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主要研究了以多种富镁矿物为原料，制备适合于大掺量粉煤灰混凝土的新型镁质膨胀材料，用以补偿大坝由于温度应力引起的收缩。通过在不同粉煤灰掺量的水泥浆体中，外掺不同比例的新型镁质膨胀材料和传统MgO膨胀剂，研究水泥浆体压蒸膨胀率的变化规律以及40℃水中长龄期养护膨胀率的变化过程及趋势。结果表明，随着膨胀材料掺量的增加，膨胀率相应增加。随着养护龄期的延长，膨胀率相应增大，到120d左右，膨胀趋于平缓。粉煤灰对传统MgO膨胀剂具有明显的抑制作用，且随着粉煤灰掺量的增加，抑制作用加强。新型镁质膨胀材料能很好的改善抑制作用，从而满足大掺量粉煤灰混凝土工程的要求。 相似文献
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虹湾幅月球数字地质图是中国首次编制的关于月球地质演化的地质图,应用的主要数据资料来源于"中国首次月球探测工程"嫦娥一号CCD影像数据、DEM数据,结合Clementine750nm影像数据,主要月坑的高分辨率图片,同时结合前人的研究成果,如主要矿物元素含量分布图、多波段反射率特征分布图等编制完成。所有的数据处理应用的是ArcMap平台,同时结合使用了MapGIS软件和Photoshop软件,数据模型采用Geodatabase地理数据模型。详细介绍了基于ArcGIS平台编制月球数字地质图的工作流程,编制方法及依据、编制规则及数据库的建立等,为今后开展月球数字地质图的编制积累了经验。 相似文献
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以盐湖副产水氯镁石为原料,与一定比例的石灰反应得到氢氧化镁和氢氧化钙的混合沉淀物,该混合物经过滤、洗涤、烘干后在一定温度下煅烧得到符合皮江法炼镁用的合成煅白。实验结果表明,该工艺是可行的,在石灰/氯化镁摩尔比2.05~2.10：1,反应时间1.5,煅烧温度为800℃,煅烧时间为60min时,合成的煅白中钙镁摩尔比： 0.95~1.07：1,煅白的平均水活度达34%,符合硅热法炼镁用中间原料煅白的参数条件。该技术可为利用盐湖氯化镁制备金属镁新工艺开发提供了数据参考。 相似文献
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甘肃金川铜镍矿石中MgO对浮选的影响 总被引：7，自引：0，他引：7
金川铜镍矿浮选精矿中MgO高,影响闪速熔炼。对金川主力矿山二矿区矿石中MgO分布特征与赋存状态的研究,分析影响浮选过程中MgO难以抑制原因。认为矿石本身MgO含量高、矿石蚀变严重、含镁矿物自然可浮性的良好是造成精矿中MgO高的主要原因。提出研究含镁矿物的浮选特性和矿石的矿物组成特点是精矿降镁的前提。 相似文献
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A. Kirfel T. Lippmann P. Blaha K. Schwarz D. F. Cox K. M. Rosso G. V. Gibbs 《Physics and Chemistry of Minerals》2005,32(4):301-313
A generalized X-ray scattering factor model experimental electron density distribution has been generated for the orthosilicate forsterite, using an essentially extinction and absorption free set of single crystal diffraction data recorded with intense, high energy synchrotron X-ray radiation (E=100.6 keV). A refinement of the model converged with an R(F)=0.0061. An evaluation of the bond critical point, bcp, properties of the distribution at the (3, –1) stationary points for the SiO and MgO bonded interactions, yielded values that agree typically within ~5%, on average, with theoretical values generated with quantum chemical computational strategies, using relatively robust basis sets. On the basis of this result, the modeling of the experimental distribution is considered to be adequate. As the bcp properties increase in magnitude, the MgO and SiO bonds decrease in length as calculated for a number of rock forming silicates. As asserted by Coppens (X-ray charge densities and chemical bonding. Oxford University Press, Oxford, 1997), large negative 2(rc) values, characteristic of shared interactions involving first row atoms, may not be characteristic of closed shell covalent bonded interactions involving second row Si, P and S atoms bonded to O. This study adds new evidence to the overall relatively good agreement between theoretical bcp properties generated with computational quantum strategies, on the one hand, and experimental properties generated with single crystal high energy synchrotron diffraction data on the other. The similarity of results not only provides a basis for using computational strategies for studying and modeling structures, defects and the reactivity of representative structures, but it also provides a basis for improving our understanding of the crystal chemistry of earth materials and the character of the SiO bonded interaction. 相似文献
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J. Zhang 《Physics and Chemistry of Minerals》2000,27(3):145-148
Isobaric volume measurements for MgO were carried out at 2.6, 5.4, and 8.2 GPa in the temperature range 300–1073 K using
a DIA-type, large-volume apparatus in conjunction with synchrotron X-ray powder diffraction. Linear fit of the thermal expansion
data over the experimental pressure range yields the pressure derivative, (∂α/∂P)
T
, of −1.04(8) × 10−6 GPa−1 K−1 and the mean zero-pressure thermal expansion α0,
T
= 4.09(6) × 10−5 K−1. The α0,
T
value is in good agreement with results of Suzuki (1975) and Utsumi et al. (1998) over the same temperature range, whereas
(∂α/∂P)
T
is determined for the first time on MgO by direct measurements. The cross-derivative (∂α2/∂P∂T) cannot be resolved because of large uncertainties associated with the temperature derivative of α at all pressures. The
temperature derivative of the bulk modulus, (∂K
T/∂T)
P
, of −0.025(3) GPa K−1, obtained from the measured (∂α/∂P)
T
value, is in accord with previous findings.
Received: 2 April 1999 / Revised, accepted: 22 June 1999 相似文献
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铁酸钙是高碱度烧结矿中的主要黏结相矿物,它的含量、结晶形态、化学成分及晶体结构等矿物学特性对烧结矿质量起着关键性作用,而烧结原料中各组分的含量直接影响着铁酸钙的生成。以Fe3O4、SiO2、CaO、MgO、Al2O3的化学纯试剂为原料,在实验室进行微型烧结实验,运用XRD、偏光显微镜、电子探针等手段,定量分析研究了原料组分中MgO、Al2O3对烧结矿中铁酸钙的生成及其矿物学特性的影响。原料中MgO含量的增加对铁酸钙的生成有一定抑制作用,尤其在MgO含量为2.0%~3.0%时,烧结矿中铁酸钙含量明显减少,其晶体形态也从以板柱状和针状为主逐渐过渡为它形不规则状;原料中Al2O3的增加,对烧结矿中铁酸钙的形成具有促进作用,即随着Al2O3的增加铁酸钙含量呈明显增加趋势,且铁酸钙的形态也由以柱状和针状为主向板柱状变化。电子探针成分分析及矿物化学式计算结果表明,铁酸钙是由Fe2O3、CaO、SiO2、Al2O3及MgO组成的复杂结晶体,其化学通式为Ca2.60Mg0.44Si1.07Al0.96Fe8.92O20。原料中MgO、Al2O3含量的变化,对铁酸钙的化学成分中Fe2O3/CaO摩尔分数比影响不大,均接近3∶2。上述研究结果对于深刻理解烧结工艺条件下铁酸钙晶相的晶体化学特征及其对烧结矿质量的影响具有重要指导意义。 相似文献