古建筑修缮中粉化石灰的占比对灰浆性能的影响

古建筑修缮现场,块状生石灰原材料粉化变质不可避免,实际施工中也难免掺入粉化石灰。为了探究粉化变质石灰的占比对灰浆性能的影响,首先利用X射线衍射(XRD)、X射线荧光光谱(XRF)和热重分析(TG)对块状生石灰及粉化石灰的纯度及变质程度进行了定性及定量分析,然后以相同水灰比、不同粉化石灰占比制样,进行性能对比及机理研究。结果表明:石灰原材料纯度高,块状生石灰未变质,为纯CaO,粉化石灰部分变质,其中CaCO_(3)含量为17.93%。粉化石灰占比增加降低了试样的表面硬度,对养护28 d的试样力学强度影响小,对养护60 d的灰浆试样力学强度有增大趋势,粉化石灰占比达到50%时降低了灰浆的耐水性、抗冻性。干燥表观密度、显气孔率、吸水率、碳化深度及扫描电镜(SEM)结果分析得出性能差异主要是由于粉化石灰胶结性降低,以及制样时粉灰所需水少,相同水灰比条件下剩余游离水多,使得粉灰试样致密度低、孔隙率及吸水率大,从而加快了碳化。工程实际使用中可将粉化石灰占比控制在40%以内。

复合喷吹脱硫剂钝化石灰的生产及应用实践

根据济南钢铁股份有限公司第一炼钢厂铁水复合脱硫的喷吹原理,探索钝化石灰的生产及应用实践,通过控制原料指标,改进研磨方式,优化生产工艺,提高其钝化效果和流动性,解决了堵枪、喷溅等问题,实现了45吨瘦长型铁水包的连续稳定喷吹。

钝化石灰在复合喷吹铁水脱硫工艺中的应用

对钝化石灰在复合喷吹铁水脱硫工艺中的脱硫机理及各阶段中的作用进行了分析，结合山西太钢不锈钢股份有限公司80t复合喷吹铁水脱硫生产实践，得出复合喷吹脱硫工艺中的钝化石灰可以提高镁粉利用率和脱硫率，加强深脱硫能力，减少温降、回硫量和扒渣铁损，降低脱硫成本。以铁水初始硫质量分数0．02％～0．03％，终点硫质量分数小于0．003％为例，复合喷吹脱硫剂消耗比单喷颗粒镁降低了2．96元／t，扒渣铁损降低了1．08元／t，扒渣剂消耗减少了0．23元／t，合计降低了脱硫成本4．02元／t。

石灰陈化机理及其在文物保护中的应用研究

采用SEM和XRD等技术手段,探讨了石灰陈化过程机理及其在文物保护中应用的可行性.结果表明,石灰在陈化过程中,随着陈化时间的增加,氢氧化钙的粒径呈现逐渐减小的趋势,形成了直径约50nm、长度约200nm的针状氢氧化钙,以及粒径为100～200nm的板状氢氧化钙;陈化石灰的纳米粒径和高反应活性较好地改善了陈化石灰糯米灰浆的抗压强度、表面硬度等物理性能,并使陈化石灰-乙醇分散液具有良好的渗透性,可较好地解决传统石灰水加固剂溶解度较小和渗透性较差的问题,为其在砖、石、土质文物保护中的应用奠定科学基础.

我国寒武系底部含磷岩系中的棘盔状化石

重点介绍产于我国扬子地台下寒武统底部含磷岩系中的部分具棘、带刺类化石的分布情况和埋藏特征。对它们的分类位置和亲缘关系也作初步探讨 ,认为它们分属于不同的后生动物类群的硬件构造。文中描述了该类化石 3属 4种 ,其中 1新属 1新种———Paradoxiconustypicalisgen .etsp .

Acid mine drainage activation mechanism on lime-depressed pyrite flotation from copper sulfide ore

The lime-depressed pyrite from Cu differential flotation tailings with acid mine drainage(AMD)as a natural activator was recovered.The effect of AMD on lime-depressed pyrite flotation was investigated by a series of laboratory flotation tests and surface analytical techniques.Flotation test results indicated that AMD could effectively activate the pyrite flotation with a sodium butyl xanthate(SBX)collector,and a high-quality sulfur concentrate was obtained.Pulp ion concentration analysis results indicated that AMD facilitated desorption of Ca~(2+)and adsorption of Cu~(2+)on the depressed-pyrite surface.Adsorption measurements and contact angle analysis results confirmed that adding AMD improved the adsorption amount of SBX collector on the pyrite surface and increased the contact angle by 31°.Results of Raman spectroscopy and X-ray photoelectron spectroscopy analysis indicated that AMD treatment promoted the formation of hydrophobic species(S~0 hydrophobic entity and copper sulfides)and the removal of hydrophilic calcium and iron species on the pyrite surface,which reinforced the adsorption of collector.The findings of the present research provide important theoretical basis and technical support for a cleaner production of copper sulfide ores.

铁水镁脱硫采用粘渣技术减少转炉回硫的实践

钝化镁铁水脱硫后,铁水渣中w(S)高,且渣量稀少,扒除干净较困难,极易造成转炉炼钢的回硫,尤其是超深脱硫钢种,回硫高时往往影响生产。选用钝化石灰作为粘渣剂,在铁水脱硫中应用,可以改变铁水渣中脱硫产物的性状,以利于扒渣,达到降低钢水回硫。

包钢炼钢厂镁基脱硫工艺研究

本文主要介绍了包钢炼钢厂脱硫扒渣站的建站目的、相关工艺参数等 ,并对其投产后的生产情况进行了介绍与简单分析。

Enhanced photocatalytic performance of cementitious material with TiO_2@Ag modified fly ash micro-aggregates

A TiO2 photocatalyst is coated on the surface of a zeolite fly ash bead（ZFAB） to improve its dispersability and exposure degree in a cement system.The application of Ag particles in TiO2/ZFAB modified cementitious materials is to further enhance the photocatalytic performance.Various Ag@TiO2/ZFAB modified cementitious specimens with different Ag dosages are prepared and the characteristics and photocatalytic performance of the prepared samples are investigated.It is observed that the multi-level pore structure of ZFAB can improve the exposure degree of TiO2 in a cement system and is also useful to enhance the photocatalytic efficiency.With an increment of the amounts of Ag particles in the TiO2/ZFAB modified cementitious samples,the photocatalytic activities increased first and then decreased.The optimal Ag@TiO2/ZFAB modified cementitious sample reveals the maximum reaction rate constant for degrading benzene（9.91×10^-3 min^-1）,which is approximately 3 and 10 times higher than those of TiO2/ZFAB and TiO2 modified samples,respectively.This suggests that suitable Ag particles coupled with a ZFAB carrier could effectively enhance the photocatalytic effects and use of TiO2 in a cement system.Thus,ZFAB as a carrier could provide a potential method for a high efficiency engineering application of TiO2 in the construction field.

Fabrication of β-Sialon/ZrN/ZrON composites using fly ash and zircon

β-Sialon/ZrN/ZrON composites were successfully fabricated by an in-situ carbothermal reduction？nitridation process with fly ash, zircon and active carbon as raw materials. The effects of raw materials composition and holding time on synthesis process were investigated, and the formation process of the composites was also discussed. The phase composition and microstructure of the composites were characterized by means of XRD and SEM. It was found that increasing carbon content in a sample and holding time could promote the formation of β-Sialon, ZrN and ZrON. The proper processing parameters to synthesize β-Sialon/ZrN/ZrON composites were mass ratio of zircon to fly ash to active carbon of 49：100：100, synthesis temperature of 1550 °C and holding time of 15 h. The average grain size ofβ-Sialon and ZrN（ZrON） synthesized at 1550 °C for 15 h reached about 2 and 1μm, respectively. The fabrication process ofβ-Sialon/ZrN/ZrON composites included the formation ofβ-Sialon and ZrO2 as well as the conversion of ZrO2 to ZrN and ZrON.

Surface modification of biomedical magnesium alloy wires by micro-arc oxidation

Magnesium alloy wires were processed by micro-arc oxidation （MAO） in a modified silicate-phosphate composite electrolyte containing hydroxyapatite （HA） nanopowders and NaOH. Effects of NaOH content in the composite electrolyte on the microstructure and properties of the MAO ceramic coatings on magnesium alloy wires were studied. It is found that the arc voltage of magnesium alloy wires in the micro-arc oxidation process is significantly reduced while the oxidation rate is accelerated. Addition of 2 g/L NaOH in the composite electrolyte is a better choice for improving corrosion resistance of magnesium alloy wires. During early simulated body fluids （SBF） immersion, the micro-arc oxidized magnesium alloy wires undergo a slow and stable degradation. After soaking for 28 d, the protective ceramic coating still shows no damage but significant degradation is observed for magnesium alloy wires after immersion for more than 60 d.

Synthesis of Crystalline Hydroxyapatite from CaCO_3 and CaHPO_4·2H_2O by Mechanochemical Method

The mixture of CaHPO 4·2H 2O and CaCO 3 was ground in an aqueous system under appropriate conditions to investigate the mechanochemical reaction for the synthesis of crystalline hydroxyapatite (HA) powder. Hydroxyapatite of high crystallinity powder including trace Ca 10 (PO 4) 6CO 3(OH) and Ca 9HPO 4(PO 4) 6OH can be synthesized by mechanical activation without further thermal treatment at a high temperature. The synthesis reaction during the grinding process was almost completed within 1h. The as-ground powder exhibits a particle distribution of 20-100nm in size with a spherical or rodlike morphology. The composition and degree of crystallinity of the mechanochemical synthesized hydroxyapatite powders were coincident with the cement-type hydroxyapatite.

Model of limestone calcination / sulfation under oxy-fuel fluidized bed combustion

The characteristics of the simultaneous calcination/ sulfation of limestone under oxy-fuel fluidized bed combustion were studied and compared with those of the sulfation of precalcined CaO. During the calcination stage, SO2 can react with product CaO and slow down the CaCO3 decomposition rate by the covering effect of the CaSO4 product. The sulfation rate of simultaneous calcinatiort/sulfation is slower than that of precalcined CaO, but with a long enough sulfation time, the calcium conversion of simultaneous calcination/sulfation is higher than that of the precalcined CaO. A grain-micrograin model is established to describe the simultaneous calcination, sintering and sulfation of limestone. The graln-micrograln model can reflect the true reaction process of the calcination and sulfation of limestone in oxy-fuel fluidized bed combustion.

Research on flue gas desulphurization with two sorbents by water spray in activated reactor

The experimental results of flue gas desulphurization with caustic lime andhydrated lime activated by water spraying in a desulphurization reactor are presented. The effectsof Ca/S molar ratio, approach to saturation of flue gas, SO_2 concentration and gas velocity onsulfur retention efficiency and calcium utilization rate are investigated. Desulphurizationcharacteristics of the two sorbents are compared. The mechanism of improving desulphurizationefficiency by water spraying is analyzed. The results show that the activities of two sorbents areimproved obviously by humidification with water spray and the caustic lime has better applicationprospect because of cheaper cost.

铁水预处理低成本生产实践

为了降低铁水预处理成本,对铁水预处理过程参数进行优化,包括喷粉速率、喷枪插入深度等参数,并且在不影响脱硫效率的前提下,采用低CaO含量的钝化石灰粉替代高CaO含量的钝化石灰粉进行喷吹脱硫尝试。结果表明,钝化石灰粉消耗减少0.963 kg/t铁,镁粉脱硫效率提高6.9%,低CaO含量的钝化石灰粉不影响脱硫率。

生活中的学问

铜器发暗怎么办 铜器在空气中置久会“生锈”。铜在潮湿的空气中会被氧化成黑色的氧化铜，锕器表面的氧化铜继续与空气中的二氧化碳作用．生成一层绿色的碱式碳酸铜CuCO3·Cu(OH)2。另外，铜也会与空气中的硫化氢发生作用．生成黑色的硫化铜。用蘸浓氨水的棉花擦洗发暗的铜器的表面，就立刻会发亮。因为用浓氨水擦洗铜器的表面，

Comparative study on SO_2 release and removal under air and oxy-fuel combustion in a fluidized bed combustor

SO2 release and removal were studied under both the air and oxy-fuel combustion conditions using an anthracite coal from the Jincheng mine in China on a bench-scale fluidized bed combustor （FBC）. Special attention was paid to the effects of the combustion atmosphere, 02 concentration, bed temperature, and limestone addition. The released amount of SO2 was clearly higher under 30% 02/70% CO2 than that of the air atmosphere. As the O2 concentration in O2/CO2 mixture increased from 21% to 40%, the released amount of SO2 increased significantly, but then it decreased when the 02 concentration increased up to 50%. The bed temperature from 860 to 920 ℃ has no obvious influence on the the SO2 release but shows a strong influence on the desulfurization with limestone in both oxy-fuel and air conditions. The maximum SO2 removal efficiency appears to be at 880 to 900 ℃ for both the air and oxy-fuel combustion conditions.

The influence of land use change on karst water quality of Shuicheng Basin in Guizhou Province

The influence of land use and land cover on ecological environment is a focus of global change research. The paper chooses an industrial city-Shuicheng in Guizhou Province-as a study area because the karst water quality around the city is deteriorating with land use and land cover change. The natural susceptibility of karst water system is an important factor leading to karst water pollution. But land use and land cover change is also a main factor according to the chemical analysis of karst water quality and land use change. So it is a good way to protect karst water through rational planning and managing of land use and land cover.

DESIGN AND APPLICATION OF DYNAMIC MONITORING AND VISUALIZATION MANAGEMENT INFORMATION SYSTEM OF KARST LAND ROCKY DESERTIFICATION

In order to study the spatial-temporal change and environmental management of regional karst LUCC (land use and land cover change) and its causative environmental effect-rocky desertification by integrating qualitative analysis and quantitative analysis, and relying on RS, GIS and GPS (3S) techniques, karst land rocky derification dynamic monitoring and visualization management information system (KLRD.DMVM.IS) is framed, which includes design aim and structure model, function design, database design and model system design. The model system design gives priority to dynamic monitoring, drive force diagnosis, comprehensive evaluation and decision support of karst rocky desertification. From the viewpoint of model type, mathematic expression and its meaning, the dynamic monitoring models are concretely devised to reflect the spatial and temporal changing features and the trend of karst LUCC and rocky desertification. Taking Du'an Yao Autonomic County of Guangxi as an example, the KLRD.DMVM.IS is systematically analyzed in the application of the process and trend of karst LUCC and rocky desertification in Du'an County, and it provides the technical support for the study on karst land rocky desertification.