离子型稀土矿硫酸镁柱浸过程中水、稀土和硫酸镁的平衡研究

采用柱浸方法研究无氨浸矿剂硫酸镁浸出离子型稀土矿,考察了浸矿过程中H2O、REO、Mg2+、SO2-4走向。结果表明,每千克稀土原矿吸水量约为344mL,稀土元素浸出率在99%以上,全过程损失率仅为0.045%,有0.24%的镁离子残留于矿体中,浸出液中镁离子总量增加4.7%,平衡率为98.76%,硫酸根总体升高0.52%。硫酸镁作为浸取剂,杂质Fe、Si的浸出率分别由硫酸铵浸矿时的0.435%、0.703%降低到0.03%、0.13%,杂质Al的浸出率基本保持不变。     

某离子型稀土矿浸出试验

以中国南方地区某离子型稀土矿为研究对象,采用搅拌浸出和柱浸的方式,研究不同条件下矿样中稀土及杂质元素的浸出情况,为离子型稀土矿产资源的绿色高效开采提供参考。结果表明,浸出液固比对离子相稀土浸出率影响较大,浸出时间影响较小,离子相稀土浸出过程时间短,反应迅速;柱浸过程中离子相稀土流出速率最快,达到平衡时间短,杂质元素前期浸出浓度高,后续拖尾严重;离子相稀土浸出率随着样品深度的增加不断降低,符合南方离子型稀土成矿规律;硫酸铵浸出过程中铵根离子损失量较大,最低损失率超过11.31%,硫酸根不参与金属离子的交换反应过程,回收率最高可达99.22%。     

柠檬酸盐配位浸出风化壳淋积型稀土矿回收稀土的研究

选用柠檬酸盐作为风化壳淋积型稀土矿的浸取剂,并将柠檬酸盐对稀土的浸出效果与硫酸盐和氯化盐等浸取剂进行了对比,考察了柠檬酸铵作为浸取剂时的最佳浸取工艺。实验结果表明,柠檬酸铵作为风化壳淋积型稀土矿浸取剂时,柠檬酸根离子与稀土离子的配位作用,能促进矿石稀土离子交换,提高稀土回收率,降低浸矿剂铵盐的用量,减小氨氮废水的污染。采用柱浸回收稀土的最佳工艺条件为:柠檬酸铵浓度3 g/L,液固比2∶1,浸取剂pH 6.0~8.0,淋洗流速0.5 min/m L,稀土浸出率可达90.01%。     

离子型稀土矿浸取剂遴选及柱浸工艺优化研究

采用规格为Φ6 cm×20 cm的有机玻璃柱柱浸方式,开展了离子型稀土矿新型无氨氮浸取剂的遴选及柱浸工艺优化研究,重点考察了浸取剂类型、浸出剂质量分数、浸出剂用量、浸出p H值对稀土浸出率的影响。研究结果表明,遴选出的硫酸镁作为离子型稀土矿新型无氨氮浸取剂,稀土浸出的效果较好,并确定了较优柱浸工艺条件:浸出剂硫酸镁质量分数为2%,浸出剂用量为液固体积质量比1.0∶1.0,浸出p H值为5.0,水洗用量为液固体积质量比1∶1,浸出的温度为室温。在上述条件下,进行3次平行实验,稀土平均浸出率达到98.40%。在此基础上,采用规格为Ф11 cm×100 cm的有机玻璃柱进行扩大柱浸实验,扩大实验结果表明,该浸出工艺稳定,稀土浸出率稳定,达到99%以上。     

离子型稀土矿浸出过程主要物质浸出规律研究

采用柱浸法研究硫酸铵浸取离子型稀土矿过程中水、稀土、硫酸铵及其他杂质离子的浸出规律. 研究表明,离子型稀土矿矿土对水有较强的吸附能力,浸矿后,矿土的含水率由17.74 %增加到33.7 %.浸出过程中,稀土浸出率可达99.98 %,杂质中Al3+浸出量比较大,SiO₃2-浸出量较小,而Fe3+几乎不浸出,各离子的浸出先后顺序为:SiO₃2-、RE3+、Al3+、Fe3+,杂质Al3+的浸出略滞后于稀土的浸出. Al3+、Fe3+浓度达到峰值时,pH值最低,随着浸矿剂和顶水的加入,浸出液的pH值开始上升,直至达到硫酸铵溶液的pH值和顶水的pH值.      

ICP-AES法测定离子吸附型稀土矿镁盐体系稀土浸出液中稀土与非稀土杂质

硫酸镁作为离子吸附型稀土矿的浸取剂,具有价格便宜、对环境影响小等优点,有望消除硫酸铵浸取过程中的氨氮污染,实现离子吸附型稀土矿的生态友好浸取。离子吸附型稀土矿浸出过程耗时长,过程中稀土浸出液所需取样数量多,而且稀土浸出液具有需要测试元素多,样品中元素含量差异大,样品之间同一元素含量差异大等特点。通过分析谱线选择、基体影响分析、谱峰漂移校正,分段计算等手段,建立了电感耦合等离子体原子发射光谱法(ICP-AES)测定镁盐体系稀土浸出液中稀土与非稀土杂质的方法。通过精密度实验、加标回收实验、空白实验及方法对比实验来验证方法的可靠性。研究表明:所建方法的方法检出限小于0.03 mg·L~(-1),被测元素的测试误差以及相对标准偏差都能控制在5%以内,可以实现对镁盐体系稀土浸出液中稀土、铝、镁、钙等元素的准确测试,获得较真实的稀土浸出率等过程参数,为硫酸镁浸取离子吸附型稀土矿这一新技术提供了分析测试保障。     

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。     

镁钙铵系浸取剂对离子吸附型稀土矿区土壤生态影响初探

离子吸附型稀土矿富含宝贵的中重稀土战略资源,工业开采过程产生的氨氮污染问题长期备受关注。分别以硫酸镁、氯化钙和硫酸铵柱浸模拟离子吸附型稀土矿浸取尾矿,以中黄13大豆为供试作物,开展了室外盆栽试验,探究其对离子吸附型稀土矿区土壤的生态影响。结果表明,与采用铵浸尾矿种植相比,采用镁浸或钙浸尾矿种植的豆苗株高相当或更高,叶片的叶绿素含量更高或相当,根系生长正常,主根明显,侧根茂盛,且地径明显更粗,这可能与镁、钙等能直接参与叶绿素合成、加速糖分运输、改善土壤板结等有关。与采用硫酸铵浸取剂浸矿相比,采用硫酸镁、氯化钙浸取剂浸矿对离子吸附型稀土矿区土壤的生态影响更小,这也为离子吸附型稀土矿绿色开采和浸矿场地污染防治指明了发展方向。     

离子型稀土矿无铵绿色浸矿剂探索研究

本文对南方离子型稀土矿开展了新型无铵绿色环保浸矿剂探索试验,研究了浸矿剂浓度、液固比和pH值对硫酸铵、硫酸镁和SAK(一种含K和Al的复盐) 3种浸矿剂浸矿的影响,并综合比较了该3种浸矿剂的浸矿效果。结果表明,RE和Fe、Si、Al、Ca杂质元素浸出率随着浸矿剂浓度和液固比增加呈现先增后趋于平缓趋势,随着pH值增大而呈现递减趋势;在浸矿剂浓度2%、液固比0.6∶1、硫酸铵和硫酸镁pH值5.0、SAK pH值3.0的条件下,进行稀土矿中金属浸出试验,Al浸出率大小顺序为硫酸铵>硫酸镁>SAK;Fe、Si和Ca则为SAK>硫酸铵>硫酸镁;相比硫酸镁,硫酸铵和SAK浸矿速度较大,洗水用量较少。从无氨氮绿色环保、浸矿效果方面考虑,确定SAK为新型浸矿剂,最优浸矿工艺参数为浸矿剂浓度2%,液固比0.6∶1,pH值3.0,此条件下稀土浸出率为96.93%,Al浸出率为13.78%。     

离子型稀土矿渗流溶浸行为研究

离子型稀土矿性质复杂,当前所采用的原地溶浸工艺适应性不强、影响因素较多,为揭示离子型稀土矿原地溶浸过程影响机制,探寻溶浸过程优化调控方法,本文以江西龙南足洞风化离子型稀土矿为研究对象,采用室内柱式溶浸法模拟原地溶浸工艺过程,开展离子型稀土矿溶浸过程影响规律研究,考察浸出过程各工艺因素对离子型稀土矿浸出效率的影响以及稀土原矿浸出前后的物质变化。研究结果表明,调控离子型稀土矿浸出过程原矿含水量4%、矿层高度43 mm,浸出剂浓度4%、浸出剂溶液p H值5.0、浸取过程固液比1.0∶0.8、浸取剂流速5 ml·min-1为最佳浸出条件参数,在原矿REO总量为0.078%的情况下,可获得浸出率为92.87%的稀土母液,母液中稀土平均浓度为1.73g·L-1,效果良好。稀土离子在浸出过程中与浸出剂的电解质NH+4发生了离子交换反应,稀土离子被交换浸出,而阳离子电解质NH+4则保留在浸渣中,整个浸出过程未生成其他新的物质,没有改变离子型稀土矿原有的晶型结构,不会影响稀土离子的渗流溶浸,有利于离子型稀土矿的绿色高效提取。     

Leaching ion adsorption rare earth by aluminum sulfate for increasing efficiency and lowering the environmental impact

The leaching efficiency(LE) of ion adsorption rare earth(IARE) by the sulfate and chloride of ammonium,magnesium and aluminum were comparatively determined using column leaching method. It is found that at equal equivalent concentration of cation, the LE of IARE by aluminum sulfate is the highest, and the zeta potential of clay mineral particles in the tailing is near to zero, which means a lower risk of landslide and pollutant emission. Furthermore, the optimum concentration of aluminum sulfate is determined to be0.02 mol/L, which is much lower than that of ammonium sulfate and magnesium sulfate. To reduce the production cost and environmental impact, we proposed a multi-stage leaching process, which was firstly leaching with ammonium sulfate and then with aluminum sulfate, following by water washing and lime neutralizing. With the ratio of ammonium sulfate to aluminum sulfate varying from 1:0 to 0.5:0.5, the residual ammonium in tailing decreases from 11.2% to 0.6%, however, the LE of RE shows an optimum value at 0.8:0.2. By neutralizing the pH of tailing with lime water to over 6, the ion concentration in water rinsing solution can meet the requirement for water discharge. At the same time, the zeta potential of clay particles is found to be around-5 mV, means a relatively lower risk of landslide. These facts indicate that the LE of IARE can be increased and the danger caused by tailings landslides and pollutant emissions can be reduced by replacing ammonium sulfate with aluminum sulfate as leaching reagent.     

Recovery of rare earths from ion-absorbed rare earths ore with MgSO4-ascorbic acid compound leaching agent

The magnesium sulfate leaching technology for the ion-absorbed rare earths ore can solve the ammonia pollution problem existing in ammonium sulfate leaching process. However, the leaching capacity of magnesium sulfate is slightly weaker than that of ammonium sulfate, resulting in a bigger consumption of magnesium sulfate. In this paper, the MgSO_4-ascorbic acid compound leaching agent had been demonstrated to deal with the ion-absorbed rare earths ore. The ascorbic acid could form a stable coordination with rare earth ions, so that it can strengthen the leaching of ion-exchangeable phase.Moreover, ascorbic acid has a strong reductive property, it can leach the colloidal sediment phase rare earth as well. The present study investigates the effect of the initial pH and the composition of leaching agent on the rare earth leaching. It is determined that the rare earth leaching efficiency is 107.5% under the condition of pH 2.00,0.15 mol/L magnesium sulfate and 1.0 g/L ascorbic acid in leaching agent. In this case, the content of the ion-exchangeable phase and colloidal sediment phase rare earth in the leaching residues are both only 0.02‰. The leaching efficiency of colloid sediment phase rare earth can be 85.7%,so that the Ce partition in the leaching liquor increases to be 5.77%. The magnesium-ascorbic acid compound leaching agent is proposed to be a promising choice to deal with the ion-absorbed rare earths ore, which can realize the efficient leaching, low consumption of MgSO_4 and environmentally friendly leaching.     

Mineral properties and leaching characteristics of volcanic weathered crust elution-deposited rare earth ore

Weathered crust elution-deposited rare earth ore is an important resource of rare earths, including grantic weathered crust elution-deposited rare earth ore and volcanic weathered crust elution-deposited rare earth ore. The development condition of the weathered crust, weathering degree and mineral composition of these ores will be different because of the differences between their parent rocks and weathered crust causes of mineralogy path. Therefore, mineral properties and leaching characteristics of volcanic weathered crust elution-deposited rare earth ore from Chongzuo(CZ), Guangxi province were investigated. It was found that the CZ rare earth ore was a typical mid-yttrium and rich-europium ore, with the overall rare earth(REE) grade in ion-exchangeable phase of 0.15%. Partide size classification showed that finer particle had a higher REE grade. Column leaching tests showed that the leaching efficiency of REE was above 94% with leaching agent concentration of 0.20 mol/L, liquid-solid ratio of 4:3, flow rate of 0.60 mL/min, and initial pH value around 5.67. Compared to ammonium sulfate leaching, magnesium sulfate leaching was advantaged by nearly zero ammonia nitrogen emission while their REE leaching was almost equivalent.     

Progress in green and efficient enrichment of rare earth from leaching liquor of ion adsorption type rare earth ores

Ion adsorption type rare earth ores (IATREOs) are a valuable strategic mineral resource in China, which feature a complete composition of fifteen rare earth elements and are rich in medium and heavy rare earth (RE) elements. In the leaching process for recovering rare earth elements from IATREOs, many impurities will be leached together with rare earth elements and enter the leaching liquor. An impurity removal-precipitation enrichment technique is currently applied to selectively recovery rare earth elements from the leaching liquor with the high content of impurities and low concentration of rare earth elements by using ammonium bicarbonate in the industry. However, a high loss of rare earth elements and severe ammonia nitrogen pollution are caused by this process. Therefore, more beneficial impurities removal technologies, mainly for aluminum, and green enrichment technologies with lower pollution are now urgently needed. For this purpose, this paper analyzed two aspects of research progress in recent decades: the green separation of rare earth elements and aluminum from leaching liquor and the green and efficient enrichment of rare earth elements. Finally, an approach for the high-efficiency and green enrichment of rare earth elements from leaching liquor of the IATREOs is proposed in several aspects, including impurity inhibition leaching, neutralization and impurity removal, alkaline calcium and magnesium salt precipitation enrichment, and centrifugal extraction enrichment.     

Reduction leaching of rare earth from ion-adsorption type rare earths ore with ferrous sulfate

The practice of in-situ leaching of the ion-adsorption type rare earths ore with ammonium sulfate could only leach most of rare earth in ion-exchangeable phase,but not the colloidal sediment phase.Therefore,the reduction leaching of rare earth from the ion-adsorption type rare earths ore with ferrous sulfate was innovatively put forward.The soak leaching process and the column leaching process were investigated in the present study.It was determined that ion-exchangeable phase could be released,and part of colloidal sediment phase rare earth could be reduction leached by the cations with reduction properties.The mechanism of reduction leaching was discussed with the Eh-pH diagram of cerium.Moreover,the stronger reduction of reductive ions,the greater acidity of leaching agent solution,and the higher reductive ion concentration,could result in the higher rare earth efficiency and the bigger cerium partition in the leaching liquor.In the ferrous sulfate column leaching process,the rare earth leaching rate and the rare earth efficiency were a little higher than with(NH_4)_2SO_4 agent,and the rare earth efficiency and the partitioning of cerium in leaching liquor could be about 102% and 5.31%,respectively.However,the ferrous sulfate leaching process revealed some problems,so compound leaching with magnesium sulfate and a small amount of ferrous sulfate was proposed to an excellent alternative leaching agent for further studies,which may realize efficiency extraction and be environment-friendly.     

羧酸盐复合浸取剂对中重稀土浸出强化研究

以缅甸稀土矿与福建稀土矿为研究对象,采用柱浸工艺方法,研究风化壳淋积型稀土矿的矿石性质,分析乙酸铵添加浓度对风化壳淋积型稀土矿轻、中重稀土浸出的影响。结果表明,缅甸和福建稀土矿分别属于中钇型中重稀土选择型稀土矿和富铕轻稀土选择型稀土矿,并且均存在铈负异常和铕负异常现象。乙酸铵最佳添加浓度为0.04mol/L,稀土浸出可达到浸出平衡,浸出率提升到95%,同时乙酸铵主要通过增强钇元素的浸出,使缅甸稀土矿轻/中重稀土比值从1.04下降到0.98,福建稀土矿轻/中重稀土比值从1.65下降到1.47,表明乙酸铵能够明显提高中重稀土的浸出。     

模拟酸雨对赣南稀土矿淋滤实验研究

采用模拟土柱淋滤实验研究酸雨条件下浸矿土壤和尾矿土壤中氮化物的迁移.选取有机玻璃管为试验柱,模拟酸雨淋滤液pH为5.4~5.6,测量两类土壤中NH₄+-N、NO₃--N、有效氮含量,实验结果表明:稀土土壤对铵态氮有一定截留作用,铵态氮流失是导致矿区土壤及周边水环境污染的主要原因;铵态氮在两类土壤的含量随着淋洗量增加而逐渐减少;硝态氮在两类土壤的含量随着淋洗量增加呈现先减少至最低再有所回升,且受土壤pH和土壤埋深影响;有效氮在两类土壤中的迁移特征与铵态氮相似. 实验研究为有效控制赣南稀土矿土壤污染和水体污染提供理论基础.