Production of Bauxite Certified Reference Material (BARC-B1201) for Nine Property Values (Al2O3, Fe2O3, SiO2, TiO2, V2O5, MnO,Cr2O3, MgO and LOI) Traceable to SI Units

The National Centre for Compositional Characterisation of Materials (NCCCM) / Bhabha Atomic Research Centre (BARC) and National Aluminium Company Limited (NALCO), India have produced an Indian origin bauxite certified reference material (CRM), referred to as BARC-B1201, certified for major (Al₂O₃, Fe₂O₃, SiO₂, TiO₂, loss on ignition - LOI) and trace contents (V₂O₅, MnO, Cr₂O₃, MgO). Characterisation was undertaken by strict adherence to ISO Guides. A method previously developed and validated in our laboratory, using single step bauxite dissolution and subsequent quantitation (of Al₂O₃, Fe₂O₃, SiO₂, TiO₂, V₂O_5, MnO, Cr₂O₃ and MgO) by ICP-AES (SSBD ICP-AES) was used for homogeneity studies and an inter-laboratory comparison exercise (ILCE) of the candidate CRM. LOI was determined by thermo-gravimetric analysis. Property values were assigned after an ILCE with participation from seventeen reputed government and private sector laboratories in India. The CRM was certified for nine property values: Al₂O₃, Fe₂O₃, SiO₂, TiO₂, V₂O_5, MnO, Cr₂O₃, MgO and LOI, which are traceable to SI units.     

非洲铝土矿地质特征、成矿规律与找矿前景研究

非洲是全球铝土矿资源最丰富的大洲,以产有多个世界级铝土矿矿床而著称。为分析该地区铝土矿的地质特征、成矿规律和找矿前景,本文在总结非洲铝土矿资源禀赋特征的基础上,探讨了该地区铝土矿资源的区域成矿地质背景、矿床类型、成矿条件、成矿特征、时空分布规律和成矿演化过程,划分了成矿区带。研究表明：①非洲铝土矿资源主要集中分布在西非地区,具有储量巨大、品位高、埋藏浅、易开采等特点;②矿床类型为红土型,是在成矿构造环境、成矿母岩、古气候、古地形地貌等多种成矿条件耦合下,铝硅酸盐岩及富铝变质岩发生深度红土化作用的产物;③成矿母岩以中新生代基性侵入岩、火山岩及古元古代变质岩、古生代变质岩为主;④赋铝土矿红土风化壳具有垂直分带性;⑤成矿构造单元以西非克拉通为主;⑥主要成矿时代为晚白垩世-新生代。根据铝土矿的成矿构造环境、成矿特征和时空分布规律,将非洲铝土矿划分为西非铝土矿成矿省和东南非铝土矿成矿省2个成矿省及6个一级成矿带,这些成矿省、成矿带是非洲重要的铝土矿矿产地和找矿远景区,找矿潜力巨大。     

黔中铝土矿及其赤泥中钪的某些特征

本文论述了黔中铝土矿和其紧密伴生硬质粘土岩及其炼铝残渣赤泥中的钪和稀土元素含量与分布特征，通过淋滤实验、酸处理实验、人工合成方钠石及电子探针分析等手段，探讨了钪在赤泥中的赋存特征。     

Availability of Bauxite Reserves

Based upon a large database, this paper analyzes the record of bauxite mine production, exploration success, and resource depletion and evaluates the availability of bauxite reserves in the near future. The record clearly shows that for the past 50 years world bauxite production rose by an annual increase of over 5% while per capita consumption rose during the same period by about 4%. Time trends of the world bauxite reserve life index (RLI); that is, known world reserves of a given year divided by world production of the same year, are episodic and seem to follow bauxite price cycles. The present-day RLI indicates adequate bauxite supply for about 180 years and is the same as it was in 1950. However, if an annual growth rate of 5% is considered, the currently known reserves will be exhausted within the next 20 years and the reserve base will be adequate for not more than 25 years. This scenario is based, of course, on the unrealistic assumption that future exploration efforts fail to discover additional reserves. Evaluation of the quality, in terms of bauxite signatures, and quantity of presently known bauxite prospects that may be mined in future suggests that there is sufficient potential for adequate bauxite supply for the next 20 to 25 years at least. Bauxite signatures cover a wide range of values that allows selection of the most favorable bauxite prospects for future mining, both in economic as well as environmental terms. Although, there is the general believe that the world abundance of bauxite resources will ensure sufficient supply to meet future demands significant additional reserves have to be discovered if exponential growth rates continue. As the question of future bauxite supply is subject to economic and geologic principles one has to take into consideration that increasing exploration maturity in many mineral provinces will make it difficult to locate additional bauxite reserves and that decreasing real commodity prices will influence the level of investment in bauxite exploration.     

孝义-霍州一带铝土矿形成的古地理环境及找矿前景

孝义—霍州一带铝土矿是指山西省孝义市—霍州市包括交口县等区域间石炭系本溪组下段的Ｇ层铝土矿。其本溪期古地理环境为一狭长的低凹盆地,其中心部位为泻湖相,由泥质岩—铁质岩或铁质岩—泥质岩区组成,泻湖边缘相由铝质岩区、泥质岩—铝质岩区、铝质岩—泥质岩区构成,铝土矿主要形成分布于该相区内。该区已成为我国最大的铝土矿资源地之一,预计该区南部（汾西西南部）西侧仍具较大找矿前景,可望今后实现地质找矿的重大突破。     

石墨炉原子吸收法测定铝矾土中的硅

通过对照硅在热解石墨管、涂钼及涂钨石墨管中的原子化行为，选用涂钼石墨管和Ｌａ做基体改进剂，石墨炉原子吸收法测定铝矾土中的硅。经铝矾土管理样分析验证，方法可靠。实际样品分析结果与重量法和钼蓝法相符，对质量分数ｗ（ＳｉＯ２）在４％水平的铝矾土进行分析（ｎ＝５），其ＲＳＤ在１２％～１７％。     

我国几个主要铝土矿床矿物的扫描电镜研究

用扫描电子显微镜和能量色散谱仪研究了我国贵州修文、河南巩县、广西平果、四川南川、广东文冒及福建漳浦等六个铝土矿床的矿物组成及微观结构。并比较了它们各自的主要特点。     

河南小关低品位铝土矿矿物成分的扫描电镜研究

本文用扫描电子显微镜和能量色散谱仪对河南小关低品位铝土矿的主要矿物成分及其微观结构进行了观察分析,并与高品位铝土矿进行了比较,发现有如下特点:低品位铝土矿的矿物成分复杂,常见多种矿物共生;铝矿物主要为硬水铝石,晶体化程度较差,或晶形不完整,结构比高品位铝土矿致密;淋滤次生孔洞及结晶完好的次生软水铝石晶体较少。     

桂西某些铝土矿床稀土元素地球化学研究

桂西铝土矿有原生沉积型和堆积型两种矿床类型，它们关系密切。对铝土矿及其围岩系统取样。进行稀土元素分析。结果表明，原生铝土矿的成矿母岩主要为下二叠统茅口灰岩，其次有少量古陆风化物的加入；原生铝土矿形成于海相的沉积环境，堆积型铝土矿由原生沉积型铝土矿风化淋滤而成。     

广西平果堆积型铝土矿矿石特征及工艺研究

广西平果岩溶堆积型铝土矿床赋存于岩溶洼地、谷地中的红土层中。可供露采，储量丰富，矿石具有中铝、高铁、高Al／Si比、低硫等特点。矿石的绝大部分由硬水铝石、针铁矿、赤铁矿和高岭石组成，含量约占85％，其它矿物含量甚少。是国内罕见的能运用拜耳法生产氧化铝的优质新型铝土矿资源。