The Geochemical Behaviour of Mine Tailings from the Touiref Pb–Zn District in Tunisia in Weathering Cells Leaching Tests

Flotation tailings associated with the extraction of Pb and Zn in the Touiref mining district, Tunisia, contain galena, sphalerite, pyrite, and marcasite in a carbonate gangue. The geochemical behaviour of oxidized and unoxidised tailings were consistent with their mineralogical and chemical characteristics. The leaching proceeded under neutral to slightly alkaline condition (pH 7.3–8.5), and positive Eh (250–470 mV). The concentrations of sulfate and Ca released during the leaching tests were associated with the neutralization of acidity by carbonates and the dissolution of gypsum initially present in the tailings. The iron precipitated, but significant amounts of Zn (5–3,300 μg/L), Cd (3–18 μg/L), and Pb (28–83 μg/L) were released during leaching, with the latter two exceeding international environmental norms (5 μg/L for Cd and 10 μg/L for Pb).     

Tailings Weathering and Arsenic Mobility at the Abandoned Zgounder Silver Mine,Morocco

The abandoned Zgounder Mine (Morocco) was exploited for Ag from 1982 to 1990 and generated nearly 490,000 t of mill tailings before it was closed without being reclaimed. The tailings contain low concentrations of sulfide (mainly as pyrite, sphalerite, and galena) and carbonates (mainly dolomite). Silicates (muscovite, albite, chlorite, labradorite, actinolite, and orthoclase) occur in high concentrations. The most abundant trace elements are As, Ti, Fe, Mn, Zn, and Pb. We studied the geochemical behavior of the mine wastes to identify the main factors controlling drainage water chemistry. Particular emphasis was put on sorption phenomena to explain the low As concentrations in the leachates despite significant As levels in the tailings. Weathering cell tests carried out on various tailings produced two types of contaminated drainage: acidic and neutral. The kinetic test leachates contained high concentrations of some contaminants, including As (0.8 mg L^?1), Co (11 mg L^?1), Cu (34 mg L^?1), Fe (70 mg L^?1), Mn (126 mg L^?1), and Zn (314 mg L^?1). Acidity and contaminants in the leachates were controlled by dissolution of soluble salts and Fe hydrolysis rather than sulfide oxidation. Batch sorption tests quantified the significance of As sorption, and sequential extraction showed that most of the As sorption was associated with the reducible fractions (Fe and Mn oxides and oxyhydroxides).     

Assessment of Metals Pollution from Tailing Sites in the North Caucuses Region,Russia

The concentrations of metals were determined in the water and bottom sediments of both the Urup and Kuban Rivers near tailings sites in the North Caucasus region of southern Russia. The average concentrations in the Urup followed the order Fe?>?Mn?>?Pb?>?Cu?>?Zn?>?Cd?>?Ni?>?Co, while in the Kuban, the order was Fe?>?Pb?>?Zn?>?Ni?>?Mn?>?Cd, with copper and cobalt not detected. The levels of Zn, Cu, Pb, Cd, and Ni were above Russia’s maximum permissible concentration in both rivers. The water pollution index (WPI) values in Urup ranged from 12.97 to 28.17, indicating that the river is extremely polluted (Class VII), while the WPI value for Kuban ranged from 2.34 to 4.33 downstream of the tailings site, which corresponds to Class IV (contaminated). Calculating the coefficient of accumulation in sediments (CAS) revealed that in Urup, the CAS values for Ni and Cu were 3046 and 11638, respectively, which indicates an emergency environmental situation, while for Co, Fe, and Mn, the situation is high level chronic pollution (CAS?>?10⁴). The Kuban CAS values of Fe and Mn were also >?10⁴, again highly and chronically polluted. Most of the metals in both rivers are bound to the sediments, with minimal mobility. The potential ecological risk is moderate to considerable in Urup, and low in the Kuban River.     

Tailings Mineralogy and Geochemistry at the Abandoned Haveri Au–Cu Mine,SW Finland

Fourteen samples from the Haveri Au–Cu mine tailings were studied by reflected-light microcopy, scanning electron microscopy, X-ray powder-diffraction, and sequential extraction methods, and 12 water samples were analyzed for total and dissolved elements to delineate the extent of sulfide oxidation and its impact on nearby surface waters. Water-soluble, adsorbed-exchangeable-carbonate (AEC), Fe (oxy)hydroxides, Fe oxide, and Fe sulfide fractions were extracted sequentially. The oxidation layer was found to vary from 50 to 140 cm: the upper part was nearly depleted in primary sulfides, especially pyrrhotite [Fe_(1?x)S] and pyrite (FeS₂); in the lower part, discontinuous cemented layers were detected. Secondary Fe (oxy)hydroxides and Fe oxyhydroxysulfates were abundant in the oxidation layer and were slightly enriched in trace elements, including As (up to 80 mg/kg), Cu (300 mg/kg), and Zn (150 mg/kg). Almost half of the As (average 25 mg/kg) were present as secondary minerals susceptible to redissolution. The pH of the vadose tailings varied from 2.46 to neutral, and the total sulfur content varied from 1 to 6.5% (average 2.9%). Aqua regia extraction showed that the Haveri tailings are characterized by low concentrations of the elements Cd, Cr, Pd, and slightly elevated concentrations of As, which are present at very low concentrations in the surface water (<6 μg/L). However, runoff that flows on top of the tailings and discharges into the nearby lake carries Co, Cu, Ni, and Zn (concentrations of each range from 500 to 1,800 μg/L). Additionally, dissolution of sulfides and Fe precipitates may mobilize trace metals in the ground water. Thus, overall, there is a small continuous release of AMD into Lake Kirkkojärvi, but the environmental impacts to the lake are presently small.     

The Impact of Mine Tailings on the Witwatersrand and the Surrounding Water Bodies in Gauteng Province,South Africa

The gross alpha and beta activity in treated water from one of the numerous gold mines in Gauteng province averaged 1.15?±?0.13 and 0.87?±?0.11 Bq L^?1, respectively. The average readings of the fissure water from the same mine were 0.56?±?0.10 and 0.52?±?0.11 Bq L^?1, respectively. Water samples collected at the foot of the Princess gold mine tailings dump in Gauteng province and from downstream, before the drainage joins other water sources, also had high average gross alpha and beta activity and high average concentrations of radionuclides. The hazard quotient value evaluated, based on ²³⁸U of the water sample types in these vicinities, was far above one, indicating that it may pose serious health risks to the inhabitants.     

Influence of Past Mining on the Quality of Surface Waters at Funtana Raminosa (Sardinia)

Cu–Pb deposits at Funtana Raminosa in Central Sardinia were intensively exploited, mostly underground, from 1917 until 1983. Flotation tailings were dumped near the mine plant. A hydrogeochemical survey carried out in 2004 showed that mine drainage collected from several galleries was circumneutral, due to the availability of carbonate minerals that buffer the acidity produced by the oxidation of Fe-bearing sulphides. The mine waters contained higher concentrations of dissolved SO₄, F, Zn, Cd, Pb, Mn, and Mo than was observed in uncontaminated spring and stream waters in the area. Drainage from the oldest flotation tailings showed much lower concentrations of Zn, Cd, and Pb than those generally observed in mine waters. In contrast, drainage from the recent flotation tailings had the highest levels of dissolved SO₄, Zn, and Cd (1,600, 30, and 0.8 mg/L, respectively) when sampled in the dry season; these were two orders of magnitude lower in the rainy season under high flow condition. Pb was ≈ 5 μg/L under different flow conditions. Water in the Rio Saraxinus, a stream that drains the entire mining area, had a relatively low level of contamination (170 μg/L Zn, 7 μg/L Cd, and 0.9 μg/L Pb).     

Hydrogeochemistry and Contamination of Trace Elements in Cu-Porphyry Mine Tailings: A Case Study from the Sarcheshmeh Mine,SE Iran

Geochemical and hydrochemical investigations were performed to understand the contamination potential of the Sarcheshmeh mine tailings. The geochemical mobility for the tailings is as follows: Cu > Cd > Co > Zn > Ni > Mn > S > Cr > Sn > As > Se > Fe = Bi > Sb = Pb = Mo. Highly mobile and contaminant elements (Cd, Cu, Zn, Mn, Co, Ni, S, and Cr), which significantly correlated with each other, were mainly concentrated in the surface evaporative layer of the old, weathered tailings, due to the high evaporation rate, which causes subsurface water to migrate upward via capillary action. The contamination potential associated with the tailings is controlled by: (1) dissolution of secondary evaporative soluble phases, especially after rainfall on the old weathered tailings, accompanied by low pH and high contamination loads of Al, Cd, Co, Mg, Cr, Cu, Mn, Ni, S, Se, and Zn; (2) processing of the Cu-porphyry ore under alkaline conditions, which is responsible for the high Mo (mean of 2.55 mg/L) and very low values of other contaminants in fresh tailings in the decantation pond; (3) low mobility of As, Fe, Pb, Sb, Mo, and Sn due to natural adsorption and co-precipitation in the tailings oxidizing zone. Speciation modeling showed that sulfate complexes (MSO₄ ⁺, M(SO₄)_(aq), M(SO₄) ₂ ^?2 , and M(SO₄) ₂ ^? ) and free metal species (M⁺² and M⁺³) are the dominant forms of dissolved cations in the acidic waters associated with the weathered tailings. In the alkaline and highly alkaline waters, trace element speciation was controlled by various hydroxide complexes, such as M(OH)⁺, M(OH) ₃ ^? , M₃(OH) ₄ ⁺² , M₂(OH) ₃ ⁺ , M(OH)_2(aq), M(OH) ₄ ^?2 , Me(OH) ₂ ⁺ , Me(OH) ₄ ^? , Me(OH) ₂ ⁺ , Me(OH)_3(aq), and Me(OH) ₄ ^? (where M represents bivalent and Me represents trivalent cations). The speciation pattern of As, Mo, and Se is mainly dominated by oxy-anion forms. The obtained results can be used as a basis for environmental management of the Cu-porphyry mine tailings.     

Geochemical and Mineralogical Characterization of a Pyritic Waste Pile at the Anjir Tangeh Coal Washing Plant, Zirab, Northern Iran

Coal washing at the Anjir Tangeh plant, in Zirab, northern Iran, has produced more than 1.5 Mt of coal wastes. These waste materials were geochemically and mineralogically characterised to guide development of an appropriate remediation scheme. Three vertical trenches up to 4 m deep were excavated from the coal waste pile surface and 25 solid samples were collected at 0.5 m intervals. The samples were analysed for total concentrations of 54 elements, paste pH, SO ₄ ^?2 , CO ₃ ^?2 , and HCO₃ ^?. The lowest pH values were measured at a depth of 0.3 m. The upper portion (1 m) of one profile was moderately oxidised, while oxidation in the other two profiles did not extend more than 0.8 and 0.5 m beneath the pile surface. The waste piles have low acid-producing potential (15–21.87 kg CaCO₃/t) and high values of acid-neutralizing potential (0.06–96.2 kg CaCO₃/t). Fe, Al, S, Na, Mn, Pb, Zn, Cd, and Ag increased with increasing depth, while Mo, Sr, Zr, and Ni decreased with increasing depth. The results show pyrite oxidation at depth and subsequent leaching of the oxidation products. Mn, Zn, Cu, Pb, Ag, and Cd are the most important contaminants of concern at this site.     

煤矸石对铜尾矿中重金属(Zn,Pb,Cd,Cr和Cu)形态及生物有效性的影响

铜尾砂堆积在地表会随着淋溶和风化作用溶出重金属元素,对环境产生一定危害,其生态修复的关键是进行基质改良,进行植物修复。通过黑麦草盆栽实验,将淮南煤矸石添加入铜尾砂,探讨矸石对铜尾砂中重金属行为的影响。结果表明:矸石添加能显著提高铜尾砂p H、有机质和养分水平(总氮、总磷和总钾),缓解尾矿砂贫瘠环境。矸石添加后,铜尾砂中Zn,Pb,Cd和Cu的交换态和碳酸盐结合态重金属逐步向铁锰结合态、有机结合态和残渣态转化(除个别处理Pb和Cu残渣态),铜尾砂中有效态Zn,Pb,Cd和Cu浓度不断降低,从而降低了黑麦草中相应重金属浓度,总体表现为铜尾砂-黑麦草系统内Zn,Pb,Cd和Cu生物活性降低效应。然而,由于矸石中Cr浓度相对铜尾砂偏高,其添加会引起尾矿砂中有效态Cr浓度及Cr迁移性增加而增大黑麦草对Cr的吸收。因此,煤矸石可对尾矿砂中Zn,Pb,Cd和Cu产生一定稳定化作用,而虽然矸石内源性Cr会释放到铜尾砂,其也可被黑麦草富集,由此,煤矸石可视为一种潜在的废弃物改良剂,对铜尾砂具有一定生态改良潜力。     

银铅无碱混选工艺分选含银低品位铅锌硫化矿石

对某含银低品位铅锌硫化矿进行了选矿工艺流程的试验研究.根据矿石性质,采用银铅混选(银铅粗精矿再磨)-锌浮选和银铅混选(银铅中矿再磨)—锌浮选两种原则工艺流程进行试验研究,银铅混选时,采用选择性的银铅捕收剂组合BK906+BK903G在近中性的无碱条件下将银矿物和硫化铅矿物浮出,获得银铅混合精矿;然后通过常规的石灰+硫酸...     

Chemical Fractionation and Contamination Intensity of Trace Elements in Stream Sediments at the Sarcheshmeh Porphyry Copper Mine, SE Iran

This paper presents chemical fractionation and contamination intensities of trace elements in stream sediments at the Sarcheshmeh mine, southeastern Iran, which is one of the world’s largest Oligo-Miocene porphyry copper deposits. Evaluation of environmental pollution indices and maximum probable background concentrations revealed that As, Cu, Cd, Mo, Pb, Sb, Se, S, and Zn are highly concentrated in the contaminated sediments, while Cr, Co, Ni, Fe, and Mn show lower enrichment values. Discharges of industrial effluents (especially those contaminated by tailings), reject waste from the semi-autogenous mill, and rock waste drainages are the main anthropogenic contaminant sources. High values of As, Cu, Fe, Mo, Pb, and Zn were associated with the oxidizable, primary sulfide, and residual sediment fractions. Relatively high percentages of Co (>92?%), Cr (>58?%), Cu (>79?%), Fe (>40?%), Mn (>97?%), Ni (>87?%), and Zn (>83?%) in the sediments associated with the rock waste drainages were readily released during the extraction of water-soluble, exchangeable, and carbonate fractions. Sediments that received reject waste drainages were also polluted by As (>351.7?mg?kg^?1), Cu (>1.58?%), Mo (>91.8?mg?kg^?1), Pb (>291.8?mg?kg^?1), and Zn (>762.4?mg?kg^?1). A large percentage of these contaminants were found to be adsorbed and co-precipitated with amorphous Fe-oxides and carbonate phases. The chemical fractionation pattern of the potentially hazardous trace elements corresponded well with the mineralogical composition of the contaminated sediments.     

铅锌尾矿氧化过程中重金属释放迁移动态

铅锌尾矿堆放造成矿山周边环境严重污染,为研究尾矿安全堆放并在堆放过程中去除一定量重金属,以广西大厂鲁塘铅锌尾矿为研究对象,研究在不同氧化剂浓度和不同液固比条件下Zn、Cd、Pb、Cu和As的释放迁移能力。结果表明:氧化环境可以有效促进各元素的释放迁移能力,氧化剂浓度越高各元素迁移出的量也越多;各元素较佳释放迁移的液固比不同,Zn元素的最适合固液比为1∶10,Cd元素的最适合固液比为1∶6,Pb元素的较适合固液比为1∶6,Cu元素的较适合固液比为1∶5,As元素的较适合固液比为1∶6。      

Pilot-scale Studies of Different Covers on Unoxidised Sulphide-rich Tailings in Northern Sweden: the Geochemistry of Leachate Waters

Abstract.  Leachate water quality from covered and uncovered unoxidised sulphide-rich tailings in six pilot-scale (5x5x3 m³) test cells was monitored during 2004 and 2005. The covers consisted of a layer of clayey till, sewage sludge, apatite or Trisoplast (a commercial mixture of tailings, bentonite, and a polymer). All layers were protected by an unspecified till except in one reference cell, where the tailings were left open. All leachate waters showed near-neutral pH as a result of neutralization by calcite in the tailings and by Ca(OH)₂ added prior to deposition. Average dissolved sulphur concentrations in the leachates were ≈ 600 mg L^-1, except in the cell with sewage sludge (300 mg L^-1). The source of sulphur was mainly pyrite oxidation, but residual sulphur probably remained from the enrichment process. The near-neutral pH favoured precipitation of metal-(oxy)hydroxides with subsequent removal of trace elements such as Cd, Cu and Pb (< 15 μg L^-1) from the solutions. High concentrations of Co, Mn, Ni, and Zn were found in leachates from the apatite, Trisoplast, and uncovered tailings cells. High As concentrations were found in the leachates in the sewage sludge and clayey till cells. The lowest metal concentrations, redox potential, and highest pH were found in the sewage sludge cell. Decreased elemental metal concentrations during 2004 suggest improved performance over time.     

Changes in Efficiency and Hydraulic Parameters During the Passive Treatment of Ferriferous Acid Mine Drainage in Biochemical Reactors

The objective of this study was to evaluate the effects of different reactive mixtures and hydraulic retention times (HRTs) on hydraulic parameters (hydraulic conductivity, k_sat, and porosity) and the efficiency of passive biochemical reactors (PBRs) for treatment of ferriferous acid mine drainage (AMD). Five 10.7 L PBRs were filled with three reactive mixtures, containing either a carbon-rich substrate (60% w/w) or an inert/neutralizing agent (50% w/w). The PBRs were tested over a 450 day period using two qualities of iron-rich AMD (4 and 1 g L^?1 Fe in AMD1 and AMD2, respectively), and two HRTs, of 5 and 7 days. During the last week of the columns’ operation, a tracer test (5 g L^?1 of NaCl) was also performed, in addition to monthly measurements using the falling head method. Changes in HRT and k_sat were evaluated throughout the experiment. The PBRs increased the pH of AMD influents from 3.5 to 6 and efficiently removed Al, Cd, Cr, Ni, Pb, and Zn (>?90%), whereas Fe was only partially and inconsistently treated. No significant differences were observed among the three tested mixtures, regardless of the HRT or the AMD quality. Results from the tracer test and k_sat measurements showed no significant decrease in the initial values of the hydraulic parameters with time except for column 3, where a slight decrease was observed. Although sorption could have been important during the start-up of the PBRs, post-testing characterization of the spent reactive mixtures showed that the Fe was mainly retained as oxy-hydroxides and sulfides. Given the PBRs’ marginal effectiveness for Fe-rich AMD, pre-treatment removal of the iron is recommended.     

Geochemistry of Mine Tailings from Processing of Siderite–Cu Ores and Mobility of Selected Metals and Metalloids Evaluated by a Pot Leaching Experiment at the Slovinky Impoundment,Eastern Slovakia

This work describes the geochemistry, mineralogy, and mobility of selected metals (Cu, Pb, Zn) and metalloids (As, Sb) in a tailings impoundment in the village of Slovinky (eastern Slovakia). The tailings were covered unevenly by slag from processing of Cu wastes. The tailings and slag both have negligible potential for acid mine drainage formation, thus neutral to alkaline conditions predominate, as shown by high paste pH values of the tailings (7.66–8.83) and neutral drainage, with pH values above 7.50. Weathering of the most abundant primary sulfides (chalcopyrite, pyrite, and arsenopyrite) releases low concentrations of As, Cu, Pb, Sb, and Zn from the tailings impoundment and in leachates from a 150 days pot leaching experiment. This is explained mostly by formation of secondary ferric oxyhydroxides (as weathering rims on the surfaces of primary sulfides or individual grains),which incorporate 4.09 wt% of As, 17.2 wt% of Cu, 1.20 wt% of Pb, 15.0 wt% of Sb, and 1.59 wt% of Zn. Elevated contents of metals and metalloids in weathering rims formed on slag components like glasses, metallic grains, and residues of blast-furnace lining indicate that secondary solid phases are controlling the mobility of the potentially toxic elements. Generally, with the exception of Cu, no separate secondary compounds of the metals or metalloids were found. The potentially toxic elements are mainly immobilized by ferric oxyhydroxides and other iron mineral phases in the tailings impoundment.     

四川某浸锌渣稳定化处理与无尾综合利用研究

为了解决会理鑫沙锌业浸锌渣堆放引起的环境污染问题，同时针对其铅、锌含量高的特点，将氧压浸锌渣和硫化钠加入棒磨机进行机械硫化固化、浮选处理。通过条件试验确定了棒磨硫化和浮选流程的参数，并对浮选尾矿进行了浸出毒性检测和制备硫磺建材的试验。试验结果表明：在合适的条件下可以同时实现铅、锌硫化率超过90%，在此基础上获得了硫品位65.26%、硫回收率7814%的硫磺精矿，铅品位45.29%、铅回收率80.02%的铅精矿，锌品位41.02%、锌回收率7014%的锌精矿。浮选尾矿重金属浸出毒性符合国家标准，利用其可制备出抗压强度大于45 MPa、吸水率小于1%的硫磺建材，最终实现了该浸锌渣的高质量稳定化与无尾综合利用。     

贵州都匀牛角塘铅锌矿区选矿尾矿中重金属元素分布特征研究

在检测贵州都匀牛角塘铅锌矿区尾矿中铅、锌、砷、锑、铊、铬、铜、锰、镍、镉和汞含量的基础上,以贵州省A层土壤背景值为参比,利用单因子污染指数法、内梅罗综合污染评价法、地累积指数法、潜在生态危害指数法对矿区尾矿中重金属污染状况进行综合评价。结果表明,矿区6个堆场尾矿突出污染元素为镉、锌,永胜堆场尾矿中突出污染元素为汞、砷、锑。矿区6个堆场尾矿原矿石主要来源于矿区铅锌矿,永胜堆场尾矿的原矿石主要来源于丹寨、独山、榕江一带的汞矿和锑矿。相关性分析说明了尾矿中重金属元素的来源,尾矿金属元素资源再利用意义不大,且潜在环境问题突出。四种方法评价结果一致,均反映矿区尾矿突出污染元素为镉、锌,永胜堆场尾矿突出污染元素为汞、砷、锑。各堆场的综合生态危害指数大小顺序为永胜>陈工>垠垠>山佳>水牛石>狮子洞>振霖,永胜堆场重金属潜在环境污染问题最严重,应当引起环保部门的重视。     

广西南丹某尾矿库矿物元素纵向分布规律研究

为了调查广西南丹某尾矿库矿物元素的纵向分布规律,参考相关标准并通过相关性分析、主成分分析、回归分析和通径分析研究了尾矿库内不同深度尾矿的矿物元素特征。结果表明,尾矿中各元素含量随深度变化均存在一定分层,表现出"二次富集"现象,且富集层尾矿表现出较好的工业利用潜力。在矿物元素分布规律的研究中发现Zn、Sb、Cd、Pb、Sn和Cu元素可归为一类,S、Fe和As元素可归为另一类,同一类矿物元素的分布规律相似;各矿物元素之间存在不同程度的相互作用,且发现了较好的拟合模型;通径分析表明S主要受到Fe、Cu和Zn的影响,Fe主要受到S和As的影响,Pb主要受到Sb的影响,Zn主要受到Cd、Cu和Sb的影响,Sn主要受到Zn、Cd和Cu的影响,Sb主要受到Pb和Zn的影响,Cu主要受到Zn、S和Sn的影响,As主要受到Fe、Sn和Cu的影响。综上表明,铅锌尾矿库中矿物元素存在"二次富集"现象,具有较好的工业利用潜力,矿物元素之间存在相互作用,进而影响各矿物元素的分布规律。      

广西某铅锌尾矿库区土壤中重金属Cd、Pb、Zn、Cu的分布特征及源解析

针对广西某铅锌尾矿库区周边土壤中重金属Cd、Pb、Zn、Cu的含量、分布特征及其污染源,采用地统计学分析法和正定矩阵因子分解法进行了探究。含量测定结果表明,尾矿库区土壤中4种金属含量平均值分别为19.49(Cd)、465.65(Pb)、206.58(Zn)和36.64(Cu) mg/kg,分别是广西土壤背景值的73.0(Cd)、19.4(Pb)、2.7(Zn)和1.3(Cu)倍;以农用地土壤标准计,超标率分别为100%(Cd)、43.5%(Pb)、43.5%(Zn)和26.1%(Cu),其平均含量为农用地土壤污染风险筛选值的65.0(Cd)、5.17(Pb)、1.03(Zn)和0.73(Cu)倍。重金属空间分布结果表明,Cd在尾矿库东面和南面区域含量达到20~80 mg/kg,西北方向在一定范围内由近及远呈梯级分布;Pb和Zn主要分布在东部和西部,Cu则主要分布在东面。源解析结果表明,该尾矿库区土壤中4种重金属的来源主要包括：铅锌工业活动源、交通运输源和土壤母质源,各污染源的平均贡献率分别为46.34%、28.02%、25.64%。铅锌工业活动和交通运输是尾矿库区土壤重金属污染的主要来源,是污染防治措施制定和实施的主要对象。     

Treatment of Acidic and Neutral Metal-Laden Mine Waters with Bone Meal Filters

Bone meal was used to treat two different mine waters: acidic (pH 4.5) mine water containing high concentrations of Fe and Al and neutral/slightly alkaline (pH 7) mine water. Original primary contaminants in both waters were Pb and Zn. The contaminants were dissolved in the acidic mine water and mostly suspended in the neutral mine water. Flow through the filter treating the acidic mine water was relatively low (0.1 L/min), but increased towards the end of the test period. Removal of Pb and Cu was very good in the acidic mine water (around 80 %); removal of Zn was slightly less (60 %) due to the final pH (≈6–6.5). Flow through the filter treating the neutral mine water was initially significantly higher (5 L/min) and the removal of Pb and Zn was less compared to the acidic mine water (50 % for Pb and 35 % for Zn). The major reason for the difference in metal removal in the two mine waters was the difference in Fe and Al sorption sites, flow rate, and pH; in order for the bone meal to dissolve and form metal phosphate, the pH has to be <7.