礦井型選煤廠外文翻譯---重介質(zhì)旋流器

1、<p><b>　　附錄A 譯文</b></p><p><b>　　重介質(zhì)旋流器</b></p><p>　　G.J.de Korte and J. Engelbrecht</p><p>　　摘 要：由荷蘭國(guó)有能源化學(xué)公司發(fā)明的重介質(zhì)旋流器在20世紀(jì)40年代已經(jīng)被大量應(yīng)用在礦物加工行業(yè)中單元處理上。重介質(zhì)旋流

2、器的應(yīng)用是從鉆石、鐵礦、鉻鐵礦相對(duì)較高的密度到相對(duì)密度低于1時(shí)塑料的分離而變化的。</p><p>　　盡管它的設(shè)計(jì)簡(jiǎn)單，但是重介質(zhì)旋流器并沒有被完全了解，并且繼續(xù)提高重介質(zhì)旋流器的工作仍然在繼續(xù)。長(zhǎng)遠(yuǎn)發(fā)展的主要目的集中在提高旋流器的效率和處理量。重介質(zhì)旋流器的性能是有許多參數(shù)決定的，并且在這章里將討論其中一些因素的影響。</p><p><b>　　旋流器的外形尺寸</b

3、></p><p>　　近代，我們見證了旋流器直徑增加到1500mm的程度，并且這些旋流器正被廣泛應(yīng)用在煤炭加工處理作業(yè)中，特別是在澳大利亞。更大的直徑也意味著更大的入料，更大的溢流口和底流口，從而更大粒度物料給入旋流器。表1中定義了荷蘭國(guó)有能源化學(xué)公司生產(chǎn)重介質(zhì)旋流器的標(biāo)準(zhǔn)尺寸和當(dāng)前產(chǎn)品趨勢(shì)。</p><p>　　表1 標(biāo)準(zhǔn)旋流器的外形尺寸</p><p>

4、　　大多數(shù)旋流器制造商仍然堅(jiān)持荷蘭國(guó)有能源化學(xué)公司的建議以及生產(chǎn)符合瑪泰集團(tuán)規(guī)格尺寸的標(biāo)準(zhǔn)旋流器。然而，我們卻需求有一個(gè)擁有更大容量、能夠處理更大物料、用更多吸熱材料制造的旋流器。后者則要求適用，因?yàn)楝F(xiàn)代采煤方法中缺少選擇性，在煤炭開采過程中混入更多的頂層以及底層頁巖以及更多低儲(chǔ)量煤的開采。例如在印度，原煤中包含了相當(dāng)大比例的高密度巖石。在表1中表明了由于這些要求而改變旋流器的外形尺寸來反應(yīng)當(dāng)前發(fā)展趨勢(shì)。</p><

5、p>　　表2展示了南非瑪泰集團(tuán)的兩種實(shí)用旋流器的入料量以及最大入料尺寸。表2中給出的值都是基于如下：</p><p>　　表2 瑪泰集團(tuán)旋流器的尺寸和容量</p><p>　　? 相當(dāng)于前九次標(biāo)稱旋流器直徑的入料</p><p>　　? 待測(cè)體積中介質(zhì)與煤的比例為3.5：1</p><p>　　? 入料煤固體的相對(duì)密度為1.6</

6、p><p>　　在圖1中展示了一臺(tái)1450mm直徑的瑪泰旋流器。</p><p>　　圖1 瑪泰集團(tuán)直徑為1450的旋流器</p><p>　　盡管較大的旋流器能夠處理大的入料粒度到140mm，但是這些粒度可能導(dǎo)致堵塞問題。旋流器通常處理最大粒度為50mm的特定粒度入料。這可能是由于在用泵將大顆粒物料打入旋流器中存在困難。</p><p>　　分

7、選粒度以及分選密度變化</p><p>　　分選粒度的定義是當(dāng)?shù)陀谟行Щ厥章实妮^小顆粒的粒度開始明顯減少時(shí)的特定粒度。Bosman（1994）提供了和旋流器直徑相關(guān)的近似分離粒度，如圖2所示。Bosman僅僅包括直徑到800mm的旋流器，而在圖中的曲線表上已經(jīng)擴(kuò)展為代表1500mm直徑的旋流器。</p><p>　　圖2 分選粒度與旋流器直的對(duì)應(yīng)曲線</p><p>

8、;　　圖3 南非旋流器的特定粒度與不合格率的對(duì)應(yīng)曲線</p><p>　　分選粒度定義的問題就是它僅僅表明效率明顯下降，沒有量化的減少。這個(gè)可能的錯(cuò)誤（EPM）不僅僅是旋流器直徑的作用，還是給料壓力、介質(zhì)密度、介質(zhì)粘度、顆粒形狀和密度以及最大入料粒度等等。許多實(shí)際的數(shù)據(jù)來自于南非，他們主要利用直徑為610mm的旋流器的操作而或得數(shù)據(jù)的（de Korte2007a），這些數(shù)據(jù)被總結(jié)在圖3中，其中表明了由于入料微粒變

9、小，缺陷確實(shí)變大了。</p><p>　　定義分選粒度導(dǎo)致一些人相信重介質(zhì)旋流器不能夠處理小于分選密度和小于3mm部分的煤炭分選，例如，應(yīng)當(dāng)篩選出旋流器的入料和用僅僅需水單元處理像螺旋選礦和搖床選礦。這也導(dǎo)致了這個(gè)行業(yè)不情愿采用大直徑旋流器。在實(shí)際中，隨著粒度減小效率也降低，但是重介質(zhì)旋流器的效率仍然比螺旋選礦和搖床選礦的效率高。表3顯示了重介質(zhì)旋流器和僅僅需水的單元的相對(duì)效率數(shù)據(jù)（de Korte和Bosman

10、2006）。</p><p>　　表3 重介質(zhì)旋流器與以水為介質(zhì)設(shè)備的比較</p><p>　　同時(shí)分選密度隨著作為特定直徑旋流器中特定粒度函數(shù)的效率改變而改變的，圖4顯示了一種610mm直徑旋流器的特定結(jié)果，這個(gè)特定結(jié)果是作為特定粒度函數(shù)的規(guī)范EPM和相對(duì)分選密度被給出的。</p><p>　　圖4 特定粒度、標(biāo)準(zhǔn)誤差和相對(duì)分選密度的對(duì)應(yīng)曲線</p>

11、<p>　　如圖5所示，在分選密度方面的轉(zhuǎn)變是重要的發(fā)現(xiàn)，與重介質(zhì)旋流器相比以水為介質(zhì)的分選設(shè)備如跳汰機(jī)、螺旋選礦機(jī)和后邊的設(shè)備分選效果更顯著。</p><p>　　圖5 特定粒度與重介質(zhì)旋流器和跳汰機(jī)的相對(duì)分選密度的對(duì)應(yīng)曲線</p><p><b>　　應(yīng)用</b></p><p>　　旋流器通常用于處理材料粒度在大約20mm和0

12、.5mm之間。大直徑旋流器的出現(xiàn)使較粗材料的處理成為可能。然而，與用泵傳送大顆粒物料有關(guān)的問題仍然限制重介質(zhì)旋流器中處理物料的上限為大約50mm。在產(chǎn)品需要按粒度分的地方，仍然習(xí)慣于布置重介室并且通過重介旋流器分選小顆粒物料。對(duì)于重介質(zhì)旋流器0.5mm總是被作為實(shí)際分選下限的粒度尺寸。然而，用重介質(zhì)旋流器將煤處理的小于0.5mm有顯著的效果。建在比利時(shí)Winterslag和Tertre 、美國(guó)Marrowbone 、南非Greensid

13、e 、澳大利亞 Curragh 的選煤廠可以作為證據(jù)。不幸的是這些廠子并不像預(yù)期的那么好。最近在磁選機(jī)的進(jìn)展促使恢復(fù)了重介質(zhì)旋流器在優(yōu)質(zhì)煤炭加工中的應(yīng)用。用重介質(zhì)旋流器可以獲得的分選效率優(yōu)于僅僅用水的操作單元，例如，螺旋選礦和搖床選礦。由于這個(gè)原因，在南非正在建設(shè)一個(gè)新的優(yōu)質(zhì)重介選煤廠。大直徑旋流器以及粗介質(zhì)在細(xì)粒重介分選的成功應(yīng)用是多級(jí)優(yōu)質(zhì)煤處理，這導(dǎo)致了一個(gè)全部有效的過程。（de Korte2002）。</p><

14、;p>　　由于重介質(zhì)旋流器的分離效率高，它們是處理難處理原煤的可供選擇的方法。它們也被應(yīng)用在產(chǎn)品的價(jià)格決定著能夠獲得的最高的收益領(lǐng)域。越來越多的重介質(zhì)旋流器被應(yīng)用在這些國(guó)家如印度和在美國(guó)易選煤中重介質(zhì)旋流器的廣泛應(yīng)用就是這的證據(jù)。</p><p><b>　　附錄B 外文文獻(xiàn)</b></p><p>　　Dense-Medium Cyclones</p&g

15、t;<p>　　G.J.de Korte and J. Engelbrecht</p><p><b>　　ABSTRACT</b></p><p>　　The dense-medium cyclone, first developed by the Dutch State Mines (DSM) in the Netherlands in the 19

16、40s, has firmly established itself as the processing unit of choice in many minerals industries. Application of the dense-medium cyclone ranges from the recovery of diamonds, iron ore, and chromite at high relative densi

17、ties (RDs) through the separation of plastics at RDs below 1.</p><p>　　Despite its simple design , the dense-medium cyclone is not fully understood, and work aimed at improving knowledge about cyclone behavi

18、or continues. The main focus of further development is intended for making cyclones more efficient and increasing throughput capacity. The performance of dense-medium cyclones is controlled by many parameters, and the in

19、fluence of some of these factors is discussed in this chapter. </p><p>　　CYCLONE DIMENSIONS</p><p>　　Recent times have seen cyclone diameters increasing to the point where 1500mm-diameter cyclon

20、es are being used in many coal processing applications, particularly in Australia. The larger diameter also implies larger feed, overflow, and underflow openings and thus allows larger particles to be fed to cyclones. DS

21、M standard dimensions and current manufacturing trends for dense medium cyclones are defined in Table 1.</p><p>　　Most cyclone manufacturers still adhere to the DSM recommendations and Multotec “standard” cy

22、clones are manufactured to these dimensions. However, there is a demand for cyclones having higher capacity, the ability to process larger feed particles, and the ability to handle higher amounts of sink material. The la

23、tter requirement applies because modern mining methods are less selective and include more roof and floor shale in the coal mined and because more low-grade reserves are being mined. In I</p><p>　　Table 2 pr

24、esents relevant coal feed capacity and maximum feed size for the two types of cyclones available from Multotec (South Africa). The values given in Table 2 are based on the following:</p><p>　　? Equivalent fe

25、ed head of nine times the nominal cyclone diameter</p><p>　　? Volumetric medium to coal ratio of 3.5:1</p><p>　　? Feed coal solids relative density (RD) of 1.6</p><p>　　A 1450-mm-di

26、ameter Multotec cyclone is shown in Figure l.</p><p>　　Although the larger cyclones can handle large feed particles up to 140 mm, these particles can cause hang-up problems. Cyclones normally operate with a

27、typical feed top size of 50 mm. This is probably because of the difficulty in pumping large particles to the cyclone.</p><p>　　BREAKAWAY SIZE AND CUT-DENSITY SHIFT</p><p>　　The breakaway size is

28、 defined as the particle size below which the recovery efficiency for the smaller particles starts to</p><p>　　decrease significantly. Bosman (1994) provides an approximate breakaway size versus cyclone diam

29、eter, as shown in Figure 2. Bosman includes cyclones only up to 800 mm in diameter, and the graph has been extended to represent cyclones of 1500-mm diameter in the figure.</p><p>　　One problem with the brea

30、kaway size definition is it indicates only that the efficiency decreases significantly, without quantifying this decrease. The probable error (EPM [ecart probable moyen]) is a function not only of cyclone diameter but al

31、so of feed pressure, medium density, medium viscosity, particle shape and density, top size of particles in the feed and so forth. Actual data from a number of South African operations (de Korte 2007a), using mostly 610-

32、mm-diameter cyclones, are summarize</p><p>　　Defining the breakaway size has led some people to believe that dense-medium cyclones are not capable of beneficiating coal that is smaller than the breakaway siz

33、e and that the minus-3-mm size fraction, for example, should be screened out of the cyclone feed and processed with water-only units such as spirals or teeter-bed separators (TBSs). It has also contributed to the industr

34、y being reluctant to adopt large-diameter cyclones. In reality, the efficiency does drop off as particles become small</p><p>　　Simultaneously with the change in efficiency as a function of particle size for

35、 a specific cyclone diameter, there is a concurrent shift in the cut density (SG50), Figure 4 shows a typical result for a 610-mm-diameter cyclone where both the normalized EPM and the relative cut density are given as a

36、 function of particle size.</p><p>　　APPLlCATIONS</p><p>　　Cyclones were traditionally used to process material between approximately 20mm and 0.5mm. The advent of large-diameter cyclones now al

37、lows coarser material to be processed. However, the problems associated with pumping large particles still limit the upper size of material processed in dense-medium cyclones to approximately 50 mm. Where sized products

38、are needed, it is still customary to install a dense-medium bath and to process only the small material via dense-medium cyclones.</p><p>　　On the lower end of the size scale, 0.5 mm was always considered th

39、e practical limit for dense-medium cyclones. However, there have been significant efforts to process coal finer than 0.5 mm with dense-medium cyclones. The plants built at Winterslag and Tertre in Belgium, Homer City and

40、 Marrowbone in the United States, Greenside in South Africa, and Curragh in Australia serve as proof. Unfortunately the results obtained from these plants were not always as good as expected. Recent advances in ma</p&

41、gt;<p>　　By virtue of their high separation efficiency, dense-medium cyclones are the method of choice for processing difficult-to-process raw coals. They are also applied in cases where the price of the product d

42、ictates that the highest possible yield be obtained. The growing number of densemedium cyclone plants being used in countries such as India and the extensive use of cyclones in the United States with easy coals are proof