国外化工技术

国外化工技术钽的制法钽是以含有钽及铌的钽铁矿或铌铁矿等为原料，经碱溶液、氢氟酸处理等预处理，再经冶炼、分离、萃取而得到。萃取方法有２～３种，矿石经碱熔、氢氟酸处理后，用甲基异丁酮溶剂萃取，分离除去铌，即得到钽。单质金属钽主要由用金属铌还原Ｋ２ＴａＦ７...     

铌钽的纸上色层分离和测定

铌、钽纸上色层分离手续简便,快速,近年来已被广泛采用。本文采用甲基异丁酮、丁酮、氢氟酸、水作为展开剂,讨论了影响铌、钽和伴生元素分离的几个因素。高含量的铌、钽以重量法测定,低含量的铌用氯代磺酚S比色测定,钽用碘绿比色测定。     

难分解铌钽矿高浓氢氧化钾浸出机理研究

实验研究了难分解铌钽矿在高浓度氢氧化钾溶液中浸出过程的机理。考察了搅拌转速、反应温度、碱矿比、初始氢氧化钾浓度和矿粒度对铌钽矿中铌的浸出速率的影响。结果表明铌的浸出速率与铌钽矿粒径的平方成反比,浸出过程受克-金-布产物层固膜扩散控制,即1 2(1-X)-3(1-X）^2/3=kt,并由阿累尼乌斯方程得到铌的表观活化能为72．21kJ．mol^-1。结合动力学实验结果和电子扫描电镜(SEM)及X-射线能谱(EDAX)分析,进一步证明了在浸出过程中铌钽矿的表面形成了固相产物层,其主要组成元素为铁、锰等,并指出六铌(钽)酸根离子([(Ta,Nb)6O19]^3.)通过固相产物层的内扩散为浸出过程的控制步骤。研究结果为浸出过程的强化提供了依据。     

KOH亚熔盐浸出低品位难分解钽铌矿的实验

研究了低品位难分解钽铌矿的KOH亚熔盐浸出条件. 探讨了反应温度、初始KOH浓度、浸出时间和碱矿比等因素对铌和钽的浸出率的影响. 结果表明，铌和钽的浸出率分别可达98%和96%，较现行氢氟酸工艺提高10%以上，提高了难处理钽铌资源的利用率. 用无毒的KOH亚熔盐取代现行工艺中高浓高毒性的氢氟酸作为反应介质，从生产源头消除了F–的三废污染，为钽、铌湿法冶金开辟了一条新的途径.     

铜尾矿和钽铌尾矿为主要原料的微晶玻璃的研究

以铜尾矿和钽铌尾矿为主要原料研制了性能优良的微晶玻璃，并研究了钽铌尾矿用量，晶核剂，CaO用量对核化和晶化过程的影响。     

单宁酸重量法和电感耦合等离子体原子发射光谱法联合测定钽铌矿中高含量的铌

钽铌矿中钽铌的含量高低不一，物理化学性质非常相似，目前常采用电感耦合等离子体原子发射光谱法和分光光度法测定，由于仪器检测范围有限，在实际检测过程中，测定含量高的样品时结果往往容易偏低，精密度和准确度很难达到要求，因此本文采用常规的重量法测定。本法运用过氧化钠熔融，盐酸酸化后，加入单宁酸沉淀溶液中的铌钽钛，沉淀过滤后经过1000℃马弗炉灼烧至恒重，即得铌、钽、钛氧化物的含量。用电感耦合等离子体原子发射光谱仪测定样品中钽和钛的含量，通过差减法用铌、钽、钛的含量减去钽和钛的含量，即得铌的含量。研究结果表明，此方法可用于测定钽铌矿中Nb>20%,Ta<20%的钽铌矿样品，有效提高了样品的精密度和准确度，稳定且可靠。     

活性和高熔点金属在硫酸中的应用

评述了活性金属(锆和钛)和高熔点金属(铌和钽)在一定温度和浓度硫酸中的耐蚀性。钛只适用于低浓度；铌适用于常压沸点以下的大部分浓度范围；钽适用于常压沸点及沸点以上的整个浓度范围；Ta40Nb合金几乎适用于所有浓度，但适用温度略低于钽而高于铌；锆适用于常压沸点及沸点以上的w(H2S04)70％硫酸。在选择适用于硫酸的最佳金属时，必须考虑操作条件，以及设备生命周期维修费用和停车费用。设计者亦必须充分考虑温度、浓度及杂质含量偏移的可能性，因为它们对金属的耐蚀性可能会有负面影响。据此建议采用活性或高熔点金属。     

钽铌冶炼过程中三废治理及综合利用

简述了钽铌湿法冶炼过程中废气、废水、废渣产生的机理及治理方法。钽铌湿法冶炼过程中废气(酸性废气、含氨废气)净化排放问题、废水(酸性废水、氨氮废水)分类处理、废渣中回收有价金属和防止放射性物质的扩散是处理钽铌湿法冶炼的关键因素。采用防堵塞移动式筛板湍球吸收塔处理含酸废气、用吹脱汽提法处理含氨废水、分类回收冶炼过程废渣,既回收了钽铌有价金属,又确保钽铌湿法废气、废水、废渣达到国家排放标准。     

钽铌湿法冶炼废水中氨氮去除方法的试验研究

为降低钽铌湿法冶炼过程所产生的废水中的氨氮,对分类处理钽铌湿法冶炼产生的各种氨氮废水进行了试验研究.结果表明,对高浓度氨氮(NH<'+><,4>-N>10000 mg/L)废水进行蒸发、冷凝、结晶,制取的氨水可返回钽铌工业使用:对中浓度氨氮(NH<'+><,4>-N 500～10000 mg/L)废水进行吹脱,吹脱后出...     

浅析氢氟酸-硫酸分解钽铌精矿的工艺及设备

主要介绍了钽铌精矿氢氟酸—硫酸的分解方法;分解过程中的影响因素;分解过程中的主要化学反应和基本流程分析讨论。介绍了钽铌精矿氢氟酸—硫酸分解过程中各种磨矿设备的原理和分解设备的不断变化,并从反应动力学和热力学的角度分析了钽铌精矿的反应速度对分解率的影响;以宁夏东方钽业股份有限公司为例说明分解改造后使用雷蒙磨、大体积分解槽和自动化投料系统对钽铌精矿分解工序所取得的效果变化。     

The anodic oxidation of superimposed niobium and tantalum layers: theory

Perriere, Rigo and Siejka have investigated the anodization of superimposed layers of niobium and tantalum, and their results are interpreted here in terms of known processes for the individual metals. Niobium oxide is less resistive to the passage of anodizing current than tantalum oxide, and it can then be shown that, when the niobium layer is superimposed, the metal order will be conserved during anodization. When the tantalum layer is superimposed, however, a partial inversion occurs, with fingers of the substrate niobium oxide pushing their way through the tantalum oxide. The latter is thus converted to a mesh, whose holes are filled with niobium oxide; because the current flows preferentially through this niobium oxide, the tantalum oxide in the mesh is almost completely divorced from the anodizing process. It then acts as a good inert, immobile marker for the purpose of measuring the transport numbers of metal and oxygen, and thus confirms the immobility of the noble gas markers used previously. The tantalum oxide originally within the holes mixes with the niobium atoms pushing their way through; these tantalum atoms then migrate outwards with the niobium atoms, but at approximately two-thirds the rate. The observed movement of the tantalum atoms thus depends on their state of aggregation within the anodic film. The experiments of Perriere et al. with oxygen isotopes can be interpreted on the basis that the oxygen order is conserved throughout the migration process     

蒸发法分离甲苯和聚乙烯的生产工艺

在超细纤维生产过程中需使用甲苯作为减量处理溶剂。介绍了采用多次蒸发浓缩的方法从减量处理生成的甲苯废溶剂中回收提取甲苯、分离聚乙烯熔体的工艺,最终达到节能降耗、环保生产的目的。     

Extraction Characteristics of Niobium(V) and Tantalum(V) on Trioctylmethyl Ammonium Chloride-Impregnated Polyurethane Foam

Abstract

A reagent-impregnated polymer material has been prepared with trioctylmethyl ammonium chloride (TOMAC) and polyurethane foam as a new type of extractant for niobium and tantalum. Niobium(V) and tantalum(V) can be easily concentrated from their hydrofluoric acid solutions with TOMAC-impregnated polyurethane foam. The log D value for tantalum(V) is more than 4 in the HF concentration range from 0.5 to 2 mol·L^?1. The recovery of tantalum(V) from hydrofluoric acid solutions containing a large amount of niobium(V) has been successfully carried out by a batch technique. Extraction characteristics of the present system are similar to solvent extraction rather than to conventional anion-exchangers with respect to the dependence of the value of log D on hydrofluoric acid concentration.     

活性白土生产中漂洗分离工艺的改进

对比传统的活性白土生产工艺,介绍对活性白土生产中漂洗工艺的改进,包括漂洗的控制及改进、用压滤取代传统的自然沉降、隔膜压滤机取代板框压滤机等,这些改进不仅提高了生产效率,降低能耗,而且对环境友好。     

碳五工艺分离过程模拟与参数优化

利用Aspen Plus软件,建立了碳五工艺分离第一萃取精馏单元的过程模拟,考查了萃取精馏塔主要操作参数如溶剂比、回流比对分离过程的影响,确定了萃取精馏塔的最佳工艺操作条件。     

Recent topics of research and development of catalysis by niobium and tantalum oxides

Current topics of catalysts containing niobium and tantalum, especially in the field of solid acid catalysis and selective oxidation of hydrocarbons are reviewed. Hydrated niobium oxide and hydrated tantalum oxide are highly acidic. Hydrated niobium oxide is active for the hydration of ethene to ethanol, and Nb–W mixed metal oxide is more active for the reaction. Acid properties of tantalum oxide are changed by being supported on SiO₂. Ta oxide/SiO₂, prepared by the chemical reaction between tantalum alkoxide and surface hydroxyl groups of SiO₂, is active and selective for the gas phase Beckmann rearrangement of cyclohexanoneoxime to caprolactam. Niobium oxide and tantalum oxide easily react with many other oxides to form mixed metal oxide phases with complex structure. Mixed metal oxide catalysts, containing molybdenum, vanadium, certain elements together with niobium are active for the selective oxidation of hydrocarbons. Especially, the selective oxidation of propane by such mixed metal oxide catalysts has been paid attention. Additionally, recent progress of environmental catalysts, promoted by niobium and tantalum compounds, namely catalysts for the pollution abatement is reviewed.     

利用溶剂从卤水中提取氯化钾的新工艺研究

本文研究了不同温度条件下甲醇对氯化钾、氯化钠单盐溶液饱和溶解度的影响,以及甲醇对氯化钾氯化钠混盐溶液饱和溶解度的影响,并提出了一种从卤水中提取氯化钾的新工艺方案。     

人造沸石处理钽铌厂矿石分解工序含氟废水的研究

对含氟量为1836mg／L的钽铌厂矿石分解工序碱性废水用沸石进行除氟试验。对未改性沸石．试验了沸石用量、废水初始浓度和振荡吸附时间对氟去除率的影响，发现未改性沸石氟去除率不高。用AlCl3溶液对其改性后，去除率明显升高，可达95％以上，处理后废水残氟量可降到10mg／L以下，达到国家污水综合排放标准中的一级标准。