whose mortar strength can come up to the stan-dard of 42.5 cement of China.     

铁矿尾矿的活化及蒸养砖的制备

采用煅烧、磁选工艺对铁矿尾矿的惰性进行改性. 以改性后的铁矿尾矿为原料制备了蒸养砖,实现了对铁矿尾矿的废物利用. 将选矿尾矿与一定量煤粉混合煅烧,使其具有火山灰活性并使尾矿中的矿石矿物转变成磁铁矿. 对煅烧尾矿进行磁选,并检测三氧化二铝和二氧化硅的总溶出率. 以活化磁选后的铁矿尾矿为主要原料,采取干压成型制备了蒸养砖. 结果表明,煅烧后磁选能够将重选尾矿、浮选尾矿中的铁含量分别降低39.41 %和45.10 %,分选出来的铁精矿的品位均在57 %以上. 同时,重选尾矿的火山灰活性提高了近3倍,磁选尾矿的火山灰活性提高近2倍. 制备蒸养砖的最佳配合比为:水泥、建筑砂与尾矿的质量比为1∶1∶8,水料比0.15,石膏掺量为总干物料的2%. 所制得蒸养砖的抗折强度、抗压强度、吸水率、软化系数、干质量损失、干燥收缩率等性能指标都达到了非烧结砖的国标要求.     

铁尾矿粉对碱矿渣泡沫混凝土力学性能的影响

为了研究铁尾矿粉对碱矿渣泡沫混凝土力学性能的影响,用掺入了铁尾矿粉的碱矿渣泡沫混凝土制成100 mm×100 mm×100 mm的立方体试块,分别将混凝土试块养护3、7、28 d后,测试其抗压强度。结果表明：随着铁尾矿粉碱矿渣泡沫混凝土表观密度的增加,其抗压强度不断增大;当铁尾矿粉的掺量从10%增加到30%时,碱矿渣泡沫混凝土的抗压强度逐渐增大;当铁尾矿粉的掺量从30%增加到50%时,碱矿渣泡沫混凝土的抗压强度逐渐减小,且强度损失较明显,随着铁尾矿粉细度的提高,碱矿渣泡沫混凝土的强度逐渐增大。     

Load-settlement behaviour of a strip footing resting on iron ore tailings as a structural fill

This study presents a laboratory investigation of load-settlement behaviour of a strip footing resting on iron ore tailings used as a structural fill.The footing was placed at various depths in the tailings bed.The relative density of the tailings was varied as D_r = 50%,70%and 90%.An incremental load was applied on the footing while observing the settlement until the failure took place.The results obtained for tailings were compared with those for the sandy soil.It is observed that the load-bearing capacity and stiffness increase with an increase in footing embedment depth and relative density.Compared to load-settlement behaviour of Perth sandy soil,the tailings fill could have as high as 22 times and 13.5 times the load-bearing capacity and stiffness,respectively.Therefore,the replacement of sandy soil with iron ore tailings for structural fills is cost-effective,and moreover,this application contributes to environmental sustainability in construction.     

一种风化低品位铁矿石的可选性试验

随着铁矿资源的日益贫乏,对低品位矿石的开发利用成为选矿的发展趋势。山东省某矿业公司矿石属于风化程度较高的低品位铁矿石,样品粒度为10～0mm,含水量1％～2％。根据试样的性质和风化矿分选的经验,采用干式磁选抛尾、干选粗精矿再磨再选的试验流程,获得品位为66％的精矿产品,对低品位铁矿石的开发利用具有一定的借鉴意义。     

AEROCRETE MADE WITH LOW SILICON TAILINGS OF CHENGCHAO IRON ORE MINE

The experimental study on the tailings from Chengchao Iron Ore Mine has been introduced briefly, By analyzing the chemical and mineral compositions of Chenchao Iron Ore. the technological process has been constituted. According to the comparison experiments. the optimal proportion of cement and lime. dosage of the additional silicon—materials, calcium-silicon proportion. dosage of aluminum powder and other parameters have been deemed. Aerocrete has been trial-produced successfully with the low-silicon irom are tailings. It has opened up a new way for the exploitation of the low-silicon iron ore tailings.     

Properties and mechanism of mine tailings solidified and filled with fluorgypsum-based binder material

The properties and microscopic structure of tailings solidification bodies, the hardening mechanism of the fluorgypsum-based binder material (FBBM) and tailings solidification mechanism were investigated. FBBM consisted of 40% fluorgypsum,25%-50% blast furnace slag,10%-35% ordinary Portland cement clinker(OPCC) and 1% activator, which was good material in binding iron ore tailings.XRD analysis showed that the properties of tailings solidification bodies was related to its ettringite content.SEM and XRD analyses of tailings solidification bodies showed that the chemical reaction was produced between FBBM and tailings in the whole hydration process. The hydration of the resulting gel material covered the surface of the tailings particles and formed a gel structure. A large number of ettringite crystals and the remaining board-like gypsum crystals took each end and constituted the structural skeleton. The filamentous network-like calcium-silicate-hydrate(C-S-H) gel bonded firmly together with ettringite crystals, dehydrated gypsum crystals and granular tailings, and formed an extremely dense whole.     

某铅锌矿石分选工艺试验研究

某铅锌矿矿石含有铅、锌及银等有价组份和铁等综合利用组份。通过分选工艺研究,确定采用浮选-磁选工艺,优先浮选铅锌,浮选尾矿用磁选工艺分选铁矿物可以获得较好的选矿指标。     

Effect of bastnaesite as reductant on hematite reduction during in-situ suspension magnetization roasting of refractory iron ore under neutral atmosphereOA

The iron tailings of Bayan Obo mines are solid waste,which occupies land area and also causes environmental pollution;however,this waste can be recycled.In this study,based on the characteristics of iron minerals and fluorocarbonate contained in Bayan Obo iron tailings,clean magnetization roasting of iron minerals by bastnaesite from iron tailings during in-situ suspension magnetization roasting in a neutral atmosphere was explored.The results show that for iron tailings with a mass of 12 g, a N...     

Asbestos tailings as aggregates for asphalt mixture

To use many asbestos tailings collected in Ya-Lu highway,and to explore the feasibility of using asbestos tailings as aggregates in common asphalt mixtures,and properties of some asphalt mixtures were evaluated as well.X-ray diffraction (XRD),X-ray fluorescent (XRF),and atomic absorption spectrophotometry (AAS) were employed to determine the solid waste content of copper,zinc,lead,and cadmium.Volume properties and pavement performances of AC-25 asphalt mixture with asbestos tailings were also evaluated comp...     

Physical Properties and Hydration of Cementitious Materials Prepared from Vanadium Slag and Phosphate Slag

The physical properties and hydration of a cementitious material, which prepared mainly from the vanadium slag and phosphate slag, were investigated. These slags were investigated can be reused as original resources to prepare cement clinker based on the fact that they mainly comprise silicon and calcium phases, respectively. In this research, a batch of cement having various grades was prepared by mixing the clinker with gypsum, tailings, and fly ash. X-ray diffraction(XRD), differential thermogravimetric(DTG) as well as scanning electron microscopy(SEM) were applied to test and analyze the physical properties and hydration of the prepared cement. Experimental results suggest that the performances of the cement meet the requirements of national standards in all aspects. Its hydration process is similar to that of common Portland cement, whose hydrates were mainly composed of C-S-H, ettringite and CH. Moreover, the addition of fine particles would accelerate cement hydration, as it provided additional surfaces to help the nucleating and growing of hydrates.     

电石渣—脱硫石膏复合激发充填材料性能及微观结构

针对传统充填材料高碳排放、高成本问题,以“绿色矿山”为理念,选用工业固废电石渣、脱硫石膏和矿渣为胶凝组分,以尾矿砂为骨料制备充填材料。利用X射线（XRD）、扫描电镜（SEM）和能谱分析(EDS)等手段研究充填料水化产物及微观形貌,并开展工作性能、力学性能和重金属固化性能试验。结果表明：所开发的充填材料凝结时间和流动度均满足矿山充填工程要求,充填体7、28 d抗压强度可达4.6、7.9 MPa,充填体浸出液中Pb、Zn浓度低于规定限值。电石渣内的氢氧化钙提供碱性环境,脱硫石膏提供硫酸根离子,两者对矿渣内的硅铝质原料复合激发,生成以钙矾石和C-A-S-H凝胶为主的水化产物。大量针棒状结构的钙矾石晶体及网状结构的C-A-S-H凝胶相互穿插,并且与尾砂颗粒紧密结合,随着龄期延长,结构更加致密,使充填体具有良好的力学性能。     

原状铁尾矿砂渗透特性试验研究

铁尾矿砂渗透特性是影响其坝体稳定性的重要因素之一。而渗透系数是表征其渗透性的重要指标。国内外学者均对渗透系数进行了广泛的研究,分别建立了相应渗透系数的计算公式。但这些公式多适用于粗粒土,其对铁尾矿砂的适用性尚不明确。因此,有必要对现有公式准确性进行验证,并建立适用于铁尾矿砂的渗透系数计算模型。通过室内变水头试验,从FC值、级配、粒径、比表面积和粉粒间孔隙比等多个角度出发,对铁尾矿砂原状样的渗透性质进行了分析。结果表明：原状铁尾矿砂的渗透系数受细粒含量影响明显,细粒含量的阀值在35%左右;应用传统渗透系数计算公式对原状铁尾矿砂渗透系数进行计算,结果并不准确;受细颗粒含量影响,原状铁尾矿砂的渗透系数与不均匀系数Cu、曲率系数Cc、平均粒径、加权平均粒径、体积比表面和粒间孔隙比es之间呈现明显的非线性关系,应用这些参数难以表征细粒含量较大时的渗透系数变化;但是,有效粒径和粉粒间孔隙比与原状铁尾矿砂的渗透系数呈现出了较好的相关性,据此建立铁尾矿砂渗透系数计算公式,其计算结果较为准确。这对陈坑尾矿坝的渗流场分析与稳定性计算具有一定意义。同时,所取尾矿砂试样主要为磁铁矿尾砂,这对类似铁尾砂渗透性计算也有一定借鉴意义。     

冶金渣制备生态型人工鱼礁混凝土的试验研究

通过正交试验研究了矿渣钢渣熟料石膏体系胶凝材料的强度。胶凝材料正交试验表明：矿渣：钢渣的复合比为7∶1,矿渣和钢渣的比表面积分别为480 m 2·kg -1和550 m 2·kg -1,并与10%的水泥熟料和10%的脱硫石膏复合的胶凝材料具有较高的强度。以优化后的胶凝材料代替水泥,并以热闷法稳定化的钢渣颗粒为骨料,可以制备出抗压强度达到65 MPa以上的人工鱼礁混凝土。利用XRD和SEM方法分析胶凝材料的水化过程,结果表明,水化反应主要生成AFt相和C-S-H凝胶,钢渣、水泥熟料和脱硫石膏的协同作用对矿渣的火山灰活性反应具有重要促进作用。     

Resource utilization of slag from desulphurization and slag skimming: A comprehensive recycling process of all components

In order to make the slag from desulphurization and slag skimming (SDSS) to be comprehensively recycled and utilized, a combined process of beneficiation and building materials preparation was proposed to recover iron from SDSS, meanwhile to apply the remaining slag tailings as cement admixture. From this process, three iron-rich products were recovered in stages by clean gravity - magnetic separation, slag tailings were left. Slag powder was prepared by ultrafine grinding of slag tailings. The stability, setting time and cement mortar strength of the slag tailings cements (STC) which were mixed with Portland cement and slag powder were studied respectively. The results showed that a proper overall performance still could be obtained at the slag powder content of 30%. Chemical composition analysis, X-ray diffraction (XRD) analysis, metallographic microscope and scanning electron microscope (SEM) analysis were employed to assess the characteristics of the SDSS and the products obtained from the whole process. The results indicated that the three iron-rich products could be used as a raw material for steelmaking and ironmaking and the relatively large amount of calcium silicate (C₂S) and tricalcium silicate (C₃S) in the slag tailings make the addition of slag powder into the Portland cement feasible.     

矿用充填胶凝材料激发剂配比智能优化决策

针对矿用充填胶凝材料不同配比的激发剂化学复合作用所引起充填胶结体单轴抗压强度复杂非线性变化问题,提出一种充填胶凝材料激发剂配比智能优化决策方法.首先,开展均匀设计试验获取不同激发剂配比充填胶结体抗压强度数值;其次,采用动态自适应交换变异概率及适应度竞争交换方式的改进遗传树表征激发剂与充填胶结体抗压强度之间的非线性复杂关系,运算至49代时即满足终止法则,收敛速度较快,函数精度高;最后,确定约束条件,建立激发剂配比优化模型,采用遗传算法的全局快速寻优技术,获得满足充填体强度要求的激发剂优化配比.结果表明:采用该智能优化方法研究铁矿新型充填胶凝材料激发剂配比,优化结果显示,满足该矿山充填体强度的胶凝材料优化配比为生石灰2.91%、石膏17.39%、矿渣粉79.7%;在该优化配比周围开展验证试验,试验结果显示为生石灰3%、石膏17%、矿渣粉80%时、充填体7、28d抗压强度均达到最大,与激发剂配比智能优化方法获得的胶凝材料配比相吻合.相比42.5水泥,用该智能优化方法获得的激发剂配比制备全尾砂充填胶凝材料,可降低材料成本22%.     

加筋铁尾矿用于道路基层的试验研究

为环保利废,试验研究利用加筋铁尾矿用于道路基层施工。选择合适的水泥剂量制成的水泥稳定铁尾矿作为半刚性基层材料,向水泥稳定铁尾矿中加入聚丙烯纤维,制成水泥稳定加筋铁尾矿,在提高其强度、改善其性能的同时,降低水泥的用量。试验结果表明：混合料水泥剂量3％,聚丙烯纤维0．3％可满足高速公路和一级路的底基层、二级及二级以下道路的基层和底基层的要求。     

铁矿尾矿库区粉尘污染源强研究

在矿山开发过程中，由于弃土、尾矿等废弃物的堆积，经受风吹日晒，会加重对大气的污染．本文就马钢公司南山铁矿尾矿库区的污染源强进行了风洞实验研究，给出了干尾矿粉尘的起动风速与粉尘粒径的关系和起尘量与风速的关系，同时指出尾矿沉积干滩表面不被破坏时，在一般风力作用下不会起尘．     

铁尾矿砂改良膨胀土基本工程性质试验研究

研究利用工业废料铁尾矿砂作为添加剂改良膨胀土的可行性与改良效果。通过室内试验,对尾矿砂改良土的基本物理性质指标、膨胀性指标、强度指标以及微观结构进行了研究。试验结果表明,随着掺砂率的增大,试验土样的界限含水率及塑性指数都减小;自由膨胀率、有荷膨胀率和膨胀力等膨胀特性指标随掺砂率的增大均降低。无侧限抗压强度和黏聚力随着掺砂率的增加先增大后减小,在掺砂率为30%时达到最大;内摩擦角随着掺砂率增大而增大。通过观察SEM试验结果,发现在掺砂率为30%时,改良土结构处于最稳定状态,说明掺铁尾矿砂改良膨胀土具有显著效果,为膨胀土改良提供了一种新方法。综合考虑各项指标,认为铁尾矿砂改良膨胀土的最佳掺入比应为30%。     

Process mineralogy of copper-nickel sulphide flotation by cyclonic-static micro-bubble flotation column

In our study we investigated a refractory copper-nickel sulfide ore separation by using a cyclonic-static micro-bubble flotation column (FCSMC). The process mineralogy of the main products was studied. Using a scanning electron micro-scope-energy dispersive system (SEM-EDS) and an X-ray spectrometer the mineral category and content of samples were analyzed. By using a mineral liberation analyzer (MLA) the mineral liberation characteristics were revealed. It is shown that in roughing feed the monomers liberation degree of nickel pyrite and chalcopyrite take up 84.11% and 88.82%, respectively. In tailings, the lost nickel pyrite and chalcopyrite are mainly monomers. Therefore, strengthening the micro-fine particle recovery capacity is the key to increase recovery.