型砂處理機(jī)破碎機(jī)構(gòu)的設(shè)計(jì)圖紙,型砂,處理機(jī),破碎,機(jī)構(gòu),設(shè)計(jì),圖紙 一種新的T曲線模型描述石灰石在沖擊式破碎機(jī)下的粉碎 摘要 在破碎機(jī)的評(píng)測(cè)，從單顆粒的測(cè)試方法得到的T系列曲線是經(jīng)常使用。眾所周知，有許多困難和問(wèn)題，在這些試驗(yàn)中。在這項(xiàng)研究中的沖擊式破碎機(jī)三種不同的灰?guī)r破裂行為進(jìn)行了研究。一種新的粒度分布模型，采用T曲線價(jià)值評(píng)估和邦德功指數(shù)的方法開(kāi)發(fā)。其結(jié)果公式的有效性證明由高回歸值（r2=0.88）。 關(guān)鍵詞：石灰石 破損 反擊式破碎機(jī) 邦德功指數(shù) 粒度分布 T曲線 1.引言 撞擊引發(fā)的巖石碎片是相關(guān)的科學(xué)和技術(shù)的許多領(lǐng)域。沖擊式磨機(jī)已在礦物，煤，水泥，化工等行業(yè)得到應(yīng)用了很長(zhǎng)時(shí)間。文獻(xiàn)表明，大量的努力已經(jīng)花費(fèi)在理解，通過(guò)實(shí)驗(yàn)和數(shù)學(xué)模擬相對(duì)于機(jī)器配置和操作條件的影響磨機(jī)的性能。然而，由于缺乏對(duì)碰撞的研磨室內(nèi)部的速度和能量分布的詳細(xì)知識(shí)，該機(jī)制仍然不清楚。【1】 自20世紀(jì)20年代后期邦德測(cè)試已使用;實(shí)驗(yàn)室和世界各地的操作中使用的程序作為一個(gè)組件粉碎的電路設(shè)計(jì)以及植物的性能進(jìn)行評(píng)估。盡管這樣的長(zhǎng)期使用性，準(zhǔn)確性的專(zhuān)題和精密邦德功指數(shù)測(cè)定的復(fù)發(fā)有很大的頻率?！?】 單粒子測(cè)試以確定的粉碎問(wèn)題礦石可被分成雙擺裝置（圖1）和降重裝置（圖2）為基礎(chǔ)的測(cè)試。 舒曼[8]報(bào)道，尺寸減小本身涉及不同能量輸入，不同的進(jìn)料粒度和不同的粒度分布。費(fèi)乃威和里默[9]曾審閱擺錘裝置上的單顆粒破碎，并指出，擺錘裝置可以是適合于任何之間的斷裂產(chǎn)物分布和粉碎能量。 雙擺錘試驗(yàn)依賴于粒子之間的破損從一個(gè)已知的高度和反彈釋放輸入擺錘和輸出擺錘。兩張擺錘，但是，有一些重要的局限性，特別是關(guān)于它的低靈活性和可重復(fù)性，長(zhǎng)的測(cè)試時(shí)間，可憐的精度估算粉碎能量反彈擺錘的二次運(yùn)動(dòng)的結(jié)果。 落錘試驗(yàn)而不同，在該粒子被放置在堅(jiān)硬的表面上，并擊中一個(gè)落錘。這兩個(gè)測(cè)試已經(jīng)被廣泛地用在粉碎的領(lǐng)域。在最近幾年中，落錘裝置正在取代的雙擺錘。標(biāo)準(zhǔn)落錘裝置裝有20公斤的質(zhì)量，這可以擴(kuò)展到50千克。有效范圍跌落高度的為0.05?1.0μm時(shí)，它表示一個(gè)廣泛能量范圍從0.01至50千瓦小時(shí)/噸（以10-50毫米的顆粒）。后續(xù)樣品制備平均每套顆粒被打破的大規(guī)模計(jì)算。從落錘試驗(yàn)結(jié)果提供能量/輸入大小/產(chǎn)品尺寸關(guān)系。這種關(guān)系是使用一組曲線來(lái)描述從提高尺寸減小的破裂事件中產(chǎn)生的尺寸分布分析或能量輸入。 在落錘試驗(yàn)，已知質(zhì)量經(jīng)過(guò)一個(gè)給定的高度落到單個(gè)粒子提供一個(gè)事件，它允許根據(jù)沖擊破碎礦石的表征。雖然，落錘試驗(yàn)具有優(yōu)勢(shì)，在統(tǒng)計(jì)上的可靠性方面與從分析中的潛在用途的數(shù)據(jù)的它擁有了相當(dāng)數(shù)量的缺點(diǎn)，包括需要特殊的設(shè)備，特別的時(shí)間長(zhǎng)度取來(lái)進(jìn)行一個(gè)測(cè)試。為每次落錘試驗(yàn)，15個(gè)樣本中5粒級(jí)測(cè)試在三個(gè)層次的能量輸入。 納拉亞南[14]使用了一種新的方法對(duì)估算從T-曲線族礦石的破碎分布函數(shù)。在該方法中，產(chǎn)品的粒度分布可以表示為一族使用的標(biāo)記點(diǎn)曲線的粒度分布的百分比經(jīng)過(guò)（t）的母粒子尺度的一小部分。因此，t2為經(jīng)過(guò)一半的開(kāi)口的百分比母體顆粒尺寸的大小，t4為四分之一和t10是十分之一的母顆粒大小。納拉亞南和懷特[15]提出的經(jīng)驗(yàn)公式與參考曲線數(shù)據(jù) T10與沖擊能量。 t10的值是由涉及到具體的粉碎能量該公式。 t10=A(1-e) TN與T10的關(guān)系可以被用來(lái)預(yù)測(cè)在不同研磨時(shí)間的產(chǎn)品粒度分布 眾所周知，有許多困難和問(wèn)題應(yīng)用落錘和雙擺錘試驗(yàn)方法，需要長(zhǎng)時(shí)間的測(cè)試時(shí)間和需要特殊的設(shè)備。在這項(xiàng)研究中，三種不同的灰?guī)r在實(shí)驗(yàn)室沖擊式破碎機(jī)破碎行為進(jìn)行了調(diào)查。新粒度分布模型方程采用t曲線價(jià)值開(kāi)發(fā)評(píng)估和邦德功指數(shù)的方法，該模型方程計(jì)算進(jìn)行了測(cè)試。 2. 材料與方法 2.1材料 來(lái)自不同地區(qū)采取了三種不同的灰?guī)r樣品土耳其的被用作實(shí)驗(yàn)材料?；瘜W(xué)石灰石樣品的性能提出了表1中 2.2標(biāo)準(zhǔn)邦德可磨性試驗(yàn) 該邦德可磨性試驗(yàn)進(jìn)行小于3.35毫米干飼料材料在標(biāo)準(zhǔn)的球磨機(jī)（30.5*30.5厘米）??以下文獻(xiàn)中描述的標(biāo)準(zhǔn)程序概要[17-24]。工作指數(shù)均在一個(gè)試驗(yàn)篩尺寸來(lái)確定106納米。它沒(méi)有升降機(jī)，所有的內(nèi)角呈圓形。邦德球磨機(jī)（圖3）在70rpm下進(jìn)行操作，并配與轉(zhuǎn)數(shù)計(jì)數(shù)器。磨礦負(fù)荷由285鐵球重20.125克。標(biāo)準(zhǔn)邦德可磨性試驗(yàn)是閉合循環(huán)干磨和篩分過(guò)程中，該方法是直到獲得穩(wěn)定狀態(tài)。此試驗(yàn)所述為遵循。 該材料是用振動(dòng)臺(tái)裝到700毫升體積。此是用于研磨試驗(yàn)的材料的體積重量。對(duì)于第一個(gè)磨削循環(huán)，磨機(jī)開(kāi)始磨轉(zhuǎn)任意選擇的數(shù)。在每個(gè)磨削周期結(jié)束時(shí)，整個(gè)產(chǎn)品從研磨機(jī)排出，并篩選在測(cè)試篩尺寸（PI）。對(duì)于丕標(biāo)準(zhǔn)的選擇是106升。篩上部分被返回到磨機(jī)用于第二運(yùn)行與新鮮進(jìn)料，以彌補(bǔ)原始重量對(duì)應(yīng)對(duì)應(yīng)到700毫升。每單位的磨旋轉(zhuǎn)周期產(chǎn)品的重量，被稱(chēng)為周期的礦石可磨性，然后計(jì)算并用于估計(jì)為等同于250％的循環(huán)負(fù)載所需的第二次運(yùn)行的轉(zhuǎn)數(shù)。該過(guò)程一直繼續(xù)，直到可磨性的一個(gè)恒定值來(lái)實(shí)現(xiàn)，這是平衡條件。此平衡條件可在6-12磨削循環(huán)到達(dá)。到達(dá)后平衡時(shí)，可磨最后三個(gè)周期的平均值。該平均值被作為標(biāo)準(zhǔn)邦德可磨（GBG）。 總最后三個(gè)周期的產(chǎn)品組合，以形成均衡其余產(chǎn)品。篩分析，開(kāi)展了對(duì)材料和結(jié)果繪制，找到80％通過(guò)尺寸產(chǎn)品（P80）的。邦德功指數(shù)值（無(wú)線）是計(jì)算得到的的方程。 圖1.雙擺裝置 圖2.重錘試驗(yàn)裝置 圖3. 邦德磨 3實(shí)驗(yàn) 首先，對(duì)已執(zhí)行的標(biāo)準(zhǔn)邦德可磨性試驗(yàn)3石灰石抽樣樣本。從測(cè)試的結(jié)果，邦德功指數(shù)值的計(jì)算4.44，10.10和13.53千瓦時(shí)/噸，然后，六個(gè)單粒級(jí)（-6.7+4.75，-4.75+2.8，-2.8+1.7，-1.7+1.18，-1.18+0.600，-0.600+0.355毫米）已測(cè)定的T-曲線族準(zhǔn)備畫(huà)面。實(shí)驗(yàn)室沖擊式破碎機(jī)（圖4），在實(shí)驗(yàn)中使用，由一個(gè)1.1千瓦的電動(dòng)機(jī)驅(qū)動(dòng)的工作原理，在2840轉(zhuǎn)的旋轉(zhuǎn)，攜帶三行錘。每個(gè)樣品取的實(shí)驗(yàn)室沖擊式破碎機(jī)的出，然后樣品過(guò)篩后的產(chǎn)品尺寸分析。 T-系列曲線與平均粒徑為比例結(jié)果不同灰?guī)r示于圖5-7。 圖4. 實(shí)驗(yàn)沖擊式破碎機(jī) 圖5.TN與平均粒度的比例-I 圖6.TN與平均粒度比例 - Ⅱ 圖7.TN與平均粒度比例-III 4 提出的粒度分布模型方程 金[25]描述的介紹從落錘試驗(yàn)獲得的產(chǎn)品粒度分布的方法。它是基于納拉亞南和懷特[26]提出的意見(jiàn)，即產(chǎn)品通過(guò)平均尺寸1/nth的餾分去注意到TN，涉及到了路過(guò)的十分之一母公司大小記為T(mén)10。另?yè)?jù)報(bào)道，這種關(guān)系是適用于不同的沖擊載荷條件下測(cè)試不同礦石類(lèi)型 在這項(xiàng)研究中，不同尺寸分布的關(guān)系已經(jīng)顯示TN值用于破碎產(chǎn)品在實(shí)驗(yàn)室直接沖擊式破碎機(jī)。作為這項(xiàng)研究的結(jié)果，與邦德功指數(shù)的累積百分比及格（TN）之間的關(guān)系（無(wú)線）和平均粒徑（倍）是由經(jīng)驗(yàn)公式描述。 實(shí)驗(yàn)值和由公式得到的計(jì)算結(jié)果所示進(jìn)行了比較得出圖8 式（3）主要是滿足在各種進(jìn)料粒度的實(shí)驗(yàn)值，和公式（3）評(píng)價(jià)在實(shí)際操作中由一個(gè)高價(jià)值回歸的粒子尺度分布（R2=0.88），尤其是當(dāng)是有用的。因此，與邦德功指數(shù)（無(wú)線），平均累計(jì)百分比及格（TN）之間的關(guān)系粒子間相互作用尺寸（X）是按經(jīng)驗(yàn)公式描述。 5．結(jié)果與討論 結(jié)果表明，石灰石-I?樣品比石灰石-II樣品更易碎，而石灰石-II樣品比石灰石-III樣品更易碎。一組曲線計(jì)算從直接的實(shí)驗(yàn)室沖擊式粉碎機(jī)和新的粒度分布方程開(kāi)發(fā)。 從破損按粒子的沖擊式破碎機(jī)產(chǎn)品粒度分布可以描述為所有參數(shù)（TN）曲線族。該產(chǎn)品的尺寸分布被認(rèn)為是歸一化的相對(duì)于顆粒尺寸。通過(guò)材料的累積百分比屬于（TN）的實(shí)驗(yàn)數(shù)據(jù)與給出的數(shù)據(jù)一個(gè)更好的結(jié)果所提出的公式進(jìn)行比較，并在工業(yè)應(yīng)用中具有潛在的用途。 在這項(xiàng)研究中，石灰石的類(lèi)型已經(jīng)出現(xiàn)很顯然發(fā)揮在粉碎中起重要作用。此外，在破碎機(jī)的選擇是發(fā)揮標(biāo)準(zhǔn)的重要作用，邦德和可磨性功指數(shù)值。 該t-曲線的可用于描述破損顆粒在單顆粒破碎試驗(yàn)的產(chǎn)品的粒度分布的粒度分布曲線族。的累積百分比傳遞參數(shù)T2，T4，T10，T25，T50和T75是由從破損的產(chǎn)品通過(guò)針對(duì)不同范圍篩尺寸的線性插值來(lái)確定。不過(guò)，也有不少困難和問(wèn)題在落錘和雙擺錘試驗(yàn)方法，例如是費(fèi)力的，需要較長(zhǎng)的測(cè)試時(shí)間和需要特殊設(shè)備。 本文介紹了調(diào)查邦德功指數(shù)和中試規(guī)模的沖擊磨粒度分布的平均粒徑的影響的結(jié)果。結(jié)果表示了粒度分布是密切相關(guān)的平均粒徑（X）和邦德功指數(shù)（無(wú)線）。測(cè)定粒度分布與實(shí)驗(yàn)，提出的公式的數(shù)據(jù)的關(guān)系已經(jīng)出現(xiàn)了高的回歸值（R2 =0.88）。 6．結(jié)論 在這項(xiàng)研究中，實(shí)驗(yàn)室破碎的三個(gè)不同灰?guī)r測(cè)試用沖擊式破碎機(jī)進(jìn)行。的平均粒徑和對(duì)產(chǎn)品粒度分布的石灰?guī)r的邦德功指數(shù)的影響規(guī)律。 其中包括了在實(shí)驗(yàn)室粉碎的自相似斷裂行為所提出的模型方程可以用來(lái)替代落錘和雙擺測(cè)試，作為其粒度分布可以更容易地評(píng)價(jià)。 沒(méi)有研究，其中已作出關(guān)于進(jìn)料，轉(zhuǎn)子速度的效果，襯設(shè)計(jì)和對(duì)沖擊式破碎機(jī)的錘頭的設(shè)計(jì)，在采石場(chǎng)中很常用的量的效果的文獻(xiàn)。因此，破碎機(jī)和研磨機(jī)制造商將有可能使這種研究具有不同的設(shè)計(jì)適用于不同的材料被開(kāi)發(fā)同類(lèi)機(jī)型的適當(dāng)?shù)倪x擇。 這項(xiàng)研究表明，產(chǎn)品的粒度分布可能是不同的不同的材料屬性。因此，看來(lái)在粉碎工序的各材料的粒度分布，必須以較低的能量成本來(lái)評(píng)估。 圖8. 對(duì)石灰石實(shí)驗(yàn)和計(jì)算TN值比較 Original Research PaperA new size distribution model by t-family curves for comminution of limestonesin an impact crusherVedat DenizDepartment of Chemical Engineering, Hitit University, orum, Turkeya r t i c l ei n f oArticle history:Received 11 July 2010Received in revised form 20 October 2010Accepted 31 October 2010Available online 13 November 2010Keywords:LimestoneBreakageImpact crusherBond work indexSize distributiont-Familya b s t r a c tIn the evaluation of crushers, t-family curves obtained from single particle test methods are frequentlyused. It is known that there are many difficulties and problems in these tests. In this study the breakagebehaviour of three different limestones in an impact crusher was investigated. A new size distributionmodel was developed by t-family value evaluation and Bond work index approach. As a result, the validityof the equation was proved by a high regression value (r2= 0.88).? 2010 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of PowderTechnology Japan. All rights reserved.1. IntroductionImpact-induced rock fragmentation is relevant for many fieldsof science and technology. Impact mills have been applied inmineral, coal, cement and chemical industries for a long time.The literature shows that substantial effort has been expended inunderstanding the impact mill performance in relation to machineconfiguration and operational conditions through experimentalwork and mathematical modelling. However, due to lack of de-tailed knowledge on velocity and energy distributions of collisioninside a milling chamber, the mechanisms are still not clear 1.Bond testing has been in use since the late 1920s; laboratoriesand operations around world used the procedure as a componentof comminution circuit design as well as evaluation of plant perfor-mance. In spite of such long-standing use, the topic of accuracy andprecision of Bond work index determinations recurs with great fre-quency 2.Single particle tests to determine the comminution behaviour ofore can be separated into twin pendulum device (Fig. 1) and dropweight apparatus (Fig. 2) based tests 37.Schuhmann 8 reported that the size reduction events couldthemselves involve varying energy input, varying feed particle sizeand varying size distribution. Flavel and Rimmer 9 have reviewedsingle-particle breakage on the pendulum device, and stated thatthe pendulum device can be suitable for obtaining the relation be-tween the breakage product distribution and comminution energy.Twin pendulum test relies on the particle being broken betweenan input pendulum released from a known height and a reboundpendulum. Twin pendulum, however, has some important limita-tions, particularly regarding its low flexibility and reproducibility,long test duration, and the poor accuracy in estimating the commi-nution energy as a result of secondary motion of the rebound pen-dulum 47.The drop weight test differs, in that the particles are placed on ahard surface and struck by a falling weight. Both tests have beenextensively used in the field of comminution. In recent years, how-ever, the drop weight apparatus are being replaced by the twinpendulum. The standard drop weight device is fitted with a 20 kgmass, which can be extended to 50 kg. The effective range of dropheights is from 0.05 to 1.0 m, which represents a wide energyrange from 0.01 to 50 kW h/t (based 1050 mm particles). Follow-ing sample preparation the mean mass of each set of particles to bebroken is calculated. The results from the drop weight testsprovide an energy/input size/product size relationship. This rela-tionship is analysed using a set of curves to describe the size distri-bution produced from breakage events of increasing size reductionor energy input 35,1011.In the drop weight test, a known mass falls through a givenheight onto a single particle providing an event that allows charac-terisation of the ore under impact breakage. Although, the dropweight test has advantages in terms of statistical reliability andthe potential use of the data from the analysis, it has a number0921-8831/$ - see front matter ? 2010 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.doi:10.1016/j.apt.2010.10.020Tel.: +90 364 2274533; fax: +90 364 2274535.E-mail address: vedatdenizhitit.edu.trAdvanced Powder Technology 22 (2011) 761765Contents lists available at ScienceDirectAdvanced Powder Technologyjournal homepage: disadvantages, including necessity a special apparatus, tiringand particularly the length of time taken to carry out a test. Foreach drop weight test, 15 samples are tested in five size fractionsat three levels of energy input 1013.Narayanan 14 was used a novel procedure for estimation ofbreakage distribution functions of ores from t-family of curves. Inthis method, the product size distribution can be represented bya family of curves using marker points on the size distribution de-fined as the percentage passing (t) at a fraction of the parent par-ticle size. Thus, t2is the percentage passing an aperture of halfthe size of the parent particle size, t4is one quarter and t10isone-tenth of parent particle size. Narayanan and Whiten 15 haveproposed empirical equations for relating the reference curve datat10with the impact energy.The t10value is related to the specific comminution energy bythe Eq. (1):t10 A1 ? e?bEcs1The tnversus t10relationships can then be used to predict theproduct size distributions at different grind times 16.It is known that there are many difficulties and problems indrop weight and twin pendulum test methods such as beinglaborious, requiring long test time and requiring a special appara-tus. In this study, breakage behaviours of three different lime-stones in a laboratory impact crusher were investigated. A newsize distribution model equation was developed by t-family valueevaluation and Bond work index approach, and this model equa-tion was tested.2. Materials and method2.1. MaterialThree different limestone samples taken from different regionof Turkey were used as the experimental materials. The chemicalproperties of the limestone samples were presented in Table 1.2.2. The test of standard Bond grindabilityThe Bond grindability tests were conducted less than 3.35 mmof dry feed materials in a standard ball mill (30.5 ? 30.5 cm) fol-lowing a standard procedural outline described in the literature1724. The work indices were determined at a test sieve size of106lm. It has no lifters and all the inside corners are rounded.The Bond ball mill (Fig. 3) is operated at 70 rpm and is equippedwith a revolution counter. The grinding charge consists of 285 ironballs weighing 20.125 g. The standard Bond grindability test is aclosed-cycle dry grinding and screening process, which is carriedout until steady state condition is obtained. This test was describedas follow 1724.The material is packed to 700 cc volume using a vibrating table.This is the volumetric weight of the material to be used forgrinding tests. For the first grinding cycle, the mill is started withan arbitrarily chosen number of mill revolutions. At the end of eachgrinding cycle, the entire product is discharged from the mill and isscreened on a test sieve size (Pi). Standard choice for Piis 106l.The oversize fraction is returned to the mill for the second runtogether with fresh feed to make up the original weight corre-sponding to 700 cc. The weight of product per unit of mill revolu-tion, called the ore grindability of the cycle, is then calculated andis used to estimate the number of revolutions required for thesecond run to be equivalent to a circulating load of 250%. Theprocess is continued until a constant value of the grindability isachieved, which is the equilibrium condition. This equilibriumcondition may be reached in 612 grinding cycles. After reachingequilibrium, the grindabilities for the last three cycles are aver-aged. The average value is taken as the standard Bond grindability(Gbg).The products of the total final three cycles are combined to formthe equilibrium rest product. Sieve analysis is carried out on thematerial and the results are plotted, to find the 80% passing sizeof the product (P80). The Bond work index values (Wi) are calcu-lated from the Eq. (2) .Nomenclaturet10the cumulative percentage passing 1/10th of the initialmean size (%)tnthe cumulative percentage passing 1/nth of the meanparticle size (%)nratio dividing to a characteristic size of the mean parti-cle sizeEcsspecific comminution energy (kW h/t)A,bore impact breakage parametersWiBond work index (kW h/t)Pitest sieve size at which the test is performed (106lm)Gbgstandard Bond grindability, net weight of ball mill prod-uct passing sieve size Piproduced per mill revolution (g/rev)F80sieve opening which 80% of the feed (lm)P80sieve opening which 80% of the product (lm)Xmean particle size (mm)Fig. 1. Twin pendulum device.762V. Deniz/Advanced Powder Technology 22 (2011) 761765Wi 1:1 ?44:5P0:23i? G0:82bg? 10=ffiffiffiffiffiffiffiP80p ? 10=ffiffiffiffiffiffiffiF80p?23. ExperimentsFirstly, standard Bond grindability tests were performed forthree limestone samples. From the result of tests, Bond work indexvalues were calculated 4.44, 10.10 and 13.53 kW h/t, respectively.Then, 1 kg sample of six mono-size fractions (?6.7 + 4.75, ?4.75 +2.8, ?2.8 + 1.7, ?1.7 + 1.18, ?1.18 + 0.600, ?0.600 + 0.355 mm)were prepared by screens for determination of the t-family curves.The laboratory impact crusher (Fig. 4), used in the experiments,works with driven by a 1.1 kW motor, rotating at 2840 rpm, carrythree rows of hammers. Each sample was taken out of the labora-tory impact crusher, and then samples were sieved for product sizeanalysis.Results of t-family curves versus mean particle size fraction fordifferent limestones were shown in Figs. 57.Fig. 3. Bond mill.Fig. 4. Impact crusher using in experiments.Fig. 5. tnversus mean size fraction for limestone-I.Fig. 6. tnversus mean size fraction for limestone-II.Fig. 2. Drop-weight test apparatus.Table 1Chemical composition of limestone samples using in experiments.Oxides (%)Limestone-ILimestone-IILimestone-IIICaO31.0346.8548.99SiO20.058.4510.60Al2O30.901.021.07Fe2O30.000.350.59MgO22.420.921.11SO30.020.070.09Na2O0.070.020.04K2O0.100.060.08Loss on ignition45.2436.5038.72V. Deniz/Advanced Powder Technology 22 (2011) 7617657634. Proposed size distribution model equationKing 25 described a method of presenting the product sizedistributions obtained from drop weight tests. It is based on theobservations made by Narayanan and Whiten 26, that the cumu-lative fraction of products passing 1/nth of the mean size was de-noted by tn, is related to that passing one-tenth of the parent sizedenoted by t10. It was also reported that this relationship wasapplicable to different ore types tested under different impactloading conditions.In this study, a different size distribution relationship has beenexposed tnvalues for crushing products in the direct laboratoryimpact crusher. As a result of this study, the relationship betweenthe cumulative percentage passing (tn) with Bond work index (Wi)and mean particle size (X) was empirically described by Eq. (3).tn406:35W0:921i? n1:1X0:108W0:668i?n2:47W?1:184i3The experimental values and the calculated results obtained byEq. (3) were compared in Fig. 8.Eq. (3) mostly satisfies the experimental values in a wide rangeof feed size, and Eq. (3) is useful especially when evaluating the par-ticle size distribution in the actual operation by a high regressionvalue (r2= 0.88). Thus, the relationship between the cumulativepercentage passing (tn) with Bond work index (Wi) and mean parti-cle size (X) was empirically described by Eq. (3).5. Results and discussionThe results showed that limestone-I sample was more friablethan limestone-II sample while limestone-II sample was more fri-able than limestone-III sample. A set of t-curves were calculatedfrom the direct a laboratory impact mill and a new size distributionequation was developed.The product size distribution from the breakage by impactcrusher of particle can be described as all-parameter (tn) familyof curves. The product size distributions were found to be normal-izable with respect to particle sizes. Cumulative percentages ofpassing material belong to (tn) the experimental data was com-pared with the proposed equation given a better results with dataand has a potential use in industrial applications.In this study, the type of limestone has emerged very clearlyplayed an important role in comminution. In addition, in crusherselection was played an important role of the standard the Bondgrindability and work index values.The t-curves are the family of size distribution curves which canbe used to describe the product size distribution of the breakageparticles during single-particle breakage tests. The cumulative per-centages passing of the parameters t2, t4, t10, t25, t50and t75aredetermined by linear interpolation from the breakage productspassing against the different range of sieve sizes. However, thereare many difficulties and problems in drop weight and twin pendu-lum test methods such as being laborious, requiring long test timeand requiring a special apparatus.This paper presents the results of an investigation into the ef-fects of the Bond work index and the mean particle size on particlesize distribution in a pilot scale impact mill. The results denote thatparticle size distribution is strongly related to mean particle size(X) and Bond work index (Wi). The relationship with data fromexperimental and proposed equation for determination of particlesizedistributionshasemergedbyahighregressionvalue(r2= 0.88).6. ConclusionsIn this study, laboratory crushing tests of three different lime-stones with an impact crusher were carried out. The effects ofmean particle size and Bond work index of limestones on productsize distribution were investigated.The proposed model equation which incorporates the self-similar breakage behaviour in laboratory comminution could beused an alternative to the drop weight and twin pendulum tests,as its particle size distributions could evaluated more readily andreliably.There are no studies in the literature which have been madeabout the effect of the amount of feed, effect of rotor speed, liningdesign and design of the hammer on the impact crushers, verycommonly used in quarries. Therefore, crusher and grinder manu-factures will be possible to make appropriate choices of such stud-ies with different designs for different material to be developingsimilar models.This study showed that product size distribution could be dif-ferent for different material properties. Therefore, it appears thatthe particle size distributions of each material in crushing processmust be evaluated in order to lower the energy costs.References1 N. Djordjevic, F.N. Shi, R.D. Morrison, Applying discrete element modelling tovertical and horizontal shaft impact crushers, Miner. Eng. 16 (2003) 983991.Fig. 7. tnversus mean size fraction for limestone-III.Fig. 8. Comparison of experimental and calculated tnvalue for limestone.764V. Deniz/Advanced Powder Technology 22 (2011) 7617652 J.B. Mosher, C.B. Tague, Conduct and precision of Bond grindability testing,Miner. Eng. 14 (2001) 11871197.3 R.A. Bearman, C.A. Briggs, T. 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