Beneficiation of the Nechalacho rare earth deposit: Flotation response using benzohydroxamic acid

Rare earth minerals (REM) may be beneficiated using a variety of separation techniques with froth flotation being the most commonly applied in operating REM separation plants. Many different collectors have been tested with traditional REM such as bastnäsite. The most successful are the hydroxamic acids. The Nechalacho deposit contains many REM for which there is minimal processing information in literature. Thus, experimental investigation into their flotation behaviour is required.This work focuses on understanding the effect of a benzohydroxamic acid collector on the flotation of a REM enriched pre-concentrate from the Nechalacho deposit (after lab-scale gravity and magnetic separation steps). The lab-scale flotation response of the REM is quantified using mass recoveries, water recoveries, QEMSCAN and chemical assay data and TOF-SIMS in order to study the recovery, entrainment and kinetics of different REM. Three different flotation schemes are investigated to determine the effect of a secondary addition of collector as well as the addition of lead ions, a known activator in hydroxamic acid flotation. It is important to note that the goal of this work is to determine fundamental flotation properties of the different REM in the Nechalacho deposit. As such, the process investigated here is not indicative in any way of the current process design for this deposit.     

我国稀土选矿联合工艺的发展现状

本文介绍了稀土选矿的发展现状,从其选矿的工艺流程进行了详细概述,综述了稀土选矿常用的磁选-浮选、磁选-重选、重选-浮选、磁选-重选-浮选联合工艺以及部分化学浸出工艺。不同地区矿石类型、结构性质的不同,导致所选择的工艺和药剂制度亦有所不同。分析研究不同类型稀土矿的选矿工艺方法,对稀土选矿技术发展具有一定指导意义。     

Study on separation of heavy rare earth elements by solvent extraction with organophosphorus acids and amine reagents

The present work describes a study of the separation of rare earth elements (REE) from heavy REE concentrate through solvent extraction. Seven extractants were investigated: three organophosphorus acids (DEHPA, IONQUEST^®801 and CYANEX^®272), a mixture of DEHPA/TOPO (neutral ester) and three amines (ALAMINE^®336, ALIQUAT^®336 and PRIMENE^®JM-T). The organophosphorus extractants were investigated in hydrochloric and sulphuric media whereas the amines performance was assessed in a sulphuric medium. The variables investigated were: concentration of the extractant agent, aqueous phase acidity, aqueous/organic volumetric ratio, contact time, stripping agent concentration (hydrochloric acid solution) and the selective stripping step. In the extraction step, the best separation factors for the adjacent elements were obtained with DEHPA and IONQUEST 801. For 1.0 mol L⁻¹ DEHPA in an initial acidity of 0.3 mol L⁻¹ H⁺, the separation factor was 2.5 Tb/Dy, 2.1 Dy/Ho, 1.9 Ho/Er, 2.0 Ho/Y and 1.1 Y/Er; for 1 mol L⁻¹ IONQUEST 801 in 0.3 mol L⁻¹ of H⁺ it was 2.7 Tb/Dy, 2.4 Dy/Ho, 2.1 Ho/Er, 2.1 Ho/Y e 1.5 Y/Er. The study concluded that for the extractants investigated, IONQUEST 801 is the most indicated for the separation of heavy REE because it has lower affinity with the REE compared to the affinity of DEPHA/REE, which makes the strip of the REE from Ionquest 801 easier than from DEHPA. Moreover, the number of stages necessary for the stripping of the REE from IONQUEST 801 is much lower than that observed when DEPHA is employed.     

岩溶区某稀土分离厂地下水环境影响预测

稀土分离项目废水成分复杂,且污染物浓度高,废水一旦进入地下水,将造成难以修复的污染。本文针对岩溶区某稀土分离厂废水泄漏污染地下水问题,采用数值模拟方法,针对防渗膜完好、防渗膜破裂、岩溶塌陷三种情景预测了污染物氯离子在岩溶含水层中的时空分布情况。结果表明:防渗膜能有效防止地下水污染,一旦破裂,在30a的模拟期内,污染物将运移至厂区外,岩溶塌陷情景下,厂区周边地表水、地下水均将会被污染。研究结果可为岩溶区的地下水污染预测提供一定的借鉴。     

The role of citric acid in the flotation separation of rare earth from the silicates

The Nechalacho project is the most advanced large heavy rare earth elements (HREE) project outside of China. Open circuit and locked cycle flotation tests along with pilot plant testing of rare earth elements (REE) concentration from the host rocks are accomplished with collectors of alkyl phosphates and the modifier of citric acid. In this study, the function of citric acid in the separation of rare metals against silicates is investigated by a combination of micro-flotation tests and time of flight secondary ion mass spectrometry (ToF-SIMS) surface chemical analysis. It was observed that there was little effect of citric acid on the REE recovery in the micro-flotation tests conditioned with de-ionized water (DIW). To evaluate the flotation response with excess secondary ions in the pulp, micro-flotation tests were performed to look at changes in recovery as a result of adding Al ions and the subsequent presence of citric acid. The results from three micro-flotation tests (DIW, DIW with the addition of 100 mg/L Al and DIW + 100 mg/L Al and 500 g/t citric acid) revealed that the addition of Al ions led to a decrease of REE grade, a lower REE minerals recovery and/or an unexpected promotion of silicates to the concentrate. Citric acid reduced the negative effect generated by the Al ions in the flotation, which was shown by an improvement in REE grade. ToF-SIMS surface analysis of undifferentiated grains from the tests with and without citric acid revealed that grains reporting to the concentrate are doing so in response to collector attachment in combination with having more secondary Al on their surface. Citric acid may partially form aqueous soluble metal–ligand complexes resulting in less Al ions on the grains surface, which were rejected to the tailings. Citric acid also may form chelation competing for adsorption on gangue minerals, resulting in a diminished effectiveness of the activation site.     

新兴产业推动稀土消费量显著增长

这是一篇矿业工程领域的论文。粉煤灰中稀土元素的高值化利用,可有效缓解我国粉煤灰污染环境的问题,拓展稀土原料的供应链,保障稀土的战略安全。本文对近年来报道的粉煤灰中稀土元素提取技术研究进行了综述,介绍了酸法、碱熔酸浸和碱浸酸溶提取工艺,以及沉淀法和萃取法分离工艺的研究进展,对比了粉煤灰直接酸浸+化学沉淀法提取稀土工艺、粉煤灰直接酸浸+萃取法提取稀土工艺和粉煤灰碱熔+酸浸+化学沉淀法提取稀土工艺流程的优缺点。指出粉煤灰中稀土的提取技术研究工作可建立在已实现工业化的粉煤灰提取氧化铝和镓工艺流程上,探索粉煤灰中铝、镓和稀土等联合提取开发,不仅可加快粉煤灰中稀土提取的工业化步伐,还可进一步实现粉煤灰综合利用,提升粉煤灰的附加值。     

贵州织金某红土型钛矿矿物学、稀土、微量元素地球化学特征分析

针对贵州织金地区的红土型钛矿资源特征,为查明该钛矿的矿物学性质和稀土、微量元素的地球化学特征内容,以贵州织金某红土型钛矿资源为研究对象,通过XRD、XRF、光学显微镜、扫描电子显微镜等研究手段,知钛元素的主要载体为锐钛矿,TiO2品位在5.02％～8.59％.分析稀土元素特征,知该地区钛矿属于LREE富集,HREE亏损...     

甘肃某微细粒嵌布磁铁矿选矿试验研究

甘肃某铁矿虽然以磁铁矿为主,但由于磁铁矿嵌布粒度微细,磁铁矿单体解离度很低。单一磁选流程磨矿粒度-400目含量达85%,精选后精矿品位57%左右,精矿品位不达标。在原矿经过粗碎干选后,入选品位达到32.28%,经过磁选-重选联合流程,磨矿粒度-300目含量达85%,最高可获得铁精矿品位66.16%,产率32.45%,回收率71.69%的较好指标。     

某富铁型稀土矿中稀土分离富集研究

国外某富铁型稀土矿中铁、稀土矿物嵌布关系复杂、连生包裹紧密,采用单一浮选工艺分离困难,本文通过优选铁矿物选择性抑制剂和稀土矿物捕收剂,形成适于该矿石分选的浮选降铁-磁选除杂的选矿工艺。研究结果表明,针对REO品位为2.95%, Fe₂O₃含量40.30的稀土矿样品,以RF-10为铁矿物抑制剂、RFS为稀土矿物捕收剂,经浮选降铁-磁选除杂工艺可以得到REO品位为36%的稀土精矿产品,铁矿物脱除率达95%,论文研究成果为含铁稀土矿的有效利用提供借鉴。     

Recovery of rare earth metals and precipitated silicon dioxide from phosphorus slag

This article presents the results of a study conducted to investigate the recovery of rare earth metals and precipitated silicon dioxide from phosphorus slag. To determine the possibility and completeness of the studied processes, thermodynamic data was obtained through the determination of the Gibbs energy and equilibrium constant of the reactions of calcium metasilicate with different reagents, namely sodium hydroxide and carbonate as well as nitric, hydrochloric, and sulphuric acids. This article also presents the results of studies on the treatment of phosphorus slags via hydrometallurgical methods using alkaline agents (sodium hydroxide and sodium carbonate) and nitric acid. The recovery of silicon in solution by the autoclave leaching of phosphorus slag using solutions of sodium hydroxide and sodium carbonate resulted in recovery efficiencies of 1.1% and 16.6%, respectively. The nitric acid treatment of phosphorus slag was studied, and the recovery efficiencies of various elements were the following: rare earth metals, 98.3–98.6%; aluminium, 96.5–98.6%; iron, 94.9–96.5%; and calcium, 99.1–99.5%. Nitric acid (46.5%) was selected as the phosphorus slag recovery agent. The cake produced after the nitric acid treatment of phosphorus slag was leached using two processes based on the use of a sodium hydroxide solution: (1) in a temperature-controlled cell under normal conditions and (2) in an autoclave. The process of leaching under normal conditions was determined to be the most effective process, resulting in an efficiency of silicon recovery into solution of 97.7%.     

Rare earth (La,Ce, Nd) and rare metals (Sn,Nb, W) as by-product of kaolin production,Cornwall: Part1: Selection and characterisation of the valuable stream

This paper analyses output streams of a kaolin plant to select the most valuable waste stream for metal recovery. The results indicate that rare metals (Sn, Nb, W) and Light Rare Earth Elements (LREEs) are pre-concentrated in the micaceous residue which contains a relatively high LREE (La, Ce, Nd) concentration of around 170 ppm. This residue have been characterised using a two-stage gravity pre-concentration process involving a Falcon concentrator and a shaking table to obtain concentrates suitable for mineralogical study. A statistical analysis, combined with qualitative mineralogy, highlights the main mineralogical associations and identifies monazite, cassiterite, Nb-rutile and wolframite as the main metal-bearing minerals. Estimation formulas for Nb and LREE using only the TiO₂ and SiO₂ content of the wastes, obtained by binary and multiple linear regression, show very accurate results suggesting a possible on-line application. This will provide tools to select the most valuable waste streams or the associated tailing dams (using historical data) for metals recovery. These selected wastes will be used for metallurgical test works to assess the potential for by-product recovery of these metals.     

从钨重选尾矿中回收铋钼选矿试验研究

广东某钨矿重选尾矿中含有回收价值的Bi 0.033%、Mo 0.029%,主要金属矿物为辉钼矿、辉铋矿、辉铅铋矿、黄铁矿、黄铜矿以及闪锌矿,主要脉石矿物为石英、长石。铋、钼多以硫化物存在。采用铋钼混选-铋钼分离流程处理试样,最终可获得铋品位为31.37%、回收率为74.24%的铋精矿;钼品位为46.68%、回收率为81.50%的钼精矿。     

上海梅山矿业公司选矿流程优化研究及实践

在对上海梅山矿业公司选矿厂选矿流程中存在的主要问题进行分析的基础上，提出了选矿流程优化科研攻关的方向，并对已取得的成绩进行了总结。     

沁水盆地晚古生代煤中稀土元素地球化学特征

摘要：研究煤中稀土元素对分析成煤环境具有重要意义。运用电感耦合等离子质谱、X射线荧光光谱、X射线衍射等方法分析了沁水盆地晚古生代煤及其顶底板炭质泥岩、粉砂岩、灰岩和黄铁矿脉中稀土元素的地球化学特征,探讨了煤中稀土元素的赋存特征及富集成因。结果表明,沁水盆地晚古生代煤中稀土元素含量整体较低,剖面上太原组煤中稀土元素的含量大于山西组,平面上具有南高北低的分布特征。煤中稀土元素主要赋存在粘土矿物和黄铁矿中,碳酸盐矿物和氧化物中稀土元素含量较低,相当部分的稀土元素赋存在有机质中。相关分析表明,稀土元素与Si、Al关系密切。研究认为,沁水盆地煤中稀土元素的富集受控于聚煤古环境,煤层及其顶底板岩石中稀土元素的来源具有一致性,成煤时期海水对泥炭沼泽的影响导致太原组煤中相对富集重稀土,但没有导致Ce的亏损。     

弱磁尾矿中稀土的工艺特征及可选性分析

通过对磁矿系列弱磁尾矿中稀土矿物工艺特征的研究及分析,阐述了弱磁系列尾矿中稀土的可选性.     

疏水团聚-磁种法回收赤泥中微细粒铁矿试验研究

云南文山铝业所产生的拜耳法赤泥铁品位为21.39%,铁主要以赤褐铁矿形式存在,分布率为76.16%,嵌布粒度微细,采用常规磁选方法难以有效回收。本文拟采用选择性疏水絮凝—磁种磁选方法对赤泥中的铁矿进行回收,选择性疏水团聚可以实现细粒弱磁性矿物选择性絮凝成颗粒较大且磁性较强的絮团,然后通过高梯度强磁选实现赤褐铁矿与脉石矿物分离。在六偏磷酸钠用量为3 kg/t、油酸用量为1.8 kg/t、煤油与油酸的体积比为2.2、聚磁介质直径为1.5 mm、矿浆流速为6 L/min、冲次为300 r/min、磁感应强度为0.85 T的优化条件下,获得的精矿铁品位为40.65％、回收率为50.93％。对在最佳选择性疏水絮凝条件下获得的矿浆,经1粗1精磁选,获得了铁品位为45.13％、回收率为39.77％的精矿。疏水团聚—磁种法作用过程不仅包括各种物理化学作用而且是利用综合力场来处理微细粒弱磁性矿物的新选别技术,其具体作用原理有待进一步的深入研究,试验指标也存在进一步提升的空间。     

西山煤田马兰矿区8号煤及其夹矸的微量与稀土元素地球化学特征

运用X射线衍射分析(XRD)、电感耦合等离子体质谱(ICP-MS)及常规化学分析方法对马兰8号煤顶板、煤样、夹矸及黄铁矿结核中的矿物组成、微量与稀土元素及常量元素等地球化学特征进行了分析。结果表明,与美国大部分煤、中国大部分煤及华北石炭二叠纪煤对比：煤样中富集Li、Zn、Ga、Sr、Hf、U、Zr、W、Sn和REEs等元素;顶板样品中富集V、Cr、Zn、Rb、Cs、Sr、Hf、U、Zr、W、Tl、Pb、Ni和REEs等元素;夹矸中富集Li、V、Cu、Ga、Sr、Ba、Hf、Th、U、Zr、Sn、W、Pb和REEs等元素;黄铁矿结核中富集Cr、Cu、As、Se、Cd、Sb、W、Tl和Pb等元素,其中有害微量元素V、Cr、Ni、Cu、Zn、As、Se、Ba、Th、Cd、Sn、Sb、Tl和Pb主要分布在黄铁矿结核、顶板及夹矸中。稀土元素分布模式表明,煤层稀土元素主要来源于陆源碎屑,同时受海水的影响,不同分层受海水影响程度不同。稀土元素含量与灰分产率的相关性分析,以及与Al和Si等造岩元素含量的聚类分析表明,马兰8号煤层稀土元素主要赋存于黏土矿物之中。     

马兰2号煤层夹矸微量与稀土元素地球化学特征及其地质意义

运用X射线衍射(XRD)、电感耦合等离子体质谱(ICP-MS)及电感耦合等离子体发射光谱仪(ICP-OES)对西山煤田马兰矿区2号煤层不同粒径夹矸的矿物组成、微量元素、稀土元素及常量元素等地球化学特征进行了分析,结合元素与矿物间关联性分析对有害微量元素的地质成因过程进行了探讨。结果表明：夹矸中矿物主要由粗粒级石英、结晶度高的高岭石、细粒级黄铁矿及锐钛矿组成,不同粒径样品中矿物组成不同;物源主要为华北二叠纪聚煤盆地北部的花岗岩,并受华北板块北缘晚古生代火山活动的影响;有害微量元素Cr,Ni和Cu受高岭石和石英控制,Zn和U分别与黄铁矿和锐钛矿关系密切。     

内蒙古阿刀亥矿晚古生代煤的微量元素和稀土元素 地球化学特征

利用电感耦合等离子体质谱(ICP-MS)、X射线荧光光谱(XRF)、工业分析等方法对内蒙古阿刀亥矿煤的微量元素和稀土元素地球化学特征进行了研究,并根据某些微量元素的含量及比值探讨了研究区的成煤环境。研究发现,与中国上陆壳相比阿刀亥矿煤中比较富集Cl,Sc,Ge,Se,Zr,Mo,Cd,In,Sb,Te,Hf,Hg,Pb,Bi和REE。稀土元素分布模式表明LREE明显富集,HREE相对亏损,Eu负异常明显,且轻稀土元素之间的分馏程度较高,重稀土元素之间的分馏程度较低,稀土元素可能主要赋存于黏土矿物中。δEu,Sr/Ba,V/（V+Ni）,V/Ni,Ni/Co值及S的含量总体上反映出阿刀亥矿泥炭的沉积环境为内陆淡水还原环境,间或受到海水的影响。     

Comprehensive recovery of the components of ferritungstite base on reductive roasting with mixed sodium salts,water leaching and magnetic separation

Ferritungstite ores have great commercial value because of the huge reserve and high content of W, Mo and Fe. But their economic recovery has long been a challenge due to its complex mineralogy and heterogeneous. The current study investigated how reductive roasting of ferritungstite ores with mixed sodium salts affected the phase evolution of W, Mo and Fe through Micro-area XRD and Powder XRD, with the goal of comprehensive transformation of ferritungstite. Reductive roasting with mixed sodium salts at 800 °C transformed ferritungstite to Na₂WO₄ and magnetite (Fe₃O₄), which were easily recovered by water leaching and magnetic separation. Furthermore, a lot of pores and gaps rather than sintering or agglomeration was observed in the ore particles after roasting by SEM-EDS, which was beneficial for the water leaching of W and Mo. As a result, 96.40% of W and 96.64% of Mo were extracted after water leaching, while an iron concentrate with an Fe content of 55.65% and recovery of 83.30% was obtained after magnetic separation. These results suggested such process would be applicable to the comprehensive recovery of valuable metals from ferritungstite ores, as well as similar tungsten ores and scraps.