贵州水银洞卡林型金矿床首次发现大量次显微-显微可见自然金颗粒   总被引：2，自引：0，他引：2  

苏文超  张弘弢  夏斌  张兴春  胡瑞忠  周国富  夏勇 《矿物学报》2006,26(3):257-260

在贵州水银洞卡林型金矿床原生富矿石的一条含砷黄铁矿细脉中发现有100余粒次显微-显微自然金颗粒(0.1~6μm),并具有清晰的显微岩相学结构。提出了该类型金矿次显微-显微可见自然金颗粒的形成过程可能与含Au热液-岩石相互作用过程中含Fe碳酸盐矿物溶解释放Fe的大量硫化物化而导致热液中Au的过饱和有关,含Fe碳酸盐赋矿围岩是形成高品位大型卡林型金矿床最重要的控制因素之一。  相似文献   

Removal of perchlorate （ClO4^-） contaminants by calcined Zn-Al layered double hydroxides     

Liang LU Yulin WANG Jing HE 《中国地球化学学报》2006,25(B08):255-255

Layered double hydroxides （LDHs） are a class of synthetic anionic clays whose structure can be described as containing brucite-like layers in which some of the divalent cations have been replaced by trivalent ions, giving rise to positively charged sheets. This charge is balanced by intercalation of anions in the hydrated interlayer regions. LDHs act as sorbents of anionic species through two types of reactions, namely, anion exchange and reconstruction, which further adds the possibility of recycling and reuse. The sorption of anions from aqueous solutions by structural reconstruction of a calcined LDHs is based on a very interesting property of these materials, the so-called memory effect： Calcination of LDHs produces intermediate non-stoichiometric oxides （CLDH） which undergo rehydration in aqueous medium and give back the hydroxide structure with different anions in the interlayers. Perchlorate＇s （ClO4^-） strong oxidizing capabilities make it ideally suited for use as a propellant in solid rocket fuel. However, this use in rocket fuel has led to the ClO4^- contamination of considerable amounts of water throughout the United States. ClO4^- has been shown to inhibit iodide uptake by the thyroid gland; and in large doses, it has been linked to anemia and fetal brain damage. This is especially a problem in China. With the recent emergence of perchlorate contamination as an important drinking water quality issue, adsorption by calcined LDHs was studied for ClO4^- removal. In this work, the effect of various factors such as （a） CLDH structure, （b） conditions for removal of ClO4^- ion, such as dosage of adsorbent, initial concentration of ClO4^-, and temperature and （c） co-existing anions in perchlorate contamination on the removal of ClO4^-, have been investigated, respectively.  相似文献   

Bromide removal and recovery with layered double hydroxides as an adsorbent     

Liang LU Jing HE Xiangjun PAN 《中国地球化学学报》2006,25(B08):107-107

Grignard regents have been applied extensively in chemical industry, especially in pharmacy. A mass of bromide-containing wastewater was produced after reaction, and ozonation of these organic contaminants can produce bromate and other brominated pollutants. The US Environmental Protection Agency （EPA） has established a maximum contaminant level of 10 μg/L for bromate in finished water. Therefore, it is necessary and significant to remove the DBP （disinfection by-products） precursor - bromide. On the other hand, since the bromine is a valuable element, recovery of it from wastewater is significant. Bromide removal is important to control DBP （disinfection by-products） contaminant and an ion exchange process is one of several treatment processes for this purpose. Layered double hydroxides （LDHs） are useful as adsorbents for bromide removal because of theft ion exchange properties. In this study, the adsorption properties of LDHs for bromide and the method of regeneration of this material were examined. It has been found that the LDHs with Mg/Al molar ratio of 2 represented the highest capacity to remove bromide ion from aqueous solution at pH 6.0. The equilibrium isotherms of uptake of bromide by CLDH were well fitted by the Langmuir equation. Bromide adsorbed on the LDHs was effectively desorbed at 30% Na2CO3 solution and the LDHs were regenerated at the same time. The regenerated LDHs could be reused repeatedly for the bromide removal. Bromide in the exhausted desorption solution was recovered as bromine by oxidation using Cl2.  相似文献   

流动注射HG-AFS法同时测定化探样品中的砷和汞     

王世东  王清全  周玉香  赵传杰 《吉林地质》2006,25(4):46-49

建立了流动注射HG-AFS测定痕量砷和汞的分析方法。把砷和汞放入20%的王水介质中,它们被硫脲-抗坏血酸预还原,待测量溶液澄清之后,将溶液与硼氢化钾一起导入反应器,产生的氢化物载气导入原子化器中测定,测定结果符合国家标准。本法改进了流动注射HG-AFS法测定砷、汞的分析方法。  相似文献   

Disposal of wastewater containing Congo Red by synthesizing layer double hydroxide in-situ     

朱荣崔康平  彭书传杨远盛陈天虎  安志环徐晓春 《中国地球化学学报》2006,25(4):390-394

Based on the principle of synthesis, a new method was put forward to dispose Congo Red anion-containing dyestuff from wastewater and its feasibility was also examined. The principle of the method is described as follows： Mg^2＋ and Al^3＋ are hydrolyzed to form Mg/Al-LDH by adding Mg^2＋, Al^3＋ and NaOH in wastewater containing anion dyestuff, which is selectively intercalated with the interlayer of LDH in order to balance positive structural charge. While Mg^2＋ and Al^3＋ are co-precipitated to form LDH, the anion dyestuff in wastewater will be removed by LDH synthesized in-situ, as is confirmed by X-ray diffraction analysis of settlings and chemical analysis of aqueous samples. In this work, we studied the influence of Mg/Al mole ratio, pH value, time and temperature of reaction on the removal of anion dyestuff and the use of Mg and Al. The experimental results showed the maximum removal efficiency of anion dyestuff could be attained when pH value was 9.0, and Mg/Al mol ratio was 2 ： 1, reaction duration was 2 hours, and the effect of temperature was not remarkable, and the removal efficiency could reach 100%. Meanwhile, the Mg and Al added could be made good use of. This technology has the advantage of extraordinary efficiency of wastewater disposal.  相似文献   

几种吸附剂吸附亚砷酸根离子过程中pH值的动态变化     

叶瑛  季珊珊  邬黛黛  张维睿 《高校地质学报》2006,12(2):228-233

观察了三种吸附剂吸附亚砷酸根离子过程中溶液pH值随时间的变化。氢氧化铁在吸附过程中的pH值变化大致可分为三个阶段，0～6分钟为第一阶段，体系的pH值快速上升，指示亚砷酸根置换了固相中的氢氧根；7～40分钟为第二阶段，pH值变化不大，指示Fe(OH)3凝胶对亚砷酸根离子的吸附达到动态平衡；40分钟后为第三阶段，溶液的pH值呈单边下降趋势，这一阶段吸附剂与被吸附的阴离子之间发生了缩合反应，并释放出H＋。Mg-Al-LDO在吸附亚砷酸根的反应过程中pH值持续上升，它具有从水溶液中获取阴离子以恢复其前驱体结构的能力，这一反应中有氢氧根生成；Mg-Fe-LDO兼有前两者的吸附机理，吸附反应过程pH值的变化趋势此介于二者之间。氢氧化铁在加热前后吸附容量变化不大，25C和90C时分别为69.7mg/g和73.7mg/g，而Mg-Al-LDO和Mg-Fe-LDO的吸附容量在25C时分别为62.4mg/g和82.5mg/g，在90C时分别增加到114.9 mg/g和199.0 mg/g。Mg-Al-LDO和Mg-Fe-LDO在90C条件下吸附容量的大幅增加，可能和溶解CO2的干扰被抑制有关。  相似文献   

ISORROPIA: A New Thermodynamic Equilibrium Model for Multiphase Multicomponent Inorganic Aerosols   总被引：16，自引：0，他引：16  

Athanasios Nenes  Spyros N. Pandis  Christodoulos Pilinis 《Aquatic Geochemistry》1998,4(1):123-152

A computationally efficient and rigorous thermodynamic model that predicts the physical state and composition of inorganic atmospheric aerosol is presented. One of the main features of the model is the implementation of mutual deliquescence of multicomponent salt particles, which lowers the deliquescence point of the aerosol phase.The model is used to examine the behavior of four types of tropospheric aerosol (marine, urban, remote continental and non-urban continental), and the results are compared with the predictions of two other models currently in use. The results of all three models were generally in good agreement. Differences were found primarily in the mutual deliquescence humidity regions, where the new model predicted the existence of water, and the other two did not. Differences in the behavior (speciation and water absorbing properties) between the aerosol types are pointed out. The new model also needed considerably less CPU time, and always shows stability and robust convergence.  相似文献   

Geochemical demobilization of metallic pollutants in solid waste—implications for arsenic in waterworks sludges     

U. Frstner  I. Haase 《Journal of Geochemical Exploration》1998,62(1-3)

During stabilization or demobilization of contaminants in solid waste materials, different approaches can be taken, which also can be combined: (1) sufficient long-term buffer capacity can be provided, according to the environmental conditions; (2) permeability for dissolved contaminants can be reduced by secondary mineral precipitations or by soft gels injected into the pore space of the waste body; and (3) new formations of ‘reservoir minerals' can incorporate potential pollutants in their internal structure. Emphasizing the geochemical engineering approach, two examples are presented from the field of water management, both focussing on the demobilization of arsenic species. The first example (after Driehaus, W., 1994. Arsenentfernung mit Mangandioxid und Eisenhydroxid in der Trinkwasseraufbereitung. Vol. 133, Ser. 15, VDI-Reports, Düsseldorf, 117 pp.) relates to the problems during purification of arsenic-rich raw water, suggesting the potential application of iron and manganese oxide minerals as oxidizing agents and mineral lattice structures for the elimination of arsenic. In the second example, contaminated sludges from water treatment plants were investigated for their leaching characteristics and long-term stability. A pH-stat test procedure was used to assess the leaching characteristics of metals at typical pH values. Due to the presence of iron and manganese oxides pentavalent arsenic is protected against conversion into the mobile trivalent form at neutral to low pH. Experimental data suggest that co-disposal with reducing organic matter and alkaline stabilization material or wastes could negatively influence the binding properties and, therefore, should be avoided.  相似文献   

Study of celestite flotation efficiency using sodium dodecyl sulfonate collector: factorial experiment and statistical analysis of data     

A. Martínez-L.  A. Uribe S.  F. R. Carrillo P.  J. Coreo A.  J. C. Ortiz 《International Journal of Mineral Processing》2003,70(1-4):83-97

Flotation tests of synthetic mixtures of celestite (SrSO₄) and calcite (CaCO₃) minerals using sodium dodecyl sulfonate as collector were carried out using a factorial experimental design 2³. The independent experimental variables included celestite grade in the feed (50% and 90% SrSO₄), conditioning pH (6.5 and 9) and sodium silicate depressant concentration (10⁻⁵ and 10⁻³ M). All experiments were performed at a constant collector concentration (10⁻⁴ M) and conditioning time of 15 min. The response variables were recovery and grade of SrSO₄ in the concentrate.The factors that had the greatest effect on the grade and recovery of celestite were the celestite grade in the feed (L) and the depressant concentration (C); also the combination of these factors significantly affected the response variables. The highest celestite yield (96% recovery, 98% grade) was obtained when a 90% of celestite grade in the feed was used.  相似文献   

锰的氧化物和氢氧化物在污染水体净化中的应用研究现状   总被引：17，自引：1，他引：17  

高翔  鲁安怀  郑辙  郑喜坤  秦善 《矿物岩石》2002,22(1):77-82

经过对锰的氧化物和氢氧化物在净化污染水体中的应用综合研究，发现该氧化物和氢氧化物样品能有效去除污染水体中的有毒有害金属离子和 氧化降解苯酚、2－丙醇、苯及印染废水等有机物，其污染净化能力主要是基于表面络合反应、表面离子交换作用和变价元素的氧化还原作用。同时介绍了锰氧化物和氢氧化物所具有的4个环境属性；离子交换、氧化还原、粒径效应和孔道效应，提出将结构特征与环境化学有机结合，深入探讨其环境属性与污染净化能力之间的关系是目前主要的研究方向。  相似文献