机械活化对氧化锌矿碱法浸出及其物化性质的影响

研究了不同活化时间、活化方式对云南兰坪低品位氧化锌矿碱法浸出的影响. 结果表明,当浸出液NH4Cl浓度2.0 mol/L、NH3×H2O浓度1 mol/L、温度30℃、浸出液与浸出矿样液固比为10 L/g时,未活化矿样浸出90 min浸出率仅为60.08%,而活化90 min矿样浸出90 min的浸出率为69.36%,为可浸出含锌物相的103.97%;先磨后浸的强化效果优于边磨边浸. 不同活化时间、活化方式不仅造成矿物的形貌、粒度分布不同,而且使矿样在球磨过程中的物相转化存在差异：活化与浸出步骤分离时,球磨过程发生了机械化学反应,矿样中ZnS被氧化成利于浸出的物相,从而比两步骤合并的浸出效果好.     

机械活化对钛铁矿高温氧化过程的影响

采用球磨对钛铁矿进行机械活化,并考察机械活化对钛铁矿高温氧化反应的影响.结果表明:机械活化导致钛铁矿晶格畸变,比表面积增大,从而显著加快了钛铁矿的氧化,降低了钛铁矿氧化反应和相转变反应温度,未机械活化的钛铁矿氧化反应在不同的条件下会生成Fe2O3与TiO2或Fe2O3与Fe2Ti3O9,由于机械活能加速了氧化过程中铁离...     

机械活化强化矿物浸出过程的研究进展

综述了近10年来国内外关于机械活化强化矿物浸出的研究工作,包括机械活化对矿物原料性质的影响,对强化矿物浸出的效果及作用机理,强化矿物浸出反应动力学.最后对机械活化的研究发展前景进行了展望.     

机械力对攀枝花钛铁矿结构及反应特性的影响

为考察攀枝花钛铁矿的还原特性,对其进行了球磨活化. 结果表明,球磨处理使钛铁矿颗粒粒径变小,晶格细化,应变增大,无序化程度和活性提高. 热重结果分析表明,球磨处理使钛铁矿还原反应开始温度降至600~700℃,并提高了反应速率,在912℃固相反应温度下,磨矿8, 4, 2, 1, 0 h失重分别为10.99%, 7.21%, 3.95%, 3.31%和0.90%.     

氧化方式对盐酸浸出攀枝花钛铁矿的影响

为获得易萃取分离的三价铁与钛的盐酸溶液,对盐酸浸出焙烧氧化与球磨氧化的攀枝花钛铁矿进行了研究. 结果表明,氧化方式对钛铁矿浸出有显著的影响. 球磨氧化明显强化了钛铁矿的浸出,钛和铁在20 min时的浸出率分别达到93%和97%;焙烧氧化则抑制了矿物特别是钛的浸出,钛和铁在260 min后的浸出率分别为40%和94%(浸渣中TiO2含量约为80%). 钛铁矿的球磨预氧化是改进和强化现有盐酸法钛白生产工艺的有效途径.     

机械活化和粉磨助剂对矿渣微粉作用的研究

研究了机械活化和粉磨助剂对矿渣微粉的作用,结果表明:矿渣的机械活化存在最佳的粉磨时间,主要在50min～65min时激活效果最好;助剂和矿渣混合后经过机械活化处理较助剂直接加入机械活化后的矿渣中得到的矿渣水泥早期强度有较为明显的提高,随着龄期的增大,差异减小;化学助剂的掺入明显减小了矿渣颗粒群的平均径,颗粒分布变宽。掺入助剂后试样的粗糙度均增大,说明颗粒表面形貌更为复杂,矿渣活性提高;粉磨过程中产生的高能量使化学试剂作用于矿渣颗粒表面,使得表面化学键的破坏加快,化学健力发生改变,矿渣玻璃体内桥氧减少,矿粉活性增加;矿粉颗粒群几何形貌指数中的粗糙度和分数维与机械活化效果的正关联度最大。     

球磨工艺对钛酸钡陶瓷介电性能的影响

研究了固相法合成BaTjO3粉体时,在滚筒磨和搅拌磨中球磨BaCO3和TiO2粉体过程中,浆料的粒度、凝聚程度与球磨时间、筒容积的关系,分析了粉体均匀性对BaTiO3、陶瓷介电性能的影响.研究结果表明:TiO2粉体在球磨过程中,粒度大小没有显著变化,导致粉体凝聚的主要原因是BaCO3粉体;应先球磨BaCO3粉体10小时后再加入TjO2粉体继续球磨2小时所得的物料颗粒要比钡钛一起球磨所得的颗粒均匀,合成BaTiO3均匀性好;采用搅拌磨时,制备的BaTiO3陶瓷介电性能优于滚筒磨.     

钛铁矿机械活化-稀酸酸解反应耦合

采用稀酸酸解反应工艺,利用机械活化-稀酸酸解反应耦合技术,在磁驱转动的球磨反应装置上进行了钛铁矿的酸解反应。考察了反应器旋转速率、酸矿比、球料比及硫酸浓度等对酸解反应的影响。结果表明,在硫酸质量分数为60%、酸矿比1.6:1、球料比10:1及反应温度90℃条件下,与原矿浸出反应空白实验相比,采用活化-浸出耦合反应的浸出速率明显提高,浸出2 h酸解率从32%提高到49%,所得钛液的稳定性大于450 mL。扫描电镜(SEM)及X射线衍射(XRD)表征结果表明,耦合反应使得矿物颗粒不断破碎、细化和脱落,使剩余未活化芯继续活化并不断反应浸出。     

机械活化辅助浸出硫化镍矿中有价金属

随着高镍三元锂电池在新能源电动汽车领域的规模化应用,全球镍资源的需求量日益增加,绿色、高效、低成本地从硫化镍矿资源中提取镍的技术备受关注。本工作提出了机械活化辅助氧化浸出硫化镍矿的提取路径,在机械活化过程中通过改变硫化镍矿结构、增加晶体无序化程度、减小粒度和增加比表面积增加硫化镍矿的反应活性,再通过Na2S2O8氧化浸出实现了常压环境中硫化镍矿中有价金属的高效浸出。考察了机械活化和浸出过程中各因素对硫化镍精矿浸出的影响,确定了较优条件。在较优条件球磨转速613 r/min、球料比20:1、球磨时间120 min、酸浓度2 mol/L、过硫酸钠浓度0.42 mol/L、浸出时间60 min、液固比5:1、搅拌速率400 r/min和浸出温度80℃下,Ni, Co, Cu和Fe的浸出率分别达98.9%, 97.7%, 98.2%和98.7%。     

高硅型铁尾矿机械活化效果及机理研究

为促进铁尾矿工程应用,以辽宁本溪高硅型铁尾矿为例,研究机械活化方式和活化时间对铁尾矿形貌及活性的影响。通过粒度分析、胶砂试验和石灰吸附测试等,探究机械活化对铁尾矿粒径分布、比表面积、活性指数和火山灰活性的影响;通过X射线衍射和扫描电镜分析,探究胶凝体系的水化反应机理。结果表明:机械活化可以优化铁尾矿粒径,提高颗粒圆度,降低颗粒表面结晶度,且粉磨40~60 min效果最佳;湿磨活化50 min时,活性指数达96.6%,火山灰活性大幅提升,湿磨活化效果显著优于干磨;机械活化促进了铁尾矿与水泥的二次水化反应,提升了胶凝体系性能。     

中低品位磷矿粉的机械力化学活化与活性表征

采用机械力化学法对中低品位磷矿石进行活化,考察了不同活化设备在不同活化条件下的磷活化性能,结果表明:原料磷矿石质地较致密坚硬,化学活性较低,磷浸出率非常低,只有3.1％.采用XQM2-2L变频行星球磨机机械活化,在机械活化120 min后得到了最佳的活性,磷浸出率为7.5％.采用AGO-Ⅱ高能球磨机进行实验,磷浸出率最佳值为10.9％,若在相同活化条件下,活化过程中加入助磨剂,则可进一步提高磷的浸出率,最佳值可达15.3％.     

Synthesis of Fe-TiC-Al2O3 hybrid nanocomposite via carbothermal reduction enhanced by mechanical activation

In this study, the feasibility of the synthesis of Fe-TiC-Al₂O₃ hybrid nanocomposite via mechanical activation followed by carbothermal reduction was investigated. The raw materials including ilmenite, carbon black and aluminum powder were milled in a high energy planetary ball mill. At different time intervals, samples were taken for characterization. After phase evaluation with XRD, some samples were heat treated in an atmosphere controlled tube furnace. Studies proved that increasing the milling time of the raw materials resulted in the formation of more amorphous phase and more active materials. Furthermore, investigations showed that after carbothermal reduction, the synthesized TiC crystallites were in the scale of nanometers and the lattice parameter had some deviation from the standard value. At higher heat treatment temperatures, the crystallite sizes increased, while the deviation from the standard lattice parameter decreased.     

Effect of mechanical activation on syntheses temperature of TiC reinforced iron-based nano-composite from ilmenite concentrate

In this research the possibility of producing Fe–TiC from ilmenite concentrate and carbon black using mechanically activated sintering has been investigated. Ilmenite and carbon black were placed in a planetary ball mill and sampled after different milling times. The activated powders were synthesized at different temperatures in an atmosphere control tube furnace. Studies showed that synthesizing temperature has been remarkably decreased by increasing the milling time. Also it was seen from the width of X-ray patterns peaks that the size of produced TiC crystals is in the order of nanometer. Furthermore the lattice parameter had deviated slightly from the standard size.     

行星搅拌球磨机超细粉碎机理分析

描述了行星搅拌球磨机的工作原理,针对物料在其中被粉碎时复杂的运动轨迹和受力方式,通过对超细粉碎过程的颗粒粉碎速度、颗粒碰撞速度的数学分析以及从流体力学角度对湿法粉碎机理的分析,综合分析了利用行星搅拌球磨机制备超细粉的机理。     

Changes in the structure of hematite by extended dry grinding in relation to imposed stress energy

The effect of extended dry milling in different mills on the structural changes of hematite concentrate has been investigated using a combination analysis of XRD line broadening, BET and particle size measurements. Structural changes were followed by XRD line broadening analysis using integral breadth method and Warren-Averbach approach. For analysis, the stress energy was estimated by considering different grinding variables in different mills and changes in the structure discussed in terms of stress energy.Within comparable range of stress energy, lower BET surface area was produced by grinding in the vibratory mill. The maximum surface area increased to 18,400 m²/kg in the vibratory mill after releasing 51,300 kJ/kg energy. The conversion of the 80% of initial hematite to amorphous phase during extended dry grinding by tumbling, planetary and vibratory mills, needs 4000, 8500 and 50,000 kJ/kg energy respectively. It was understood that vibratory mill introduces the minimum lattice strain and gives the largest crystallites when applying the same level of stress energy. The smallest crystallites with grinding in tumbling, vibratory and planetary mills were obtained about 17.3, 13.5 and 5.6 nm after releasing 5230, 51,300 and 15,600 kJ/kg respectively. For these levels of stress energy, in turn, the microstrain <ε_L=10 nm²>^1/2 exceeds 4.4 × 10^− 3, 3.9 × 10^− 3 and 5.3 × 10^− 3.It was further revealed that higher concentrations of defects (Amorphization and excess energy) per unit surface area were induced by grinding in the planetary and tumbling mills. A theoretical calculation of the energy contribution to the long-lived defects indicated that products from tumbling and planetary mills have higher excess energy compared to the products from vibratory mill for the same stress energy. The maximum theoretical excess energy was estimated about 75.4, 80.0 and 81.3 kJ per mole of the ground hematite with tumbling, vibratory and planetary mills after releasing 5230, 51,300 and 15,600 kJ/kg of stress energy respectively. Grinding in vibratory mill needs much more energy to reach the same effect as the other used mills. A comparison of specific energy input and stress energy among the used mills points out that for generation of the same levels of stress energy, the planetary mill consumes more energy than the other used mills.     

机械活化木薯淀粉制备双醛淀粉的研究

采用搅拌球磨机对木薯淀粉进行机械活化,以活化60 min的木薯淀粉为原料,NaIO4为氧化剂制备双醛淀粉,并以醛基摩尔分数为评价指标,考察活化时间、反应时间、反应温度、氧化剂用量、NaIO4浓度及体系pH等因素对木薯淀粉氧化反应的影响。结果表明,机械活化对木薯淀粉的氧化反应有显著的强化作用。双醛淀粉的醛基摩尔分数随活化时间的延长而增大;活化60 min的淀粉在反应时间90 min、反应温度30℃、n(NaIO4)∶n(AGU)=0.8∶1、NaIO4的浓度0.5 mol/L、体系pH=4的条件下制得的双醛淀粉x(醛基)=95.4%,而在相同条件下,由原木薯淀粉制得的双醛淀粉x(醛基)=58.2%。利用红外光谱仪、扫描电子显微镜和X射线衍射仪对产物的结构进行了表征。     

Effects of mechanical activation on the digestion of ilmenite in dilute H2SO4

The commercial sulfate process for pigment production uses concentrated sulfuric acid(N 85 wt% H_2SO_4) as feeding material and discharges 8–10 tons of spend dilute acid(20 wt% H_2SO_4) per ton of product. Re-using spend acid to leach ilmenite can cut the waste emission and save fresh feeding acid. However, the leaching reaction with dilute acid is very slow and the digestion efficiency is fairly low. This paper describes a wet-milling process to enhance the dilute-acid leaching of ilmenite that makes it possible to produce TiO_2 pigment in a more environmentally benign routine. The leaching kinetic study of unmilled ilmenite, dry milled 60 min ilmenite and wet milled 60 min ilmenite was conducted by revision of the shrinking core model(SCM), incorporation of particle size distribution(PSD) into SCM. The results revealed that mechano-chemical activation method significantly increased the leaching efficiency of titanium from 36% to 76% by reducing the particle size and increasing the reaction contact area. On the other hand, the milling process increased the lattice deformation and amorphization of crystalline, which lowered the activation energies in the leaching process. Compared with dry milling operation, wet milling is more effective, the particle size distribution of wet-milled ilmenite was much narrower, smaller, and more uniform. Wet milling of ilmenite makes the leaching reaction with dilute acid(60 wt% H_2 SO_4) practicable and the re-use of spend acid becomes possible and economical.     

Self-propagating high-temperature synthesis in mechanically activated mixtures of boron carbide and titanium

Self-propagating high-temperature synthesis in both the modes of both layer-by-layer combustion and dynamic thermal explosion was carried out using preliminary mechanical activation of B₄C–Ti powder mixtures in a planetary ball mill. Preliminary mechanical activation conditions of reaction mixtures that provide a reduction in the reaction initiation temperature to 600 ± 20?C were determined. The reaction products consist of mixtures of TiC and TiB₂ with submicron grain size. The results of x-ray diffraction and electron microscopy studies of activated samples and reaction products are presented.     

机械活化甘蔗渣与丙烯酸(钠)的接枝共聚反应

采用搅拌球磨对甘蔗渣进行机械活化,以不同活化时间的甘蔗渣为原料,过硫酸铵和亚硫酸钠为引发剂,在水溶液中与部分中和的丙烯酸进行接枝共聚反应。以接枝率和接枝效率为评价指标,考察了活化时间、丙烯酸与甘蔗渣的用量比、反应时间和反应温度等因素对接枝反应的影响。并采用SEM、FT-IR对甘蔗渣和产物进行表征。结果表明:机械活化明显强化了甘蔗渣与丙烯酸的接枝共聚反应,接枝率和接枝效率随着活化时间的延长而增大,主要是由于机械活化破坏了甘蔗渣中木质素对纤维素的包裹作用,降低纤维素的结晶度,提高了其反应活性。以活化1.5 h的甘蔗渣为原料进行接枝共聚反应,在反应时间为3 h、丙烯酸(体积,ml)与甘蔗渣(质量,g)的用量比为6、反应温度为60℃的条件下,制得接枝率和接枝效率分别为165.29%和82.70%的接枝共聚产物。