从低品位稀土抛光渣中回收CeO_2的试验

抛光渣是抛光粉在使用过程中因混入杂质而失去使用价值的废弃物,传统的丢弃或掩埋处理不仅造成资源的浪费,而且造成环境污染。本研究以某低品位铈基稀土抛光渣(CeO_2含量为0.88%)为试样,采用初步沉降预富集,硫酸+双氧水浸出,氨水、Na2S相继除杂,草酸沉淀,沉淀产物高温煅烧工艺进行了CeO_2回收试验。结果表明:(1)废弃抛光渣在pH=9的情况下沉降8 h,可得到CeO_2品位为1.70%、回收率为84.62%的预富集产物。(2)预富集产物在硫酸浓度为0.5 mol/L,用量为100 m L,双氧水用量15 m L,反应温度为80℃情况下水浴加热、搅拌、浸出3.5 h,稀土浸出率可达94.70%。(3)用氨水、Na2S对浸出液进行了除杂处理,Al~(3+)、Fe~(3+)、Pb~(2+)、Zn~(2+)的去除率分别为94.03%、76.67%、99.89%、99.94%,然后用草酸沉淀稀土,稀土沉淀率为91.82%。(4)稀土草酸盐沉淀产物高温煅烧得到CeO_2含量为93.48%的晶体,纯度较高,扫描电镜观察表明,该CeO_2晶体多呈块状。     

矿山污水中和沉淀物的微观结构与固液分离特性的关系

为了改善处理和利用矿山酸性污水的工艺,研究了用不同方法所得中和沉淀物的沉降和过滤特性。用CaCO_8作中和剂所得的沉淀物的固液分离特性比用Ca(OH)_2的好得多。细菌氧化可大大加快溶液中Fe~(2+)氧化至Fe~(3+)的速率,这是用CaCO_3中和时必需的预处理。用CaCO_3和Ca(OH)_2作两步中和时,溶液中Fe~(3+)的比率越高,中和沉淀物的固液分离特性越好。考查了中和沉淀物的微观结构,并指出,中和过程中生成的石膏的OKO面的结晶程度与沉淀物的固液分离特性有密切的联系。     

铜熔炼烟尘中铜的回收试验研究

为了回收铜熔炼烟尘中的有价金属,对某铜冶炼厂产生的高铜、高砷烟尘进行了性质分析,确定了烟尘中主要元素的赋存状态及含量。结果表明,烟尘中铜和锌主要以硫酸盐和氧化物的形式存在,砷主要以氧化物的形式存在,具有良好的浸出特性。采用低浓度酸浸—硫化沉淀法回收烟尘中的铜,并考察了絮凝剂对硫化物矿浆沉降性能的影响。结果表明:(1)在初始硫酸浓度为40 g/L,浸出温度为50℃,浸出时间为90 min,液固体积质量比为4∶1 mL/g的条件下,Cu、Zn、As的浸出率分别为96.33%、96.52%和83.72%。(2)硫化沉铜时,在硫化钠过量系数为1.3,p H值为3.0,反应时间为20 min的条件下,Cu的沉淀率可达到99.99%,硫化沉淀产物主要物相为Cu S,其中铜的品位为56.90%,可直接用于工业生产。沉铜后液可继续回收Zn等有价金属。(3)加入絮凝剂可使硫化沉淀的粒径变大,加速矿浆的沉降并且有助于固液分离。     

金属离子对铜蓝和黄铁矿浮选行为的影响

通过单矿物浮选试验和浮选溶液化学计算的方法,考察了丁基铵黑药浮选体系中Cu~(2+)、Fe~(2+)、Fe~(3+)和Ca~(2+)对铜蓝和黄铁矿可浮性的影响。结果表明,四种离子对铜蓝、黄铁矿的可浮性的影响很大,均表现出不同程度的抑制作用,尤其相同浓度下Fe~(3+)的抑制作用最为显著。此外,金属离子氢氧化物沉淀是其抑制矿物的有效组分。     

稀土尾矿中萤石、重晶石浮选分离研究

对紫金山含铜酸性废水的处理与回用开展了实验室研究,采用了预中和-硫氢化钠沉淀、预中和-铁屑置换与低压反渗透膜分离技术三种处理方法。其中预中和-硫氢化钠沉淀产品渣铜品位>60%,铜回收率>94%,尾液铜<0.5mg/L;预中和-铁屑置换产品渣铜品位>35%,铜回收率>90%;低压反渗透膜分离技术处理废水实现铜回收率≥99%,膜渗透产水稍作中和即可作为铜矿浮选厂的工业回用水或达标外排,富集有价金属铜的浓缩液可直接进入湿法厂的“萃取-电积”系统作进一步回收。采用膜分离法处理硐坑水可极大地减少中和渣浆堆放量,有效减轻矿山库容压力,在提高矿山资源的循环使用率方面具有显著的经济、技术优势。     

膨润土-钢渣复合颗粒对Zn~(2+)的去除机理

为了探索酸性矿山废水中重金属离子的高效协同处理方法和开发新型多功能处理材料,采用自行研制的膨润土-钢渣复合颗粒对含Zn~(2+)酸性矿山废水的去除效果和实验现象进行对比实验研究,并利用SEM和XRD进行微观分析,结果表明:该复合颗粒不仅可以释放碱度中和酸,而且对Zn~(2+)的吸附、化学沉淀作用发生于整个反应过程,对Zn~(2+)的平衡去除量可达8.01 mg/g;SEM表面微观分析揭示了复合颗粒表面吸附Zn~(2+)并形成沉淀后还会继续吸附Zn~(2+)并发生聚沉作用,即发生了吸附-聚沉协同作用;XRD微观分析进一步揭示了Zn~(2+)在复合颗粒表面的赋存状态主要以Zn-SiO相结合的矿物相以及Zn_(12)(CO_3)_3SO_4(OH)_(16)聚合沉淀存在。膨润土-钢渣复合颗粒可发挥吸附-聚沉协同作用,是处理含重金属离子酸性矿山废水的优良多功能矿物环保材料。     

粉煤基沸石对Cu~(2+)吸附行为的实验研究

研究了粉煤基沸石对水溶液中重金属铜离子的吸附特性。结果表明,在温度35℃,pH值在3~5,液固比200∶1,初始浓度800 mg/L条件下,粉煤基沸石对Cu~(2+)基本达到吸附饱和,饱和吸附量122 mg/g;Langmuir模型和Freundlich模型可描述粉煤基沸石对Cu~(2+)的吸附特性;粉煤基沸石对铜离子的吸附行为是氢氧化铜沉淀和离子交换吸附共同作用的结果。     

高铜高铋高碲中和渣综合利用新技术研究

采用二次酸洗脱铜、亚硫酸钠还原碲、中和沉淀铋的方法对铜、碲、铋等含量较高的中和渣进行了综合利用的新技术研究,形成了一整套的工业化的回收技术.碲、铜、铋的回收率可分别达到92.8%,95.5%,97.2%,该工艺设备简单,易操作,适应性较强,经济效益显著..     

含镍废液制备硫酸镍并深度除Fe、Cu、Zn

本文以镀镍行业产生的含Fe、Cu、Zn等杂质的硫酸镍废液为原料,通过采用氧化、化学沉淀、P204多级萃取等低成本的方法,实现了Fe、Cu、Zn等主要杂质的深度去除,制备出符合HG/T 2824-2009中Ⅰ类一等品的硫酸镍产品。试验重点考察了双氧水用量用量对除铁的影响,以及中和pH值、萃取pH值、萃取相比等技术参数对Fe、Cu、Zn、Ni除杂率的影响,并按照最佳条件处理了一批10 L废液得到2300 g硫酸镍产品,一次结晶率达60%。试验结果表明:用双氧水氧化后石灰中和至pH值5.0,Fe离子沉淀完全;在中和终点pH值4.5~5.7范围内,Fe、Cu、Ni的沉淀率随pH值的增大而增大,Zn的变化不大;pH值达5.7,Cu的沉淀率达98.4%;P204对金属离子的萃取顺序为:Fe3+Zn~(2+)Cu~(2+)Fe~(2+)Ni~(2+);P204可有效萃取分离Fe、Cu、Zn等杂质;经萃取分离后硫酸镍溶液中Fe、Cu、Zn的含量全部达到10-3g/L以下。     

含铜铁酸性废水处理硫化氢研究

为了达到以废治废及节约成本的目的,针对硫化沉淀工艺回收酸性废水中的铜不可避免地产生硫化氢气体的问题,进行了含铜铁酸性废水吸收硫化氢气体试验研究。研究结果表明:采用含铜铁酸性废水吸收硫化沉淀系统产生的硫化氢气体,无论在技术上,还是经济上都切实可行;含铜铁酸性废水吸收硫化氢的过程中,Fe~(3+)发挥着主要作用,可有效氧化硫化氢;建议用三级串联含铜铁酸性废水新水吸收硫化氢气体,之后末端增加一级10%氢氧化钠溶液吸收,可保证尾气中的硫化氢全部被吸收完毕。     

Integrating sulfidization with neutralization treatment for selective recovery of copper and zinc over iron from acid mine drainage

The most commonly used commercial process for acid mine drainage (AMD) treatment today is lime neutralization. However, it is accompanied by the treatment of produced metal hydroxide precipitate. Because of the decrease in the capacity of landfill disposal site and the increase in the price of base metals such as copper (Cu) in recent years, it is expected that not only to treat but also to recover these base metals from AMD. For the subsequent smelting process, the major issue is how to separate the Cu and zinc (Zn) over iron (Fe) from AMD as selectively as possible.In this work, we attempted to achieve this objective by modifying the present lime neutralization treatment process with sodium hydrosulfide (NaHS) sulfidization. An AMD sample generated from an abandoned copper mine located in east Japan was utilized in this study. At first, lime neutralization was applied to the AMD to find the precipitation behaviors of Cu, Zn, and Fe. Next, NaHS sulfidization as well as the integration with lime neutralization were conducted to separately precipitate Cu, Zn, and Fe from the AMD. Finally, two modified treatment approaches for selectively recovering Cu and Zn over Fe from the AMD were proposed. The results of consecutive experiments for the two proposed approaches showed that Cu, Zn, and Fe in the AMD were removed and separated into individual precipitates, and that the concentrations of each heavy metal in the final effluent were also able to meet the Japanese effluent standards.     

Thallium Contamination in the Raibl Mine Site Stream Drainage System (Eastern Alps,Italy)

The Raibl mine (Cave del Predil village, northern Italy) belongs to the Pb–Zn minerogenetic district in the southeastern Alps, hosted in Middle Triassic carbonates. The drainage water quality reflects the high acid-buffering capacity of the carbonate rocks, which controls the mobility of most metals. In particular, Fe is non-detectable in solution, having formed hydrous-oxides precipitates. Molybdenum, Ni, Zn, Cd, Pb, and Tl are present, and the Pb, Tl, and Zn concentrations sometimes exceed the Italian regulatory thresholds. Thallium concentrations substantially exceed the 2 µg/L limit at some sampling stations, ranging between 12 and 30 µg/L in the mine drainage, and reaching 5 µg/L downstream of the mine site, despite strong dilution. The data indicate that Tl behaves almost conservatively and is not significantly scavenged by the Fe precipitates. The elevated Tl represents a potential risk for the stream ecosystem. Although Tl is not regulated in drinking water in Italy or the European Community, its distribution in natural waters may help to determine if health actions should be taken.     

Geochemical Characterisation of Seepage and Drainage Water Quality from Two Sulphide Mine Tailings Impoundments: Acid Mine Drainage versus Neutral Mine Drainage

Seepage water and drainage water geochemistry (pH, EC, O₂, redox, alkalinity, dissolved cations and trace metals, major anions, total element concentrations) were studied at two active sulphide mine tailings impoundments in Finland (the Hitura Ni mine and Luikonlahti Cu mine/talc processing plant). The data were used to assess the factors influencing tailings seepage quality and to identify constraints for water treatment. Changes in seepage water quality after equilibration with atmospheric conditions were evaluated based on geochemical modelling. At Luikonlahti, annual and seasonal changes were also studied. Seepage quality was largely influenced by the tailings mineralogy, and the serpentine-rich, low sulphide Hitura tailings produced neutral mine drainage with high Ni. In contrast, drainage from the high sulphide, multi-metal tailings of Luikonlahti represented typical acid mine drainage with elevated contents of Zn, Ni, Cu, and Co. Other factors affecting the seepage quality included weathering of the tailings along the seepage flow path, process water input, local hydrological settings, and structural changes in the tailings impoundment. Geochemical modelling showed that pH increased and some heavy metals were adsorbed to Fe precipitates after net alkaline waters equilibrated with the atmosphere. In the net acidic waters, pH decreased and no adsorption occurred. A combination of aerobic and anaerobic treatments is proposed for Hitura seepages to decrease the sulphate and metal loading. For Luikonlahti, prolonged monitoring of the seepage quality is suggested instead of treatment, since the water quality is still adjusting to recent modifications to the tailings impoundment.     

Assessment of Metal Contamination in the Mine Water of the West Bokaro Coalfield,India

This study was carried out in the West Bokaro coalfield area of the Jharkhand state of India to assess water quality for drinking and domestic purposes. Thirty mine water samples were collected from opencast and underground mines, and concentrations of Al, As, Ba, Cr, Cu, Fe, Mn, Ni, Se, and Zn were determined using ICP-MS. Spatial distribution maps were prepared using GIS software so that the quality of the mine water could be easily understood. Metal concentrations were higher in the pre-monsoon season than in the post-monsoon season, irrespective of location, but there were more significant seasonal variations in the opencast mine water than in the underground mine water. The concentrations of Al, Ba, Fe, Mn, and Ni exceeded the desirable as well as the permissible drinking water limits in both seasons. The quality of the surface water as well as the groundwater in the region may be adversely affected by the high metal concentrations in this mine water.     

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.     

Passive Treatment of Circumneutral Mine Drainage from the St. Louis Mine Tunnel,Rico, CO: Part 1—Case Study: Characteristics of the Mine Drainage

This publication is a case study of the seasonal variability of mine water drainage from the Saint Louis Tunnel (SLT) at the inactive Rico-Argentine mine site located in southwestern Colorado. It is an introductory paper for the two passive water treatment system technology evaluations contained in this issue. Mine water chemistry changes from baseflow to a snowmelt runoff event (SMRE) where snowmelt runoff follows preferential migration pathways to flush acidic weathering products from the upper mine workings to the SLT. Baseflow mine drainage is characterized as circumneutral, with Zn, Cd, Mn, and Ni concentrations primarily in the dissolved form. Dissolved Zn, Mn, Fe, and potentially Cd illustrate equilibrium with carbonate minerals. Total concentrations of Fe, Cu, Pb, and As are primarily in the suspended form and suggest sorption to Fe oxides. Mine water chemistry during the SMRE reflects mixing of circumneutral baseflow waters with more acidic waters flushing the upper mine workings. Geothermal activity provides for a consistently warm mine water discharge from the SLT. The two seasons that provide the most challenge to passive water treatment of SLT mine drainage are the SMRE period and the low flow stage of the Dolores River. Mine water flow and chemistry during SMRE are highly correlated with Dolores River flow and this site conceptual model was and will be used to assist in pilot project evaluation, water treatment system design, monitoring system design, a seasonal compliance approach, and water management.

     

Evaluation of Metal Attenuation from Mine Tailings in SE Spain (Sierra Almagrera): A Soil-Leaching Column Study

A laboratory study was undertaken using mine tailings and soil columns to evaluate some of the natural processes that can control the mobility of metals at Pb–Ag mine tailings impoundments. The effects of buffering, pH, and salinity were examined with tailings from the El Arteal deposit. Al, Ba, Cd, Cu, Fe, Mn, Ni, Pb, Sr, and Zn were mobilized when the tailings were leached. However, when the mine tailings were placed above alluvial soils, Al, Ba, Cd, Cu, Mn, Pb, and Zn were retained, although Fe and Sr clearly remained mobile. Most of the metal retention appears to be associated with the increase in pH caused by calcite dissolution. The sorption of some metals (Cu, Pb, and Zn) onto oxyhydroxides of Fe and Mn, sulphates, clay materials, and organic matter may also explain the removal of these metals from the leachate.     

Heavy Metal Pollution Index of Ground Water of an Abandoned Open Cast Mine Filled with Fly Ash: a Case Study

Ground water samples were collected from the periphery of a fly ash filled open cast mine, from within the mine property, and from a half kilometre away from the site. Concentrations of metals such as Cu, Zn, Cd, Pb, and Cr were consistently below the permissible limit for drinking water, but concentrations of Fe and Mn were above the permissible limit. The data were used to calculate a heavy metal pollution index (HPI). The HPI of the ground water of the ash filled mine was 36.67, which was below the critical index limit of 100. The HPI of Dhanbad Township ground water, from very near to the mining area, was 11.25. The results indicate that leachate from the fly ash filled mine has apparently contaminated the ground water to a limited extent.     

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.     

煤矿酸性矿井水中有害元素的迁移特性

利用电感耦合等离子质谱（ICP-MS）、离子色谱（IC）和X射线衍射（XRD）等方法研究了马兰煤矿酸性矿井水及其沉淀物的化学成分和物相组成,并通过吸附解吸实验和PHREEQC水化学模拟计算研究了典型酸性矿井水样品中Pb,Th,U,Be,Zn,Ni,Co,Cd,Cu,As,Cr,V,Ba等有害元素的迁移特性.研究表明：① 煤矿酸性矿井水中SO^2-₄,Fe,Mn,Al,Pb,Th,U,Be,Zn,Ni,Co,Cu等离子含量较高,对环境存在潜在危害;② 酸性矿井水中有害元素的迁移主要受pH,Fe-Al-Mn含量和水体颗粒物矿物组成的控制;③ Fe,Al和Mn的含量随pH上升而迅速下降,并控制着Pb,Th,U,Be,Zn,Ni,Co,Cu等潜在有害微量离子的迁移行为; ④ 各离子随pH上升被去除的先后顺序为: Th>Fe>Pb >Cr>Al>Cu>Be>U>Zn>As>Cd>Mn>Co>Ni>Ba;⑤ 酸性矿井水中V不能够随pH的升高而去除,反而会有更多的V溶解在水中.