外文翻譯模版—反應(yīng)擠出法氫氧化鈉分解白鎢礦

1、Sodium Hydroxide Digestion of Scheelite by Reactive Extrusion反應(yīng)擠出法氫氧化鈉分解白鎢礦 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. 根據(jù)熱力學(xué)分析，只要氫氧化鈉濃度足夠高，即使在相對低的溫度下，白鎢礦也能被分解。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. 至于提高氫氧化濃度的方法，在固定的氫氧化鈉用量的情況下減少水的用量要比在固定的液固比取得情況下增加氫氧化鈉的用量更經(jīng)濟。But the viscosity of slurry will be increased with the solid to liquid ratios increased, 但是隨著液固比的增加礦漿的粘度也會上升，which will make the m

5、ass transfer more difficult if the conventional stirring equipment is still employed. 這使得使用傳統(tǒng)的攪拌設(shè)備會使傳質(zhì)變得困難。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. 雙螺旋桿擠壓機十分適合于高黏性高分子材料的實驗，同時傳質(zhì)也非常好。T

6、herefore, it is considerable to apply this equipment to treat the highly viscous scheelite slurry.因此，可以考慮將此設(shè)備應(yīng)用于處理高粘度的白鎢礦礦漿。 Based on these, a novel technology of sodium hydroxide digestion of scheelite is proposed. 基于此，提出一項新穎的氫氧化鈉分解白鎢礦技術(shù)。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. 在溫度為120，螺桿旋轉(zhuǎn)速度為160rpm，反應(yīng)時間為3.5h，氫氧化鈉用量是理論量的2.2倍的實驗條件下，殘渣WO3 含量和WO3浸出率分別為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.結(jié)果表明，在較低的溫度下，用反應(yīng)擠出法就能夠使氫氧化鈉分解白鎢礦。Key words: Scheelite; Digestion; Sodium hydroxide; Reactive extrusion關(guān)鍵字：白鎢礦；消化；氫氧化鈉；1. IntroductionApproximately two-thirds of tungsten reserves consist of scheelite in the

9、 world1. 世界上大約三分之二的鎢儲存在白鎢礦中。Currently, with the consumption of wolframite, scheelite has become a kind of major industrial raw material. 目前，隨著黑鎢礦的消耗，白鎢礦已經(jīng)成為工業(yè)上的主要原材料。Scheelite was mainly digested by soda autoclaving 2,3, hydrochloric acid leaching 4, and soda roasting 5. 白鎢礦分解的主要方法有碳酸鈉高壓分解法，鹽酸浸出法和碳酸

10、鈉焙燒法。Traditionally, it was considered that scheelite can not be decomposed by NaOH under commercial conditions 6. 人們認為，在commercial conditions下，白鎢礦是不可能被氫氧化鈉分解的。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. 然而在十九世紀八十年代，李等人研制出一種the caustic thermomilling process，這種方法不僅能夠直接處理高鈣含量的黑鎢礦，而且還能處理黑白鎢混合礦，甚至白鎢礦。The process has been successfully applied on a commercial scale in fifteen tungsten plants in China 8. 這一方法已

12、經(jīng)成功的應(yīng)用于中國的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.除了機械活化的作用，該方法中的高濃度氫氧化鈉也有利于分解鎢礦石。 Recently, the thermodynamics of NaOH digestion of scheelite was

13、 reanalyzed 9.最近，研究人員重新分析了氫氧化鈉分解白鎢礦的熱力學(xué)。 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. 結(jié)果表明，氫氧化鈉分解白鎢礦時，溫度并不是起決定性因素，只要堿濃度足夠高

14、，哪怕是在一個相對較低的溫度，白鎢礦依然能夠被分解。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;之所以該過程能在常壓下進行，是因為高濃度的氫氧化鈉是的溶液的沸點增加了。 and it can also provide a powerful driving force for the dig

15、estion reaction dynamically.同時還動態(tài)地為分解反應(yīng)提供了一個推動了。 There are two approaches to obtain high concentration of NaOH solution.有兩種方法可以獲得高濃度的氫氧化鈉溶液。 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.從表面上

16、看，似乎在一定氫氧化鈉用量的情況下減少水的用量要比在一定液固比的情況下增加氫氧化鈉的用量更經(jīng)濟。 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，隨著液固比的增加，礦漿的粘度也會隨之增大，這使得反應(yīng)容器中的鋼球會相互粘附，傳質(zhì)也變得困難了。 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，為了降低原材料的成本同時也獲得有利的傳質(zhì)效

18、果，開發(fā)一些新的設(shè)備是有必要的。Twin screw extruder is widely used to work with macromolecular materials with high viscosity 10-15.雙螺旋桿擠壓機已經(jīng)被廣泛的應(yīng)用于高粘度的高分子材料的研究當中。 It works as a continuous operation, integrating polymerization, modification and forming processes into one step, shortening the process period significa

19、ntly.雙螺旋桿擠壓機操作連續(xù)，集成聚合、修改和合成過程一步到位，極大的縮短了生產(chǎn)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. 擠出機中的螺旋桿同時帶來了強勁的壓縮、剪切以及混合高粘度熔融物料的效果，大大加快了傳質(zhì)。Therefore, it is considerable t

20、o apply this equipment to treat the highly viscous scheelite slurry.所以，考慮將此設(shè)備應(yīng)用于高粘度白鎢礦礦漿的分解。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.考慮到雙螺旋桿擠壓機能夠處理高粘度物料的特性，本文提出了一種新穎的技術(shù)：通過雙螺旋桿擠壓機，用氫氧化鈉分解白鎢礦。 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、本文考察了浸出溫度、氫氧化鈉用量、反應(yīng)時間以及螺旋桿轉(zhuǎn)速這四個因素對實驗過程的影響。2. Experimental2.1 Reagents and analysis2.1試劑和分析Scheelite concentrate was donated from Chongyi Zhangyuan Tungsten CO.LTD of Jiangxi province, China. 原料白鎢礦來自于章源鎢業(yè)。It was pretreated by dry grinding and sieved to the size of -325 meshes (<45m) for the experi

23、ments.實驗所用的原料經(jīng)過干式磨碎至-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).用可見分光光度計測得物料含WO369.87%。 All chemicals used were of analytical grade and no further purification is needed.使用的所有化學(xué)藥品均為分析純,不需要進

24、一步凈化。 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.對白鎢礦樣本進行XRD分析，其中的物相如圖一顯示，主要成分為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, 浸出實驗所用的雙螺旋桿擠壓機，如圖2所示。the twin screw extruder consists of barrel, screws, thermocouples, control panel, feed port, heating circle, gear case and bracket.雙螺桿擠出機由桶,螺旋桿,熱電偶,控制面板,

26、進料口,加熱圈,齒輪箱和支架組成。 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.螺旋桿長度600毫米，直徑30毫米。實驗所用的螺旋桿的光學(xué)照片如圖3所示。 The screw arris and kneading block of the screws can propel and shear the slurry.螺絲的螺棱和捏合塊可以推動和剪切泥漿。2.3 Experi

27、mental procedures2.3實驗方法In a typical experiment, firstly, a certain amount of NaOH (192.7-289.0g) was dissolved in 145mL of water completely, 首先，將一定量的氫氧化鈉(192.7-289.0g)完全溶解于145mL的純水中，and then 400g of scheelite concentrates were fed to the alkaline solution to obtain mixture slurry. 然后將400g白鎢礦加入到氫氧化鈉

28、溶液中，配的混合礦漿。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.接著將混合礦漿加入擠壓機中，在溫度為90-130、轉(zhuǎn)速為100-160 rpm的實驗條件下反應(yīng)1.5-4h。 Furthermore, the hot slurry was discharged and dilu

29、ted with water, then filtrated to produce the Na2WO4 solution.最后，將擠出的熱礦漿用水稀釋后過濾，得到Na2WO4溶液。The WO3 extraction ratio was calculated according to the following equation:用下式計算三氧化鎢浸出率：WO3= 1-(Qs/Qc) ×Rs ×100% (1)Where: 其中：WO3 is the extraction ratio of WO3, %;WO3指三氧化鎢浸出率；Qs is the content of i

30、nsoluble WO3 in dried filtration cake, %; Qs指干濾餅中不溶性鎢的含量；Qc is the content of total WO3 in the concentrates, %; Qc指白鎢礦中三氧化鎢含量；Rs is the mass ratio of the dried cake to the concentrates.Rs指干濾餅與白鎢礦的質(zhì)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. 在堿用量為理論量的3倍、螺旋桿旋轉(zhuǎn)速度為100rpm以及反應(yīng)時間為3h的條件下，考察了溫度（90 to 130）對氫氧化鈉分解白鎢礦的影

32、響。The content of WO3 in the solid residue and WO3 extraction ratio in each test were shown in Fig.4.各族試驗中的殘渣含鎢量以及鎢浸出率如圖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.結(jié)果表明，殘渣中不溶性鎢含量降低至3.5%，同時，當溫度升高到120時，WO3浸出率達到98.19%。 Further increasing of temperature did little to the variation of WO3 in the residue. 進一步提高溫度對降低殘渣中的鎢含量幾乎沒有作用。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.溫度是影響白鎢礦分解的重要因素之一。對于以往傳統(tǒng)的堿分解過程，溫度大概在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.本文中的分解溫度卻比傳統(tǒng)的低了40度，120 的溫度足以保證分解反應(yīng)的完成。3.2 Ef

35、fect of the screw rotating speed3.2螺旋桿旋轉(zhuǎn)速度的影響The effect of the screw rotating speed on the decomposition process was evaluated under the following conditions, 考察旋轉(zhuǎn)速度對分解過程的影響，固定以下條件，i.e., slurry temperature at 120, NaOH dosage of three times to that of the stoichiometry and reaction time for 3h. 即，礦漿

36、溫度為120，氫氧化鈉溫度為3倍的理論量，反應(yīng)時間為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.其結(jié)果如圖5所示，隨著轉(zhuǎn)速的增加，殘渣中鎢含量單調(diào)遞減。 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. 當轉(zhuǎn)速增加到160 rpm，殘渣中鎢含量降低至2.53%，相應(yīng)地，鎢提取率為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. 隨著轉(zhuǎn)速的增加，螺旋桿對高粘度礦漿的剪切力以及其

38、活化效應(yīng)也增強了。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. 同時，熱交換和傳質(zhì)速率也得到了提升，也使得更多新的礦粒表面充分地暴露在浸取劑中。Hence, the reaction rate was promoted obviously.因此,反應(yīng)速率有了明顯提升。3. 3 Effect of reaction tim

39、e3.3反應(yīng)時間的影響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. 在礦漿溫度為120、堿用量為3倍用量、旋轉(zhuǎn)速度為160rpm的條件下考察了反

40、應(yīng)時間對實驗結(jié)果的影響，其結(jié)果如圖6所示。The results indicated that the content of insoluble WO3 in the residue decreased with the prolonging of reaction time. 結(jié)果表明，隨著反應(yīng)時間的延長，殘渣中鎢含量越來越少。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%. 當反應(yīng)時間為3.5h時，殘渣含鎢降低到1.38%，相應(yīng)的浸出率達到99.27%。When time was further prolonged, there was little variation on the content of the insoluble WO3 in the residue.繼續(xù)增加反應(yīng)時間，對降低渣含鎢作用不大。3.4 Effect of NaOH dosage3.4堿用量的影響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. 在反應(yīng)時間為3.5h、礦漿溫度為120、轉(zhuǎn)速為160rpm的條件下，考察了堿用量（2至3倍的理論量）對實驗結(jié)果的影響，如圖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%. 從圖7我們可以看到，隨著堿用量的增加，渣含鎢降低至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%. 當堿用量為2.2倍的

44、理論量時，渣含鎢為1.54%，相應(yīng)的浸出率為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結(jié)果顯示，擠壓機中礦漿成分主要為Na2WO4 和 Ca(OH)2。So, scheelite can be decomposed with sodium hydroxide by adopting this technology. 綜上所述，用反應(yīng)擠出法分解白鎢礦是可行的。The results fully a

45、ccorded with the thermodynamic phase diagram 9 about the process of sodium hydroxide digestion of scheelite.其結(jié)果完全符合熱力學(xué)相圖中白鎢礦的氫氧化鈉分解的過程。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.與傳統(tǒng)的堿浸出過程相比，盡管反應(yīng)溫度較低以及幾乎相同的堿用量，用反應(yīng)擠出法也能夠獲得相似的分解結(jié)果。4. ConclusionThe results obtained from this investigation show that Scheelite can be decomposed completely with sodium hydroxide by reactive extrusion. 反應(yīng)擠出法氫氧化鈉分解白鎢礦是完全可行的。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. 最佳分解條件為：堿用量為理論量的2.2倍，礦漿溫度為120，螺旋桿轉(zhuǎn)速為160rpm以及反應(yīng)時間為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. 在上述最佳條件下，渣含鎢為1.54%，浸出率為99.18%。Compared with the traditional NaOH leaching process, this novel process could be conducted at a lower temperature. 相比于傳統(tǒng)的堿浸出工藝，反應(yīng)擠出法的特點在于更低的溫度（降低40度）。AcknowledgementThis work was supported by a grant from the Ma

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