Mineralogical and geochemical alteration of Hitura sulphide mine tailings with emphasis on nickel mobility and retention     

Päivi M. Heikkinen  Marja L. Räisänen 《Journal of Geochemical Exploration》2008

Weathering of Hitura (W Finland) nickel sulphide mine tailings and release of heavy metals into pore water was studied with mineralogical (optical and electron microscopy, X-ray diffraction) and geochemical methods (selective extractions). Tailings were composed largely of serpentine, micas and amphiboles with only minor carbonates and sulphides. Sulphides, especially pyrrhotite, have oxidized intensively in the shallow tailings in 10–15 years, but a majority of the tailings have remained unchanged. Oxidation has resulted in depletion of carbonates, slightly decreased pH, and heavy metal (Ni, Zn) release in pore water as well as in the precipitation of secondary Fe precipitates. Nevertheless, in the middle of the tailings area, where the oxidation front moves primarily downward, released heavy metals have been adsorbed and immobilized with these precipitates deeper in the oxidation zone. In contrast to what was seen in pore water pH, but in accordance with static tests of the previous studies, the neutralisation potential ratio (NPR) calculated based on the mineralogical composition and the total sulphur content suggested that tailings are ‘not potentially acid mine drainage (AMD) generating’. However, the calculated buffering capacity of the tailings resulted largely from the abundant serpentine because of the low carbonate content. Despite its slow weathering rate, serpentine may buffer the acidity to some extent through ion exchange processes in fine ground tailings. Nevertheless, in practice, acid production capacity of the tailings depends primarily on the balance between Ca–Mg carbonates and iron sulphides. NPR calculation based on carbonate and sulphur contents suggested, that the Hitura tailings are ‘likely AMD generating’. The study shows that sulphide oxidation can be significant in mobilisation of heavy metals even in apparently non-acid producing, low sulphide tailings. Therefore, prevention of oxygen diffusion into tailings is also essential in this type of sulphide tailings.  相似文献   

内蒙古西河盆地新近纪“红土”记录的沉积环境          下载免费PDF全文

孙黎明杨用彪  吴云霞方晓峰李路华  李耀辰赵永峰 田立富 《中国地质》2008,35(4):683-690

笔者从岩性地层、孢粉组合、地层对比等方面,对西河盆地红层的地层时代与沉积环境,进行深入的研究和探讨并追朔其地质演化历程。本区首次发现的孢粉组合是以草本植物蒿属为优势种,松、胡桃及禾本科为次优势种的疏林灌丛草原,其中胡桃属、榆属为典型的古—新近纪属种。根据岩性特征及生物特征综合分析研究,认为西河盆地“红土”地层属于新近系上新统宝格达拉组（N2b）,地层层序类型在平面上体现出从盆地边缘到中心沉积环境由河流、冲积扇、三角洲到湖泊的变化规律。  相似文献   

Modelling the equilibrium speciation of nickel in the Tweed Estuary, UK: Voltammetric determinations and simulations using WHAM     

Andrew Turner  Manuela Martino   《Marine Chemistry》2006,102(3-4):198-207

The complexation of dissolved Ni has been evaluated in a rapidly-flushed, rural estuary (Tweed, UK) by ligand exchange-adsorptive cathodic stripping voltammetry. Results suggest the presence of strongly binding ligands, L, throughout, with average stability constants of about 10¹⁹ and which are saturated by ambient Ni concentrations. Equilibrium speciation calculations incorporating these constants in WHAM, version 6, predict an increase in Ni complexation (as NiL) from about 50% of total dissolved Ni in fresh water to over 90% in sea water. Equivalent calculations using the default-mode fulvic and humic substances (FS and HS, respectively) encoded in the WHAM database predict a reduction in complexation (as NiFS + NiHS) from about 20% in fresh water to less than 1% in sea water. Discrepancies arising from the two approaches are largely attributed to the different analytical detection windows employed. Thus, a better representation of Ni complexation is derived from including both types of complexant in the speciation calculations, resulting in estimates of net complexation in excess of 60% of total dissolved Ni throughout the estuary. The uncertainties and assumptions inherent in all computations illustrate the difficulty in measuring or predicting metal complexation in estuaries.  相似文献   

Environmental aspects of selected trace metals in soils and waters surrounding Singaran Nala, Raniganj Coalfield     

Supriyo Das 《中国地球化学学报》2006,25(B08):24-25

The Raniganj Coalfield is the oldest coalfield in India that has been continuously and extensively mined since the late eighteenth century. The present study reports a geochemical investigation and environmental quality assessment using soil and water in the area surrounding a stream, locally known as Singaran Nala （Nala means storm water drains in Bengali）, in the Raniganj Coalfield. Soil （top soil, mud, silty clay and laterite） and rock samples （sandstone and shale） were collected from the study area and were analyzed for trace metals （Cr, Cu, Fe, Mn, Ni and Zn）. Surface waters from the stream and the Damodar River as well as ground waters from hand pumps and underground mine pits were collected. Water samples were analyzed for major ions （Na^＋, Ca^2＋, Mg^2＋, Cl^-, HNO3^- and SO4^2-） and trace metals （Cu, Fe, Mn, Ni, and Zn）. Trace metal concentrations in soil samples are found higher than the average world soil composition. Nevertheless, trace metal （Cr, Cu, Ni and Zn） concentrations in soils exceed or reach the maximum allowable concentrations （MAC） proposed by the European Commission for agricultural soils. In particular, Ni concentrations exceed the typical value for cultivated soils. Chromium, Cu and Ni concentrations in laterite and Cr concentration in topsoil exceed the ecotoxicological limit.  相似文献   

Deformability characteristics of brazilian laterites     

Jacques De Medina  Laura M. G. Motta  João D. G. Dos Santos 《Geotechnical and Geological Engineering》2006,24(4):949-971

This paper summarizes the resilient and permanent deformation characteristics of laterite gravels, determined by cyclic loading in triaxial tests of compacted specimens. A study of laterite pavements was carried out on eight paved road sections in the state of Mato Grosso. Also reported is the influence of fine sand admixture, specimen size and soaking in two laterite samples from Roraima and Rondônia in the North of Brazil. The experimental relationships of resilient moduli against applied stresses are interpreted empirically for models what may be incorporated in a structural analysis of full depth of laterite pavement.  相似文献   

碳酸盐岩红土中1．4nm间层矿物及其环境意义     

朱立军 《矿物岩石地球化学通报》1996,(3)

碳酸盐岩红土中１．４ｎｍ间层矿物及其环境意义朱立军（贵州工学院，贵阳５５０００３）关键词红土，间层矿物，土壤环境１．４ｎｍ间层矿物是指由绿泥石晶层与２：１型含水膨胀层交互连生所构成的不规划间层粘土矿物，其中２：１型含水晶层可以是蒙脱石层，也可以是蛭石...  相似文献   

Effect of chemical fertilizers on the fractionation of Cu,Cr and Ni in contaminated soil   总被引：1，自引：0，他引：1  

Jie Liu  Chang-Qun Duan  Yi-Nian Zhu  Xue-Hong Zhang  Cheng-Xian Wang 《Environmental Geology》2007,52(8):1601-1606

Effect of chemical fertilizers (urea, NH₄Cl, Ca(NO₃)₂, KCl and KH₂PO₄) on the fractionation of Cu, Cr and Ni was studied by a 4-month incubation experiment. Using sequential extraction procedure, it was found that the application of fertilizers could change the distribution of Cu, Cr and Ni in the fractions of soil. Applying urea (CO(NH₂)₂) significantly decreased the concentrations of Cu, Cr and Ni in water soluble plus exchangeable (WE) fraction, but increased those in Fe–Mn oxides bound (FM) fraction (p < 0.01). However, application of NH₄Cl caused an increase in the WE fraction by 27.7% for Cu, 111.5% for Cr and 20.4% for Ni. The CO(NH₂)₂ raised the soil pH from 4.51 to 4.96, whereas NH₄Cl lowered the pH of soil by 0.44 units. The WE fraction of the three heavy metals was significantly increased, while the FM fraction was significantly decreased by adding KCl (p < 0.01). Moreover, the supply of KH₂PO₄ reduced the WE and carbonate bound (CB) fractions of Cu, Cr and Ni in the soil, however, it raised Cu and Ni in the residual (RS) fraction and Cr in the FM fraction. In addition, the mobility index indicated that KCl and NH₄Cl increased the mobility of Cu, Cr and Ni in the soil, whereas urea and KH₂PO₄ decreased the mobility of the three metals in the soil. These results suggest that applying chemical fertilizers does not only provide plant nutrients, but may also change the speciation and mobility of heavy metals in the soil.  相似文献   

红土型金矿床综述(英文)   总被引：1，自引：0，他引：1  

Zang Weisheng  William S.Fyfe  Chen Yuan 《现代地质》2001,15(2):142-150

近二十年来 ,热带地区普遍存在的红土型风化作用及其对矿床与矿化带的影响引起了普遍的关注。红土型风化壳的主要矿物成分是以铁铝的氧化物及氢氧化物和粘土矿物为主 ,如针铁矿、赤铁矿、铝土矿、高岭石及石英等 ,与其未风化的母岩相比 ,含有相当高的铁和铝。红土型风化过程中 ,易溶元素均不同程度地被淋滤 ,而难溶元素则相对富集。红土型金矿床就是在这样强烈的风化作用中由原生的金矿化带进一步富集而成 ,并可形成极富的矿体。金矿体常常赋存于风化壳的上部 ,易于露天开采。目前 ,在澳大利亚、巴西、巴布亚新几内亚、印度以及非洲的一些国家均发现了红土型金矿床。红土型风化剖面一般可分为 5个特征带 ,由上而下为 :表土带、铁质带、斑点带、浅色带、腐岩带 ,下面即为未风化的母岩 ,金矿体主要赋存于铁质带和斑点带中。红土型风化壳厚度变化很大 ,薄则几米 ,厚可达数百米。金在风化过程中往往向矿化带两侧运移 ,矿体常呈上宽下窄状。次生金常呈自形晶、树枝晶、浑圆状及不规则状产出 ,并常常与铁质结核共生。一般地说 ,次生金的成色很高 ,因为红土型风化作用常常是在氧化并且酸性的地球化学环境中进行 ,金和银主要以氯化物的形式运移 ,局部地球化学环境的变化可导致金的沉淀 ,而银的氯化物则较稳定 ,?  相似文献   

碳酸盐岩红土风化壳主要特征及红土成因探讨—以贵州典型剖面为例   总被引：12，自引：0，他引：12  

李景阳  朱立军  梁风 《水文地质工程地质》2001,28(5):7-11,16

本文总结提出了碳酸盐岩风化壳成因证据及其演化特点，对风化壳红土成因进行了讨论。  相似文献   

中国红土型金矿床研究综述   总被引：9，自引：1，他引：8  

曹新志 《地质科技情报》1998,17(1):50-54

对红土型含矿床的勘查现状,矿化特征及成矿规律进行了探讨和总结,认为它形成于第三系－第四系红土风化壳内,可包括狭义的铁帽型金矿床,;概述了红土型金矿床的有效勘查方法和具体勘查方案。  相似文献