EFFECT OF FINE GRINDING ACTIVATION ON LEACHING BEHAVIOUR OF SCHEELITE CONCENTRATE

The influence of mechanical activation on the leaching behaviour of scheelite was studied by means of fine grinding in an attritor and subsequently HCl leaching in presence of PO_4^(3-). Results showed that after fine grinding in the attritor,the reaction rate of scheelite with HCl-Na_3PO_4 solution was remarkably increased,the extraction of W increased from about 8 to 99%.The IR spectra and X-ray diffraction analysis indicated that in addition to an enlargement of surface area the fine grinding action had made also changes of fine struc- ture and reactivity of solid surface,hence the leaching process of scheelite can be carried out under mild leaching conditions.

Effects of mechanical activation and oxidation-reduction on hydrochloric acid leaching of Panxi ilmenite concentration

The effects of oxidation-reduction treatment and mechanical activation on the hydrochloric acid leaching performance of Panxi ilmenite concentration were investigated.The results show that both of oxidation-reduction treatment and mechanical activation significantly accelerate the extraction of Fe,Ca and Mg from Panxi ilmenite concentration;however,the CaO and MgO contents of the calcined residues obtained from oxidized-reduced ilmenite concentration are higher than the standard values required by chlorination process.The Ca and Mg in oxidized-reduced ilmenite concentration can be leached much faster after mechanical activation,yielding a synthetic rutile which meets the requirements of chlorination process containing 90.50% TiO2 and 1.37% total iron as well as combined CaO and MgO of 1.00%.The optimum oxidation and reduction conditions are as follows：oxidization at 900 ℃ in the presence of oxygen for 15 min and reduction at 750 ℃ by hydrogen for 30 min.

Mechanical Activation of Alkaline Leaching of Scheelite Concentrate

The mechanochemical activation for leaching scheelite concentrate with NaOH solution was studied on a laboratory scale. Tungsten recovery more than 98% can be obtained for treating either scheelite concentrate with 66.37% WO 3 or middle grade scheelite concentrate with 41.83% WO 3 using relative low NaOH consumption.

SODA DECOMPOSITION OF LOW－GRADE TUNGSTEN ORE THROUGH MECHANICAL ACTIVATION

Leaching of lowgrade refractory tungsten ore was carried out through mechanical activation. The effect of temperature, amount of Na2CO3, addition of NaOH, ratio of liquid to solid and leaching time on the recovery of WO3 was studied. The WO3 recovery upto 96%～99% has been achieved when the tungsten ore was digested by soda not more than three times stiochiometric amount at 185～195 ℃ for 10～20 h. The WO3 recovery can increase 10%～15% compared to that of conventional soda autoclave process.

A NEW TECHNOLOGY FOR PRODUCTION O F HIGH PURITY PARATUNGSTATE AMMONIUM FROM LOW GRADE TUNGSTEN CONCENTRATE

ＡＮＥＷＴＥＣＨＮＯＬＯＧＹＦＯＲＰＲＯＤＵＣＴＩＯＮＯＦＨＩＧＨＰＵＲＩＴＹＰＡＲＡＴＵＮＧＳＴＡＴＥＡＭＭＯＮＩＵＭＦＲＯＭＬＯＷＧＲＡＤＥＴＵＮＧＳＴＥＮＣＯＮＣＥＮＴＲＡＴＥＳｕｎＰｅｉｍｅｉＣｈｅｎＺｈｏｕｘｉＬｉＨｏｎｇｇｕｉＬｉＹｕｎｊ...

Selective leaching of calcium from mechanically activated mixed rare earth concentrate

The loss of rare earths(REs)takes place during the pre-decalcification process of mixed rare earth concentrate.In an effort to reduce such RE loss,a novel idea to improve the leaching selectivity of Ca to REs by applying selective mechanical activation was proposed.First,regarding the key minerals affecting the leaching selectivity of Ca to REs,the differences in the mechanical activation behaviors of CaF_(2) and REFCO_(3) were studied,and we find that the lattice strain of CaF_(2) increases from 0.21%to 0.42%,whereas that of REFCO_(3) increases from 0.31%to 0.40%.Notably,CaF_(2) demonstrates a larger lattice strain than REFCO_(3),indicating greater mechanical activation energy storage and higher leaching activity.Next,the HCl leaching process was studied.A significant leaching selectivity of Ca to REs,from 21.6 to 35.1,is achieved through mechanical activation.The Ca leaching rate reaches 80.7%when the RE loss is 2.3%in the activated sample.This study provides an novel approach for achieving selective extraction of specific components via mechanical activation pretreatment.

CAUSTIC DECOMPOSITION OF SCHEELITE AND SCHEELITE－WOLFRAMITE CONCENTRATES THROUGH MECHANICAL ACTIVATION

Based on physicochemical study of the reaction between scheelite and NaOH, a new decomposition process for scheelite and scheelitewolframite concentrate, i. e., mechenically activating caustic decomposition has been developed, and it has been successfu

Preparation of High－purity Sodium Tungstate from Low－grade Tung－sten－concentrate with a High Content of Calcium and Other Impurities

A new technological process for production of talium tungstate from low-grade tungsten-concentrate witha high content of calcium and other impurities has been studied. The experiments showed that average tungstenleaching efficiency of more than 96. 92 % can be obtained with a low NaOH consumption by using the mechani-cal activating caustic decomposition , and the content of main impurities (P, As, Si) in Na_2WO_4 solution ob-tained is competitive with that from standard wolframite concentrate by traditional caustic decomposition. Afterrecovering caustic liquor by first crystallization, molylxlenum is removed from Na_2WO_4 solution by ion ex-change method. High-purity sodium tungstate is obtained by second crystallization of Na_2WO_4 solution. Thistechnology has the advantages of good adaptability for raw materials, high removing efficiency of impurities,high tungsten recovery and high economic benefit.

黑白钨混合矿的苏打连续浸出工艺研究

采用卧式连续加压浸出釜进行了苏打连续分解黑白钨混合矿的实验研究,考察了各工艺参数对混合矿分解率的影响。结果表明,在黑白钨混合矿磨矿细度-0.050 mm、浸出温度200℃、液固比2.1∶1、苏打用量为理论量4倍、氢氧化钠用量25 kg/t矿、进料速度10 m^(3)/h条件下,钨分解率达99.55%,渣中WO_(3)含量仅0.28%。连续浸出方式相对间歇浸出方式具有操作简单、生产效率高、综合能耗低、分解率稳定、自动化程度高等优点。

密闭机械活化浸出电石渣制备高纯钙溶液

电石渣是工业生产过程产生的碱性危废,利用于CO_(2)固化,将有助于“碳达峰、碳中和”目标早日实现。在碱性环境中,用氯化铵浸出剂可选择性浸出Ca,使电石渣中的Ca与其他杂质分离开来,从而制备高纯度含钙溶液,之后将所得富钙液与CO_(2)反应制备高纯碳酸钙,从而实现固废资源化。以氯化铵为浸出剂,球磨机为浸出反应设备,采用密闭机械活化手段进行处理,探究了浸出剂用量、机械搅拌转速、反应时间和液固比等工艺参数对电石渣中Ca浸出率的影响。结果表明,在氯化铵用量为理论用量的1.1倍、球磨机转速500 r/min、反应时间10 min和液固比4∶1最佳反应条件下,Ca浸出率可达到89.76%,滤液Ca浓度高达79.4 g/L。相较于常规浸出,采用密闭机械活化手段可提高Ca浸出率3个百分点,且可大幅度降低氨气挥发,保证良好操作环境。

机械活化及其在湿法炼锌中的应用

本文首先概述矿物机械活化的基本原理及其对矿物强化作用.然后对其在湿法炼锌中的硫化锌精矿焙烧、锌焙砂浸出、硫化锌精矿直接浸出等方面应用取得进展进行综述.

钨矿物原料碱分解的理论与工艺

针对难处理白钨矿的冶炼问题,采用热球磨(机械活化)工艺,成功地实现了高钙黑钨矿乃至白钨矿的氢氧化钠分解并在国内广泛推广应用,这种工艺过去国外专家基于理论分析和工程实践认为是不可能的。针对新技术带来的理论问题,进行了详细的热力学研究,在实验测定的基础上,绘制了(CaO-)Na2O-WO3-H2O系赝三元相图。该赝三元相图不仅对机械活化碱分解白钨矿的工艺给出了合理的热力学解释,同时还说明即便在单纯的高压釜中白钨矿的碱分解过程也有良好的热力学窗口,为碱压煮分解工艺提供了理论基础,使之成为当前钨矿分解的主流工艺。此外,(CaO-)Na2O-WO3-H2O系赝三元相图从理论上还预测了更为普遍的白钨矿常压碱分解的工作窗口,即过程中保持NaOH浓度超过临界值,则甚至不必采用高温压煮的工作条件也能实现白钨矿的分解。研究中考虑到较低温度下高浓度NaOH分解矿浆具有极高黏度的特性,为解决分解过程的传质和动力学传质问题,借鉴了高分子塑料加工领域处理高黏度物料的成功经验,发明了在双螺杆挤出机中,连续分解黑、白钨精矿的"反应挤出法"碱分解工艺。

细磨活化对白钨矿浸取行为的影响

本文研究了细磨活化对白钨矿浸取行为的影响.实验结果表明,细磨活化后白钨矿在HCl-Na_3PO_4介质中的浸出速率显著加快,钨的浸出率由原来的约8％提高到99％以上.红外光谱和X射线分析结果表明,细磨除了使白钨矿比表面积显著增大外,还在固体的表面和内部产生缺陷结构,增加了矿物表面的反应活性,改善了白钨矿的分解,使得白钨矿的浸出能在较低的温度顺利进行。

用草酸从白钨矿中配合浸出钨试验研究

研究了用草酸从白钨矿精矿中浸出钨,考察了草酸浓度、液固体积质量比、浸出温度、浸出时间对钨浸出率的影响。结果表明:在草酸浓度2.5 mol/L、液固体积质量比60 mL/1 g、浸出温度95℃、浸出时间4 h条件下,钨浸出率达98.93%;浸出过程符合收缩核模型,表观活化能为55.27 kJ/mol,浸出反应受化学反应控制。

机械活化强化高磷粗铁精矿酸浸脱磷的工艺及机理

采用高压辊磨机对鲕状高磷铁矿经磁化焙烧-磁选所得的高磷粗铁精矿进行机械活化,对不同活化程度的高磷粗铁精矿进行硫酸浸出脱磷,研究机械活化对酸浸脱磷的影响规律,探讨机械活化强化高磷粗铁精矿酸浸脱磷机理。研究结果表明:高磷粗铁精矿铁品位为54.92%,磷质量分数为0.76%;高磷粗铁精矿直接酸浸后铁精矿品位为55.74%,磷质量分数为0.33%,脱磷率为63.79%,铁回收率为84.64%;而对机械活化后的高磷粗铁精矿进行酸浸时,铁精矿品位提高到58.02%,磷质量分数降低至0.10%,脱磷率提高到88.99%,铁回收率为88.42%;机械活化使高磷粗铁精矿细化分散,颗粒内产生裂纹及选择性解离,浸出过程中反应物扩散阻力下降,易于扩散到矿物颗粒表面及其内部参与反应;颗粒形貌及晶体结构均受到破坏,矿物颗粒处于高能亚稳态,活性增强,从而进一步强化脱磷。

机械活化铅锌烟尘强化硫酸浸出的工艺研究

以含铅锌烟尘为原料,采用机械活化-硫酸浸出的湿法冶炼工艺分离铅锌烟尘中的金属铅及锌。着重研究了机械活化前后不同的硫酸浓度、液固比、浸出温度、浸出时间等工艺条件对原料中Zn浸出率及Pb入渣率的影响。实验结果表明,机械活化前,H2SO4直接浸出铅锌烟尘的最佳工艺参数为H2SO4浓度175 g/L、液固比7∶1、浸出温度60℃、浸出时间60 min。在最佳工艺条件下,Zn浸出率达92.47%,Pb入渣率为90.30%。原料机械活化30min后,最佳工艺条件变为H2SO4溶液浓度150 g/L、液固比5∶1、浸出温度50℃、浸出时间40 min。此时Zn浸出率达91.52%及Pb入渣率为95.36%。机械活化后铅锌烟尘的Zn浸出率及Pb入渣率对H2SO4溶液浓度、液固比、浸出温度、浸出时间的依赖性明显降低。

机械活化在俄罗斯钨精矿分解中的应用

阐述了机械活化的基本原理及其在某些矿石分解过程中具有的重要意义,指出机械活化既可加速分解过程,又能提高浸出率,同时达到节能降耗的双重目的。介绍了俄罗斯在钨精矿分解中对机械活化的研究和应用情况。

超高浓度溶液化学与∑型捏合机械力化学反应器

本文针对含钼白钨矿的碱分解工艺,提出了超高浓度溶液化学的概念,选择∑型捏合机械力化学反应器为手段,成功地解决了一种白钨矿的碱分解课题,为节能、环保、经济的湿法冶金工艺开辟了一条新路。利用超高浓度溶液化学原理,采用∑型捏合机械力化学反应器,对含有微量钼的白钨矿碱分解进行了操作简单、运行方便的试验。结果表明,以化学比（RC=1.5-2.0）为基础,液/固比（RL=0.16～0.18）为条件,经过100℃,1 h的捏合,金属钨的浸出率超高96.5%,钼的浸出率超高60%。这一令人难以置信的结果表明,超高浓度溶液化学是未来湿法冶金工艺发展最重要的课题之一;而∑型捏合机械力化学反应器是实现超高浓度溶液化学中最具潜力的化工设备之一。

从细粒钨锡混合精矿中分离白钨矿的试验研究

湖南某钨锡多金属矿是典型的难选复杂矿产资源,有用矿物嵌布关系复杂,钨锡综合回收利用难度大。研究针对含WO342.97%、Sn 2.15%的钨锡混合精矿,采用自主研发的高效捕收剂TA-3药剂以及“白钨常温浮选-酸浸”工艺分离白钨精矿,获得含WO365.48%、Sn 0.15%的白钨精矿和含WO339.52%、Sn 5.96%的黑钨锡精矿,白钨精矿WO3回收率67.70%、Sn回收率3.70%,黑钨锡精矿WO3回收率32.20%、Sn回收率96.28%,成功实现了混合精矿中白钨矿的高效分离,并为锡的综合回收创造了有利条件。

白钨精矿与黑白钨混合矿碱分解的方法与设备

引言 NaOH分解法为钨冶金中分解黑钨精矿的常用方法,它具有工艺简单,分解率高等特点。但在通常条件下,由于NaOH与白钨矿(CaWO_4)难以反应,因此过去国内外学者都认为在工业条件下用NaOH法处理白钨精矿是不可能的;即使对黑钨精矿而言,也要求其中混杂的白钨矿相当少(Ca<1.0％),才能有好的分解效果,因而不得不要求选矿工作者将两者仔细分选,并要求用不同的工艺分别处理。我国过去主要是处理黑钨精矿,因此现有企业的流程和设备主要适用于黑钨精矿的碱分解法。