层次分析法在某银矿尾矿库废水处理中的应用

研究了投加量对三种水样中总氰、总铜、总锌处理效果的影响,并采用层次分析法分析得出漂白粉处理某银矿尾矿库废水的最佳投加量。结果表明:层次分析法能使总氰、总铜、总锌多条去除率曲线综合成一条总去除率曲线,从而更容易判断出最佳投加量为2.5 g/L;当漂白粉的投加量为2.5 g/L、pH=8、接触反应时间为60 min时,可使原水水质在一定范围内变化的某银矿尾矿库废水处理达标;稳定性验证试验表明,层次分析法分析得出的漂白粉最佳投加量,可使含氰废水的处理出水稳定达标。     

复垦尾矿库土壤生态系统服务价值评估

在测定不同复垦年限尾矿库土壤理化性状的基础上,从侵蚀控制、肥力保持和物种保育3个方面揭示不同复垦年限尾矿库土壤生态服务价值量变化情况。研究结果表明:1)随着复垦年限的增加,土壤侵蚀模数逐年降低,复垦12年后土壤侵蚀模数降低至12.67 t/(hm~2·a),有效控制了土壤侵蚀,保育了土壤;2)随着复垦年限的增加,土壤理化性质得到了有效改善,土壤生态系统服务价值总体增加,保育物种功能价值比重显著提升。     

城市垃圾肥在锡矿尾砂库植被重建中的应用

在广西大厂矿区废弃的锡矿尾砂库上进行植被的重建试验。设对照组、垃圾肥处理组和覆土组,种植固氮植物银合欢(Leucaenaleucocephala)。100d时采样分析,垃圾肥处理组的银合欢生长状况最好,重金属从土壤到植物的迁移明显降低,说明在锡矿尾砂库植被重建中,可以利用垃圾肥替代土壤,银合欢可以作为锡矿尾砂库植被重建的先锋树种。     

Residuary Toxic Elements And PAHs in Sediments of the Zbiornik Gilow Tailings Pond and Zimmica Stream from Lubin District, Southwest Poland

Eight selected elements (As, Cd, Co, Cu, Pb, Zn, Cr and Ni) were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) in five samples from the tailings pond (Zbiornik Gilow) and waste water stream (Zimmica) in the Kupferschiefer mining district in Southwest Poland. Waste water from mining and concentration plants was discharged into Zbiornik Gilow pond for 30 years before 1989. Below Zbiornik Gilow the water flows through Zimmica stream, and then discharges into the River Odra. The analytic results indicate that the contamination of As, Cd, Co, Cu, Pb and Zn has spread out over 5km, and the contamination by Ni and Cr extends for 1.5km along the Zimmica stream although the stream has been abandoned since 1989. These elements could still be toxic for plants, animals and humans. Polycyclic aromatic hydrocarbons (PAHs) were determined by GC and GC/MS. The results of the sediment samples show a contamination of PAHs only in trace contents.     

4种草对铅锌尾矿污染土壤重金属的抗性与吸收特性

盆栽试验的结果表明,高羊毛、早熟禾、黑麦草、紫花苜蓿在纯尾矿污染土壤或经处理的尾矿污染土壤上都能生长,但在处理的土壤上生长的植物长势明显优于对照,其中紫花苜蓿的生物量所受影响比其他几种草坪草更大,说明其重金属抗性低于其他几种植物。单位面积上 4 种植物体内重金属质量分数高低均为 w(Zn)>w(Pb)>w(Cu)>w(Cd),但每种植物对 Cd、Pb、Zn 和 Cu 的吸收质量分数和分布均不相同,一般为根系质量分数大于茎叶。加入改良剂(CaCO3)和有机肥(菜枯)使生长在铅锌尾矿污染土壤上的 4 种草坪草生物量显著增加,植物体中的 Cd、Pb、Zn 质量分数下降,但 Cu 质量分数反而上升,结果单位面积上草坪草吸收各重金属元素的量均有所增加,可见利用改良措施与草坪草相结合的方法来修复重金属污染土壤具有可行性。     

不同时空铅锌矿渣中耐受重金属细菌群体的变化

利用含不同浓度铅锌的选择平板 ,对堆积时间分别约为 1 0、2 0和 80a的铅锌矿渣堆表层和下层的耐受细菌群体进行了调查。与对照土样相比 ,矿渣堆中细菌总量减少。堆积时间短的矿渣堆 ,细菌数量少 ,上下层数量差异不大 ;堆积时间长的 ,细菌数量较高 ,上层数量比下层大。矿渣堆中有大量耐受铅锌的细菌群体 ,耐受水平越高的群体数量越少。在空间分布上 ,耐受群体主要集中在下层。随堆积时间延长 ,耐受群体比例减少。铅锌对细菌的胁迫效应不同 ,尽管矿渣堆主要表现为铅污染 ,但其中仍有大量耐受Zn2 + 的群体 ,耐受水平达 1 0mmol·L-1 ,没有发现能够耐受如此高浓度Pb2 + 的群体。此外 ,发现有部分细菌的生长依赖于 0 .5mmol·L-1 的Pb2 + 和Zn2 + 。     

Mineralogical and geochemical characterization of arsenic in an abandoned mine tailings of Korea

The mineralogical and chemical characteristics of As solid phases in arsenic-rich mine tailings from the Nakdong As–Bi mine in Korea was investigated. The tailings generated from the ore roasting process contained 4.36% of As whereas the concentration was up to 20.2% in some tailings from the cyanidation process for the Au extraction. Thin indurated layers and other secondary precipitates had formed at the surfaces of the tailings piles and the As contents of the hardened layers varied from 2.87 to 16.0%. Scorodite and iron arsenate (Fe₃AsO₇) were the primary As-bearing crystalline minerals. Others such as arsenolamprite, bernardite and titanium oxide arsenate were also found. The amorphous As–Fe phases often showed framboidal aggregates and gel type textures with desiccation cracks. Sequential extraction results also showed that 55.7–91.1% of the As in tailings were NH₄-oxalate extractable As, further confirmed the predominance of amorphous As–Fe solid phases. When the tailings were equilibrated with de-ionized water, the solution exhibited extremely acidic conditions (pH 2.01–3.10) and high concentrations of dissolved As (up to 29.5 mg L⁻¹), indicating high potentials for As to be released during rainfall events. The downstream water was affected by drainage from tailings and contained 12.7–522 μg L⁻¹ of As. The amorphous As–Fe phases in tailings have not entirely been stabilized through the long term natural weathering processes. To remediate the environmental harms they had caused, anthropogenic interventions to stabilize or immobilize As in the tailings pile should be explored.     

Bioremediation of metal contamination

A study was initiated to evaluate the use of the fungus Aspergillus niger for bioleaching and then todetermine the effect of process steps, the tailingsconcentration and type of substrate. An oxidized miningtailing containing mainly copper (7240 mg kg^-1 tailings) was studied. A sucrose and mineral salts medium was initially used to produce citric and gluconic acids by A. niger atvarious concentrations of tailings (1, 5, 7, 10 and 15% w/v).Maximal removal of up to 60% of the copper was obtained forthe 5% tailings when the organic acid supernatant was addedto the tailings. In a single step process, A. niger wasthen grown in the presence of mining tailings at variousconcentrations. Maximum copper solubilization (63%) occurredwith 10% mining tailings using sucrose as the substrate.Other substrates were then evaluated including molasses, corncobs and brewery waste (10% mining tailings). Sucrose gavethe best results for copper removal, followed by molasses,corn cobs and brewery waste. Other experiments usingultrasound as a pretreatment showed that 80% removal of thecopper could be obtained for a 5% tailings concentration. Inconclusion, leaching of copper from mining tailings istechnically feasible using A. niger but furtherresearch will be required to increase the economic feasibilityof the process.     

Study on the cementitiousness of asbestos tailings

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酸浸渣制取硫酸亚铁的研究

论述了利用金矿冶炼中的酸浸尾渣制取硫酸亚铁溶液，主要考察了温度、反应时间、硫酸浓度、硫酸用量对铁浸出率的影响，得出了酸浸尾渣制取硫酸亚铁的最佳工艺条件。