外文翻译模版—反应挤出法氢氧化钠分解白钨矿

1、Sodium Hydroxide Digestion of Scheelite by Reactive Extrusion反应挤出法氢氧化钠分解白钨矿 Zhongwei Zhaoa,b* Corresponding author. Tel: +86 0731 8830476; fax: +86 0731 8830477. E-mail address: zhongweizhao, Yong Lianga, Xuheng Liu a,c, Ailiang Chena, Honggui LiaaSchool of Metallurgical Science and Engineering, Cen

2、tral South University, Changsha 410083, Hunan, Chinab Hunan Key Laboratory of Hunan Province for Metallurgy and Material Processing of Rare Metals, Changsha 410083, Hunan, Chinac National Engineering Lab for High Efficiency Recovery of Refractory Non-ferrous Metal Resources, Changsha 410083, Hunan,

3、ChinaAbstract: According to the thermodynamic analysis, scheelite can be decomposed（被分解） as long as the NaOH concentration is high enough, even at relatively low temperatures. 根据热力学分析，只要氢氧化钠浓度足够高，即使在相对低的温度下，白钨矿也能被分解。As for the approaches of increasing NaOH concentration, it is more economical reduci

4、ng the water dosage at fixed NaOH dosage than increasing the NaOH dosage at a fixed ratio of liquid to solid. 至于提高氢氧化浓度的方法，在固定的氢氧化钠用量的情况下减少水的用量要比在固定的液固比取得情况下增加氢氧化钠的用量更经济。But the viscosity of slurry will be increased with the solid to liquid ratios increased, 但是随着液固比的增加矿浆的粘度也会上升，which will make the m

5、ass transfer more difficult if the conventional stirring equipment is still employed. 这使得使用传统的搅拌设备会使传质变得困难。Twin screw extruder is a kind of equipment suitable to work with highly viscous macromolecular materials, and good mass transfer can be easily obtained by it. 双螺旋杆挤压机十分适合于高黏性高分子材料的实验，同时传质也非常好。T

6、herefore, it is considerable to apply this equipment to treat the highly viscous scheelite slurry.因此，可以考虑将此设备应用于处理高粘度的白钨矿矿浆。 Based on these, a novel technology of sodium hydroxide digestion of scheelite is proposed. 基于此，提出一项新颖的氢氧化钠分解白钨矿技术。Under the conditions at temperature 120, screw rotating speed

7、 at 160rpm, reaction time for 3.5h and the NaOH dosage 2.2 times to that of the stoichiometry, the content of WO3 in the residue and the WO3 extraction are 1.54% and 99.18%, respectively. 在温度为120，螺杆旋转速度为160rpm，反应时间为3.5h，氢氧化钠用量是理论量的2.2倍的实验条件下，残渣WO3 含量和WO3浸出率分别为1.54%和99.18%。The results indicate that s

8、cheelite can be decomposed with sodium hydroxide by reactive extrusion at a lower temperature.结果表明，在较低的温度下，用反应挤出法就能够使氢氧化钠分解白钨矿。Key words: Scheelite; Digestion; Sodium hydroxide; Reactive extrusion关键字：白钨矿；消化；氢氧化钠；1. IntroductionApproximately two-thirds of tungsten reserves consist of scheelite in the

9、 world1. 世界上大约三分之二的钨储存在白钨矿中。Currently, with the consumption of wolframite, scheelite has become a kind of major industrial raw material. 目前，随着黑钨矿的消耗，白钨矿已经成为工业上的主要原材料。Scheelite was mainly digested by soda autoclaving 2,3, hydrochloric acid leaching 4, and soda roasting 5. 白钨矿分解的主要方法有碳酸钠高压分解法，盐酸浸出法和碳酸

10、钠焙烧法。Traditionally, it was considered that scheelite can not be decomposed by NaOH under commercial conditions 6. 人们认为，在commercial conditions下，白钨矿是不可能被氢氧化钠分解的。However, in the 1980s, Li et al. 7 developed the caustic thermomilling process which can treat not only the high-calcium-content wolframite b

11、ut also the scheelite-wolframite concentrate blends and even the scheelite concentrates directly. 然而在十九世纪八十年代，李等人研制出一种the caustic thermomilling process，这种方法不仅能够直接处理高钙含量的黑钨矿，而且还能处理黑白钨混合矿，甚至白钨矿。The process has been successfully applied on a commercial scale in fifteen tungsten plants in China 8. 这一方法已

12、经成功的应用于中国的a commercial scale in fifteen tungsten plants。In addition to the mechanical activation, high NaOH concentration is another beneficial contribution to decompose the tungsten ores in this process.除了机械活化的作用，该方法中的高浓度氢氧化钠也有利于分解钨矿石。 Recently, the thermodynamics of NaOH digestion of scheelite was

13、 reanalyzed 9.最近，研究人员重新分析了氢氧化钠分解白钨矿的热力学。 The results indicate that temperature is not the decisive factor for the NaOH digestion of scheelite and scheelite can be decomposed as long as the NaOH concentration is high enough, even at a relatively lower temperature. 结果表明，氢氧化钠分解白钨矿时，温度并不是起决定性因素，只要碱浓度足够高

14、，哪怕是在一个相对较低的温度，白钨矿依然能够被分解。The increase of NaOH concentration can cause the increase of boiling point of solution which makes it possible that the process can be carried out under the atmosphere pressure;之所以该过程能在常压下进行，是因为高浓度的氢氧化钠是的溶液的沸点增加了。 and it can also provide a powerful driving force for the dig

15、estion reaction dynamically.同时还动态地为分解反应提供了一个推动了。 There are two approaches to obtain high concentration of NaOH solution.有两种方法可以获得高浓度的氢氧化钠溶液。 It seems that it is more economical reducing the water dosage at the fixed NaOH dosage than increasing the NaOH dosage at a fixed ratio of liquid to solid.从表面上

16、看，似乎在一定氢氧化钠用量的情况下减少水的用量要比在一定液固比的情况下增加氢氧化钠的用量更经济。 But the viscosity of slurry will be increased with the solid to liquid ratios increased, which makes the steel balls in the reactor adhere each other and the mass transfer difficult in the thermom

17、illing process.但是，随着液固比的增加，矿浆的粘度也会随之增大，这使得反应容器中的钢球会相互粘附，传质也变得困难了。 Therefore, in order to cut the cost of raw materials as well as obtain beneficial mass transfer for high viscosity materials system, some new equipment should be developed for the sodium hydroxide based route. 因此，为了降低原材料的成本同时也获得有利的传质效

18、果，开发一些新的设备是有必要的。Twin screw extruder is widely used to work with macromolecular materials with high viscosity 10-15.双螺旋杆挤压机已经被广泛的应用于高粘度的高分子材料的研究当中。 It works as a continuous operation, integrating polymerization, modification and forming processes into one step, shortening the process period significa

19、ntly.双螺旋杆挤压机操作连续，集成聚合、修改和合成过程一步到位，极大的缩短了生产周期。 The rotating screws in the extruder also can bring strong compression, shearing, and mixing on the molten materials of high viscosity, drastically accelerating the mass transfer. 挤出机中的螺旋杆同时带来了强劲的压缩、剪切以及混合高粘度熔融物料的效果，大大加快了传质。Therefore, it is considerable t

20、o apply this equipment to treat the highly viscous scheelite slurry.所以，考虑将此设备应用于高粘度白钨矿矿浆的分解。Taking account of the properties that twin screw extruder has for the processing high-viscous feedstock, a novel technology was put forward to decompose scheelite with sodium hydroxide by using twin

21、 screw extruder in this paper.考虑到双螺旋杆挤压机能够处理高粘度物料的特性，本文提出了一种新颖的技术：通过双螺旋杆挤压机，用氢氧化钠分解白钨矿。 The relative experimental parameters which are concerned in the process such as leaching temperature, NaOH dosage, screw rotating speed and reaction time on the process would be investigated in the present study.

22、本文考察了浸出温度、氢氧化钠用量、反应时间以及螺旋杆转速这四个因素对实验过程的影响。2. Experimental2.1 Reagents and analysis2.1试剂和分析Scheelite concentrate was donated from Chongyi Zhangyuan Tungsten CO.LTD of Jiangxi province, China. 原料白钨矿来自于章源钨业。It was pretreated by dry grinding and sieved to the size of -325 meshes (<45m) for the experi

23、ments.实验所用的原料经过干式磨碎至-325目。 The powder sample was analyzed to contain 69.87wt% of WO3 by visible spectrophotometry (TAS-990, Beijing Purkinje General Instrument CO.LTD, China).用可见分光光度计测得物料含WO369.87%。 All chemicals used were of analytical grade and no further purification is needed.使用的所有化学药品均为分析纯,不需要进

24、一步净化。 The phase compositions of scheelite concentrate sample were evaluated by X-ray diffraction pattern (XRD, Dmax/2550VB+, Rigaku Corporation, Japan), and it is shown in Fig.1 that the main phase was CaWO4.对白钨矿样本进行XRD分析，其中的物相如图一显示，主要成分为CaWO42.2 EquipmentsLeaching experiments were carried out with

25、a co-rotating twin screw extruder (SYSLG32-II, Jinan Saibainuo Technology Development CO. LTD，China), and as showed in Fig.2, 浸出实验所用的双螺旋杆挤压机，如图2所示。the twin screw extruder consists of barrel, screws, thermocouples, control panel, feed port, heating circle, gear case and bracket.双螺杆挤出机由桶,螺旋杆,热电偶,控制面板,

26、进料口,加热圈,齿轮箱和支架组成。 The length of screw is 600mm, and its diameter is 30mm.The optical photo of the screws employed in the experiments was shown in Fig.3.螺旋杆长度600毫米，直径30毫米。实验所用的螺旋杆的光学照片如图3所示。 The screw arris and kneading block of the screws can propel and shear the slurry.螺丝的螺棱和捏合块可以推动和剪切泥浆。2.3 Experi

27、mental procedures2.3实验方法In a typical experiment, firstly, a certain amount of NaOH (192.7-289.0g) was dissolved in 145mL of water completely, 首先，将一定量的氢氧化钠(192.7-289.0g)完全溶解于145mL的纯水中，and then 400g of scheelite concentrates were fed to the alkaline solution to obtain mixture slurry. 然后将400g白钨矿加入到氢氧化钠

28、溶液中，配的混合矿浆。Secondly, the mixture slurry was charged into the extruder, where the extrusion reaction was conducted under the temperature of 90-130and the rotating speed as 100-160 rpm for 1.5-4h.接着将混合矿浆加入挤压机中，在温度为90-130、转速为100-160 rpm的实验条件下反应1.5-4h。 Furthermore, the hot slurry was discharged and dilu

29、ted with water, then filtrated to produce the Na2WO4 solution.最后，将挤出的热矿浆用水稀释后过滤，得到Na2WO4溶液。The WO3 extraction ratio was calculated according to the following equation:用下式计算三氧化钨浸出率：WO3= 1-(Qs/Qc) ×Rs ×100% (1)Where: 其中：WO3 is the extraction ratio of WO3, %;WO3指三氧化钨浸出率；Qs is the content of i

30、nsoluble WO3 in dried filtration cake, %; Qs指干滤饼中不溶性钨的含量；Qc is the content of total WO3 in the concentrates, %; Qc指白钨矿中三氧化钨含量；Rs is the mass ratio of the dried cake to the concentrates.Rs指干滤饼与白钨矿的质量比。3. Results and discussion3. 1 Effect of leaching temperatureThe effect of leaching temperature on de

31、composition of scheelite by sodium hydroxide was studied from 90 to 130 while keeping other conditions as the following: NaOH dosage is three times to that of stoichiometriy, screw rotating speed at 100rpm and reaction time for 3h. 在碱用量为理论量的3倍、螺旋杆旋转速度为100rpm以及反应时间为3h的条件下，考察了温度（90 to 130）对氢氧化钠分解白钨矿的影

32、响。The content of WO3 in the solid residue and WO3 extraction ratio in each test were shown in Fig.4.各族试验中的残渣含钨量以及钨浸出率如图4所示。 The results indicated that the content of insoluble WO3 in the solid residue decreased to 3.5% and the WO3 extraction ratio could reach 98.19% as the temperature of slurry bein

33、g increased to 120.结果表明，残渣中不溶性钨含量降低至3.5%，同时，当温度升高到120时，WO3浸出率达到98.19%。 Further increasing of temperature did little to the variation of WO3 in the residue. 进一步提高温度对降低残渣中的钨含量几乎没有作用。Temperature is one of the important parameters to the decomposition of scheelite. For the traditional NaOH process, the

34、leaching temperature was about 160 8.温度是影响白钨矿分解的重要因素之一。对于以往传统的碱分解过程，温度大概在160。 While in this study, the temperature was 120, which was 40 lower than that of the traditional process but was found to be enough for the accomplishment of decomposition reaction.本文中的分解温度却比传统的低了40度，120 的温度足以保证分解反应的完成。3.2 Ef

35、fect of the screw rotating speed3.2螺旋杆旋转速度的影响The effect of the screw rotating speed on the decomposition process was evaluated under the following conditions, 考察旋转速度对分解过程的影响，固定以下条件，i.e., slurry temperature at 120, NaOH dosage of three times to that of the stoichiometry and reaction time for 3h. 即，矿浆

36、温度为120，氢氧化钠温度为3倍的理论量，反应时间为3h。The data were drawn in Fig. 5 shows that with the increase of screw rotating speed, the content of insoluble WO3 in the solid residue was monotonously reduced.其结果如图5所示，随着转速的增加，残渣中钨含量单调递减。 When the speed was adjusted up to 160 rpm, the content of insoluble WO3 in the resi

37、due was reduced to 2.53%, equivalent to the WO3 extraction of 98.62% correspondingly. 当转速增加到160 rpm，残渣中钨含量降低至2.53%，相应地，钨提取率为98.62%。With the increase of the screw rotating speed，the shear force and activation effect of screws on the highly viscous slurry became stronger16,17. 随着转速的增加，螺旋杆对高粘度矿浆的剪切力以及其

38、活化效应也增强了。At the same time, the heat exchanging and mass transferring rate were promoted and much more fresh surfaces of ores were exposed to lixiviants more sufficiently. 同时，热交换和传质速率也得到了提升，也使得更多新的矿粒表面充分地暴露在浸取剂中。Hence, the reaction rate was promoted obviously.因此,反应速率有了明显提升。3. 3 Effect of reaction tim

39、e3.3反应时间的影响The effect of reaction time on the process was summarized for the experiment conducted under the conditions of slurry temperature at 120, NaOH dosage of three times as that of the stoichiometriy and screw rotating speed at 160rpm, as shown in Fig. 6. 在矿浆温度为120、碱用量为3倍用量、旋转速度为160rpm的条件下考察了反

40、应时间对实验结果的影响，其结果如图6所示。The results indicated that the content of insoluble WO3 in the residue decreased with the prolonging of reaction time. 结果表明，随着反应时间的延长，残渣中钨含量越来越少。When the reaction time is set at 3.5h, the content of insoluble WO3 in the residue was reduced to 1.38%, corresponding to the WO3 extr

41、action of 99.27%. 当反应时间为3.5h时，残渣含钨降低到1.38%，相应的浸出率达到99.27%。When time was further prolonged, there was little variation on the content of the insoluble WO3 in the residue.继续增加反应时间，对降低渣含钨作用不大。3.4 Effect of NaOH dosage3.4碱用量的影响NaOH dosage to the stoichiometry is adjusted from 2 to 3times, and the effect

42、 of NaOH dosage on the process was summarized, as described in Fig.7, under the conditions of reaction time for 3.5h, slurry temperature at 120 and screw stirring speed at 160rpm. 在反应时间为3.5h、矿浆温度为120、转速为160rpm的条件下，考察了碱用量（2至3倍的理论量）对实验结果的影响，如图7所示。It can be seen from Fig. 7 that the content of insolubl

43、e WO3 in the residue decreased with the increase of NaOH dosage and was no more than 2%. 从图7我们可以看到，随着碱用量的增加，渣含钨降低至2%以下。As the NaOH dosage was 2.2 times to that of the stoichiometry, the content of insoluble WO3 in the residue was 1.54%, corresponding to the WO3 extraction ratio of 99.18%. 当碱用量为2.2倍的

44、理论量时，渣含钨为1.54%，相应的浸出率为1.54%。In addition, the XRD spectrum (Fig.8) showed that the main phases of extruded slurry were Na2WO4 and Ca(OH)2. 此外，XRD结果显示，挤压机中矿浆成分主要为Na2WO4 和 Ca(OH)2。So, scheelite can be decomposed with sodium hydroxide by adopting this technology. 综上所述，用反应挤出法分解白钨矿是可行的。The results fully a

45、ccorded with the thermodynamic phase diagram 9 about the process of sodium hydroxide digestion of scheelite.其结果完全符合热力学相图中白钨矿的氢氧化钠分解的过程。Therefore, compared with the traditional NaOH leaching process, though the reaction temperature is lower and NaOH dosage is almost the same, the same decomposition r

46、esults can also be achieved in the novel reactive extrusion process.与传统的碱浸出过程相比，尽管反应温度较低以及几乎相同的碱用量，用反应挤出法也能够获得相似的分解结果。4. ConclusionThe results obtained from this investigation show that Scheelite can be decomposed completely with sodium hydroxide by reactive extrusion. 反应挤出法氢氧化钠分解白钨矿是完全可行的。The optim

47、um digestion condition is as follow: the dosage of alkali is 2.2 times to that of the stoichiometry, temperature at 120, the screw rotating speed at 160rpm and reaction time for 3.5h. 最佳分解条件为：碱用量为理论量的2.2倍，矿浆温度为120，螺旋杆转速为160rpm以及反应时间为3.5h。Under this condition, the content of WO3 in the residue and th

48、e WO3 extraction ratio are 1.54% and 99.18%, respectively. 在上述最佳条件下，渣含钨为1.54%，浸出率为99.18%。Compared with the traditional NaOH leaching process, this novel process could be conducted at a lower temperature. 相比于传统的碱浸出工艺，反应挤出法的特点在于更低的温度（降低40度）。AcknowledgementThis work was supported by a grant from the Ma

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