溶剂萃取法提取钨研究现状

近年来溶剂萃取法提取钨技术有所发展,其中以碱性条件下萃取钨和双氧水配合萃取分离钨钼技术的研究最为突出。概述了在近十年来用溶剂萃取法制备钨化合物取得的新技术、新方法;分析了酸性介质、碱性介质等条件下溶剂萃取钨的机理和特点,并讨论了两类介质溶剂在萃取钨工艺中各自的优缺点,特别介绍了在碱性介质下以季铵盐为萃取剂,碳酸氢铵为反萃剂,苛性钠为再生剂萃取钨的工艺机理以及在近年来所取得的成果;总结了利用钨钼过氧络合物性质差异分离钨钼和利用季铵盐与钨钼结合能力不同分离钨钼的两种工艺特点和最新进展。     

从钨矿苏打浸出液中直接萃取钨的连续运转试验

采用工业实际钨矿苏打浸出液在离心萃取系统中进行了季铵盐直接萃取钨的连续运转试验。结果表明,过程运行稳定;当料液中Mo/WO3在4%左右时,在优化的操作条件下,WO3的萃取率大于97%,反萃液WO3浓度大于160g/L,杂质P、Si的除去率大于97%。长期运转试验表明,有机相在累计运转1000h后萃取-反萃取性能保持不变。试验结果为碱性介质萃取钨新工艺的工业化铺平了道路。     

钨湿法冶炼新工艺技术的应用

简述了郴州钻石钨制品有限责任公司在钨湿法冶炼新工艺技术方面的应用，并对钨湿法冶炼工艺今后的发展提出了建议。     

溶剂萃取法在钨湿法冶金中的应用

概述了溶剂萃取技术在钨冶金方面的应用。主要介绍了钨酸钠溶液的萃取转型、碱性条件下钨酸钠溶液直接萃取和萃取法分离钨、钼工艺研究进展。认为今后钨的溶剂萃取技术研究方向应是自动化、智能化,缩短工艺流程,寻求新型高效萃取剂和清洁生产工艺。     

柿竹园预脱铁脱泥黑白钨混浮钨矿选矿新工艺研究

柿竹园多金属矿Ⅲ矿带西北角矿石,性质变化大,较难选。研究采用磁选脱铁-浮选脱泥-黑白钨混浮新工艺处理该矿石。新工艺与原工艺相比,在原矿、钨粗精矿WO3品位相近的对应条件下,小型闭路试验WO3回收率提高15.04%。工业试验在产出钨粗精矿WO3品位13%时,新工艺WO3回收率比原工艺提高2.11%;产出钨粗精矿WO3品位22%时,回收率提高5.23%。     

离子交换串柱吸附与串柱解吸工艺的探索与实践

对钨的离子交换串柱吸附和串柱解吸新工艺作了简要论述。指出在相同条件下新工艺比原工艺的钨的吸附容量（以WO3计）增大约100mg/g干树脂，解吸高峰液中的WO3浓度比原工艺高约80g/L，且液中杂质元素含量下降，因此，产品APT质量提高，APT生产率比原工艺增加约15g/L，而原辅材料氯化铵的消耗量可下降约10%，表明新工艺具有明显的经济效益。     

适应钨资源形势的变化开拓钨冶金的新工艺

根据我国钨资源中白钨比例日益增加且日益复杂难选的现状，指出在钨冶金工业中加强白钨矿处理新工艺，抑制杂质和净化除杂（特别是钼）新工艺研究的必要性，以及与选矿有机配合，由完全处理标准精矿转变为因厂制宜，因矿制宜适当处理次精矿、复杂矿甚至难选钨中矿的必要性，简单介绍了近年来我国在这方面的新成就，特别是钨矿物原料热球磨碱分解工艺及新除钼工艺的情况。     

一种回收处理APT结晶母液等含钨稀溶液的离子交换工艺

本研究开发了一种钨冶炼领域的离子交换新工艺，该离子交换工艺钨的吸附容量大，解吸的钨酸钠溶液钨浓度高、碱度低。该工艺具有运行成本低、回收效率高等特点，可用于APT结晶母液等含钨稀溶液的转型与浓度的富集。     

从废钨渣中酸法回收钽铌的研究

阐述了从废钨渣中酸法回收铌钽的新工艺,采用稀酸脱硅-浓酸脱铁、锰-HF酸浸出-蒸发浓缩工艺,可处理氧化钽和氧化铌含量分别为0.14%和0.59%的钨渣。通过实验确定了最佳的处理条件,在最优条件下可得到含氧化钽8.0 g/L和氧化铌35.4 g/L的HF酸溶液,该溶液可直接用于工业生产,钽和铌的回收率达到80%以上。该工艺既可实现钨渣中钽、铌、硅等资源的回收利用,又可减轻大量钨渣堆存引起的环境污染问题。     

钨绿色冶炼工艺研究方向和技术进展

我国钨冶炼技术世界领先，但由于Na+和Cl-无法闭路循环，沿袭百年的碱（酸）浸出-净化-铵盐转型湿法工艺难以达到废水零排放要求.“钨精矿火法直接制取碳化钨”和“熔盐电解直接制取碳化钨或金属钨”工艺，在金属提纯和分离杂质方面存在难以克服的缺陷，同时存在酸洗废液排放的问题.铵盐不变体系白钨闭路冶炼工艺研究结果表明，与现行白钨碱法-离子交换工艺相比，全流程金属回收率提高2.6%，达到98.1%，APT产品加工成本下降30%，可实现白钨无酸碱闭路冶炼和杂质元素的绿色分离，过程无废水排放.     

钨离子交换工艺中钨锡分离新工艺(Ⅲ)——钨精矿的焙烧预处理研究

在分析SnO2和Cu2FeSnS4碱浸出热力学行为差异的基础上,研究了钨精矿焙烧预处理对锡浸出率的影响。研究表明,苛性钠浸出钨精矿时,SnO2极难浸出,浸出率接近为零,而Cu2FeSnS4的浸出率则高得多,在一般浸出条件下,可高达40%～50%。钨精矿经过氧化焙烧后,可明显降低锡的浸出率,在焙烧温度为700～800℃、焙烧时间为2 h工艺条件下,Cu2FeSnS4所含硫化状态的锡就可完全转化为SnO2。锡的浸出率由5.96%下降至1.05%。     

钨精矿预焙烧分离钨锡工艺研究

在分析SnO2和Cu2FeSnS4碱浸出热力学行为差异的基础上,研究了钨精矿焙烧预处理对锡浸出率的影响。研究表明,苛性钠浸出钨精矿时,SnO2极难浸出,浸出率接近为零,而Cu2FeSnS4的浸出率则高得多,在一般浸出条件下可高达40%~50%。钨精矿经过氧化焙烧后,可明显降低锡的浸出率,在焙烧温度为700~800℃、焙烧时间为2 h工艺条件下,Cu2FeSnS4所含硫化状态的锡就可完全转化为SnO2。锡的浸出率由5.96%下降至1.05%。     

从碱浸出液中萃取钨稀释剂的筛选及对萃取性能的影响

测定了从我国某炼油厂选用的几种不同组分的石油馏分及国内常用的煤油用于季胺盐萃取钨作稀释剂的一些物理性能(包括密度、粘度、闪点) ,并与国外胺类萃取剂常用的稀释剂SC-150进行了比较 ;考察了各稀释剂用于碳酸型季胺盐萃取钨时 ,对萃取剂萃取性能的影响。结果表明 :所选三种石油馏分与煤油和SC -150物理性能相似 ,用作季胺盐萃取钨时动力速度较快 ,1min内达到萃取平衡 ;用于萃取钨时 ,石油馏分作稀释剂比煤油作稀释剂的分相性能更好 ,其中有两种分相时间小于4min,可供工业生产选用 ;稀释剂对萃取饱和容量和钨与杂质的分离系数影响不大。     

Leaching of oxidized zinc ores in various media

The leaching of various oxidized zinc ores in different solvents has been studied in laboratory tests by agitation leaching and in some cases by percolation leaching. Some tests have also been carried out on synthetic zinc compounds.The comparison of the leaching of four different Belgian ores in sulfuric acid, sulfurous acid, ammonium hydroxide and sodium hydroxide, shows that the better results are obtained with sulfuric acid and with caustic soda when the concentration of the latter is high enough. All the ores respond very well to leaching except one which is very rich in iron and can be processed only with concentrated caustic soda. Mineralogical studies have shown that smithsonite is completely leached but that hemimorphite is refractory to leaching in any solvent studied.The leaching in alkaline media (ammonia, caustic soda, diethylenetriamine) has been studied on five different ores. It is confirmed that hemimorphite is difficult to dissolve. Good results are obtained only with caustic soda at high temperature. In ammoniacal solutions, the presence of ammonium carbonate enhances the leaching of hemimorphite but decreases the leaching of smithsonite. The optimum concentration of diethylenetriamine is 250 g/l.Caustic soda leaching tests were carried out on pure compounds and showed that ZnO, Zn(OH)₂, PbO, PbCO₃ and 2PbCO₃βPb(OH)₂ dissolve very rapidly and completely, that the leaching of Zn₂SiO₄ is controlled by kinetics and that the leaching of ZnS, PbS and PbSiO₄ is very poor, their solubility product being very quickly attained.The percolation leaching by sulfuric acid has been tested on Belgian ores and the good results obtained support the idea that this kind of ore could be successfully treated in this way.     

真空挥发法脱除钼硫化后液中负二价硫的研究

采用真空挥发的方式将钼硫化后液中的游离负二价硫脱除.考察了铵硫比、挥发时间、温度、钨钼浓度等因素对硫挥发以及后续季铵盐萃取除钼的影响.结果表明,挥发温度和铵硫比是影响硫挥发率的重要因素.在真空度-80 kPa、挥发温度60 ℃、铵硫物质的量比大于3,可获得较优的硫挥发率;真空挥发过程中,铵分解产生的氢离子可促进钼的硫化反应,有利于钨钼分离.含钼溶液充分硫化反应后,采用真空挥发的操作,既可回收部分硫,还可在后续季铵盐萃取过程中获得更好的除钼效果;当溶液中铵浓度过高,真空挥发进行到一定程度时则会使部分钨结晶析出.      

从高压碱浸液中提取钼钨新工艺

针对某氧化钼钨粗精矿高压碱浸后得到的浸出液钼钨含量均较高、钼钨分离困难的特点,确定了钼钨浸出液镁盐净化除杂、钼钨共沉淀、干燥、钼钨酸铵制备的工艺流程,主要考察了氯化铵用量、沉淀时间、pH、温度、溶液浓度对钼沉淀率的影响。结果表明,最终获得的产品含Mo 47.57%、WO310.13%,杂质磷、砷分别为0.0027%、0.041%,产品符合生产钨钼合金的要求。     

资源、环境与能源压力促使仲钨酸铵第三代生产工艺技术诞生

简单介绍了第三代仲钨酸铵生产工艺和处理高磷、高钼低品位白钨矿的实验结果。该新工艺的基本特点是直接从苏打高压浸出液中萃取钨,萃余液返回浸出,形成闭路工艺。其第二个特征是从纯钨酸铵溶液中,利用专用的"反应-固液分离一体化装置"用树脂沉淀法预除钼后再深度除钼。其第三个特征是采用节能浓缩技术浓缩洗树脂的洗水及解钼液,有价元素返回流程,硫酸铵浓缩固化成化肥销售,实现水零排放。     

碱性体系中砷的反萃性能研究

针对溶剂萃取法处理含砷烟尘碱浸液中的砷未能实现高效反萃的问题,探究了以4%H2O2+饱和Na2CO3为反萃剂的试验效果。结果表明,在25℃、相比O/A=1、油水接触时间7min的条件下,4%H2O2+饱和Na2CO3可将该体系负载有机相中99%以上的砷反萃下来,同时得到可直接利用的循环萃取性能良好的再生有机相,有助于实现季铵盐萃取碱性溶液中砷的低成本和高效短流程化生产。     

Processing of Tungsten Preconcentrate from Low Grade Ore to Recover Metallic Values

Abstract

For the exploitation of a low grade tungsten deposit of Tapaskonda, A.P., India containing 0.1-0.16% WO₃, preconcentrate with 13.06% WO₃ was produced by physical beneficiation. This concentrate containing ferberite along with small amount of wolframite minerals was treated following two routes viz. soda ash roast-leach and alkali pressure leach processes. The parameters such as time, temperature, concentration of alkali, etc., have been studied to optimise the recovery of tungsten. In the soda roast -leach process about 89% tungsten was recovered by roasting the concentrate at 1073 K for 4h under the oxidising conditions. In the alkali pressure leaching process, tungsten recovery was 94% at 463K for 20bar pressure, 100g/L sodium hydroxide and 60 minutes time. The leaching kinetics followed diffusion control model with lixiviant reacting the mineral phase through the porous product layer. An activation energy of 31.2kJ/mole was acquired in the temperature range 428-473 K. The leach liquor was purified with respect to different impurities by a two-stage precipitation process. Tungsten from the purified leach solution was extracted by 10% Alamine-336 and 10% isodecanol in kerosene. The loaded metal when stripped with NH₄OH produced ammonium paratungstate (APT) solution which was crystallised to get the crystal of APT. The alkali pressure leach-solvent extraction process was thus found attractive for treating such concentrates.