Recovery of calcium carbonate from steelmaking slag and utilization for acid mine drainage pre-treatment

The conversion of steelmaking slag (a waste product of the steelmaking process) to calcium carbonate (CaCO(3)) was tested using hydrochloric acid, ammonium hydroxide and carbon dioxide via a pH-swing process. Batch reactors were used to assess the technical feasibility of calcium carbonate recovery and its use for pre-treatment of acid mine drainage (AMD) from coal mines. The effects of key process parameters, such as the amount of acid (HCl/calcium molar ratio), the pH and the CO(2) flow rate were considered. It was observed that calcium extraction from steelmaking slag significantly increased with an increase in the amount of hydrochloric acid. The CO(2) flow rate also had a positive effect on the carbonation reaction rate but did not affect the morphology of the calcium carbonate produced for values less than 2 L/min. The CaCO(3) recovered from the bench scale batch reactor demonstrated effective neutralization ability during AMD pre-treatment compared with the commercial laboratory grade CaCO(3).     

An evaluation of waste gypsum-based precipitated calcium carbonate for acid mine drainage neutralization

Precipitated CaCO(3) compounds recovered from pulped waste gypsum using some carbonate and hydroxide-based reagents were evaluated for their utilization in acid mine drainage (AMD) neutralization. The neutralization potentials, acid neutralization capacities and compositions of the CaCO(3) compounds were determined and compared with some commercial CaCO(3). It was observed that CaCO(3) recovered from waste gypsum using Na(2)CO(3) significantly neutralized AMD compared with commercial CaCO(3) and that recovered using both (NH(4))(2)CO(3) or NH(4)OH-CO(2) reagents. Moreover, a higher acid neutralization capacity of 1,370 kg H(2)SO(4)/t was determined for CaCO(3) recovered from waste gypsum using Na(2)CO(3) compared with an average of 721 and 1,081 kg H(2)SO(4)/t for ammonium-based CaCO(3) and commercial CaCO(3) respectively. The inorganic carbon content for the CaCO(3) recovered using Na(2)CO(3) and ammonium-based reagents of 49 and 34% respectively confirmed their observed neutralization potentials and acid neutralization capacities, while energy dispersive X-ray fluorescence suggested absence of major oxide impurities, with the exception of residual SO(4)(2-) and Na(2)O which still requires further reduction in the respective compounds.     

Regeneration of barium carbonate from barium sulphide in a pilot-scale bubbling column reactor and utilization for acid mine drainage

Batch regeneration of barium carbonate (BaCO(3)) from barium sulphide (BaS) slurries by passing CO(2) gas into a pilot-scale bubbling column reactor under ambient conditions was used to assess the technical feasibility of BaCO(3) recovery in the Alkali Barium Calcium (ABC) desalination process and its use for sulphate removal from high sulphate Acid Mine Drainage (AMD). The effect of key process parameters, such as BaS slurry concentration and CO(2) flow rate on the carbonation, as well as the extent of sulphate removal from AMD using the recovered BaCO(3) were investigated. It was observed that the carbonation reaction rate for BaCO(3) regeneration in a bubbling column reactor significantly increased with increase in carbon dioxide (CO(2)) flow rate whereas the BaS slurry content within the range 5-10% slurry content did not significantly affect the carbonation rate. The CO(2) flow rate also had an impact on the BaCO(3) morphology. The BaCO(3) recovered from the pilot-scale bubbling column reactor demonstrated effective sulphate removal ability during AMD treatment compared with commercial BaCO(3).     

矿井水资源利用的研究进展与展望

矿井水的开发利用是缓解缺水矿区水资源紧张的有效途径.矿井水相对稳定的排放量和无有机物污染,处理比较容易,使得矿井水进行资源开发利用具有可行性,同时矿区的水资源不足使矿井水的开发利用具有必要性.本文针对洁净矿井水、高悬浮物矿井水、高矿化度矿井水、酸性矿井水和含有害有毒元素或放射性元素5种类型的矿井水.介绍了化学混凝、气浮、蒸馏、离子交换、膜分离、酸碱中和、生物化学、人工湿地等方法在矿井水处理中的应用.国家提出到2010年全国煤矿矿井水利用量达到36×103m3,利用率达到70%的目标.针对这种情况,分析了矿井水开发利用中存在的问题, 提出了开发利用矿井水的主要对策建议.     

废弃煤矿矿井水在煤岩体入渗过程中的水岩作用机理研究

为弄清废弃矿井矿井水对地下水污染的机理和规律,以阜新煤矿废弃矿井为研究对象,利用室内土柱试验模拟了在矿井水淋溶和清水淋滤(模拟雨水)下.煤矿采空区矿井水中不同污染物质(总硬度、SO22-4、Cl-和总铁)对地下水的污染情况及污染因子在煤岩体中的迁移情况,应用质量守恒原理探讨了矿井水在饱和煤岩体人渗过程中的水岩作用.结果表明,矿井水在入渗过程中,通过运移累积、吸附转化、溶解解析和离子交换等水岩作用对地下水产生污染.     

西北内陆地区露天矿外排水对水环境影响评价

我国西北内陆地区蕴含丰富的煤炭资源,采煤过程中会产生大量疏干水,为保证露天采矿的正常运行,及解决露天矿的外排水对水环境污染的问题,以内蒙古自治区西乌珠穆沁旗白音华煤田三号露天矿为例,全面评价河道排污口的设置及疏干水的排放对河道水质的影响评价。通过数据分析和模型模拟,得出入河排污口满足高日罕河西乌珠穆沁旗工业用水区的要求,对水环境不会产生不利影响,为类似项目起到借鉴和参考作用。     

硫酸盐还原菌分离及其处理煤矿酸性废水工艺的实验研究

针对煤矿酸性废水直接排放污染水资源的问题,试验选用污泥样作为筛选样品富集硫酸盐还原菌,采用稀释涂布-叠皿夹层厌氧培养法分离纯化SRB,研究了SRB对煤矿酸性废水中Fe2+和SO42-的去除效果。试验结果表明:分离纯化得到的SRB符合典型的"S"型生长曲线,SRB的最佳生长条件为34℃、p H为7、70%乳酸钠作为碳源。综合比较接种不同量SRB对煤矿酸性废水的处理效果可知,接种10%SRB的处理效果较好,接种时间为5d时对煤矿酸性废水中SO42-和Fe2+的去除率分别为74. 71%和99. 18%。     

Biological treatment of heavy metals in acid mine drainage using sulfate reducing bioreactors.

The uncontrolled release of acid mine drainage (AMD) from abandoned mines and tailing piles threatens water resources in many sites worldwide. AMD introduces elevated concentrations of sulfate ions and dissolved heavy metals as well as high acidity levels to groundwater and receiving surface water. Anaerobic biological processes relying on the activity of sulfate reducing bacteria are being considered for the treatment of AMD and other heavy metal containing effluents. Biogenic sulfides form insoluble complexes with heavy metals resulting in their precipitation. The objective of this study was to investigate the remediation of AMD in sulfate reducing bioreactors inoculated with anaerobic granular sludge and fed with an influent containing ethanol. Biological treatment of an acidic (pH 4.0) synthetic AMD containing high concentrations of heavy metals (100 mg Cu(2+)l(-1); 10 mg Ni(2+)l(-1), 10 mg Zn(2+)l(-1)) increased the effluent pH level to 7.0-7.2 and resulted in metal removal efficiencies exceeding 99.2%. The highest metal precipitation rates attained for Cu, Ni and Zn averaged 92.5, 14.6 and 15.8 mg metal l(-1) of reactor d(-1). The results of this work demonstrate that an ethanol-fed sulfidogenic reactor was highly effective to remove heavy metal contamination and neutralized the acidity of the synthetic wastewater.     

褐煤/麦饭石固定SRB颗粒处理含铬酸性矿山废水试验

针对硫酸盐还原菌(SRB)生物法处理酸性矿山废水(AMD)易受重金属离子和高酸度的抑制与毒害等问题,采用玉米芯为碳源的微生物固定化技术,分别构造以麦饭石和褐煤为填料的1~#和2~#固定化颗粒,对比处理含Cr~(6+)、SO_4~(2-)的模拟酸性矿山废水的效果。实验结果表明:1~#颗粒废水中COD的平均释放量(898 mg/L)要高于2~#颗粒废水中COD的平均释放量(698.9 mg/L),而2~#颗粒对AMD中p H提升(4～7.47)和对Cr~(6+)、SO_4~(2-)的平均去除率(96.57%、36.50%)要高于1~#颗粒对AMD中p H提升(4～7.04)和对Cr~(6+)、SO_4~(2-)的平均去除率(85.96%、20.85%)。可见,褐煤颗粒有比麦饭石颗粒较强的调酸、吸附金属离子和异化硫酸盐活性的能力。     

同步除S、脱N、除P矿山废水综合治理的思考

为提高含硫酸盐矿山废水的处理效果并使其资源化,提出了以矿区未经处理不允许直接排放的生活污水为碳源,在厌氧条件下,利用SRB(硫酸盐还原菌)、脱氮硫杆菌等微生物,在厌氧生物反应器中处理矿区废水,达到同步除S、脱N、除P的效果,并回收单质硫这一新思路,并对其可行的原理进行分析,最终实现矿山废水的综合治理和"以废治废"综合治理的目的.     

唐口矿井井下排水及供水系统方案的设计优化

唐口矿井为特大型千米立井,矿井涌水量大,排水费用高,井下供水减压难度大,常规的设计方案不能很好地解决这些问题.通过设计优化,提出了将井下排水、矿井水处理及井下供水等相对独立的单项工程综合考虑,不仅可解决供水减压及排水设备磨损的难题,同时可带来可观的经济效益.     

年楚河流域水资源开发利用现状分析

年楚河流域位于西藏日喀则地区 ,是雅鲁藏布江的一级支流 ,其河谷平原是“西藏的粮仓”。流域多年平均水资源总量为 15 0 5亿m3 。受特殊的地理位置、地形条件影响 ,水资源时空分布不均 ,流域水资源利用率低、保灌面积小 ,严重制约了当地农牧业的发展。本文介绍该流域水资源开发利用现状 ,为研究年楚河流域水资源发展战略和可持续利用提供参考。     

煤田矿井涌水量预测三维数值模型

针对煤田矿井涌水量预测的复杂性,以山西平朔安家岭井工矿为例,在概化出矿区水文地质概念模型的基础上,建立了安家岭井工矿矿井涌水量预测的地下水三维非稳定流数值模拟模型,并结合矿井生产,按矿井掘进工作面进行了平水期和丰水期两个方案的涌水量预测,获得了各工作面不同时期地下水位分别疏干到4#煤底和9#煤底的矿井涌水量。该方法将矿井涌水量预测和矿井的水文地质结构及矿井生产进度紧密结合起来,具有较高的精度。     

长沟峪煤矿急倾斜煤层群裂隙演化及渗流规律

以北京长沟峪矿区急倾斜煤层群为工程背景,利用离散元方法分析计算煤采动影响下覆岩裂隙场演化以及降雨入渗规律;随着急倾斜煤层群分部开采,采动裂隙场存在顺序叠加现象,采动影响下覆岩裂隙分布复杂性呈现非线性递增趋势,并逐步形成裂隙演化阻水机制。利用分形理论计算张开裂隙与闭合裂隙的分布维数,得出裂隙闭合率与采空区入渗量之间存在非对称曲线关系,并且入渗量变化滞后于阻水结构的形成。     

碳酸钙沉淀势理论计算模型及其应用

水质化学稳定性评价指数较多,其中碳酸钙沉淀势(CCPP)是一个能定量分析CaCO3溶解或沉淀的精确指数.从理论上推导了CCPP计算模型,并基于Matlab计算求解.模型计算结果与已有相关软件的计算结果相比,该理论模型的计算值更接近试验结果,可以用其代替试验值进行水质化学稳定性分析.     

岩溶地区公路两侧土壤污染研究

通过对岩溶地区不同路段的公路两侧污染物进行调查、取样、测试、分析研究,说明了土壤中的Cu、Pb、Zn和石油类污染物的分布规律,为岩溶地区公路两侧土壤污染治理提供了实验依据。     

任楼煤矿生产用水水源的开发研究

针对任楼煤矿生产用水水源紧缺的现状,分析地下水资源系统构成,提出了涌水量减少的原因和解决生产用水的途径及开发地下水资源的重要性.并研究了塌陷区地表水源的水质、水量、水压问题,通过分析,论述矿井生产用水水源的可行性,为矿井未来发展提供可靠的后备水源.     

攀枝花盐边县太田煤矿区水文地质特征及涌水量预测

以太田煤矿区为研究对象, 在大量收集研究区域地质资料, 气象资料的基础上, 分析研究区地质条件及水文地 质条件。将太田区煤矿水文地质类型划分为以大气降雨补给为主的水文地质条件简单的裂隙充水矿, 其后重点分 析矿床充水条件及充水通道, 根据分析, 最后选择/ 大井法0及/ 暴雨峰值系数法0初步预测标高 1 300 m 处矿坑正常 涌水量及多年最大涌水量。本次调查研究结果可为矿井建设生产提供科学的水文地质资料。     

煤矿采空区高层建筑场地稳定性评价

某业主拟在贵阳金阳新区一煤矿采空区上建办公大楼和生活区，其中：办公大楼为高层建筑，其他为多层建筑。因采空区边界、浸水、塌顶情况复杂，近地表又属岩溶地层，可行性研究论证涉及场地的稳定和评价和采空区勘探技术等难题，技术难度较大。经采用多种勘探手段和评价方法，认为该场地基本适宜建筑，为业主解决了一大难题。目前办公大楼已建成，未发现异常现象，证明前期的勘察结论是合适的。     

五龙煤矿涌水量及可利用水量评价

为了有效利用五龙煤矿矿坑排水,并对矿坑排水量进行有效预测,在调查分析矿坑涌水量数据的基础上,利用水文学的方法分离矿坑涌水量的稳定和随机成分,并对未来(2010年、2015年、2020年)矿坑涌水量进行预测,据此获得了五龙煤矿可利用设计水量的序列数据。