Fundamental aspects of biosorption of lead (II) ions onto a Rhodococcus opacus strain for environmental applications

Lead is present in different types of industrial effluents, being responsible for environmental pollution. Biosorption of heavy metal ions by biological material is a promising technology with a potential for treating mineral processing wastewater. In this fundamental work, the biosorption of Pb(II) ions from aqueous solutions using the bacteria Rhodococcus opacus was investigated as a function of contact time, initial metal ion concentration and temperature. The equilibrium studies showed that the biosorption is well described through the Langmuir isotherm model in comparison to the Freundlich model in the concentration range studied (20–200 mg/L). The biosorption capacity obtained from Langmuir equation increased from 86.2 to 95.2 mg/g as the temperature was increased from 15 to 35 °C. Experimental data were also tested in terms of biosorption kinetics using pseudo-first order and pseudo-second-order kinetic models. The result showed that the biosorption processes of lead ions followed well pseudo-second-order kinetics and the adsorption rate constant increased with increasing temperature. The activation energy of biosorption (E_a) was determined (30.4 kJ/mol) using the pseudo-second-order rate constants. The positive values of both ΔH⁰ and ΔS⁰ obtained suggest that the biosorption of lead (II) ion on the R. opacus was spontaneous and endothermic in nature.     

Assessment of bauxite refining residue (red mud) as a liner for waste disposal facilities

Red mud (RM), a waste arising from the bauxite refining, was studied to assess its suitability as a compacted liner material. The geotechnical and hydraulic conductivity (K) characteristics of the RM, as well as the effect of desiccation, were evaluated. RM has index properties satisfying the requirements to achieve low K. The compaction–permeability studies showed that RM may be compacted to a dense homogeneous mass using a moderate compactive effort, while lowest K (?1?×?10^?7?cm/s) was achieved for RM compacted slightly (0.4–4%) wet of optimum. Shear strength test revealed high values of friction angle and cohesion for compacted RM, and its tight structure was also evidenced by its low compressibility and maximum settlement under load. Desiccation adversely affected the permeability of compacted RM, but to a lesser extent than generally observed for clays. These results suggest that RM could be potentially utilised as a low-permeability barrier to be laid down under engineered landfill sites.     

离子液体在LiNi_(0.5)Mn_(0.25)Co_(0.25)O_2合成中的应用

采用离子液体[bmim]BF_4为模板剂,研究低热固相反应法合成钾电池电极材料.在试验中先合成离子液体[bmim]BF_4,接着采用正交试验方法进行低热固相反应法合成锂电极材料,通过数据挖掘获得了最佳的合成条件.用XRD,TG-DTA,IR及TEM表征在最佳条件下合成得到的产物,该产物为70nm左右、结晶良好的复合材料LiNi_(0.5)Mn_(0.25)Co_(0.25)O_2.     

专用型埋刮板输送机(Ⅰ)

介绍了８种用来输送某一种（或某一类）物料或在特定的工作场合下使用的专用型埋刮板输送机的特点及用途。     

Adsorption of Pb(II), Zn(II) and Cr(III) on coal fly ash porous pellets

In the present work the application of fly ash porous pellets as adsorbent of lead(II), zinc(II) and chromium(III) ions from aqueous solution was studied. Experiments were carried out using porous pellets developed from fly ash derived from Megalopolis, Greece coal-burning power plant. The material was shaped into spherical agglomerates, after wetting and tumbling in a laboratory scale granulator. The adsorption of heavy metals on fly ash pellets was studied as a function of the initial metal concentration, solution pH and temperature. Kinetic studies indicated that sorption follows a pseudo-second-order model. Adsorption isotherms of lead, zinc and chromium were determined for agglomerated material using the Langmuir equation. The adsorption capacity of fly ash pellets reached at 0.22 mmol Pb/g pellet, 0.27 mmol Zn/g pellet and 0.44 mmol Cr/g pellet. Furthermore adsorption from bimetallic solutions (Cr–Zn, Cr–Pb and Pb–Zn) took place in order to study presumable antagonistic effects on adsorption of heavy metals. Finally, the stabilization of metal saturated pellets was studied. The stabilization procedure took place in structures made of concrete, where 75% of cement was replaced by raw fly ash. The evaluation of the procedure through leaching tests showed excellent heavy metals stabilization in concrete blocks.     

Index to Volume 66 (1991)

The History of Mineral Collecting, with Notes on 1200 Early Mineral Collectors by Wendell E. Wilson, vol. 6, no. 6 issue of the Mineralogical Record. Published by the Mineralogical Record, P.O. Box 35565, Tucson, AZ 85740, 264 pages; 1994; $49 hardbound. $24 softbound (plus $1 postage and handling). Reviewed by Si and Ann Frazier

Software: MINLOG: The Gem and Mineral Collector's Information Manager by Beaver Software Development, Inc., P.O. Box 1608, Marietta, GA 30061–1608; $225 (demo disk $5). Reviewed by Dr. Robert Cook     

Application of modified polypropylene (crude) fibers concrete to strengthen the support structures in deep mine roadway

The an thors developed a new composite cement base material by mixing the high tenacity polypropylene (coarse) fiber in plain cement base for the cement-layer-spray technology. By studying the key parameters of the fiber dosage, the spray layer thickness, and the fiber reinforced concrete injection time, etc. It is found that the ideal volume ratio of polypropylene (crude) fiber is 0.8% (V/V), and the secondary lining fiber concrete spraying should start when the shrinkage rate is lower than 0.5 mm/d, and the optimal thickness of shotcrete is 120 mm. The supporting effects and the economic benefits were studied using a real project practice, and the result obtained can be a good reference for practical applications of this new supporting material in the future.     

Mechanism of aqueous uranium (VI) uptake by natural zeolitic tuff

The objective of this study was the examination of the ability of a natural zeolitic tuff to remove hexavalent uranium from aqueous solutions under various conditions. In order to achieve this goal, batch experiments were conducted to investigate the effect of pH, retention time, solid/liquid ratio and the presence of CO₃²⁻ and SO₄²⁻ ions in the solution. The results indicated that the natural zeolitic tuff is an effective material in the pH region 5–9 when the content of carbonates in the solution is controlled by the dissolution of the atmospheric carbon dioxide. In the case that the content of carbonates in the solution is controlled by geochemical processes and thus is enough high, the natural zeolitic tuff was proven an ineffective material. The interpretation of the results based on the aqueous chemistry of U(VI) containing aqueous solutions as well as on the physicochemical properties of the natural zeolite/solution interface indicates that the U(VI) uptake by the zeolitic tuff is attributed to an adsorption mechanism.     

Memory effects in rocks (review)

Conclusion The given review indicates that both in our country and abroad an active scientific search is being carried out in the area of memory effects of rocks. The results obtained confirm the prospects of using these effects in geocontrol, mainly for solving problems related to evaluating the space—time dynamics of the stress—strain state of rocks and to obtaining quantitative estimates of stresses in the mass.At the same time, it follows from an analysis of the material presented that the degree of study of various memory effects is different and decreases in accordance with the order of their examination in the present review.The absolute majority of works have an experimental character. Attempts at a theoretical interpretation of the observed effects are single and at present have not permitted creating physicomathematical models adequately explaining their nature and mechanisms.The regularities of memory effects under conditions of triaxial unequal-component loading of rocks are virtually unstudied. Furthermore, there are no unequivocal answers to questions: about the characteristics of manifestations of memory properties in rocks of various genetic groups and deposits; about the effect on these manifestations of the regimes of the initial (natural) action and secondary action directed at extracting the information contained in the memory; about the limiting (maximum and minimum) levels of thermodynamic actions which are still remembered by the rock; about the time of preservation of memory as a function of the level of noise effects of various physical nature, etc.The search for answers to these question today is hampered by the absence of unified method approaches in investigations of memory effects, without which a correct comparison and generalization of their results is impossible.The authors are grateful to Yu. M. Kartashov and L. L. Panas'yan for offering certain materials used in the present work.Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 5, pp. 57–69, September–October, 1994.     

新型煤矿用聚氯乙烯（硬）管材的研制

目前煤矿用的给排水管、正压风管、喷浆管和抽放瓦斯管等，长期以来主要采用的是各类金属管材，由于井下的使用环境恶劣，易腐蚀和生锈，维修和更换频繁，因此，金属管材的使用成本较高，铺设施工也比较麻烦。与金属管材相比，塑料管材有以下优点：(1)密度小，仅为铁的1／8，重量轻，易于煤矿井下搬运，降低工人劳动强度，提高工作效率；(2)耐化学腐蚀好，不生锈、不需要防腐处理；     

Comparing Approaches for Simulating the Reactive Transport of U(VI) in Ground Water

The reactive transport of U(VI) in a well-characterized shallow alluvial aquifer at a former U(VI) mill located near Naturita, CO, was predicted for comparative purposes using a surface complexation model (SCM) and a constant K _d approach to simulate U(VI) adsorption. The ground water at the site had U(VI) concentrations that ranged from 0.01 to 20 μM, alkalinities that ranged from 2.5 to 18 meq/L, and a nearly constant pH of 7.1. The SCM used to simulate U(VI) adsorption was previously determined independently using laboratory batch adsorption experiments. Simulations obtained using the SCM approach were compared with simulations that used a constant K _d approach to simulate adsorption using previously determined site-specific K _d values. In both cases, the ground water flow and transport models used a conceptual model that was previously calibrated to a chloride plume present at the site. Simulations with the SCM approach demonstrated that the retardation factor varied temporally and spatially because of the differential transport of alkalinity and dissolved U(VI) and the nonlinearity of the U(VI) adsorption. The SCM model also simulated a prolonged slow decline in U(VI) concentration, which was not simulated using a constant K _d model. Simulations using the SCM approach and the constant K _d approach were similar after 20 years of transport but diverged significantly after 60 years. The simulations demonstrate the need for site-specific geochemical information on U(VI) adsorption to produce credible simulations of future transport.     

A conditional fractal (fBm) simulation approach for orebody modelling

Abstract

Fractal methods provide scale-invariant approaches to modelling the in-situ variability of orebody attributes. Fractional Brownian motion (fBm) models are a specific class of random fractals that offer a fast and efficient way to generate simulations of pertinent orebody characteristics. fBm models are constructed using the Weierstrass-Mandelbrodt equation and a fractal co-dimension inferred from the available data. Unconditional fBm simulations can be further constrained to existing data to generate conditional simulations reproducing the (i) available data, (ii) data statistics, and (iii) power law variogram and fractal co-dimension. The computational efficiency of the conditioning process is improved based on dual kriging. Testing conditional fBm simulation in a controlled environment indicates that it is an efficient approach to generating multiple realisations, when the available conditioning data is in the order of several hundred. The efficiency and performance of the approach suggest that it may be particularly suitable for delineating ore/waste boundaries and grade control.     

微波作用下温度对白云鄂博稀土铁矿固氟效率的影响

针对白云鄂博稀土铁矿在“选冶”过程中的固氟问题,以白云鄂博稀土铁矿为原料,通过XRD、化学检测、单因素实验以及红外光谱拟合分析法,研究了在微波作用下碳酸氢钠在不同温度下的固氟效果。实验结果表明最佳固氟温度条件为： 973.1K,在碳酸氢钠占比40%、焙烧恒温时间60min时可获得固氟率最高为83.49%；利用傅里叶红外光谱以及二阶导光谱法定量分析焙烧固氟矿物,结果表明：随焙烧温度的升高,氟化钠的吸收峰峰峰面积呈现递增趋势,温度873.1K、973.1 K分别与773.1 K相比增加了109.27%、120.16%,在973.1K焙烧温度下的氟化物含量较多且有稳定的红外吸收峰；同时,加入钠剂的固氟宏观反应过程符合Avrami-Erofeev动力学模型,属于随机成核及随后生长的化学反应控制,表观活化能为58.19 KJ/mol。该实验结论,对于开发白云鄂博稀土铁矿绿色回收工艺,具有参考研究价值。     

Optimierte Herstellungs- und W?rmebehandlungsparameter walzplattierter Magnesium(AZ31)-Aluminium(1050)-Verbundwerkstoffe

The roll cladding-process enables the combination of material properties of aluminium and magnesium. This paper focuses on the development of a material compound of Mg(AZ31) and Al(1050). Sensitivity analyses, in combination with special testing methods, make it possible to find optimal manufacturing parameters. With attention to prospective applications of the compound, mechanical values and thermomechanical characterisation using a Gleeble-3800-system were additionally performed. The important interface zone between the metal multilayers was analysed systematically by scanning electron microscope (SEM) and micro hardness testing. Based on this information important conclusions about the hot forming process and the thermal treatments can be derived.     

Stress-field evaluation by geostructural and geomechanical prospection: The case history of the machaerus rock-mass (Hashemite Kingdom of Jordan)

On the bases of a field geostructural and geomechanical survey, we evaluate the stress field and structural regime responsible for the deformation of the rock-mass in the Machaerus area, the Hashemite Kingdom of Jordan, on the eastern side of the Dead Sea Transform Fault. The resulted data are compared to those from deep mines and base tunnels in order to evaluate the potentiality of using geostructural data to envisage the stress-field for new geoengeneering projects. It resulted the Machareus rock mass was deformed at a depth of about 500–900 m with a deviatoric stresses of the order of σ ₁ =15 MPa, σ ₂ =10 MPa and σ ₃ =−25 MPa, being σ ₃ vertical. The stress field orientation is consistent with the left-lateral kinematics of the nearby Dead-Sea transform fault.     

膨润土基复合材料在废水处理中的应用研究进展

膨润土储量大、分布广、物理化学特性优良,广泛应用于工业废水处理。但是天然膨润土及改性膨润土直接作为吸附剂,存在着吸附容量小、固液分离难等缺点。为弥补这些缺陷,近年来研究者以膨润土或者改性膨润土为基底制备膨润土基复合材料并将其运用到废水处理。本文综述了改性膨润土和膨润土基复合材料的制备方法,以及其在无机和有机废水处理中的应用和循环再生性能的研究进展。目的是为开发新型、高效的膨润土基复合材料及其在废水处理中的应用提供思路与方法。      

Simulation of Action of Chemically Active Gas Jets on the Failed Material

The efficiency of action is shown for chemically active jets under low pressures of deceleration (10 ⁵– 10 ⁶Pa/). The experiments make it possible to isolate filtration of chemically active jet substance into the material failed as one of the main processes of the phenomenon under investigation.     

金刚石复合片(PDC)的缺陷分析及优化制备

针对高温高压(HPHT)合成金刚石复合片(PDC)常出现的缺陷问题, 对PDC腔体组装及制备工艺进行了优化。结果表明, 稳定均一的温度、压力场以及适量的烧结助剂是合成优质PDC的关键。在HPHT条件下(5.2～5.6 GPa, 1 400 ℃, 5 min), 通过选用传压保温效果好的绝缘坩埚及屏蔽材料作为腔体组装, 采用Ni、Fe基合金高压熔渗法及保压慢降温工艺, 成功制备了Φ8、Φ15 mm的PDC, 其具有致密的组织结构, 缺陷几率明显降低; PDC磨耗比为10⁴数量级, 热稳定温度约为800 ℃, 金刚石层具有较低的残余压应力(低于0.16 GPa)。最后选用优质PDC样品进行了刀具试制, 刀具的实际使用效果良好。     

Solvent extraction of gold(I) from alkaline cyanide solutions by the cetylpyridinium bromide/tributylphosphate system

This paper explores the solvent extraction of KAu(CN)₂ from alkaline cyanide solutions using quaternary ammonium cetylpyridinium bromide (CPB) as an extractant with the addition of tributylphosphate (TBP) as a modifier. It also investigates the influence of several variables on gold extraction, including the molar ratio (β) of CPB to Au(I), the volume percentage of TBP (φ_TBP), NaCl concentration, phase ratio (AQ/ORG), and gold concentration in the aqueous phase. The results indicate that nearly all of the Au(I) (>98%) was transferred from the aqueous phase into the organic phase when β = 1 and φ_TBP = 30 vol%. We also carried out experiments for treating 20 L synthetic aurocyanide solution containing 10 mg/L Au(I) with column-shaped extraction equipment. The results demonstrated the recovery of more than 94.5% of Au(I) after two successive stages of extraction, and the Au(I) concentration in the raffinate was less than 0.5 mg/L. KSCN solution was used to strip the gold-loaded organic phase, and about 90% of Au(I) could be reverse extracted into the aqueous phase when the KSCN concentration reached 3.0 mol/L. The results obtained in this paper establish that the CPB/TBP extraction system has potential for practical application in the extraction and separation of gold from alkaline aurocyanide solutions.     

Review of Benthic Invertebrate Fauna in Extremely Acidic Environments (pH ≤ 3)

Some benthic invertebrate species are able to colonise habitats in extremely acidic waters. We compiled a list of acid-resistant benthic invertebrates from the literature and extended it by studying extremely acidic mining lakes in eastern Germany. Acid-resistant species were registered for some habitats with pH ≤ 3, such as volcanic lakes, acid strip streams, and acidic mining lakes. Twenty nine taxa were found in waters with pH below 3. Diptera comprised 48.3% of the total number of taxa, followed by Coleoptera with 10.3%, Trichoptera 10.3%, Ephemeroptera, Megaloptera, and Plecoptera each with 6.9%, and Odonata, Hirudinea, and Acari each with 3.5%. Chironomus (Diptera: Chironomidae) were the most common genus in extremely acidic environments with 9 species. In Germany, Chironomus crassimanus was found to be the most abundant species in extremely acidic mining lakes. Generally, aquatic insects were the most common group of benthic invertebrates.