钢铁冶金专业英语市公开课金奖市赛课一等奖课件

1、Specialty English for Iron & Steel Metallurgy Xu-ling Chen （陈许玲） E-mail： Mobile telephoneQQ number：413645166第1页Teaching Purpose掌握钢铁冶金工程基本专业英语词汇，能够阅读钢铁冶金及相关行业英文文件，及时掌握国外相关领域发展动态和新技术。提升翻译技巧和分析难句能力，正确、通顺、快速地把冶金专业英文资料译成汉字，初步掌握把汉语专业文章译成英文能力和英语听说能力。第2页Teaching ContentTheories and Technics of

2、AgglomerationTheories and Technics of IronmakingTheories and Technics of SteelmakingIntroduction of Iron and Steel Industry in World第3页Section Agglomeration 1.1 Trends in Agglomeration 1.1.1 The growth of sintering and pelletizing 1.1.2 Location of sintering and pelletizing plants 1.1.3 Future devel

3、opments 1.2. Modern Agglomeration Practice 1.2.1 Sintering 1.2.2 Pelletizing造块SinteringPelletizingBriquetting第4页Section Agglomeration1.1.1 The growth of sintering and pelletizing Sinter production grew slowly from its inception, in 1911, to the commencement of the Second World War, reaching six mill

4、ion tons in both the U.S.A. and the U.S.S.R. by 1940. Pelletizing commenced much later, in the early 1950s in the U.S.A. and not until the middle 1960s in the U.S.S.R. The growth of sinter and pellet production in these two countries, and of sinter production in the U.K., is shown in Figure 1.1.第5页S

5、ection Agglomeration1.1.1 The growth of sintering and pelletizing The following aims have resulted in the growth of sintering and pelletizing in these and other countries:(l) To improve the size grading and the reducibility of the furnace burden without wasting the ore fines.(2) To utilize certain w

6、aste products containing iron, e.g. blast-furnace flue dust.(3) To minimize the quantity of volatile matter charged to the furnace.(4) To utilize fine concentrates produced from low-grade ores.(5) To enable ore fines and concentrates to be processed at or near the mine site and thus to enhance the v

7、alue of exported ore.粒度组成size/grain distribution;size composition;dimension ratiocause；lead to；bring about第6页Section Agglomeration1.1.1 The growth of sintering and pelletizing Both sintering and pelletizing enable item 1 to be accomplished. Pelletizing is superior in that the final product size is m

8、ore closely controlled but there is no evidence to suggest that the close size-grading of pellets enables either the output or the thermal efficiency of a blast furnace to be better than that which can be obtained using sinter. Sinter plants are better suited than pellet plants for utilizing waste m

9、aterials, and in certain American works which use high proportions of pellets, the sinter plant has been reduced almost to the role of processor of waste materials and calciner of flux. However, a pelletizing plant has been built in Italy solely to process pyrites residues, a by-product from the sul

10、phur industry, and in Canada pellets are produced from the by-products of the non-ferrous industry.煅烧；熔剂硫铁矿烧渣硫；有色第7页Section Agglomeration1.1.1 The growth of sintering and pelletizing Volatiles are contained in the flux and also, to a lesser extent, in certain ores. The addition of limestone to the s

11、inter mix to produce a fluxed sinter, (basicity l.0-1.4) has been practised for many years, and more recently super-fluxed inters with basicities as high as 3.0-4.0 have been made. The use of such sinters enables a mixture of ores, or pellets, and sinter to be used as blast-furnace burden with only

12、a minimum of raw (uncalcined) flux. It has also been common practice for some years to sinter low-grade ores of high volatile content. This has greatly improved furnace operation in those regions of the United Kingdom and Western Europe where such ores are the basis of ironmaking. calcium carbonate

13、burnt lime 生石灰；dolomite 白云石；olivine 橄榄石；serpentine 蛇纹石；magnesite 菱镁石第8页Section Agglomeration1.1.1 The growth of sintering and pelletizing Two pellet plants in North America have been built to process limonite ore at the mine and so ship a richer product, in a more desirable physical state, to the st

14、eelworks. Fluxed pellets have been made and charged to the blast furnace, but only in relatively small quantities, and it is too early to assess their behaviour in the blast furnace. It is unlikely, however, that it would be economically justifiable to transport flux to the pelletizing plant and the

15、n ship it, as part of the fluxed pellet, for a considerable distance to the steelworks.Limonite 褐铁矿Hematite 赤铁矿；Magnetite 磁铁矿；Siderite 菱铁矿；Goethite 针铁矿第9页Section Agglomeration1.1.1 The growth of sintering and pelletizing Pelletizing was developed initially as a method of processing fine concentrates

16、. Extensive tests were carried-out in the U.S.A. around 1950 to develop ways of agglomerating the fine concentrates obtained from taconites（铁燧石）. Both sintering and nodulizing were tried and abandoned as less suitable than pelletizing. The widespread development of low-grade ore bodies in the U.S.A.

17、, Canada and elsewhere, in the 1950s and 1960s, provided the stimulus for the growth of pelletizing capacity which is shown in Figure 1.2. More recently a number of pellet plants have been built to produce pellets from high-grade ore fines. This enhances the value of the product.第10页1.1.2 Location o

18、f sintering and pelletizing plants Sintering is always likely to be carried out at the steelworks. Sinter does not withstand handing very well, and the less the handling between the sinter plant and the blast furnace, the better. Added to this is the fact that certain of the raw materials, e.g. flue

19、 dust and coke breeze, arise within the works. On the other hand, pelletizing is likely to be carried out at or near the mine site. There are some exceptions to this; at Chiba, the Kawasaki（川崎） Steel Company commenced making pellets in 1953. The fine ore used in the works was divided into two stream

20、s, that most suited to pelletizing, e.g. fine concentrates, and that most suited to sintering, e.g. the undersize from ore screening. It was claimed that in this way sintering practice was improved and the pre-treatment of the pelletizing mix was minimized. Pellet plants have been built at two other

21、 Japanese works and another has been built in Holland. However, the vast majority of new plants are being built at or near the mines. Pelletizing works most effectively if the raw material feed is consistent, and this can more easily be ensured if the pellet plant and the mine are closely linked. Th

22、ere is also an understandable desire on the part of the exporting country to provide a more valuable material. The data on page 12 gives an example of the difference in value between pellets and the ore fines from which they were produced.第11页Figure 1.2 World pellet capacity It is dangerous to predi

23、ct future developments from what has happened in the past. However, certain trends are fairly clear. Sintering will continue to be important. The increasing emphasis on a closely sized burden renders it inevitable that ore and pellet screenings will continue to be produced at the steelworks. It is m

24、ost improbable that all the fines arising at the mines will be pelletized before dispatch. It is much more likely that a balance will always be maintained between fines sold relatively cheaply and the more expensive pellets. Add to this the necessity for utilizing waste materials arising in the stee

25、lworks, e.g. flue dust, and the desire to calcine the flux before charging it to the furnace, and the future of sintering appears to be assured. The only developments which could upset this would be the development of a new agglomeration process or a modification of the pelletizing process which ena

26、bles it to accommodate a coarser feed. The only new process which has appeared over the horizon in recent years is hot briquetting, and this has not fulfilled its earlier hopes. Recent work has established that pellets can be made from certain ore mixes without having all the input finely ground, bu

27、t some grinding is still necessary and not all ore mixes are suitable for this type of pelletizing operation. This work has not been carried out on a large scale and the behaviour of such pellets in the blast furnace has not been investigated. Status of sintering and pelletizing第12页Section Agglomera

28、tion Pelletizing also appears to have an assured future. Taking a long-term view, an increasing proportion of the blast-furnace burden is likely to come from low-grade deposits. These can be pelletized most conveniently at or near the mine and shipped in the processed form. It is also probable that

29、the present trend of pelletizing part of the ore-rich fines before selling will continue. It is not possible to predict how the overall balance between sintering and pelletizing will change with time. In any case it is likely to vary greatly from country to country, and both processes could eventual

30、ly be rendered unnecessary by radical new developments in ironmaking. Status of sintering and pelletizing第13页Section Agglomeration Metallized agglomerates The aim in recent years has been to minimize the metallurgical load on the blast furnace. This has resulted in limiting the chemical operations t

31、o be performed to the reduction of iron oxides, together with small quantities of other oxides, and slag formation. The volume of slag has been reduced to the necessary minimum so that the heat needed for melting has been minimized. The main thermal load is the energy required for reducing iron oxid

32、e, and the work to be done in the blast furnace would be reduced if part of the oxygen was removed before charging. Because of the operating conditions within the blast furnace, reducing the higher oxides to ferrous oxide does not lower the blast-furnace fuel consumption. To achieve this it is neces

33、sary to reduce at least a proportion of the iron to the metallic state.第14页Section Agglomeration Metallized agglomerates It is not possible to make highly reduced sinter by increasing the coke content of the mix. The higher bed temperatures obtained, and the reducing atmosphere, lead to the producti

34、on of a high proportion of partly reduced ferruginous slag. On the other hand, highly reduced (metallized) pellets can be produced by modifications of the normal hardening procedure. Metallized pellets can be made from fired oxidized pellets, but it is also possible to harden the green pellets under

35、 reducing conditions to produce the metallized pellets in one operation. Two methods are being used commercially, a horizontal rotary kiln and a vertical-shaft kiln.第15页Section Agglomeration Metallized agglomerates The SL/RN process uses a horizontal rotary kiln. Green or fired pellets and a solid f

36、uel - fine coal or coke - and fine flux are fed into the rotary drum. The solids travel through the drum counter-current to the combustion gases from a gas- or oil-fired burner located in the exit from the drum. The reduced pellets are cooled in a second drum, and separated from the spent flux and e

37、xcess solid fuel. Figure 1.3 shows the layout of an SL/RN plant. Commercial plants have been built in New Zealand, South Korea and Canada. 第16页Figure 1.3. The SL/RN processSection AgglomerationSponge iron第17页Section Agglomeration Metallized agglomerates A number of shaft-furnace processes have been

38、developed. In the Wiberg process, fired oxidized pellets are reduced in a shaft by gases produced in an electrically heated gas carburizer. In the Midland Ross shaft process (Midrex process), fired oxidized pellets are reduced in a shaft by gases produced by reforming methane(甲烷). The same method of

39、 producing reducing gases is used in the Purofer process, but here the intention is to use unfired green pellets and to reduce and harden in the same operation. Commercial shaft-furnace plants are in operation or under construction in Sweden, Japan, the U.S.A., and Germany. Metallized agglomerates c

40、an also be produced by reducing fine iron ore, for example in fluidized beds, and briquetting the product. A commercial plant using this method has been built in Venezuela.第18页Section Agglomeration Metallized agglomerates Metallized pellets have only been used as a blast furnace burden for short tri

41、al periods. The results were encouraging in that outputs rose and coke rates fell, but the economic advantages are very doubtful. Whilst metallized agglomerates may be used to a limited extent as a blast-furnace feed, it seems likely that, in the main, they will be melted and refined directly to ste

42、el, thus by-passing the blast furnace altogether. In this case, the manufacture of metallized pellets becomes an alternative ironmaking process like those described in Chapter 3. This is borne out practically, since most of the processes for making metallized pellets can also operate using sized ore

43、 which, when reduced, is melted and refined to steel.第19页Section Agglomeration Technical bases of sinter and pellet-plant design and operation Before 1945 little was known of the basic principles underlying the sintering process, and the design, construction and operation of sinter plants was largel

44、y based on experience. In the next fifteen years or so great efforts were made to rectify this position. Laboratory studies were carried out aimed at elucidating the basic theory, both chemical and physical, and pilot-plant studies and investigations on commercial plants were made to provide a basis

45、 for plant design and operation. During this period, work was carried out in many countries in universities, research associations, steelworks and by plant manufacturers. Interchange of information was good and the results were rapidly incorporated into the design and operation of sinter plants. Thr

46、ee international meetings were held during this periodin London in 1953, in Paris in 1957, and in Philadelphia in 1961which provided useful opportunities for the exchange of information.第20页Section Agglomeration Technical bases of sinter and pellet-plant design and operation At about the same time,

47、the basic research and development which led to the establishment of the pelletizing industry was being carried out. Much of the basic work was carried out in the University of Minnesota and later by Jernkontoret in Sweden. As soon as it had been proved that pelletizing was of potential commercial i

48、mportance, i.e. by the early 1940s, the American (and later the European) plant manufacturers carried out on the mechanism of balling and on the problems connected with heat for the commercial exploitation of the idea. During this period, basic studies were carried out on the mechanism of balling an

49、d on the problems connected with heat flow during pellet firing.第21页Section Agglomeration Technical bases of sinter and pellet-plant design and operation At the present time, the design and operation of both sinter and pellet plants are firmly based on an understanding of basic factors which control

50、 the processes. The basic theory is discussed in the early chapters of each section, and the application of this theory to construction and operation of commercial plants is considered in later chapters.第22页Section Agglomeration1.2. Modern Agglomeration Practice 1.2.1 Sintering 1.2.2 Pelletizing第23页

51、Section Agglomeration Figure 1.4 shows the general arrangement of a sinter plant. The plant may conveniently be divided into the following sections: (1) Proportioning of raw materials (2) Mixing (3) Loading of mix on to strand (4) Ignition (5) Sintering (6) Sinter treatment (7) Waste gas system Gene

52、ral plant layout第24页Section Agglomeration General plant layoutFigure 1.4 General arrangement of a sinter plant第25页Section AgglomerationThe raw materials used are as follows:(1) Iron ore fines, normally -1/2 in. (12 mm). It is undesirable to have larger lumps and it is also undesirable to have an und

53、uly high proportion of l00 mesh (150 m) material. Usually a mixture of ore fines is used.(2) Fuel, normally 1/8 in. (3 mm) coke breeze; fine anthracite is sometimes used.(3) Blast-furnace flue dust.(4) Flux, limestone and/or dolomite -1/8 in. (3 mm).Other additives, converter dust, borings, turnings

54、, etc., are sometimes used. Proportioning of raw materials第26页Section Agglomeration The raw materials may be blended by laying them down and reclaiming them from beds outside the sinter plant proper, or the individual components may be stored separately and conveyed to separate bunkers in the sinter

55、 plant. From these bunkers the various materials are withdrawn via feeders, often associated with devices to ensure that the feed rate is maintained constant, and collected on a gathering belt. Sometimes all the raw materials, including flue dust and fuel, are collected on the same belt, and sometim

56、es the ore fines, flue dust, and coke breeze are collected separately. Proportioning of raw materials第27页Section Agglomeration The proportioned raw materials are next mixed and moistened. This is usually done by passing them through a drum fitted with paddles, water being added to impart permeabilit

57、y to the mixed materials. After this initial mixing, the moist mix may be rolled in a drum to give increased permeability. Mixing第28页Section Agglomeration The mix is now ready to be loaded on to the strand. The aim is to lay down the material evenly across the width of the strand with the minimum of

58、 compacting. A number of means have been devised for effecting this, for example a swinging spout, a roll feeder and a vibrating-tray feeder. In some sinter plants a thin layer of inert material, such as sized sinter, is first laid on the grate bars and the sinter mix is loaded on top of this hearth

59、 layer. Immediately after loading the surface of the mix is levelled by passing it under a plate, the cut-off plate, which is set so as to give the desired thickness of mix on the strand. Normally this is between 12 and 18 in. (300-450 mm). Loading the mix on to the strand第29页Section Agglomeration N

60、ext the mix is ignited by means of gas or oil burners. Normally the burners are set in a brick-lined hood which covers a length of strand, but vertical burners which impinge directly on to the mix are sometimes used. Igniting耐火砖衬里炉罩第30页Section Agglomeration Thereafter sintering proceeds, air being s