外文翻譯--新型水泥生產(chǎn)工藝的可行性研究要求

1、<p>　　新型水泥生產(chǎn)工藝的可行性研究要求</p><p>　　英國WS Atkins專家R.Hogg, D Frame 和M.E. Asim討論大型水泥設(shè)備工程的理論可行性。</p><p>　　針對(duì)西班牙語和法語的版本請(qǐng)參考本雜志的后面特別翻譯部分。</p><p><b>　　楊聞達(dá)譯</b></p><p

2、><b>　　引言</b></p><p>　　開始建造一套完整的新型水泥生產(chǎn)工藝設(shè)備或在已有的水泥生產(chǎn)設(shè)備上進(jìn)行主要設(shè)備生產(chǎn)能力的擴(kuò)充改造，這些計(jì)劃都應(yīng)該在詳細(xì)的技術(shù)經(jīng)濟(jì)分析的基礎(chǔ)上實(shí)施。這樣的研究涉及到采用最好的技術(shù)方案、總的成本和總的運(yùn)營(yíng)支出這些方面，同時(shí)也涉及到生產(chǎn)、所需的勞動(dòng)力及在一定時(shí)間段內(nèi)投資回收的運(yùn)營(yíng)規(guī)模，它能體現(xiàn)出工程較好的經(jīng)濟(jì)可行性。</p><

3、p>　　一項(xiàng)典型的可行性研究主要需解決以下問題：</p><p><b>　　市場(chǎng)調(diào)查分析。</b></p><p><b>　　生料的供給。</b></p><p>　　廠址選定及設(shè)備的安裝研究。</p><p>　　工程及工藝的概念設(shè)計(jì)。</p><p><b

4、>　　互換性分析。</b></p><p>　　包括基礎(chǔ)設(shè)施的支出預(yù)算。</p><p><b>　　工程時(shí)間表。</b></p><p>　　投資分析，風(fēng)險(xiǎn)評(píng)估，財(cái)務(wù)結(jié)構(gòu)的發(fā)展。</p><p><b>　　項(xiàng)目費(fèi)用。</b></p><p><b&

5、gt;　　財(cái)務(wù)狀況的討論。</b></p><p>　　所有的可行性研究報(bào)告必須包含技術(shù)方面的問題，它在解釋市場(chǎng)研究與合理的資金規(guī)劃之間的完整關(guān)系上是很重要的。</p><p><b>　　預(yù)先可行性研究</b></p><p>　　為了使所有的費(fèi)用最低化，為了能很快地達(dá)到工程可行性的預(yù)定指標(biāo)，預(yù)先可行性分析是必需的。</p&

6、gt;<p>　　預(yù)先可行性研究是在以很低費(fèi)用支出的條件下完成的。當(dāng)有充足的準(zhǔn)備條件時(shí)它又能顯示出完整可行性分析的公正性。預(yù)先可行性研究要調(diào)查市場(chǎng)、尋求原材料、籌集資金和準(zhǔn)備運(yùn)營(yíng)費(fèi)用，從而擬訂一份商業(yè)計(jì)劃。這樣就知道可能的投資回收、對(duì)風(fēng)險(xiǎn)的分析和所在的運(yùn)營(yíng)環(huán)境。</p><p>　　典型的預(yù)先可行性研究過程從開始將需4到6周才能完成，而研究中的大多數(shù)工作都是在辦公桌上參照內(nèi)部的數(shù)據(jù)庫來完成的?，F(xiàn)場(chǎng)考

7、察過程是根據(jù)水泥生產(chǎn)、本地建筑、民事工程費(fèi)用支出、土地費(fèi)用、特殊地方的獨(dú)特性以及在當(dāng)?shù)毓S運(yùn)營(yíng)所要求的費(fèi)用支出確定合適的生料。辦公桌上的研究工作注重于現(xiàn)在工廠、機(jī)械設(shè)備、財(cái)務(wù)、對(duì)市場(chǎng)的考察及主要設(shè)備安置和工藝路線的確定。</p><p>　　在預(yù)先可行性研究清楚地展現(xiàn)出這項(xiàng)工程是值得進(jìn)行的后，完整的可行性研究才能開始。</p><p><b>　　完整可行性研究</b>

8、;</p><p><b>　　市場(chǎng)調(diào)查</b></p><p>　　市場(chǎng)研究的主觀目的是滿足在一定區(qū)域背景和工廠計(jì)劃的市場(chǎng)范圍內(nèi)對(duì)各種水泥的需要。市場(chǎng)研究尋求滿足現(xiàn)在以及預(yù)計(jì)在以后長(zhǎng)達(dá)5到7年這段時(shí)間內(nèi)的水泥使用需求。這樣的預(yù)測(cè)與市場(chǎng)的指導(dǎo)價(jià)結(jié)合，形成在計(jì)劃操控下可能的收入趨向。</p><p>　　這方面的專家必須要有對(duì)全球水泥工業(yè)的相關(guān)認(rèn)

9、識(shí)，以及能對(duì)市場(chǎng)最新的狀況和可能的發(fā)展趨勢(shì)有所把握，這樣才能進(jìn)行可行性研究。各個(gè)公司和地區(qū)都是這樣的，同時(shí)又體現(xiàn)了各自獨(dú)特的背景，這樣的背景卻是必須要充分把握的。通常所運(yùn)用的方法是首先研究公司和分析它的優(yōu)勢(shì)和劣勢(shì)，戰(zhàn)略性方向和動(dòng)向。在證實(shí)公司為實(shí)現(xiàn)其目標(biāo)制訂的成功性很大的近期規(guī)劃中，這方法是不可或缺的。</p><p>　　所運(yùn)用的方法的第二階段是通過調(diào)查涉及工業(yè)大范圍的公開數(shù)據(jù)，進(jìn)行市場(chǎng)觀察，現(xiàn)場(chǎng)研究，將原先的

10、討論實(shí)踐到具體的背景下。</p><p>　　公開數(shù)據(jù)是研究者和專家對(duì)已知的客觀趨向進(jìn)行分析和對(duì)未知的新信息進(jìn)行推敲和比較所得出的。單單依靠幾個(gè)月前的舊信息，且忽視在水泥生產(chǎn)方面的國際性觀點(diǎn)、趨勢(shì)是不夠的，這樣所得到的水泥需求也總是失去指導(dǎo)性的。</p><p>　　收集那些公布的數(shù)據(jù)是一個(gè)持續(xù)的過程，但是是在確定調(diào)查研究的基地后的工作，并且已收集的信息應(yīng)該通過第一手獲得的工業(yè)資料和觀點(diǎn)盡

11、可能被證實(shí)。公司、政府組織和其他的工業(yè)協(xié)會(huì)總是希望提供他們自己的市場(chǎng)評(píng)估，并且需要注意不去妥協(xié)于任何被強(qiáng)加的觀點(diǎn)，準(zhǔn)備給出自己的見解。</p><p>　　這個(gè)階段中，在已經(jīng)把握好那些廣泛收集的公開數(shù)據(jù)和工業(yè)主張后，專家的工作就是正確地定義特定產(chǎn)品所針對(duì)的市場(chǎng)，另外還有市場(chǎng)中可能的變化。這些變化總要靠具有歷史意義的關(guān)系來預(yù)料的。例如，這些關(guān)系包括國民生產(chǎn)總值和所有建設(shè)活動(dòng)的關(guān)系，經(jīng)濟(jì)增長(zhǎng)和房屋建造的關(guān)系，或者是水

12、泥消耗和人口數(shù)量的關(guān)系。圖1說明了這一點(diǎn)。如不考慮那些客觀意見和不認(rèn)清水泥使用者對(duì)不同型號(hào)的水泥需求的變化，這樣的預(yù)測(cè)是錯(cuò)誤的。對(duì)這些方面的分析在一些非發(fā)達(dá)國家是尤其重要的。在這些非發(fā)達(dá)國家，不樂觀的生長(zhǎng)率在顯著的短時(shí)間內(nèi)會(huì)改變建設(shè)活動(dòng)的平衡性。</p><p>　　另外可能會(huì)給市場(chǎng)帶來負(fù)擔(dān)的商業(yè)信息是收費(fèi)表、進(jìn)口關(guān)稅和部分的津貼。即使是在自由經(jīng)濟(jì)時(shí)期，經(jīng)濟(jì)的很多方面都與戰(zhàn)略的重要性，以及政府為維持國內(nèi)匯率總會(huì)通

13、過確定一定的價(jià)格表，或提高進(jìn)口關(guān)稅的措施有關(guān)。如果取消進(jìn)口關(guān)稅或者價(jià)格只依據(jù)供求關(guān)系來變化，這在市場(chǎng)條件下將是很重大的變化；譬如，國內(nèi)公司會(huì)突然發(fā)現(xiàn)他們自己毫無競(jìng)爭(zhēng)能力。隨著進(jìn)口商品的價(jià)格越來越低，水泥粉磨和熟料的需求平衡可能會(huì)有顯著變化，這取決于政府所采納的政策的變化，而專家的主要工作之一就是預(yù)計(jì)它們。</p><p>　　最后要強(qiáng)調(diào)的一點(diǎn)是競(jìng)爭(zhēng)者的反應(yīng)。它也許是在決定市場(chǎng)研究的各方面問題中的唯一并且是最重要的

14、難題。要想得知其他的投資計(jì)劃、政府許可、可能的競(jìng)爭(zhēng)數(shù)據(jù)、在競(jìng)爭(zhēng)者中主要的競(jìng)爭(zhēng)者和合作伙伴，這樣的過程是很困難也是很費(fèi)時(shí)的，同時(shí)它也總是遠(yuǎn)遠(yuǎn)不夠的。競(jìng)爭(zhēng)者不單單是國內(nèi)的或者是長(zhǎng)期以來以同樣的可預(yù)測(cè)的銷售途徑來銷售他們的產(chǎn)品的，現(xiàn)在越來越多的公司希望靠縱向的統(tǒng)一他們的運(yùn)營(yíng)來減少對(duì)供求方的依賴性。這將能幫助建造他們自己的工廠或發(fā)展他們自己的用于直接進(jìn)口水泥的深水港。其他的公司也許會(huì)決定轉(zhuǎn)變成賣方，例如，賣罐裝混凝土。某些大客戶也許會(huì)和這樣的一

15、個(gè)公司簽訂長(zhǎng)期合作協(xié)約或?qū)で蟾蟾鼜V遠(yuǎn)的市場(chǎng)去買進(jìn)水泥。研究的組合方式有很多，這取決于公司在昂貴的廠房和機(jī)械設(shè)備投資的金額。這樣的研究是為了了解投資所要針對(duì)的顧客，也是為投資者們確定這樣的投資確實(shí)擁有一個(gè)最廣闊的市場(chǎng)的。</p><p><b>　　原材料的考證</b></p><p>　　對(duì)于生料礦藏的儲(chǔ)量和質(zhì)量，我們必須對(duì)它們有很準(zhǔn)確的認(rèn)知。對(duì)原材料廣范圍的搜尋可

16、以以研究臺(tái)上的研究及借助《國家地質(zhì)勘探》這本書的數(shù)據(jù)和使用的地質(zhì)圖譜為指導(dǎo)來開始。這樣的搜尋將包括調(diào)查無線的照?qǐng)D記錄和衛(wèi)星圖片，例如查看Landsat或SPOT衛(wèi)星圖片。</p><p>　　緊接著研究臺(tái)上的工作是現(xiàn)場(chǎng)考察那些規(guī)劃地點(diǎn)，這工作是由地質(zhì)專家通過現(xiàn)場(chǎng)考察以往鑒定的地理水平線和巖石層，從而能深入地研究。第一步取樣品工作。在可能有很好跡象的巖石層、山中開辟的道路、現(xiàn)在已有的開采進(jìn)行引導(dǎo)性挖掘，或者在計(jì)劃開

17、采的測(cè)試點(diǎn)進(jìn)行引導(dǎo)性鉆孔。礦區(qū)的樣品測(cè)試需要提供儲(chǔ)存的氧化鈣、硅、鋁和鐵含量原始指標(biāo)。這樣的測(cè)試是簡(jiǎn)單的、快捷的、經(jīng)濟(jì)的。地質(zhì)專家能調(diào)整礦區(qū)調(diào)查工作和最大化地收集發(fā)現(xiàn)的有用信息。</p><p>　　最有指望的樣品收集工作是在測(cè)試實(shí)驗(yàn)室進(jìn)行化學(xué)分析后，掌握了充足的化學(xué)質(zhì)量的數(shù)據(jù)和已確定可能的數(shù)量時(shí)，決定開始完全開鑿工作。</p><p>　　主要的生料成分或者石灰石是鉆孔所要的核心。對(duì)地質(zhì)

18、進(jìn)展需要進(jìn)行詳細(xì)記錄，如把核心開采出來、記錄，并把它們分類放入核心箱內(nèi)（圖2）；從鉆核中獲得個(gè)別的和混合性的樣品，并送到習(xí)慣于對(duì)水泥生料進(jìn)行測(cè)試的實(shí)驗(yàn)室。為了減少鉆孔成本，對(duì)第一次鉆的孔的原始結(jié)果進(jìn)行快速分析并知道結(jié)果是必要的，同時(shí)也是為了更深遠(yuǎn)地確定隨后鉆孔的地點(diǎn)、角度和方向。</p><p>　　化學(xué)分析的數(shù)據(jù)和源于核心的地質(zhì)記錄，這些信息可以用于確定地質(zhì)結(jié)構(gòu)和儲(chǔ)量。最佳的采石發(fā)展計(jì)劃和對(duì)移動(dòng)型設(shè)備的要求才可

19、以有所發(fā)展。</p><p>　　次要的生料成分，如粘土或頁巖，需要通過擴(kuò)大型鉆孔或用移動(dòng)型液壓開采機(jī)進(jìn)行測(cè)試定點(diǎn)開采，也或者一定情況下實(shí)行人工開采來證實(shí)。這些原料需要進(jìn)行類似于石灰石的記錄和化學(xué)分析。</p><p>　　通過使用生料的化學(xué)分析結(jié)果，可以進(jìn)行設(shè)計(jì)生料混合比了。所使用的室內(nèi)程序有很多附加技術(shù)要求。第一，所有的標(biāo)準(zhǔn)方程必須要適合如石灰的濕度、含硅比例、含鋁比例、液壓部件的條件

20、。這些方程需要編到程序中。第二，混合比設(shè)計(jì)必須通過調(diào)整混合物的成分和觀察在標(biāo)準(zhǔn)比例范圍下的反應(yīng)結(jié)果來改進(jìn)。最后，費(fèi)用支出方面可以加到生料上以獲得好生料混合物。這樣可以減少生料的費(fèi)用，同時(shí)也能滿足以上標(biāo)準(zhǔn)。</p><p><b>　　過程工藝設(shè)計(jì)</b></p><p>　　對(duì)于特定的工廠，最佳的工藝路線是依靠包括生料礦藏的物理和化學(xué)性質(zhì)的許多方面來設(shè)計(jì)的。廠房和機(jī)械

21、設(shè)備是基于以下幾個(gè)方面來選擇的：</p><p><b>　　生料礦藏的儲(chǔ)備。</b></p><p>　　生料的濕度和其他的物理性質(zhì)。</p><p>　　不希望存在的化學(xué)成分。</p><p>　　礦物學(xué)（特別是硅的成分和含量）。</p><p>　　生料的粗糙度、耐磨性和燃燒特性。</

22、p><p>　　主要生料成分內(nèi)所缺乏的附加特性要求。</p><p>　　燃料品種及相應(yīng)的費(fèi)用支出。</p><p><b>　　環(huán)境保護(hù)要求。</b></p><p>　　可用電力、高效要求和費(fèi)用支出要求。</p><p><b>　　建造的地形和要求。</b></p&g

23、t;<p><b>　　市場(chǎng)規(guī)定。</b></p><p><b>　　勞動(dòng)力和保養(yǎng)規(guī)定。</b></p><p>　　受潮問題、沖擊問題和自然儲(chǔ)藏的生料成分的性質(zhì)，這些決定著如何地開采主要和次要的生料成分、如何地處理和改善運(yùn)輸條件。儲(chǔ)藏的地質(zhì)環(huán)境和生料成分的硬度也將決定怎樣計(jì)劃開采場(chǎng)和怎樣決定開采的方法。</p>&

24、lt;p>　　生料的濕度和伴隨著濕度變化而導(dǎo)致其他性質(zhì)的變化，兩者對(duì)主要的破碎機(jī)和備料系統(tǒng)的選擇有著重要的作用。當(dāng)考慮到生料磨系統(tǒng)預(yù)熱裝置所排出廢氣的最佳溫度時(shí)，濕度起到很大的作用。在回轉(zhuǎn)窯系統(tǒng)裝置、所用的旋風(fēng)級(jí)別的數(shù)量和為了將生料烘干而采用的生料磨加熱裝置間，熱量必須保持平衡。</p><p>　　在生料中不希望存在的化學(xué)元素的成分有鉀、鈉、氧化鎂、氯和硫酸銅。在選擇回轉(zhuǎn)窯系統(tǒng)的類型時(shí)要仔細(xì)考慮這些。不同

25、的非純生料會(huì)含有硫酸銅及窯內(nèi)燃料中也存在硫酸銅。這將導(dǎo)致我們必須對(duì)分流系統(tǒng)的承受力和外形尺寸加以考慮。</p><p>　　在不同的國家，對(duì)生料的礦物研究也有很大的不同。在回轉(zhuǎn)窯的煅燒工程中，生料成分開采的方法和化學(xué)成分對(duì)化合反應(yīng)后生成的化合物的特性有著很明顯的影響作用。明顯地，礦物研究將使窯內(nèi)燃料的損耗和回轉(zhuǎn)窯的煅燒環(huán)境有很多變化，當(dāng)為了獲得較經(jīng)濟(jì)的水泥從而對(duì)一定比例的化學(xué)成分進(jìn)行化合時(shí)，必須要預(yù)料生料將怎樣的

26、反應(yīng)。這樣的預(yù)計(jì)過程是基于實(shí)驗(yàn)室內(nèi)以部分的可行性研究為指導(dǎo)的燃燒和粉磨測(cè)試。</p><p>　　從所有潛在和能看到的水泥設(shè)備的控制器的工作記錄上可看出，能量和燃料的使用是兩個(gè)關(guān)鍵控制參數(shù)。水泥工業(yè)都意識(shí)到最大化利用熱能的重要性。從窯內(nèi)廢氣到生料或者是從熱的廢渣到燃燒氣體中安裝終端熱交換器的方法已經(jīng)很好地被采用了。</p><p>　　如今，越來越多的人們?cè)诓粩嗟貙ふ腋咝Ю媚茉捶椒ê透呷?/p>

27、燒率的燃料。一定范圍采用節(jié)能的工藝和設(shè)備都作為考慮對(duì)象。以經(jīng)濟(jì)為標(biāo)準(zhǔn)，這方面也是很重要的，同時(shí)市場(chǎng)證實(shí)了在這方面有很大的支配能力和能相應(yīng)的減少產(chǎn)品的成本。所以人們廣泛地接受了這些。</p><p>　　在生料磨和水泥熟料磨中所采用的含有球磨機(jī)、高效選粉機(jī)、低壓旋風(fēng)預(yù)熱裝置及垂直的高壓輥式磨和最近介紹的水平輥式磨（因此稱為Horomill）的生料磨系統(tǒng)能使得能量的損耗有很大降低。對(duì)于好的生產(chǎn)工藝的選擇必須確保它能使

28、電力消耗得以降低。</p><p>　　采用擁有隔熱壁的高效循環(huán)裝置和增多預(yù)熱器的數(shù)量以最大化利用回轉(zhuǎn)窯內(nèi)所排出的廢氣的熱量，這將很大地減少燃料的消耗。設(shè)計(jì)采用輔助設(shè)備，例如回轉(zhuǎn)窯的廢氣排放管道、回轉(zhuǎn)窯的煅燒設(shè)備、流量控制閥和其他設(shè)備都會(huì)對(duì)燃料消耗有側(cè)面的影響。</p><p>　　如今，另一個(gè)有所發(fā)展的是采用對(duì)從冷卻機(jī)到生料磨中所有的熱廢氣進(jìn)行傳遞的裝置，從而節(jié)省熱能來滿足對(duì)生料的烘干要

29、求。淘汰一些接收裝置或其他帶有輔助設(shè)備的冷卻收塵系統(tǒng)，這樣的準(zhǔn)備工作在減少工廠運(yùn)營(yíng)資本上有著很大的優(yōu)越性。</p><p>　　Feasibility study requirements for a new cement plant</p><p>　　R.Hogg, D Frame and M.E. Asim, WS Atkins Consultants, UK, discuss th

30、e theory and practice of undertaking large cement plant projects.</p><p>　　FOR SPANISH AND FRENCH VERSIONS PLEASE REFER TO THE SPECIAL TRANSLATED SECTION AT THE BACK OF THE ISSUE</p><p>　　Introd

31、uction</p><p>　　The decision to start the construction of an entirely new cement plant facility, or a major capacity extension at an existing cement works, should always be based on a detailed techno-economi

32、c feasibility study. Such a study will indicate to the promoter the viability of the business in terms of the best technical solution, the overall capital and operating casts, the magnitude of the operation in terms of p

33、roduction and workforce needed, and the return on his investment over a period of time.</p><p>　　A typical feasibility study deals with the following issues:</p><p>　　Marketing study.</p>

34、<p>　　Raw materials proving.</p><p>　　Site studies.</p><p>　　Conceptual engineering and process design. </p><p>　　Analysis of alternatives.</p><p>　　Project cost

35、including infrastructure.</p><p>　　Project schedule.</p><p>　　Investment analysis, risk assessment, development of financial structures.</p><p>　　Project finance.</p><p&g

36、t;　　Discussion with financing institutions.</p><p>　　Whilst any feasibility study must include technical aspects, it is important to realize the full implications of marketing research and accurate financial

37、 projections.</p><p>　　Pro-feasibility study</p><p>　　In order to minimize front end expenditure and to quickly obtain a firm indication of the likely project viability, a pre-feasibility study

38、is performed.</p><p>　　The pre-feasibility study is carried out at low cost, but in sufficient detail to show whether a full feasibility study is justified. The pre-feasibility study will examine the market

39、place, the raw materials, capital and operating costs, and develop a business plan to show the likely returns on the investment, and identify the risks and scale of operation involved.</p><p>　　Typically thi

40、s exercise will take four to six weeks to complete, commencing with a site visit. However, the study is largely performed by desk research and reference to the in-house date base. The site visit is used to determine the

41、suitability of raw materials for cement manufacture, local building and civil engineering costs, cost of land and peculiarities of the particular site location, and local cost of consumables required in the operation of

42、the plant. The desk research concentrates upon </p><p>　　In the event of the pre-feasibility study showing a clear indication that it is worthwhile to proceed with the project, then a full feasibility study

43、can be initiated.</p><p>　　Full feasibility study</p><p>　　Market research</p><p>　　The objective of the market study is to establish the demand for the various types of cement in t

44、he context of the region or market area of the proposed plant. The study seeks to establish the current and forecast cement usage over a 5-7 year period. The forecast is then used together with the indicated selling pric

45、es to generate the likely revenue stream for the proposed operation.</p><p>　　The consultant must have considerable experience in the global cement industry and be able to approach a feasibility study with a

46、n excellent knowledge of prevailing market conditions and likely trends. Each individual company and market does, however, present a unique set of circumstances which must be fully understood. The normal approach adopted

47、 is first to study the company and identify its strengths and weaknesses, strategic direction and motivation. This is essential in providing an immedia</p><p>　　The second stage of the marketing survey, desk

48、 research, puts the initial discussions into context by examining a wide range of published data relevant to the industry.</p><p>　　Sources of published data are collated and compared by a team of researcher

49、s and consultants in an operation to substantiate known trends and uncover new information. It is not sufficient to rely on information several months old, and without an international perspective, trends in cement produ

50、ction and demand are frequently misleading.</p><p>　　Collecting published data is an on-going process, but having established a background to the study, information should, where possible, be verified using

51、independent sources with firsthand accounts of the industry and its outlook. Companies, government organisations and other industry associations are often willing to provide their own assessment lf markets, but care need

52、s to be taken not to compromise any party prepared to give its view.</p><p>　　Armed with a comprehensive selection of published data and industry opinion, the job of the consultant at this stage is to accura

53、tely define not only the market size for a particular product, but the likely change in that market. Such changes are often predicted by historic relationships between, for instance GDP and overall construction activity;

54、 economic growth and housing starts of cement consumption and population size. Figure 1 illustrates this point. Without taking into account subjective </p><p>　　Other economic information likely to have a be

55、aring on the market are government tariffs, import duties and sector subsidies. Even in free market areas, many aspects of economies are regarded as being of strategic importance and governments frequently strive to pres

56、erve national interests wherever possible by fixing prices of imposing import tariffs. Should import tariffs be relaxed of prices allowed to move in line with supply and demand, there will be an appreciable change in the

57、 market condit</p><p>　　This last point highlights what is perhaps the single most important yet difficult to determine aspect of a market study: competitor reaction. Knowing of others investment plans, gove

58、rnment licensing, likely dates of completion, principle contractors involved and distribution partners is difficult and time consuming, but it is not enough. Competitors are not just nationals of those who have historica

59、lly sold their product through the same predictable channels of distribution. There are an increa</p><p>　　Raw materials proving</p><p>　　The volume and quality of the raw material deposits have

60、 to be established with accuracy. A wide ranging search for raw materials may start with desk research and consultation with National Geological Survey data and available geological mapping. The search will include exami

61、nation of aerial photography records and satellite imagery e.g. Landsat or SPOT.</p><p>　　The desk research is followed buy site visits to the proposed location by geologists who take the study a step forwar

62、d by making on-site examinations of previously identified geological horizons and outcrops. The first samples are taken by channeling from promising outcrops, road cuttings, recent excavations or from purpose excavated t

63、est pits. Field testing of the samples is required to provide an initial indication of the calcium carbonate, silica, alumina and iron content of the deposit. The </p><p>　　The most promising samples are che

64、mically analysed in testing laboratories and when sufficient data has been obtained in terms of chemical quality, and the probable volume established, a decision to mount a full drilling campaign can be made.</p>

65、<p>　　The primary raw material or limestone, is core drilled and careful records of the geological progression is made as the cores are recovered, recorded and laid sequentially in the core boxes,(Figure 2). Individ

66、ual and composite samples are taken from the cores and sent to laboratories experienced in the testing of cement raw materials. In order to minimize drilling costs is essential that the initial results of the first boreh

67、ole are analysed rapidly and the results known in order to make further</p><p>　　The information obtained from the chemical analyses and the geological record derived from the cores in then used to establish

68、 the geological structure and the volume of the deposit. The optimum quarry developments are then developed.</p><p>　　The secondary raw materials, clays or shales, may be proven by means of auger drilling of

69、 by test pit excavation using mobile hydraulic excavators or in some cases by hand excavation. These materials are similarly recorded and chemically analysed as for the limestones.</p><p>　　Using the chemica

70、l analysis of the raw material, computerized raw mix designs can be carried out. The in-house program used has several facilities which can be called upon. Firstly, all the necessary standard equations which must be sati

71、sfied for lime saturation, silica ratio, alumina ratio, hydraulic modulus, etc., are built into the program. Secondly, the mix design can be refined by adjusting the compound composition and observing the effect upon the

72、 standard ratios. Finally, cost factors can</p><p>　　Process design</p><p>　　The optimum process route for a specific plant is dependent upon a number of factors including the physical and chemi

73、cal nature of the raw material deposits. The selection of plant and machinery is made based on the following factors”</p><p>　　Disposition of the raw material deposits.</p><p>　　Moisture content

74、 and other physical properties of the raw materials.</p><p>　　Level of undesirable chemical elements.</p><p>　　Mineralogy (particularly the content and size of silica).</p><p>　　Abr

75、asiveness, grindability and the burnability of the raw materials.</p><p>　　Fuel types and relative costs.</p><p>　　Environmental protection requirements.</p><p>　　Electrical power a

76、vailability, cost and energy efficiency requirements.</p><p>　　Site topography and congstraints.</p><p>　　Market constraints.</p><p>　　Labour and maintenance constraints.</p>

77、<p>　　The disposition of the raw materials in terms of dip and strike and physical location dictate how the primary and secondary raw material quarries are opened up, how they are to be worked and how the access ro

78、ads are to be developed. The geological method of deposition and hardness of the raw materials will also determine how the quarry is to be planned and the methods of extraction determined.</p><p>　　The moist

79、ure content of the raw materials and the change in their characteristics as the moisture content alters has an important effect upon the choice of the primary crusher and storage systems. The moisture content has even gr

80、eater implications when considering the raw milling system to be proposed in conjunction with the optimum temperature of preheater exit gas. A balance has to be struck between the requirements of the kiln system, the num

81、ber of cyclone stages that can be used, and the hea</p><p>　　The level of undesirable chemical elements in the raw materials, such as potassium, sodium, magnesia, chlorides and sulfur requires careful consid

82、eration in the selection of the type of kiln system. The varying levels of impurity elements in conjunction with the sulfur in the raw material and possible additional sulfur intake from the kiln fuel, lead to the necess

83、ary decisions to be made relating to the acceptance and sizing of a bypass system.</p><p>　　The mineralogy can vary greatly among raw materials in different countries. The method of deposition and the occurr

84、ence of the chemical elements in each of the raw materials can have a marked effect on the characteristics of combination in the kiln burning process. Notably this leads to variations in kiln fuel conditions. Predictions

85、 upon how the raw-materials will behave when combined in the necessary proportions to obtain a commercial cement, are based upon laboratory burning and grinding test</p><p>　　Energy and fuel usage are two ke

86、y matters high on the agenda of all potential and existing cement plant operators. The cement industry has always been very conscious of making the maximum use of heat energy, and to this end heat transfer from the kiln

87、gases to the raw materials, of from the hot clinker to the combustion air, has always been utilized.</p><p>　　Today more than ever the efficient use of energy and fuel is sought affair and a range of plant a

88、nd equipments available for consideration. Technical economy of scale is also an important factor and where the market justify large capacity plant, correspond with reductions in the cost of products are achieved.</p&

89、gt;<p>　　Energy consumption is be reduced through the use of roll-milling systems for raw meal in plant of tube mills, high efficiency separators in both the raw milling and cement milling departments, low pressur

90、e drop cyclones in the preheater of the burning process, and by the preheater of high pressure grinding rolls, and recent introduction of the horizontal roller mill, the so-called Horomill. The selection of the optimum p

91、lanning processes ensures that the KWh/h electrical power consumption minimi</p><p>　　Fuel consumption is reduced the introduction of efficient cyclones construction with heat resistant tubes and an increase

92、 in the number of stages of preheater to mount maximum use of the hot gases leaving from the kiln. Fuel consumption is also siderable affected by the designation ancillary plant such as the kiln separators, gas ducting,

93、kiln burner, flow control valves and instrumentation.</p><p>　　Another recent development is the transfer of all the hot exhausted gases form the clinker cooler back onto the raw mill, thus saving on the hea

94、t required for drying the raw material. This arrangement also has the acute advantage of reducing the capital of the plant by the elimination of a cipitator or other clinker cooler collection system and its associating e