Neutralizing Coal Mine Effluent with Limestone to Decrease Metals and Sulphate Concentrations

Abstract.   This paper describes pilot scale tests of a novel process for the neutralisation of acidic mine water. Leachate from a waste coal dump was neutralised with limestone, and iron, aluminium, and sulphate were removed. Specific aspects studied were: the process configuration; the rates of iron oxidation, limestone neutralisation, and gypsum crystallisation; the chemical composition of the effluents before and after treatment; the efficiency of limestone utilisation; and the sludge solids content. The acidity was decreased from 12,000 to 300 mg/L (as CaCO₃), sulphate from 15,000 to 2,600 mg/L, iron from 5,000 to 10 mg/L, aluminium from 100 to 5 mg/L, while the pH increased from 2.2 to 7.0. Reaction times of 2.0 and 4.5 h were required under continuous and batch operations respectively for the removal of 4 g/L Fe (II). The iron oxidation rate was found to be a function of the Fe (II), hydroxide, oxygen, and suspended solids (SS) concentrations. The optimum SS concentration for iron oxidation in a fluidised-bed reactor was 190 g/L. Up-flow velocity had no influence on the rate of iron oxidation in the range 5 to 45 m/h. Sludge with a high solids content of 55% (m/v) was produced. This is high compared to the typical 20% achieved with the high density sludge process using lime. It was determined that neutralisation costs could be reduced significantly with an integrated iron oxidation and limestone neutralisation process because limestone is less expensive than lime, and a high-solids-content sludge is produced. Full scale implementation followed this study.     

某金矿尾矿浮选回收金工艺研究

某金矿尾矿含金0.68 g/t,含银4.50 g/t,具有较高的综合利用价值,为进一步回收有用元素,对某金矿尾矿进行了工艺矿物学和选别工艺流程研究。原矿物相分析结果表明,金以自然金和包裹金的形式存在,其中自然金占56.50%。浮选试验结果表明：在-0.074 mm 80%的条件下,采用1粗1扫3精的浮选工艺流程,可获得金品位27.68 g/t、银品位107.311 g/t、金回收率72.18%、银回收率42.77%的金精矿,综合回收效果较好。     

硫代硫酸盐法回收某金矿废水池污泥中金的研究

在NaOH、Na2SO3的协同作用下,探索了硫代硫酸盐法回收某金矿废水池污泥中金的条件。通过单因素和正交试验得出：在反应温度50-55℃,反应时间3h,试剂与干污泥的最佳质量比为：Na2S2O3·5H2O 72．1％,NaOH 11.3％,Na2SO3 11.3％,此时浸金率可达90．1％以上。     

石灰石矿山闭坑后复垦研究

结合石灰石矿山闭坑后，采空区和废石场的复垦绿化问题的实际状况，提出一些建议。     

江西某金矿尾矿再选试验研究

江西某金矿浮选尾矿属于低品位难处理含金硫化矿，由于尾矿长期堆存，部分硫化矿石表面氧化程度高，为确定该尾矿资源开发再利用工艺，进行了选矿试验。工艺矿物学研究结果表明，矿石中Au品位为0.70 g/t，为主要的回收元素，主要以单体金和硫化物包裹金的形式存在，其次以氧化物包裹金的形式存在；根据该矿石性质特点，采用以多硫化钠为硫化剂的浮选工艺流程处理该矿石。粗选条件试验表明，粗选多硫化钠最佳用量为80 g/t，粗选的最佳矿浆pH值为8；在条件试验的基础上进行硫酸铜、丁铵黑药、丁基黄药和多硫化钠用量正交试验，并对试验结果进行验证试验，最终确定优水平组合为硫酸铜50 g/t、丁基黄药150 g/t、丁铵黑药50 g/t，多硫化钠80 g/t；在矿石粗选磨矿细度为-0.074 mm占90%、矿浆pH为8、煤油用量100 g/t、多硫化钠用量80 g/t、丁基黄药+丁铵黑药用量(150+50) g/t，硫酸铜用量50 g/t，水玻璃用量200 g/t，2#油用量40 g/t的条件下，经“1粗2精2扫”的闭路试验，可获得Au品位13.25 g/t、Au回收率57.16%的浮选金精矿，相较于未添加多硫化钠的浮选流程，精矿指标良好，研究结果为该矿山和类似矿山的尾矿资源回收利用提供一定的参考。     

Design Criteria for Limestone Neutralization at a Nickel Mine

Abstract.   Design criteria were developed for the construction of a full-scale limestone neutralization plant to treat leachate from the waste rock of a nickel mine, using data from laboratory studies, pilot-scale studies, and operation of a full-scale limestone handling and dosing facility. We learned that: limestone powder can be slurried to a constant slurry density of 60 g/L; Fe (II) can be oxidised at low pH (2.5) at a rate of 16.1 g/(L/d) using geotextile as a medium; and that the integrated Fe (II)-oxidation and limestone neutralization process allows neutralization, Fe (II)-oxidation, and gypsum crystallization to take place at the same time, provided that the solids concentration is high (greater than 30 g/L). A full-scale plant with a capacity of 50 m³/h was designed and constructed. The plant consists of the following stages: biological Fe (II)-oxidation, a fluidised-bed limestone neutralization reactor, a complete-mix gypsum crystallization reactor, and a clarifier.     

提高安徽某金矿金回收率的试验研究

试验表明影响某矿金浮选指标的两个主要因素为磨矿细度和浮选pH值;利用金矿物浮选速度的差异,提出了快速浮选流程内部结构改进方案,使金精矿品位提高了0.97g/t,回收率提高了4.40个百分点。     

某石灰岩矿山超深竖井帷幕灌浆设计

结合工程实例,介绍某水泥厂石灰岩矿山超深渗漏竖井帷幕灌浆工程的设计方案和实施效果,提出在竖井壁外围四周的岩体钻小孔灌注水泥浆形成防渗帷幕的设计思路,并给出了具体的注浆钻孔分布、口径、深度及灌浆水泥标号、水灰比、压力、结束标准等技术参数,为类似工程提供参考经验。     

某金矿浮选试验研究

对金矿原矿品位为1.53 g/t,主要载金矿物为黄铁矿和黄铜矿的某金矿,进行了着重回收金属硫化矿物的探索实验,确定采用碳酸钠调浆和丁铵黑药＋丁基黄药组合使用的方式进行浮选条件实验。经过条件试验确定了最佳磨矿细度为-200目65.05%,碳酸钠用量为1 000 g/t,丁铵黑药与丁基黄药配制比例为1∶3,用量为60 g/t。开路试验采用一次粗选、三次精选、一次扫选工艺,由于金精矿品位较高,但一次扫尾矿品位较高,故闭路试验采用一粗、两精、两扫工艺流程,得到了金品位为70.26 g/t、回收率为92.30%的浮选金精矿。     

基建矿井灰岩水的治理

贵州省六矿务局苦竹林矿是高计年产15万t的小型矿井。建井期间，井底车场绕道、内水仓、吸水小井岩底板出水总量达620m^3/h。经过3.5个月井下注浆堵水施工，全矿井石炭系灰岩总涌水量降到10.98m^3/h，堵水率达98.23%。     

吉家洼金矿氰化尾矿浮选回收金工艺的实践

针对吉家洼金矿氰化尾矿品位偏高,对氰化尾矿采用浮选回收金工艺获得金精矿品位39.60 g/t,回收率41.00%较高的技术经济指标.对金矿尾矿再回收有较好的指导意义.     

青海五龙沟金矿中金的赋存状态研究

青海五龙沟金矿石贵金属矿物以自然金为主,金品位为2.43 g/t,伴生低品位银,属于微细粒—超微细粒浸染型含碳、砷的极难选冶金矿石。为给该矿石的开发利用提供依据,采用X荧光分析法、化学分析、矿相显微镜、X射线衍射分析及MLA矿物自动定量系统等手段对矿石的化学成分、结构构造、矿物组成及金的赋存状态进行研究。结果表明:(1)矿石有价元素为金、银,有害杂质砷、碳含量较高,含金矿物主要有自然金及方锑金矿、黑铋金矿、碲金银矿等;(2)金粒大多数呈显微、超显微分散状态包含于毒砂及斜方砷铁矿中,其次包含于绢云母、绿泥石和石英等脉石矿物中,少数与黄铁矿和磁黄铁矿连生或包裹,显微镜中可见金不多,粒度大多小于1μm;(3)金嵌布粒度以微细粒为主,98.45%金粒粒度小于0.04 mm;黄铁矿、毒砂和磁黄铁矿的嵌布粒度以中细粒为主,均处于浮选的适宜范围;(4)金的选矿回收与硫砷化物的回收密切相关,尤其是要重视毒砂的回收。研究结果可以为该金矿石的合理开发利用提供技术依据。     

菲律宾某尾矿中金的赋存状态

菲律宾某尾矿库中矿样是金矿全泥氰化的浸渣,古Au0.88g/t,含Ag4.94g/t.在传统显镜观察及化学物相分析等研究办法基础上,结合矿物自动分析仪MLA查明尾矿库中金的赋存状态.矿样中82.95%的金以自然金、银金矿形式存在,17.05%以碲金矿、碲金银矿形式存在.自然金、银金矿产出粒度一般小于0.125mm,碲金矿、碲金银矿产出粒度均小于0.020mm,金矿物产出特征复杂,主要以硫化矿物包裹体、褐铁矿包裹体、石英及方解石等脉石矿物包裹体形式存在.     

贵州某金矿尾矿综合利用研究

为给贵州某金矿综合利用其尾矿资源提供初步的技术基础,进行了试验研究,试验采用浮选的方法先将金富集在金精矿中,然后对这种金精矿采用焙烧-氰化浸出的方法进行处理。试验取得了较好的效果:金精矿品位达到43.4g/t,回收率达到90.56%,尾矿品位为0.21 g/t;焙烧后金精矿的浸出率可达80.94%。因此,在该金矿进行尾矿的综合利用是完全可行的。     

某黄金矿山高浓度含氰废水处理试验

某黄金矿山针对含氰废水中含有高浓度氰化物和重金属等特点,分别采用酸化回收法和硫化回收法对废水中的铜进行回收,考察铜的回收效果。回收铜渣经过高温脱氰处理后满足《黄金行业氰渣污染控制技术规范》（HJ 943—2018）作为有色金属冶炼的替代原料要求,可以精矿产品形式计价外售;废水再经降氰沉淀法深度处理,进一步降低氰化物和重金属含量。在最佳试验条件下,废水中总氰化物浓度＜50 mg/L,处理后废水能循环利用至生产工艺中,且能保证工艺稳定运行。     

Optimizing the Effluent Treatment at a Coal Mine by Process Modelling

Abstract:   The water network of a coal mine was audited and simulated by an interactive steady state model and the results were used to optimise the mines water management strategy. Simulation of the interactions showed that calcium carbonate powder could be used as an alternative to lime for neutralization of acid water at a reagent cost saving of 56%. Gypsum crystallization would reduce sulphate concentrations in the neutralization plant by 30% and in the coal processing plant by 60%. The capital cost for a neutralization/gypsum crystallization plant for separate treatment of coal discard leachate and less polluted streams would cost 3.0 million Rand (R), compared to R10.3 million for combined treatment. Only slightly less (8.9 t/d vs. 9.5 t/d) sulphate removal would be achieved during separate treatment. The over-saturation index (OSI) value can be controlled effectively by removing sulphate from the feed water for coal processing. Sulphate has to be lowered to 350 mg/L in a flow of 222 m³/h to obtain an OSI value less than 1. The capital cost of a 222 m³/h biological sulphate removal plant was estimated at R21.8 million (R4.1 million/(ML/d)); the running cost was estimated at R13.7 million/a (R4.10/m³). Pre-washing of the coal would reduce capital and running costs.     

陕西洛南金矿金钼分离新工艺

研究用选冶联合工艺从陕西洛南金矿综合回收金、银、铅、钼.原矿先经过混合浮选抛尾,得到含金、银、铅、钼等的混合精矿,钼品位由0.18%提高到4.21%,钼回收率为79%,金品位由2.19g/t提高到48.86g/t,金回收率为85.58%.混合精矿经过氧化焙烧、脱硫脱碳、NaCO3选择性浸出、蒸发浓缩等工序生产钼酸钠,达到金、银、铅与钼的分离以及超低品位钼的低成本回收.     

龙门山石灰石矿排土场场址选择

通过运距、安定性、占用耕地、容量、容积与面积比、场内及下方工业设施和村庄、对河道的影响等方面，对龙门山石灰石矿原设计排土场与新选排土场进行对比分析。综合比较，新排土场最佳，其次为杨凹排土场。云中寺排土场的选址不恰当，茅子山2#和3#排土场与云中寺排土场相差不大，建议不予利用。事实证明云中寺排土场多次发生滑塌事故，还发生泥石流，造成巨大经济损失，花费巨大治理费用和相当多的人力和物力。     

石灰石矿矿山地质环境治理实践

介绍了攀钢集团矿业公司石灰石矿依靠科技进步，进行地质环境综合治理的几点实践经验，并提出了进一步加强矿山环境治理的设想。