广西扶绥喀斯特型铝土矿氢氧同位素特征及地质意义

扶绥铝土矿是近年来在桂西南地区探获的一个典型喀斯特型铝土矿床。在野外地质工作的基础上,通过显微镜观察、X射线衍射、氢氧同位素测试等手段,对矿床中矿物组合及一水硬铝石、高岭石的氢氧同位素进行分析,探讨成矿环境的变化及硬水铝石的成因。结果表明:硬水铝石、高岭石是铝土矿石中的主要矿物,其次为勃姆石、赤铁矿、锐钛矿,沉积期矿石中还含有绿泥石和黄铁矿等,沉积期后矿石中含叶腊石、伊利石等,堆积矿石中均不含勃姆石。氢氧同位素测试表明:一水硬铝石的δ~(18)O值为0.95%~1.98%,δD值为-6.5%~-7.94%;高岭石δ~(18)O值为1.3%~1.89%,δD值为-7.04%~-8.97%。矿物组合指示,铝土矿沉积于缺氧环境中,沉积期后转变为富氧环境,且经历了干湿交替的气候变化。一水硬铝石氢氧同位素组成与钙红土三水铝石有较好的协调性,且兼具"风化壳"及"红土"的特征,反映其由钙红土风化壳演化而来。高岭石氢氧同位素组成推算沉积阶段温度为33℃,沉积期后为18℃,与二叠纪末期—中三叠世海水温度相似。扶绥沉积铝土矿的形成是对二叠—三叠纪全球气候变化的响应,且沉积阶段三水铝石或勃姆石向硬水铝石的转换与古特提洋俯冲作用有关的火山活动有密切关系;堆积铝土矿的形成则与印支运动及后来的表生喀斯特化作用密切相关。     

越南红土型铝土矿的研究

应用化学分析、相分析和拜耳法溶出技术，研究越南南方红土型铝土矿（三水铝石型铝土矿）。矿石中的铝矿物以三水铝石为主，部分试样中含有一水软铝石。针铁矿中的部分铁原子被铝原子替代。形成铝针铁矿，还有磁铁矿和钛铁矿。在１４５℃下仅能溶出三水铝石，溶出其他含铝矿物需要提高温度。拜耳法处理铝硅比为２４的矿石，每吨氧化铝的矿石理论用量为２．３７ｔ，赤泥量为０．８３ｔ，碱的化学损失为４０ｋｇ。     

三水铝石相变和软铝石晶种性能

研究和应用国外含－水软铝石的三水铝石型土矿用混联法生产氧化铝，在拜耳法系统中，低温下溶出三水铝石，含软铝石的赤泥送烧结系统。研究了低温溶出时三水铝石相变为软铝石的温度，由于中外双方在溶出三水铝石的温度选择上有分歧，在资料中有关三水铝石相变为软铝石的温度也有不同的叙述，研究指出在溶出条件下相变的温度为１５５℃。含有软铝石的赤泥浆液在分离洗涤时，资料中认为软铝石有晶种作用。从溶液中析出含水Ａｌ２Ｏ３。     

探讨铝土矿成因的两个模拟实验

岩石红土化生成铝土矿的实质是风化淋滤作用,碱、碱土和硅被流动的雨水带走,铝硅酸盐矿物分解,同时铝、铁、钛等残余物富集成矿;矿物可以在一定条件下转化,随着外界温度升高,铝矿物按照三水铝石-勃姆石-硬水铝石-刚玉的序列转化;本文是首次在我国通过风化淋滤实验和矿物转化实验,用实验方法研究我国一水硬铝石型铝土矿生成过程的部分研究成果,是我国第二届铝土矿地质学术会议上交流的论文之一中的一部分。     

希腊一水硬铝石型铝土矿的处理方法

一水硬铝石型铝土矿全世界大多数已知铝土矿资源中都含有三水铝石成份;一水软铝石含量很少。一水硬铝石在几乎所有铝土矿中都存在,但一般是少量的。除了在印度库奇(kutch)半岛的某些小矿床探测到一水硬铝石局部富集外,红土化铝土矿床所含一水硬铝石不到0.5％。所有真正的     

贵港式铝土矿的地质特征（上）

贵港式红土型铝土矿产于广西中部岩溶平原的泥盆纪碳酸盐岩红土风化壳中,形成时代为第四纪更新世,含矿层厚0.4～14m,平均2～4m,其中大于1mm的颗粒状净矿为矿石,含矿率平均800～1000kg/m~3,四个矿区算术平均品位的算术平均值为Al_2O_3 26.08％,Fe_2O_3 43.97％,SiO_2 9.61％,A/S=2.71。含矿层上面的表层红土厚0～5.16m。三水铝石是最主要的含铝矿物,约占矿物总量的25％～40％,一般为30％左右;针铁矿是最主要的铁矿物,约占1/3～1/2,通常为40％左右,赤铁矿也是主要铁矿物,含量约5％～10％:这三种矿物约占矿物总量80％,针铁矿与赤铁矿的晶格中有少量铝替代,当用拜耳法生产氧化铝时,这部分铝不能回收。采用先拜耳法溶出Al_2O_3,后催化焙烧制取金属化球团的工艺流程,可以合理利用贵港铝土矿石的特点,经济效益良好。     

氧化铝纤维制备过程中拟薄水铝石晶相控制研究

以工业铝酸钠溶液为原料制备氧化铝纤维过程中,拟薄水铝石是其中间产物,拟薄水铝石的纯度将直接影响到氧化铝纤维产品的质量。本文应用X-射线衍射图谱,研究了不同反应条件下,拟薄水铝石及其主要杂质三水铝石、丝钠铝石三者在晶相上的变化,通过调整反应溶液的p H值、反应温度、反应浓度、加料方式等反应条件,尽可能降低三水铝石、丝钠铝石杂相的出现,从而获得具有较纯晶相、极低杂质含量的拟薄水铝石,以满足生产高质量氧化铝纤维产品的需要。     

进口三水铝石矿中一水软铝石的溶出性能研究

以一水软铝石-三水铝石混合型铝土矿低温溶出赤泥为试验原料,研究了溶出温度、溶出时间、母液苛碱浓度、母液分子比及溶出固含对一水软铝石溶出性能的影响,并分析了一水软铝石在低温拜耳法生产工艺条件下难以溶出的原因.试验结果表明:在溶出温度145℃、母液苛碱浓度212 g/L、母液分子比5左右的条件下,一水软铝石的溶出率可以达到...     

三水铝石与一水软铝石的自行析出

当把浓铝土矿矿浆加热到160℃时,一水软铝石即析出,并在溶出阶段的热交换器器壁上结疤。在赤泥分离状态下,三小铝石便析出在不含一水软铝石的赤泥里。只有一水软铝石存在于赤泥中,始能析出。在赤泥中含有各种矿物时,针铁矿会对三水铝石的析出显示出最大的种子作用。钙的各种化合物都能控制三水铝石的析出,但不能控制一水软铝石的析出。     

从经济观点探讨采用石灰拜耳法的可能性

目前世界上生产氧化铝的主要原料是三水铝石型、一水软铝石型和一水硬铝石型铝土矿。我国采用的主要是一水硬铝石型,而且绝大部分是属于中等品位和较低品位的铝土矿。对于铝硅比4～10的一水硬铝石型铝土矿,我     

Prospects of the Use of Synergetic Approach to Solution of Problems of the Science of Nanomaterials

A synergetic approach to solution of problems of self-controlled synthesis of nanostructures and creation of self-organizing nanotechnologies is considered in connection with the superproblem of creation of materials with functional properties resembling those of biosystems. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 55 – 61, July, 2005.     

Kinetics of the oxidation of metals — Influence of self-diffusion of metal

The importance of the self-diffusion of a metal during its oxidation by a gas is treated for the cases of nonstoichiometric oxides having either interstitial cation or cation vacancies. We have established a general relationship for the reaction rate when a mixed diffusion process occurs. From this relationship, we have shown that the pressure dependence can be different, according to whether the rate-determining process is the self-diffusion through the metal or through the product.     

Features of formation of the structure in production of blanks of disks of heat-resistant nickel alloys

Conclusions To provide a high level of mechanical properties in wrought blanks of cast ÉP741NP and ÉP962 alloys it is necessary to form controlled structures. A necklace-type structure formed in homogenizing isostatic treatment, subsequent thermomechanical working including alternation of the operations of deformation in the (+)-area and recrystallization anneals, and final heat treatment is preferable. The temperature conditions of all stages of thermomechanical working are strictly controlled, especially the final operation of deformation and heating for hardening. To eliminate hardening cracks and distortions it is necessary to use molten salts at t=600°C as quenchants. The use of multiple production operations makes it possible to significantly reduce the structural inhomogeneity related to inhertance of the original dendritic structure. However, the structure of the final semifinished product is nevertheless characterized by a difference in occurrence of the processes of polygonization and recrystallization between the former dendritic cells and the interdendritic spaces in deformation and heat treatment.To obtain structurally homogeneous blanks for gas turbine engine parts it is necessary to use basically new methods of remelting such as vacuum double electrode remelting and electron beam remelting with an intermediate vessel.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 25–29, December, 1991.     

Ab-initio calculation of enthalpies of formation of intermetallic compounds and enthalpies of mixing of solid solutions

A large number of ab-initio calculations of energies of formation of intermetallic compounds have been performed in the last 15 years. The currently used methods are listed. The paper presents a review of the aluminium based compounds which have been studied. Comparisons of calculated and experimental enthalpies of formation are provided for aluminim-3d and-4d transition metal alloys at equiatomic composition. The modelling of the enthalpies of mixing of solid solutions based on a given lattice is described.     

试论洋务派教师聘任的思想

洋务派在洋务学堂的办学活动中,为了解决西学专业学科的教学困难,采用了聘请外籍教师的应急措施.他们以真才实学,合同制管理作为主导思想,并认为这种解决师资的途径只是权宜之计,并非久远.从客观上看,洋务派的教师聘任思想有深刻的历史影响.     

胫骨生物陶瓷复合材料的微结构增韧机理

扫描电镜观察显示胫骨是一种由羟基磷灰石和胶原蛋白组成的自然生物陶瓷复合材料.羟基磷灰石具有层状的微结构并且平行于骨的表面排列.观察也显示这些羟基磷灰石层又是由许多羟基磷灰石片所组成,这些羟基磷灰石片具有长而薄的形状,也以平行的方式整齐排列.基于在胫骨中观察到的羟基磷灰石片的微结构特征,通过微结构模型分析及实验,研究了羟基磷灰石片平行排列微结构的最大拔出能.结果表明,羟基磷灰石片长而薄的形状以及平行排列方式增加了其最大拔出能,进而提高了骨的断裂韧性.     

Mechanism of Nucleation of Precipitates of Carbides of Refractory Metals Under Hot Rolling of Automotive Sheet Steel

Metal Science and Heat Treatment - The problem of formation of properties in microalloyed sheet steels is considered. The cause and the possible mechanism of precipitation of carbides of refractory...