离子型稀土尾矿硫酸镁高效淋洗脱除氨氮技术研究

针对赣南地区离子型稀土尾矿残存氨氮带来的长期拖尾问题,通过室内柱浸模拟矿区环境,采用淋洗药剂集中淋洗的方法脱铵,开展了淋洗药剂筛选、淋洗工艺优化、淋洗效果验证及尾矿残留淋洗药剂的脱除等方面的研究。结果表明,硫酸镁是适合赣南地区离子型稀土尾矿氨氮淋洗的药剂;当硫酸镁溶液的浓度为2.5%(质量分数)、pH值为5、注液强度为0.3 mL/min时,淋洗效果较好,淋洗液固比为2.9时,尾矿氨氮淋出率为96.97%。将硫酸镁淋洗尾矿在pH值为5.7的雨水中浸泡60天后,浸泡液氨氮浓度低于15 mg/L的直接排放标准。集中淋洗后的尾矿加注顶水可将尾矿中残留的镁离子淋洗下来循环利用,不会对离子型稀土尾矿矿区造成二次污染。     

氨氮在高岭土上的吸附解吸规律研究

治理离子吸附型稀土矿山氨氮污染的首要任务是探清其在矿区土壤中的吸附解吸规律。以化学纯高岭土为吸附剂,硫酸铵为吸附质,研究pH在3、4、5、6条件下氨氮在高岭土表面的等温吸附实验得出,pH越大,氨氮在高岭土表面的单位吸附量越高,其最大吸附量可达9μmol/g;连续提取氨氮解吸实验得到物理吸附态、离子交换吸附态及化学吸附态氨氮最大吸附量分别为0.85μmol/g、3.7μmol/g和3.4μmol/g。根据各吸附态氨氮在黏土矿物表面的吸附解吸规律,在此基础上研究推断,造成离子吸附型稀土矿山氨氮长期性污染的主要氮源是离子交换态氨氮,在原地浸矿结束注完顶水后,再注入高岭土悬浊液,使残留在矿体中的离子交换态氨氮转化成化学吸附态氨氮,则可以很好地治理尾矿山氨氮污染。     

废催化剂中稀土资源的回收与综合利用

研究了从废催化剂中湿法回收稀土。失效催化剂中稀土的含量约2%~5%,主要包含有镧和铈。实验结果表明,酸浸法能够浸出废催化剂中的稀土。用正交试验得出盐酸浸出实验的最佳条件为:浸出温度、固液比、盐酸浓度、浸出时间分别为30℃、1∶8、4.8mol/L、2 h,浸出率高达98.3%。浸出后,浸液pH调到约2,选择性沉淀稀土离子。从废催化剂中回收稀土的全过程总回收率达95%,Al离子也可被回收再利用。     

离子吸附型稀土矿再吸附试验研究

针对离子型稀土矿原地浸矿中的再吸附问题,进行了实验室条件试验,探讨了离子型稀土矿再吸附存在的条件,提出避免离子型稀土矿浸出再吸附的措施。结果表明稀土母液与稀土矿相互接触越充分,再吸附效果就越好;母液稀土离子浓度升高或母液液固比增大,会使稀土矿再吸附量增大;母液中阳离子离子交换能力大于稀土离子,会抑制稀土矿再吸附,交换能力小于稀土离子,会促进稀土矿再吸附;pH值升高再吸附量先增大后减小。同时,为避免浸出过程再吸附,应该选择合适的浸取剂浓度与液固比。     

膜分离技术处理离子型稀土矿稀土开采废水

对离子型稀土矿开采废水采用膜分离集成工艺进行处理,以便回收其中的稀土,降低出水的氨氮。结果表明,在经过废水的预处理后,两级反渗透膜的工艺能将废水中的氨氮降低到5.04 mg·L~(-1),低于15 mg·L~(-1)的废水排放指标。而出水中的稀土离子为0。经过反渗透浓缩回收的高浓度氨氮可循环回用于稀土的浸出过程中,而浓缩回收的稀土可通过纳滤膜进行再次回收富集。稀土回收率达到了92.98%。研究发现,稀土开采废水的预处理对氨氮的去除效果很关键。     

光催化处理低浓度氨氮废水

采用溶胶-凝胶法制备了比表面积为73.69 m²·g^-1和中位粒径(D₅₀)为1.134μm的TiO₂光催化剂,通过添加La、Ce、Pr、Nd、Gd等稀土元素对TiO₂光催化剂进行改性。运用XRD、BET、粒度和氨氮分析等表征手段,考察了稀土离子掺杂、催化剂加入量、H₂O₂加入量和紫外光照时间等因素对TiO₂光催化处理稀土冶炼氨氮废水的影响。结果表明,稀土离子掺杂可有效提高TiO₂光催化处理氨氮废水的能力。在最佳光催化工艺条件下,添加La、Ce元素样品的氨氮去除率均达到80%以上,氯化铵废水中的氨氮浓度可显著降至14 mg/L,达到了稀土工业污染物排放标准中新建企业氨氮限值要求(15 mg/L)。     

纳滤浓缩稀土母液沉淀上清液的实验研究

以赣州某稀土公司浸矿所得稀土母液经NH₄HCO₃除杂沉淀后的上清液为处理对象,主要研究纳滤技术对原液中稀土离子的浓缩效率,以及对NH₃-N分离回收情况,以期能够为工业化分离应用提供借鉴.实验表明,当原液中稀土离子浓度为142.9 mg/L,氨氮浓度为346.1 mg/L时,在操作压力为0.8 MPa,进水pH值为6.49,运行温度为25 ℃的条件下,浓缩液侧稀土离子截留率达到95 %以上,Ca2+、Mg2+、Mn2+、Zn2+等杂质离子截留率能够达到75 %~90 %,透过液侧氨氮浓度为原浓度的60 %左右,有一定的浓缩效果;6.0 L的稀土母液沉淀上清液浓缩至0.6 L时,RE3+浓度升高至1 242.0 mg/L,浓缩了近8.69倍.      

南方离子型稀土矿山生产尾液低浓度稀土回收及氨氮脱除的工艺实践

介绍了某稀土开发公司采取"石灰乳沉淀回收稀土-曝气吹脱-折点氯化除氨氮"工艺处理南方离子型稀土矿山生产尾液,回收了其中的低浓度稀土,并对溶液中的氨氮进行脱除,使之能达标排放.生产实践表明,该工艺可以将稀土矿山低浓度浸出液中含量低于0.1 g/L的稀土进行回收,可获得含稀土(折REO)5％～10％的中钇低铕型混合稀土氢氧...     

支撑液膜法分离铕和钇

本文在详细研究了单一稀土Eu~(3+)、Y~(3+)在聚砜—P_(204)支撑液膜体系中迁移行为的基础上,尝试利用聚砜—P_(204)支撑液膜体系对Eu~(3+)、Y~(3+)的混合稀土进行分离。实验结果表明控制适当的实验条件,利用此支撑液膜体系可以对这两种稀土离子进行有效分离。升高原液酸度,降低膜相载体浓度,可以提高此支撑液膜体系的选择性,有利于稀土离子分离。     

离子型稀土矿山氨氮污染及其治理研究进展

离子型稀土矿山氨氮污染治理是矿山环境保护的重要组成部分。本文对离子型稀土矿山氨氮污染及其治理现状进行了综述,总结了氨氮对土壤、水体的危害,赋存形式及其去除方法。根据氨氮在土壤及水体的赋存形式,对已经开采的离子型稀土矿山,采取土壤淋洗技术去除氨氮;对正在开采的离子型稀土矿山,重点论述了注液工程与收液工程的优化,无铵化浸矿以及矿山智能监控系统。     

膜技术在稀有金属冶炼中的应用

介绍了离子交换膜及压力驱动膜在稀土，钨，铼的提取冶金工艺中的应用，涉及的膜过程包括膜电解，扩散渗析，电渗析，反渗透，纳滤，超滤。归纳了膜分离技术的6大优点及在冶金领域可以发挥重大作用的4个方面，指出了膜技术在稀有金属领域中的广阔应用前景。     

Physical–Chemical Treatment of Groundwater Contaminated by Leachate from Surface Disposal of Uranium Tailings

Leaching of trace elements including heavy metals, nonmetals, and radionuclides from surface impoundments of tailings generated during uranium mining and milling often leads to groundwater contamination. This paper reports results from coagulation and membrane filtration experiments designed to evaluate the capabilities of these processes to remove molybdenum, selenium, uranium, radium, thorium, and other mono- and divalent ions from contaminated groundwater in a shallow unconfined aquifer influenced by uranium tailings. A 10 mg Fe3+/L dose at pH 4 and 10 was found to be very effective for removing radium and thorium that were associated with particles in the raw water. Molybdenum and uranium removals by coagulation are consistent with surface complexation and electrostatic interactions between major coagulant and contaminant complexes in solution. Poor selenium removal suggests that selenate [Se(VI)] was the dominant species in the surficial groundwater. Permeation coefficients (intrinsic transport parameters) for dissolved ions and complexes across three new generation thin-film composite nanofiltration and reverse osmosis membranes evaluated obeyed Gaussian distributions with ionic charge having a mean value of zero. Thus, dissolved solute rejection from brackish multicomponent solutions appears to be only a function of the magnitude of ionic charge and not its sign (positive or negative). Solute permeation coefficients decreased in a power-law fashion with increasing product of molecular weight and absolute ion charge suggesting that both properties determine their removal by nanofiltration and reverse osmosis membranes. Because nanofiltration and reverse osmosis were found to be highly effective for removing a variety of ionic solutes they can be employed in pump and treat operations for groundwater purification prior to reinjection.     

纳滤膜对稀土离子的动态吸附行为及截留特性

采用经碳纳米管改性的亲水化纳滤膜浓缩提取稀土浸出液中的稀土离子,探究纳滤膜表面对La3+、Nd3+、Pr3+、Ce3+和Y3+5种稀土离子吸附动力学行为,考察稀土离子半径的大小对纳滤膜吸附性能和截留性能的影响.结果表明,Freundlich吸附方程比Langmuir方程能更好地描述稀土离子在纳滤膜表面上的动态吸附行为,用Freundlich吸附方程拟合后的结果相关度系数R2能达到0.999以上;在初始浓度为5×105 μg/L,温度为25 ℃,运行压力为0.6 MPa的实验条件下,纳滤膜对稀土离子的浓缩提取过程中,初始阶段的截留机理取决于纳滤膜表面的吸附作用和膜孔的机械筛分效应,膜面吸附达到平衡后以膜孔的机械筛分效应为主,此时La3+、Nd3+、Pr3+、Ce3+和Y3+的截留率分别为94.21 %、81.25 %、85.80 %、89.90 %和81.18 %,表明经碳纳米管改性的亲水化纳滤膜能高效浓缩截留稀土浸出液中的稀土离子.      

Membrane combination technic on treatment and reuse of high ammonia and salts wastewater in rare earth manufacture process

With the rapid development of rare earth industry in China,high NH3-N and high salts wastewater generated in rare earth manufacture process had caused serious environment pollution especially for surrounding water body.Traditional treatment processes were either incapable of reducing pollutants concentration to the levels regulated by law or prohibitively expensive and difficult to operate.In this paper,a hybrid process which integrated air stripping pretreatment and low pressure reverse osmosis(LPRO) was proposed to treat this wastewater containing high ammonia and salt.Mechanism of treatment and remediation of ammonia and salt polluted water body was investigated.Influences of temperature,pH,and air stripping time on removal ratio of ammonia efficiencies were also discussed.Relationship among trans-membrane pressure drop(ΔP),additions ratio,stability of membrane and the possibility of water reuse were studied.The results showed that removal ratio of ammonia after LPRO desalination process could reach up to 98%,fluoride amounted to more than 99% and desalt efficiencies reached up to 95%,and stripped gas ammonia could be effectively recovered.Water quality had been improved significantly to meet reuse or discharge standards.     

Effect of impurity ions on preparation of novel saponifier for rare earth extraction

Magnesium bicarbonate,prepared by the carbonation of magnesium hydroxide slurry,was used as a novel saponifier to eliminate the ammonia nitrogen pollution in the rare earth extraction separation process.The effect of impurity ions introduced by system on the carbonation reaction of magnesium hydroxide was studied in the work.The results showed that the presence of Ca2+ could lead to side reactions so as to reduce the conversion rate of magnesium hydroxide,and a small number of rare earth ions would have great influence on the carbonation reaction.What’s more,there was no influence on carbonation reaction with the low concentration of Na+or Mg2+,the conversion rate of magnesium hydroxide could reach above 96%.This paper showed a practical theory which could provide scientific guidance for the preparation of novel saponifier in rare earth extraction separation process.     

稀土氨氮废水治理及资源化集成技术的研究

以吸附法与化学沉淀法的集成技术组成氨氮废水处理的闭路循环系统,用自制的MgHPO4(MHP)为吸附剂,对NH4+浓度为5175mg/L稀土硫酸铵废水进行了氨氮吸附性能实验,研究发现pH、MHP的投加量和氨氮初始浓度是影响氨氮去除效果的关键因素。在室温下,调节反应体系pH=9.5,MHP用量按摩尔比n(MHP)∶n(NH4+)=2∶1投料,搅拌吸附30min,氨氮去除率可达85.7%,且氨氮初始浓度越高,吸附效果越好。MHP再生与循环使用实验表明,MAP焙烧可使MHP再生,同时可回收高浓度的氨水,MHP循环使用三次,氨氮的去除率均在70%以上。如果采用MHP二级吸附法后,再用MAP沉淀法处理废水,可使出水氨氮浓度降低为87mg/L,累计氨氮去除率可达到98%以上。     

全泥氰化工艺尾水综合回收新工艺

针对全泥氰化工艺尾水开展100t/d工业试验研究,开发纳滤、反渗透二段浓缩铜银络合离子工艺,通过置换、中性萃取、酸性反萃、电积全新工艺技术,在不改变尾水理化性能的条件下,实现了活化游离氰根,提高金、银浸出率,综合回收电积铜的目的。     

半风化离子吸附型稀土的浸取实验

针对龙南某矿山的半风化离子型稀土进行浸取试验研究.矿样中全相品位为 0.11 %,其中离子相稀土含量为 0.083 7 %.考察了浸取剂种类,浸取剂浓度,淋洗液固比以及尾水液固比对浸取的影响,其最佳柱浸浸取条件为:HT-13 浓度 2 %,淋洗液固比（指质量比,下同）为 0.4:1,尾液水液固比为0.6:1, 在此条件下稀土离子相浸出率为 98.06 %. 在放大试验中 HT-13 浸出液中稀土离子浓度为1.14 g/L,铝浓度为 10.8 mg/L,铁浓度为 7.8 mg/L,且 HT-13 可以循环使用.      

扩散渗析法应用于石煤提钒酸浸液预处理研究

采用扩散渗析法对石煤提钒酸浸液进行预处理,考察料液(酸浸液)流速、水料(水/酸浸液)流速比对处理后液pH、硫酸回收率、水反渗率、离子截留率的影响。研究表明,在料液流速12mL/min、水料流速比1.0~1.1的最佳条件下,预处理后的酸浸液pH由0.04提高到1.0,硫酸回收率为71.12%,水反渗率为14.95%,钒截留率为95.50%。主要杂质离子铝、铁、镁、钾、氟、磷、硫的截留率分别为99.04%、97.37%、98.01%、85.12%、98.33%、91.16%、69.96%。扩散渗析预处理实现了酸浸液pH的提升,同时回收酸可以重新利用。