外文翻譯--為金羅斯的里奧帕拉卡圖礦產(chǎn)公司(rpm)擴(kuò)產(chǎn)而設(shè)計(jì)的半自磨機(jī)和球磨機(jī)回路【優(yōu)秀】

1、<p>　　加拿大不列顛哥倫比亞省</p><p><b>　　英屬哥倫比亞大學(xué)</b></p><p><b>　　部采礦工程</b></p><p>　　為金羅斯的里奧帕拉卡圖礦產(chǎn)公司(RPM)擴(kuò)產(chǎn)</p><p>　　而設(shè)計(jì)的半自磨機(jī)和球磨機(jī)回路</p><p&g

2、t;　　斯圖爾特麥克塔維什1，路易斯阿爾巴諾通多2，韋恩菲利普斯3，安納托利亞席爾瓦4 著</p><p>　　1.冶金主管，加拿大安大略省多倫多市SNC-蘭萬(wàn)靈公司工程師及創(chuàng)建者，加拿大；</p><p>　　2.項(xiàng)目經(jīng)理，金羅斯的里奧帕拉卡圖礦產(chǎn)公司(RPM)，巴西；</p><p>　　3.技術(shù)服務(wù)總管，美洲金羅斯公司，巴西；</p><p

3、>　　4.冶金學(xué)家，金羅斯的里奧帕拉卡圖礦產(chǎn)公司(RPM)，巴西；</p><p><b>　　摘要</b></p><p>　　金羅斯的里奧帕拉卡圖礦產(chǎn)公司(RPM)在巴西的黃金開采正在擴(kuò)大產(chǎn)量，從目前的18 000 000噸/年增至添加了38英尺半自磨機(jī)回路后的50 000 000噸/年。本文介紹了擴(kuò)產(chǎn)原理，設(shè)備的擇選以及由于礦石日益堅(jiān)硬而導(dǎo)致的礦石加工流程

4、的變化。同時(shí)論述了適應(yīng)流程的布局構(gòu)思。</p><p><b>　　緒論</b></p><p>　　帕拉卡圖公司的礦石開采于巴西，位于距米納斯吉拉斯州西北部的巴西利亞西南方向230公里處。擁有83 000人口的帕拉卡圖市就在采礦地點(diǎn)南面2千米處。</p><p>　　采礦于1987年開工，同時(shí)加工6百萬(wàn)噸/年的礦床氧化部分。該工廠氧化礦石的產(chǎn)

5、量相繼提高到約13百萬(wàn)噸/年，并于1997年通過加設(shè)研磨機(jī)及采用浮游選礦加工硫化礦使產(chǎn)量繼續(xù)增加。2005年，該工廠加工了17萬(wàn)噸礦石，并且生產(chǎn)了價(jià)值為274美元/盎司的黃金180 519盎司。2005年年底的儲(chǔ)量是11.8億噸等級(jí)為0.40克/噸的金礦，共計(jì)15.2萬(wàn)盎司黃金。</p><p>　　該礦床以其0.40克/噸的低黃金含量而出名。</p><p><b>　　礦石&

6、lt;/b></p><p><b>　　地質(zhì)背景1</b></p><p>　　帕拉卡圖發(fā)生了一系列的化石葉礦化，形成了廣泛的形變和特征優(yōu)良的石英石香腸構(gòu)造及相關(guān)的硫化物礦化。該地存在4個(gè)礦化范圍，通過氧化和風(fēng)化程度以及礦物中的硫化物區(qū)分。當(dāng)?shù)芈劽腃, T, B1和B2采礦區(qū)迄今已經(jīng)耗盡了C和T范圍內(nèi)的大部分。余下的工程儲(chǔ)備集中在B1和B2范圍內(nèi)。</

7、p><p>　　B1和B2范圍包含砷豐富區(qū)（大于2500百萬(wàn)分之一）和低礦化型砷，以及局限于中央的高砷晶狀體部分中的劇烈形變硫化物（IDS）礦化。IDS類型礦石的砷含量超過4000百萬(wàn)分之一。</p><p><b>　　礦床類型1</b></p><p>　　帕拉卡圖的礦床是一種在原始層狀沉積基質(zhì)（化石葉）中細(xì)微嵌入型黃金礦化的變質(zhì)類黃金。帕拉卡

8、圖的化石葉由于在板塊構(gòu)造過程中產(chǎn)生高度形變。原始的沉積巖已經(jīng)連續(xù)經(jīng)歷了至少三個(gè)階段的熱液蝕變，這使得金在原始碳沉積物中移動(dòng)。</p><p><b>　　礦化1</b></p><p>　　帕拉卡圖的化石葉經(jīng)過熱液轉(zhuǎn)化為次級(jí)的綠片巖相，形成普遍的絹云母石英變化。硫化物礦化為大量的毒砂和含有磁黃鐵礦的黃鐵礦以及少量黃銅礦、閃鋅礦和方鉛礦。黃金與毒砂和黃鐵礦有密切的關(guān)系，

9、因?yàn)橛坞x的細(xì)小金粒主要沿毒砂和黃鐵礦晶界，以及獨(dú)立的晶粒縫隙處出現(xiàn)。超薄切片分析表明92％的黃金是游離的。黃金晶粒的平均尺寸通常為50-150微米。</p><p>　　RPM公司為擴(kuò)產(chǎn)工程開展的采礦計(jì)劃中，礦石的硬度預(yù)計(jì)將在開采進(jìn)程中穩(wěn)步增加。實(shí)驗(yàn)室邦德球磨工作指標(biāo)從起初的5.0千瓦時(shí)/噸提升到高達(dá)13.6千瓦時(shí)/噸。</p><p>　　由于礦石料軟且易碎，目前開采不能使用炸藥。采礦時(shí)

10、使用推土機(jī)破碎礦石，然后直接裝入拖運(yùn)卡車。礦石移交到破碎機(jī)時(shí)會(huì)包含大量的粉末。硬礦石的爆破才剛剛開始，并將在擴(kuò)產(chǎn)中得到日益廣泛的應(yīng)用。</p><p><b>　　工廠現(xiàn)狀</b></p><p>　　最初的加工計(jì)劃是加工上限為6百萬(wàn)噸/年的氧化礦石，其實(shí)驗(yàn)室邦德球磨功指數(shù)為3.0千瓦時(shí)/噸。該工廠目前通常加工18百萬(wàn)噸/年且平均功指數(shù)為6.9千瓦時(shí)/噸的軟硫化礦。&

11、lt;/p><p>　　目前礦磨流程如圖1所示。</p><p>　　圖1 ：目前的磨礦回路</p><p>　　礦石是由100噸的卡車被移至破碎機(jī)的進(jìn)料斗，然后轉(zhuǎn)移到四臺(tái)并列的德國(guó)Hazmag公司的1320型錘磨機(jī)。該破碎機(jī)的排放篩選標(biāo)準(zhǔn)為25.4毫米，尺寸超規(guī)的礦石使用HP200型圓錐破碎機(jī)進(jìn)行開路破碎。破碎回路卸除的是出料粒度為13毫米的排料，并且被移至磨礦回路。

12、</p><p>　　四臺(tái)初級(jí)球磨機(jī)和一臺(tái)細(xì)磨機(jī)被用于生產(chǎn)出料粒度為75微米的最終產(chǎn)品。篩選機(jī)由氣旋篩的部分下溢供料，從而獲取自由黃金和附有黃金的粗毒砂。重選精礦與浮選精礦相結(jié)合并且精磨到40微米后濾出。2005年黃金的回收率為78.2 ％，其中81.2 ％回收于浮選回路，96.3 ％回收于精選回路。</p><p>　　錘磨機(jī)磨損率高，不能應(yīng)對(duì)較硬的礦石。礦石在破碎回路中有形成扁平石料的

13、傾向，造成一些圓錐破碎機(jī)的運(yùn)行問題。當(dāng)沒有運(yùn)作在阻塞狀態(tài)時(shí)，扁平石料可以滑過破碎機(jī)；當(dāng)阻塞時(shí)，破碎機(jī)堵塞導(dǎo)致主軸承壽命減短。</p><p>　　目前工廠超出設(shè)計(jì)能力的主要原因之一是運(yùn)行時(shí)磨機(jī)中的被測(cè)礦石的工作指標(biāo)明顯低于預(yù)計(jì)的實(shí)驗(yàn)室邦德球磨功指數(shù)。如圖2所示，裝料脹滿的狀態(tài)下，RPM系數(shù)會(huì)影響推動(dòng)物料通過磨機(jī)到達(dá)作業(yè)點(diǎn)的能力。作為初級(jí)磨機(jī)，他們還要在高達(dá)450 ％的循環(huán)負(fù)荷下運(yùn)作。</p><

14、;p>　　礦石硬度的增加和現(xiàn)有錘磨機(jī)破碎機(jī)帶來(lái)的相關(guān)高成本費(fèi)用，以及加工更高噸位的需求都是為擴(kuò)產(chǎn)選定半自磨機(jī)回路的主要因素。</p><p><b>　　測(cè)試工作</b></p><p>　　包含了一個(gè)半自磨機(jī)試驗(yàn)工廠的廣泛測(cè)試工作已經(jīng)利用RPM的礦石完成。這項(xiàng)測(cè)試工作由Delboni等人在本次會(huì)議上的一個(gè)獨(dú)立文件中提出。加工工廠的資料也被用于發(fā)展和提供擴(kuò)建工程

15、的設(shè)計(jì)標(biāo)準(zhǔn)。</p><p>　　最影響磨礦回路設(shè)計(jì)的主要因素是邦德球磨功指數(shù)中的“RPM系數(shù)”。磨礦回路中測(cè)量功率的實(shí)際數(shù)據(jù)與實(shí)驗(yàn)室邦德球磨功指數(shù)的預(yù)計(jì)功率相比，表明現(xiàn)有球磨機(jī)產(chǎn)品的消耗功率約占實(shí)驗(yàn)室預(yù)計(jì)邦德球磨測(cè)試結(jié)果的63 ％。這以實(shí)驗(yàn)室邦德功指數(shù) 1.6的因數(shù)表示。該系數(shù)由試驗(yàn)工廠中半自磨機(jī)和球磨機(jī)的測(cè)試工作確定。Orway Mineral Consultants公司的希德爾認(rèn)為該修正系數(shù)源于磨機(jī)供料中的

16、高比例的細(xì)粉。</p><p>　　試驗(yàn)工廠的測(cè)試工作還指出，該系數(shù)隨著實(shí)驗(yàn)室邦德功指數(shù)的增加而增加。系數(shù)如圖2所示。用于擴(kuò)產(chǎn)的系數(shù)為常數(shù)1.6.</p><p>　　圖2：RPM功指數(shù)系數(shù)</p><p>　　數(shù)值較低的實(shí)驗(yàn)室邦德球磨功指數(shù)是源于現(xiàn)有工廠的運(yùn)算，而較高的功指數(shù)是從試驗(yàn)工廠的測(cè)試工作中獲得。</p><p>　　實(shí)驗(yàn)室和工廠中

17、的冶金測(cè)定已經(jīng)表明，黃金與毒砂在重力選礦中密切相關(guān)。</p><p>　　目前工廠利用球磨機(jī)氣旋篩下溢的重力回收粗毒砂。被回收到重力選礦，并作為重力回路供料的黃金也得到增加。</p><p><b>　　設(shè)計(jì)準(zhǔn)則</b></p><p>　　擴(kuò)產(chǎn)工程的大多數(shù)設(shè)計(jì)標(biāo)從現(xiàn)有工廠的運(yùn)行和試驗(yàn)工廠的測(cè)試工作中獲得。初期的磨礦回路工程針對(duì)較軟的礦石，并且

18、最初新工廠只配置了一臺(tái)球磨機(jī)。由于礦石硬度的增加，裝配了第二臺(tái)球磨機(jī)。隨著軟礦的消耗，現(xiàn)有的破碎回路將被關(guān)閉，并且現(xiàn)有的球磨機(jī)被納入半自磨機(jī)回路。半自磨機(jī)的供料速度將增加。圖3表示采礦計(jì)劃中礦石硬度的變化曲線和磨機(jī)供料速度的變化。</p><p>　　圖3：LOM供料速度和實(shí)驗(yàn)室測(cè)量的邦德球磨功指數(shù)</p><p>　　下頁(yè)的表1提供了磨礦回路最初16年運(yùn)作的主要指標(biāo)。</p>

19、<p><b>　　發(fā)展流程</b></p><p>　　RPM磨礦回路的最初擴(kuò)產(chǎn)計(jì)劃只包含一臺(tái)單獨(dú)的半自磨機(jī)，加工量為30 000 000噸/年。磨機(jī)將運(yùn)行在配有氣旋篩的閉合回路中，并且最終產(chǎn)品的出料粒度為250微米的。利用現(xiàn)有的球磨機(jī)可以磨出的出料粒度為75微米?；诘V石儲(chǔ)量的增加，工程中止并且開發(fā)了一種包含兩臺(tái)球磨機(jī)的新式半自磨。為擴(kuò)產(chǎn)設(shè)計(jì)的流程如下頁(yè)的圖4所示。<

20、/p><p>　　表1 ：加工設(shè)計(jì)指標(biāo)</p><p>　　工程最初幾年，礦石很軟，其實(shí)驗(yàn)室邦德球磨功指數(shù)為5千瓦時(shí)/噸，后來(lái)逐步增加到10千瓦時(shí)/噸。經(jīng)測(cè)定起初有充足功率來(lái)裝配半自磨機(jī)和一臺(tái)獨(dú)立的球磨機(jī)，其產(chǎn)量為3970噸/小時(shí)，最終產(chǎn)品的出料粒度為250微米。功率分配需要半自磨機(jī)的排料更細(xì)小，這個(gè)問題通過將帶有球磨機(jī)氣旋篩下溢的半自磨機(jī)部分關(guān)閉得以實(shí)現(xiàn)。由于粗供料氣旋篩的運(yùn)作存在問題，獨(dú)立

21、的半自磨機(jī)分級(jí)回路沒能被采用。由于礦石變得較硬，專用半自磨氣旋篩也不允許半自磨機(jī)部分關(guān)閉。雖然預(yù)計(jì)功率以支持獨(dú)立的球磨機(jī)，但令人擔(dān)心的是通過獨(dú)立磨機(jī)的數(shù)量會(huì)導(dǎo)致裝料脹滿。</p><p><b>　　圖4： 擴(kuò)展流程圖</b></p><p>　　這個(gè)問題通過牽引一些球磨機(jī)的氣旋篩下溢到現(xiàn)有的球磨機(jī)得以解決。隨著更多的硬礦石被加工，裝配了第二臺(tái)球磨機(jī)，并且加工流程變成

22、了配有兩臺(tái)閉路球磨機(jī)的傳統(tǒng)開路半自磨機(jī)。</p><p>　　在第九年的時(shí)候，現(xiàn)有的錘磨機(jī)礦磨回路被關(guān)閉，同時(shí)現(xiàn)有的球磨機(jī)被納入半自磨機(jī)回路并且半自磨機(jī)的供料速度提至5090 噸/小時(shí)。預(yù)計(jì)這是半自磨機(jī)生產(chǎn)力的安全上限。由于礦石硬度的增加，半自磨機(jī)的功率將成為瓶頸，并且回路的產(chǎn)量將從5090 噸/小時(shí)減少。一旦發(fā)現(xiàn)足量的硬礦石，附加的研磨測(cè)試工作將結(jié)束。</p><p>　　測(cè)試工作和目前

23、工廠的運(yùn)作表明，通過增加黃金和砷的重力回收實(shí)現(xiàn)了更多的黃金回收。為了最大限度地回收粗毒砂，并且減少球磨機(jī)氣旋篩供料泵中重力回路的影響，專用重力回路供料泵被裝配在氣旋篩供料泵箱體上，同時(shí)重力回路的尾料返回到同一個(gè)氣旋篩供料泵箱內(nèi)。注入到篩選機(jī)中的稀釋水被用于氣旋篩。</p><p><b>　　設(shè)備選型</b></p><p><b>　　常規(guī)標(biāo)準(zhǔn)</b

24、></p><p>　　設(shè)備的主要選擇基準(zhǔn)是只使用有驗(yàn)證記錄的設(shè)備。這項(xiàng)標(biāo)準(zhǔn)是為了滿足快速提升到設(shè)計(jì)生產(chǎn)水平的需要。單線設(shè)備被選用到成本費(fèi)用較低的項(xiàng)目。</p><p><b>　　破碎機(jī)</b></p><p>　　選定的初級(jí)破碎機(jī)是中心距為1300毫米的齒輥破碎機(jī)。多數(shù)的礦石很細(xì)碎表明有形成洞眼和堵塞的趨勢(shì)，尤其是在潮濕的時(shí)候。令人擔(dān)

25、心的是，回旋破碎機(jī)會(huì)被粉末堵塞，特別是雨季時(shí)。更普遍的礦石組織由板層組成，其中一些可以穿過回旋破碎機(jī)使半自磨機(jī)供料中出現(xiàn)大顆?！，F(xiàn)有破碎回路中的圓錐破碎機(jī)的運(yùn)作經(jīng)驗(yàn)表明，存在破碎機(jī)堵塞并造成軸和軸承損壞以及排料中存在大塊板層的憂慮。</p><p><b>　　半自磨機(jī)</b></p><p>　　根據(jù)只選擇有驗(yàn)證記錄的設(shè)備的標(biāo)準(zhǔn)，磨機(jī)的最大尺寸是38英尺。若將大型磨

26、機(jī)用于運(yùn)作，會(huì)遇到排料能力和磨機(jī)驅(qū)動(dòng)的問題。加工中有大量的具有良好的運(yùn)營(yíng)歷史的38英尺磨機(jī)。</p><p>　　由于裝機(jī)功率為20兆瓦，雙齒輪驅(qū)動(dòng)器超限，并且選擇了環(huán)形電動(dòng)機(jī)驅(qū)動(dòng)器。變速驅(qū)動(dòng)器的內(nèi)在能力有利于預(yù)測(cè)采礦過程中礦石硬度的變化。已充分證實(shí)環(huán)形電動(dòng)機(jī)還具有其他優(yōu)點(diǎn)，如微調(diào)和裝料卡塞保護(hù)，這里不予討論。</p><p>　　多年來(lái)，半自磨機(jī)的裝球量一直在穩(wěn)步增加，已經(jīng)達(dá)到酷似初級(jí)球

27、磨機(jī)的狀態(tài)。為了降低裝配時(shí)的裝機(jī)功率，半自磨機(jī)裝球量設(shè)計(jì)為18 ％ 。磨機(jī)裝球量規(guī)格為18 ％，其總裝料量為35 ％。加工軟礦石時(shí)，也有可能將更高的裝球量與更低的裝料量結(jié)合。</p><p>　　襯板的設(shè)計(jì)基于殼體上間距為606毫米的60行帶。200毫米寬的推料機(jī)，可以起到適當(dāng)?shù)谋Ｗo(hù)以防推料機(jī)間堵塞。襯板外形由于半自磨機(jī)負(fù)載的變化而呈現(xiàn)顯著變化。在運(yùn)作的初期階段關(guān)閉了部分磨機(jī)，生產(chǎn)細(xì)碎的產(chǎn)品。此時(shí)襯板外形低矮以方

28、便更多的球磨機(jī)行動(dòng)。當(dāng)加工較硬礦石時(shí)，襯板外形高大以提高階梯量和沖擊破損。</p><p>　　磨機(jī)頂部對(duì)外被鉆出36排1.8米隔柵。該隔柵最初是38毫米的狹縫，但因?yàn)榈V石日益變硬而改進(jìn)，而且可以進(jìn)行碎石的生產(chǎn)和破碎。隔柵的設(shè)計(jì)面積大約為0.25平方米每柵。</p><p>　　礦漿的排放被認(rèn)為是磨機(jī)運(yùn)作的關(guān)鍵。根據(jù)磨機(jī)的雙向旋轉(zhuǎn)標(biāo)準(zhǔn)，選擇了徑向礦漿推料機(jī)，并且礦漿推料機(jī)的深度增至650毫

29、米。磨機(jī)的設(shè)計(jì)排量最高為4470立方米/小時(shí)，研磨速度為臨界速度的75 ％，每個(gè)礦漿箱每次旋轉(zhuǎn)排料0.22立方米。預(yù)計(jì)這樣隔柵后的凈深度將小于0.5米。</p><p><b>　　表2：礦石設(shè)計(jì)產(chǎn)量</b></p><p>　　半自磨排料的篩分經(jīng)過試驗(yàn)，分別審查了采用獨(dú)立轉(zhuǎn)筒篩，排料振動(dòng)篩或者轉(zhuǎn)筒篩和振動(dòng)篩聯(lián)合使用的方案。根據(jù)不得使用大于目前安裝在其他地方的設(shè)備的標(biāo)

30、準(zhǔn)，采用獨(dú)立轉(zhuǎn)筒篩的方案被否決。振動(dòng)篩系統(tǒng)必須使用3.0 m x 7.3 m的篩子并行運(yùn)作，所以需要兩個(gè)以上的篩子。因?yàn)殡y以分離半自磨三種方式的排料，并且建筑面積不足，此方案也被否決。最終選擇了轉(zhuǎn)筒篩和振動(dòng)篩聯(lián)合使用的方案。加工時(shí)轉(zhuǎn)筒篩計(jì)劃篩分56%的排料，配以10%的循環(huán)負(fù)荷。</p><p><b>　　表3：篩分標(biāo)準(zhǔn)</b></p><p>　　這種組合篩機(jī)與埃

31、斯康迪達(dá)銅礦的直徑11.5米半自磨機(jī)的加工方式十分相似。</p><p>　　當(dāng)磨機(jī)運(yùn)行在的配有氣旋篩的閉環(huán)回路時(shí)，篩網(wǎng)尺寸將增加到25毫米，以提供更多的容量。</p><p><b>　　球磨機(jī)</b></p><p>　　球磨機(jī)的選型基于11.3千瓦時(shí)/噸的實(shí)驗(yàn)室邦德球磨平均工作指數(shù)。其計(jì)算依據(jù)1.6的RPM系數(shù)。因?yàn)橐捎脙膳_(tái)并用的磨機(jī)，

32、所以選擇兩臺(tái)直徑7.3米，長(zhǎng)12米，裝機(jī)功率為12.5兆瓦的磨機(jī)。經(jīng)過對(duì)驅(qū)動(dòng)器適用性的分析，磨機(jī)的裝機(jī)功率與雙齒輪傳動(dòng)驅(qū)動(dòng)器的機(jī)械性能匹配。</p><p>　　對(duì)球磨機(jī)驅(qū)動(dòng)系統(tǒng)進(jìn)行的研究，包括環(huán)形電動(dòng)機(jī)，雙齒輪同步電動(dòng)機(jī)，以及雙齒輪繞線轉(zhuǎn)子電動(dòng)機(jī)。驅(qū)動(dòng)器的選擇標(biāo)準(zhǔn)包括成本費(fèi)用，加工費(fèi)用以及可操作性。</p><p>　　重點(diǎn)考慮的操作問題之一是對(duì)磨機(jī)的裝料卡塞保護(hù)。大型球磨機(jī)容易裝料卡塞

33、，特別是當(dāng)RPM工程中粘土含量高時(shí)。環(huán)形電機(jī)產(chǎn)品有裝料卡塞探測(cè)系統(tǒng)，可以非常準(zhǔn)確地發(fā)現(xiàn)裝料卡塞，并且采取相應(yīng)的糾正措施，如反向轉(zhuǎn)動(dòng)或緩沖磨機(jī)負(fù)荷。繞線轉(zhuǎn)子驅(qū)動(dòng)器可以平穩(wěn)啟動(dòng)，達(dá)到全速需要30秒。這使得開機(jī)時(shí)卡塞或部分裝料卡塞被排除之前存在5-6秒鐘，并造成磨機(jī)的損傷。這種系統(tǒng)不如環(huán)形電機(jī)驅(qū)動(dòng)器可靠，并且疏導(dǎo)部分的裝料卡塞時(shí)齒輪和傳動(dòng)裝置上會(huì)產(chǎn)生沖擊負(fù)荷。同步驅(qū)動(dòng)系統(tǒng)通過離合器硬啟動(dòng)。所以從開始到全速需5-6秒，并且從開始到裝料卡塞疏通約

34、一秒。通過使磨機(jī)旋轉(zhuǎn)到約70度處部分啟動(dòng)然后釋放可以獲得保護(hù)。如果磨機(jī)停在與開機(jī)前有10度差異的其余位置，可知負(fù)載已被移除，沒有卡塞，因此磨機(jī)可以安全啟動(dòng)。</p><p>　　驅(qū)動(dòng)器的對(duì)照如表4所示。驅(qū)動(dòng)效率的評(píng)估表中明，低速同步的效率最高，但該系統(tǒng)的成本費(fèi)用也很高。繞線轉(zhuǎn)子電動(dòng)機(jī)系統(tǒng)的評(píng)估效率最低，同時(shí)成本費(fèi)用最低。</p><p>　　表4：球磨機(jī)驅(qū)動(dòng)器對(duì)照</p>&

35、lt;p>　　基于成本費(fèi)用最低，并且可提供RPM礦石所需的裝料卡塞保護(hù)，最終選定雙齒輪機(jī)繞線轉(zhuǎn)子電動(dòng)機(jī)驅(qū)動(dòng)器。</p><p>　　球磨機(jī)配備磁鐵球來(lái)取代傳統(tǒng)的球轉(zhuǎn)筒篩。這些個(gè)體可以通過減小細(xì)磨介質(zhì)的平常循環(huán)負(fù)荷，以減少氣旋篩和氣旋篩供料泵中的耗損。</p><p>　　球磨機(jī)還在排料尾端凸耳處裝配了一個(gè)護(hù)球柵。該攔柵防止磨球在停產(chǎn)期間或過量礦漿流過磨機(jī)的時(shí)候流出。凸耳處攔柵的反向旋

36、轉(zhuǎn)使球返到磨機(jī)內(nèi)。</p><p><b>　　布局和回路描述</b></p><p><b>　　破碎機(jī)</b></p><p>　　礦石由250噸的卡車傾倒入490噸力的破碎機(jī)送料斗中。礦石利用傾斜裙板喂料機(jī)回收，且排料經(jīng)斜置柵后進(jìn)入輥式破碎機(jī)。柵篩的碎石和破碎機(jī)的排料在廢棄排料區(qū)合并。</p><

37、p>　　礦石迄今在每個(gè)處理階段都輕松破碎。大多數(shù)的礦石幾乎不含太大的石料，但可能包含一些能跨過破碎機(jī)供料的扁平石料。為了解決這個(gè)問題，準(zhǔn)備了碎石機(jī)，用來(lái)處理裙板喂料機(jī)的排料，從而達(dá)到破碎上限。斜置柵用來(lái)攔除破碎機(jī)供料中的碎石以減少軋輥的沖刷磨損。破碎機(jī)沒有破碎掉的大塊礦石可由破碎機(jī)的反向旋轉(zhuǎn)清除。</p><p>　　破碎機(jī)被安裝在輥?zhàn)由弦员阌诰S修。</p><p><b>

38、;　　礦磨</b></p><p>　　礦磨回路的布局如圖5（下頁(yè)）所示。碎石礦的回收來(lái)源于儲(chǔ)蓄和半自磨機(jī)的排料。半自磨機(jī)的排料穿過溢流轉(zhuǎn)筒篩，然后進(jìn)入獨(dú)立的振動(dòng)篩中。準(zhǔn)備了兩個(gè)振動(dòng)篩，被安排于備用加工中，并且安裝在導(dǎo)軌上，以便維修時(shí)方便快捷。振動(dòng)篩篩出的大塊礦石經(jīng)一系列傳送帶循環(huán)送回到半自磨機(jī)供料處。如果以后需要的話，將配備碎石破碎機(jī)。球磨機(jī)位于半自磨機(jī)旁邊，以便氣旋篩的下溢可以作為所需的供料移至半

39、自磨機(jī)中。獨(dú)立的半自磨排料泵排料進(jìn)入分離機(jī)箱，然后依靠重力進(jìn)入球磨機(jī)氣旋篩供料泵箱。每臺(tái)球磨機(jī)配備一臺(tái)獨(dú)立的氣旋篩供料泵和獨(dú)立的旋風(fēng)機(jī)。正常操作時(shí)氣旋篩的下溢回流到對(duì)應(yīng)的球磨機(jī)中，而上溢進(jìn)入浮選回路。</p><p>　　部分氣旋篩供料由每個(gè)氣旋篩供料泵箱提供，并且被泵入每個(gè)球磨機(jī)回路的重力回路。重力回路的尾礦排料利用重力被排入氣旋篩供料泵箱。獨(dú)立的重力供料泵允許篩選機(jī)遠(yuǎn)離標(biāo)準(zhǔn)區(qū)域，位于氣旋篩下游，并允許較短的供

40、料和排料線路，可以更便于操作和維修。</p><p>　　在礦石較軟的加工初期階段，還沒有裝配第二臺(tái)球磨機(jī)，但是需要兩套氣旋篩來(lái)處理礦漿。裝配了兩套旋風(fēng)機(jī)，并且在氣旋篩供料箱上安裝了兩臺(tái)氣旋篩供料泵?！癆”臺(tái)旋風(fēng)機(jī)位于半自磨機(jī)和一臺(tái)球磨機(jī)的連線中間，以便氣旋篩的下溢依靠重力被分離流向半自磨機(jī)和球磨機(jī)A中?！癇”旋風(fēng)機(jī)位于球磨機(jī)A的另一邊，并且下溢可以在球磨機(jī)A和位于新建工廠山腳下的現(xiàn)有工廠中的現(xiàn)有球磨機(jī)中間分離。

41、</p><p>　　當(dāng)加工較硬礦石時(shí)，裝配了球磨機(jī)B，并且氣旋篩供料泵由原來(lái)的球磨機(jī)A的氣旋篩供料泵箱轉(zhuǎn)移到球磨機(jī)B的氣旋篩供料箱上。然后氣旋篩的下溢直接靠近球磨機(jī)。</p><p><b>　　圖5：礦磨回路布局</b></p><p>　　在第九年時(shí)，目前的球磨機(jī)到位，半自磨機(jī)排料分離機(jī)箱經(jīng)過改良，將部分球磨機(jī)回路供料分配到現(xiàn)有球磨機(jī)中。

42、這將成為變流量，以便兩臺(tái)大型球磨機(jī)的供料可以保持在相對(duì)恒定的狀態(tài)。因?yàn)槟壳坝形迮_(tái)球磨機(jī)，所以他們根據(jù)需要啟閉。</p><p>　　礦磨回路由一臺(tái)涉及到三臺(tái)磨機(jī)的橋式起重機(jī)操作。起重機(jī)的尺寸決定于為施工和維修設(shè)置的獨(dú)立最大升降機(jī)，其也是半自磨機(jī)的活動(dòng)部分。需要沿著灣渠清理磨灣，該磨灣可以將溢流的過量礦漿引到緊急積水池。</p><p><b>　　摘要和結(jié)論</b>&

43、lt;/p><p>　　RPM的擴(kuò)產(chǎn)計(jì)劃提供了一個(gè)獨(dú)特的、為低等級(jí)高噸位的金礦設(shè)計(jì)一種靈活礦磨回路的機(jī)會(huì)。整個(gè)礦磨回路的設(shè)計(jì)采用嚴(yán)謹(jǐn)?shù)牟襟E，其中目前加工中選擇的都是有穩(wěn)定的運(yùn)行歷史的設(shè)備。</p><p>　　在礦石較軟的加工初期階段，磨機(jī)有體積限制。希望半自磨機(jī)能在礦漿匯集狀態(tài)下工作，此時(shí)，關(guān)閉了部分的球磨機(jī)氣旋篩。為了適應(yīng)該狀態(tài)，礦漿排放的深度被延長(zhǎng)。當(dāng)一臺(tái)磨機(jī)獨(dú)立作業(yè)時(shí)，此磨機(jī)加工接近裝

44、料脹滿的狀態(tài)。攔球柵用來(lái)保持磨球留在磨機(jī)中。</p><p>　　擴(kuò)產(chǎn)回路的能力是最大限度的整合現(xiàn)有礦磨回路中可用的設(shè)備。這需要非常靈活的回路設(shè)計(jì)。起初幾年，現(xiàn)有的磨機(jī)用來(lái)減少體積限制，并且隨后的幾年中，隨著礦石硬度的增加，現(xiàn)有的球磨機(jī)被用來(lái)提供所需的額外磨削功率。</p><p><b>　　鳴謝</b></p><p>　　我們很榮幸對(duì)SN

45、C-蘭萬(wàn)靈公司的雷沃爾頓和Orway Mineral Consultants公司的伯尼希德爾對(duì)于這項(xiàng)工作的幫助致謝。并感謝RPM和SNC-蘭萬(wàn)靈公司的經(jīng)理對(duì)本篇文章的許可。</p><p><b>　　參考文獻(xiàn)</b></p><p>　　1漢森,W,2005,帕拉卡圖采礦技術(shù)報(bào)告, 塞達(dá)記錄</p><p>　　2希德爾,B,2005,金羅斯

46、金礦里奧帕拉卡圖礦產(chǎn)公司(RPM)粉碎回路審查, 內(nèi)部報(bào)告</p><p>　　DEPARTMENT OF MINING ENGINEERING</p><p>　　UNIVERSITY OF BRITISH COLUMBIA</p><p>　　Vancouver, B. C., Canada</p><p>　　SAG AND BALL

47、MILL CIRCUIT DESIGN FOR KINROSS’ RIO</p><p>　　PARACATU MINERACAO (RPM) EXPANSION</p><p>　　By Stuart McTavish1, Luis Albano Tondo2, Wayne Phillips3, and Anatalia Silva4</p><p>　　1Chi

48、ef Metallurgist, SNC-Lavalin Engineers and Constructors Inc Toronto,ON, Canada; 2Project Manager, Kinross Rio ParacatuMineracao (RPM), Brazil; 3Director of Technical Services, KinrossAmericas, Brazil; 4Metallurgist, Kinr

49、oss Rio Paracatu Mineracao (RPM),Brazil</p><p><b>　　ABSTRACT</b></p><p>　　Kinross’ Rio Paracatu Mineracao (RPM) gold mine in Brazil is expanding production capacity from the present

50、18 000 000 t/a to 50 000 000 t/a with the addition of a 38’ SAG mill circuit. This paper describes the expansion philosophy, the equipment selected, and the flowsheet variations required to process the ore as it becomes

51、progressively harder. Layout considerations to accommodate the flowsheets are also discussed.</p><p>　　INTRODUCTION</p><p>　　The Paracatu mine is located in Brazil, 230 km south west of Brazilia

52、 in the north west portion of the State of Minas Gerais. The city of Paracatu, which has a population of 83 000 people is just 2 km south of the mine.</p><p>　　The mine started operation in 1987, processing

53、6 Mt/a of the oxide portion of the deposit. The plant throughput increased to approximately 13 Mt/a of oxide ore, and in 1997 capacity was expanded through an additional grinding mill and flotation capacity to process th

54、e sulphide ore. In 2005 the plant processed 17 Mt of ore and produced 180 519 ounces of gold at a cash cost of 274US$/oz. Reserves at year end 2005 were 1.18 billion tonnes at a grade of 0.40 g/t Au, containing a total o

55、f 15.2 millio</p><p>　　The ore deposit is noted for its low grade of 0.40 g/t gold.</p><p><b>　　ORE</b></p><p>　　Geological Setting 1</p><p>　　Mineralizatio

56、n at Paracatu occurs within a series of phyllites that have been extensively deformed and feature well-developed quartz boudins and associated sulphide mineralization. There are four mineralized horizons, differentiated

57、by the degree of oxidation and weathering as well as sulphide mineralogy. Locally known as the C, T, B1 and B2.Mining to date has exhausted the majority of the C and T horizons. The remaining reserves for the project are

58、 hosted in the B1 and B2 horizons. </p><p>　　The B1 and B2 horizons includes both arsenic rich zones (greater than 2500 ppm) and low arsenic type mineralization as well as Intensely Deformed Sulphide (IDS) m

59、ineralization which is localized in the central portion of the high arsenic lenses. The IDS type ore has an arsenic content greater than 4000 ppm.</p><p>　　Deposit Type 1</p><p>　　The Paracatu d

60、eposit is a metamorphic gold system with finely disseminated gold mineralization hosted within an original bedded sedimentary host (phyllites). The phyllites at Paracatu are highly deformed as a result of tectonic proces

61、ses. The originally sedimentary rocks have been successively altered by at least three phases of hydrothermal alteration, which has remobilized gold within the original carbonaceous sediments.</p><p>　　Miner

62、alization 1</p><p>　　The Paracatu phyllites have been hydrothermally altered to lower greenschist facies resulting in pervasive quartz-sericite alteration. Sulphide mineralization is dominantly arsenopyrite

63、and pyrite with pyrrhotite and lesser amounts of chalcopyrite, sphalerite and galena. Gold is closely associated with arsenopyrite and pyrite and occurs predominantly as fine grained free gold along the arsenopyrite and

64、pyrite grain boundaries, in fractures in the individual arsenopyrite and pyrite grains. Thin s</p><p>　　The mine plan developed by RPM for the expansion project predicts a steady increase in ore hardness as

65、the mine progresses. Laboratory Bond ball work indices range from an initial 5.0 kWh/t to a high of 13.6 kWh/t.</p><p>　　The mine does not use explosives at the present as the ore is soft and friable. Mining

66、 uses dozers to rip the ore, which is then direct loaded into haul trucks. The ore contains a significant amount of fines when delivered to the crusher. Blasting in harder ore has just started and will</p><p&g

67、t;　　be used increasingly during the expansion.</p><p>　　EXISTING PLANT</p><p>　　The original processing plant was designed for the processing of the oxide cap at a rate of 6 Mt/a at a Laboratory

68、 Bond ball Wi of 3.0 kWh/t. The present plant is currently processing 18 Mt/a of soft sulphide ore with an average Wi of 6.9 kWh/t.</p><p>　　The existing grinding flowsheet is provided in Figure 1.</p>

69、<p>　　Figure 1: Existing Grinding Circuit</p><p>　　The ore is delivered by 100 t trucks into crusher feed bins and delivered to four parallel Hazmag 1320 hammer mills. The crusher discharge is screene

70、d at 25.4 mm with the oversize being crushed in HP 200 cone crushers, which operate in open circuit. The crushing circuit discharge has a P80 of 13 mm and is conveyed to the grinding circuit.</p><p>　　Four p

71、rimary ball mills and a regrind mill are used to produce the final product with a P80 of 75μm. Jigs are fed from a portion of the cyclone underflow to capture the free gold and coarse arsenopyrite with attached gold. The

72、 gravity concentrate is combined with the flotation concentrate and is reground to 40μm prior to leaching. Gold recovery in 2005 was 78.2% with 81.2% recovery in the flotation circuit and 96.3% recovery from the concentr

73、ate leach circuit.</p><p>　　The hammer mills experience high wear rates, which becomes prohibitive with the harder ore. The ore also has a tendency to generate flat material in the crushing circuits, which r

74、esults in some operational problems with the cone crushers. When they are not operated under choke conditions, the flat material slides through the crusher; when choke fed, the crushers pack resulting in short main beari

75、ng life.</p><p>　　One of the main reasons that the existing plant has exceeded design capacities is that the operating work index of the ore measured in the mills is significantly lower than that estimated f

76、rom the laboratory Bond ball Wi. The RPM factor as noted in Figure 2 has resulted in the ability to push more feed through the mills up to the point of operating in swollen charge conditions. As primary mills, they also

77、operate under very high circulating loads of up to 450%.</p><p>　　The increasing hardness of the ore and the related high operating costs with the existing hammer mill crushers, and the need to process highe

78、r tonnages were the main factors in selecting a SAG mill mill circuit for the expansion.</p><p><b>　　TEST WORK</b></p><p>　　Extensive test work including a SAG mill pilot plant campa

79、ign has been completed on the RPM ore. This test work is presented by Delboni et al in a separate paper at this conference. The operating plant data has also been used to develop and support the design criteria for the&l

80、t;/p><p>　　expansion project.</p><p>　　The main factor having the largest impact on the design of the grinding circuit is the “RPM factor” on the Bond ball Wi. Operating data, where the measured po

81、wer in the grinding circuit is compared to the estimated power from the laboratory Bond ball Wi, indicates that the power consumed in the existing production ball mills is approximately 63% of hat estimated by the labora

82、tory Bond ball test. This is expressed as a divisor of the laboratory Bond Wi of 1.6. This factor was also confirmed in th</p><p>　　The pilot plant test work also indicated that the factor increased as the l

83、aboratory Bond Ball Wi increased. The factors are noted in Figure 2. The factor used for the plant expansion was a constant 1.6.</p><p>　　Figure 2: RPM Wi Factor</p><p>　　The factor values for t

84、he lower laboratory Bond Ball Wi are from the existing plant operation while the higher Wi point was obtained from the pilot plant test work.</p><p>　　Metallurgical evaluations in the laboratory and plant ha

85、ve demonstrated that gold is closely associated with arsenopyrite in a gravity concentrate.</p><p>　　The existing plant uses gravity on the ball mill cyclone underflow to recover coarse arsenopyrite. The gol

86、d recovery to the gravity concentrate also increases as the feed to the gravity circuit increases.</p><p>　　DESIGN CRITERIA</p><p>　　Most of the design criteria for the expansion project were ob

87、tained from the existing plant operation and the pilot plant test program. The initial operation of the grinding circuit is based on a softer ore, and only one ball mill is installed in the new plant initially. As the or

88、e hardness increases, the second ball mill is installed. Following the depletion of the soft ore, the existing crushing circuit will be shut down and the existing ball mills are incorporated into the SAG mill circuit. T&

89、lt;/p><p>　　Figure 3: LOM Mill feed rate and Laboratory Bond Ball Wi</p><p>　　The main criteria for the grinding circuit for the first 16 years of operation are provided in Table 1 on the next page

90、.</p><p>　　FLOWSHEET DEVELOPMENT</p><p>　　The initial expansion plans for the RPM grinding circuit considered a single SAG mill only, processing 30 000 000 t/a. The mill was to be run in closed

91、circuit with cyclones and to produce a final product P80 of 250μm. The existing ball mills were to be utilized to grind to a P80 of 75μm. Based on increased ore reserves, this option was dropped and a new single SAG with

92、 two ball mills was developed. The flowsheet selected for the expansion is shown in Figure 4 on the next page.</p><p>　　Table 1: Process Design Criteria</p><p>　　In the early years of operation,

93、 the ore is soft with a Laboratory Bond Ball Wi starting at 5 kWh/t and gradually increasing up to 10 kWh/t. It was determined that there would initially be sufficient power installed in the SAG mill and a single ball mi

94、ll to grind 3970 t/h to a final product P80 of 75μm. The power split required a finer discharge on the SAG mill, and this was accomplished by closing the SAG mill up partially with the ball mill cyclone underflow.A separ

95、ate SAG mill classification </p><p>　　Figure 4: Expansion Flowsheet</p><p>　　This was addressed by directing some of the ball mill cyclone underflow to the existing ball mills. When the more com

96、petent ore is processed, the second ball mill is installed and the flowsheet becomes a traditional open circuit SAG mill with two ball mills in closed circuit.</p><p>　　In year 9 the existing hammer mill cru

97、shing circuit is shut down and the existing ball mills are incorporated into the SAG mill circuit and the feed rate to the SAG mill is increased to 5090 t/h. It is estimated that this is the upper safe limit for the SAG

98、mill from a volume throughput capacity. The SAG mill power will become the bottleneck as the ore hardness increases and the circuit throughput will decrease from the 5090 t/h as the ore becomes harder. Additional grindin

99、g test work will be co</p><p>　　Test work and existing plant operations have confirmed that additional gold recovery is realised with increased gravity recovery of the gold and arsenopyrite. In order to maxi

100、mize the recovery of coarse arsenopyrite and to reduce the impact of the gravity circuit on the ball mill cyclone feed pumps, dedicated gravity circuit feed pumps were installed on the cyclone feed pump box, with the gra

101、vity circuit tailings returning to the same cyclone feed pump box. Dilution water added to the jigs was u</p><p>　　EQUIPMENT SELECTION</p><p>　　General Criteria</p><p>　　The main ba

102、sic criteria for the selection of equipment was to use only equipment that had a proven track record. This criterion was set due to the requirements for a fast ramp up to design production levels. Single line equipment w

103、as selected to lower the capital cost of the project.</p><p><b>　　Crusher</b></p><p>　　The selected primary crusher is a 1300 mm centre-to centre toothed roll crusher. The majority o

104、f the ore is fines that exhibit the potential to rat hole and pack, particularly when wet. There was concern that a gyratory crusher would pack with fines particularly during the rainy season. The more competent componen