河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文Influence of some rock strength properties on jaw crusher performance in granite quarryAbstract：The influence of rock strength properties on Jaw Crusher performance was carried out to determine the effect of rock strength on crushing time and grain size distribution of the rocksInvestigation was conducted on four different rock samples namely marbledolomite1imestone and granite which were representatively selected from fragmented lumps in quarriesUnconfined compressive strength and Point load tests were carried out on each rock sample as well as crushing time and size analysisThe results of the strength parameters of each sample were correlated with the crushing time and the grain size distribution of the rock types。The results of the strength tests show that granite has the highest mean value of 101.67 MPa for Unconfined Compressive Strength(UCS)test6.43 MPa for Point Load test while dolomite has the least mean value of 30.56 MPa for UCS test and 0.95MPa for Point Load test。According to the International Society for Rock Mechanic OSRM)standardthe granite rock sample maybe classified as having very high strength and dolomite rock sample，low strengthAlso，the granite rock has the highest crushing time(2 1O s)and dolomite rock has the least value(50 s)Based on the results of the investigation，it was found out that there is a great influence of strength properties on crushing time of rock types1 IntroductionThe strength of a material refers to the materials ability to resist an applied forceStrength property of rock is the ability of the rock material to resist failure when load is applied without yielding or fractureThe mechanical properties of rock depend upon 河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文the interaction between the crystals，particles and cementation material of which it is composedThe yield strength of a material is an adequate indicator of the materials mechanical strength and is the parameter that predicts plastic deformation in the materialfrom which one can make informed decisions on how to increase the strength of a material depending on its micro-structural properties and the desired end effectStrength is considered in terms of compressive strength，tensile strength，and shear strength，namely the limit states of compressive stress，tensile stress and shear stress， respectivelyAccording to Reference，the effect of dynamic loading is probably the most important practical part of the strength of materials，especially the problem of fatigueRepeated loading often initiates brittle cracks，which grow slowly until failure occursIt is of paramount importance to first carryout size reduction of an ore or rock material on a laboratory scale for the ore or rock material to be profitably andeconomically processed industriallyThis permits the determination of parameters such as liberation size，grindability，coarse to medium to fine proportion in any product of the crushing and grinding equipment and the proportion of values of gangues in the finesJaw Crusher is used for crushing rock material in mines and quarries。It provides the latest technology in heavy duty crusher design that delivers high production，infinite setting adjustment，larger feed opening bolted mainframe，cast swing，jaw holder and optional positioning of the crusher support feet to suit installation requirementThis crusher is designed for exceptional heavy and continuous application with heavy duty part for optimum operation and long life and this can be influenced by the strength properties of the rockThe influence of rock strength property can result to the loss of capacity to perform the stipulated function for which jaw crusher was designed The UCS was the main quantitative method for characterizing the strength of rock materialsPoint load test is used to determine rock strength indexes in geotechnical practiceRock lithologies were classified into 河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文general categories and conversion factors were determined for each categoryThis allows for intact rock strength data to be made available through point load testing for numerical geotechnical analysis and empirical rock mass classification systems such as the Coal Mine Roof Rating(CMRR)Crushing is an integral portion for mineral processing operations and is critical for the preparation of ore for downstream process for mineral processing operationsCrushing of quarried rock is carried out in stages，with the primary crushing stage typically carried out using jaw crusher and subsequent(secondary and tertiary)From field observation，the greater the number of crushing stage，the higher the amount of fine produced as a proportion of total plant throughoutThe type of crusher used also directly controls the amount of fines produced A recent study of quarry fines looked at possible relationship between quarry plant operation and the generation of quarry finesThe conclusion drawn have been critically revealed that hard rock aggregate plant production is directly proportional to the number of crushing stages；it increases with an increase in production stageLow reduction fines generation at each stage especially where the rock or mineral are fragile，however，the cumulative fines production may be higher than a process using fewer stages with higher reductionThe panicle size analysis is the method used to determine the particle size distribution or the grain size distribution of rockore materialsIn practice，close size control of feed to mineral processing equipment is required in order to reduce the size effect and make the relative motion of the particles separation dependentThe particle size distribution of a matedal is important in understanding its physical and chemical propeniesIt affects the strength and load bearing properties of rocksThe easiest conventional method of determining mineral particle size is sieve analysis，where grain size is separated on sieve of different sizes河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文apertures using Sieve ShakerThus the particle size distribution is defined in tems of discrete size ranges and measured in micronIt is usually determined over a list of size ranges that covers nearly all the sizes present in the sample Some methods of determination allow much narrower size ranges to be defined that can be obtained by use of sieves and are applicable to panicle sizes outside the range available in sievesHowever，the idea of notionalsievethatretainsparticles above a certain size andpassespanicles below that size is universally used in presenting panicle size distribution data of all kindsThe size distribution may be expressed as arangeanalysis，in which the amount in each size range is listed in order of fineness of particlesIt may also be presented incumulative formin which the total of all sizesretainedorpassedby a single notionalsieveis given for a range of sizesRange analysis is suitable when a particular ideal midrange panicle size is being sought while cumulative analysis is used where the anlount of under-size orover-sizemust be controlled2 Materials and methodThe rock samples used for the investigation were obtained from different quarries in NigeriaDolomite，limestone and marble samples were collected from Edo State and granite rock samples from Ondo State。 NigeriaFive boulders of each rock type of dimension 90 cm50 cm50 cm were representatively selected from recently blasted portion of the rocks which were ftee from natural defects，that is,discontinuities such as cracks，joints，fractures etc were packed properly to avoid damage during transportationFor the unconfined compressive strength test，the rock sample was cut into square shape with dimension of 60 mm60 mm with masonry saw and Vernier caliper was used to measure the dimensionAlsofor the point load test，the rock samples were broken into irregular shape 河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文with sledge hammerVernier caliper was used to measure the diameter and length of irregular shaped rock samples from the different locationsThe mean value for length ad diameter was detemined 。 The rock samples were prepared and tested in the laboratory to Intemational Society for Rock Mechanics Standard for each strength test carried out using Masonry Saw Machine and Compression Testing Machine and Point Load Tester respectivelyThe readings were taken and recordedThe size reduction of equal weighed of the rock samples was done using Laboratory Jaw crusher and the particle size distribution was carried out in notional set of sieves using Sieve ShakerThe crushing times were taken and recorded and the weights of samples retained on the sieves recorded for size distributionThe rock sample were cut into square shape by using masonry cutting machine，the cut samples were smooth，free of abrupt irregularities and strengthFive specimen of each of the rock samples were tested and the failure load was recorded for each test as the failure was observed axlally in the compressive testing machineSome lumps of the different rock types were then crushed using the Laboratory Jaw crusher and taken record of the crushing timesThe screening of the crushed rock samples was carried out in a set of sieve using the Laboratory Sieve ShakerThe sieve was arranged in the order of decreasing apenure：4700，2000，1700，11 80，850，600，425，and 212 by placing the sieve that has the largest opening at the top and the least opening at the bottomA tight fitting pan or receiver was placed below the bottom sieve to receive the finest grained which is referred to as undersizeThe crushed sample was placed on the top sieve and a lid was used to cover it to prevent escape of the rock sample during me processThe set of the sieve was then placed in a sieve shaker which vibrates the sieve for proper screeningThis operation was carried out on each of the rock sample for five minutesThis was achieved by using the automatic control timer of the sieve shakerAfter the screening analysis，the retained sample on each sieve was measured on weigh balance and 河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文recorded to the cotresponding sieve opening size河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文顎式破碎機(jī)在花崗巖采掘中受巖石強(qiáng)度性能的影響摘要： 巖石強(qiáng)度性能的影響在顎式破碎機(jī)性能上取決于破碎的時(shí)間和巖石粒度分配。調(diào)查被分為了四個(gè)不同的巖石樣品，既是從采 破碎的 的 性的大理石， 石，石 石，和 巖樣品。 樣品 了在 同的破碎時(shí)間和粒 分 的 強(qiáng)度和 。 樣品的currency1“ 和的破碎時(shí)間和fi巖石fl 的粒度分配的。強(qiáng)度 巖是的101.67MP的 強(qiáng)度，6.43MP的”， 石在 強(qiáng)度了30.56，在”的為0.95MP。 巖石機(jī)強(qiáng)度， 巖樣品被分fl為了 的強(qiáng)度 石為 的強(qiáng)度。， 巖 的破碎時(shí)間 21.， 石 的破碎時(shí)間 5.0。 于的 ， 巖石fl 的破碎時(shí)間 強(qiáng)度性能的影響。介紹的強(qiáng)度 currency1的能currency1。巖石的強(qiáng)度性能是 時(shí)巖石 破的能currency1。巖石的currency1學(xué)性取決于 間的 ，是 粒和 。 的 強(qiáng)度是 的機(jī)強(qiáng)度的“ 是 性的 ，從 從 微觀 構(gòu)特性和期望效如何提 的強(qiáng)度 智的決定。強(qiáng)度被認(rèn)為分別是 強(qiáng)度， 拉強(qiáng)度， 剪強(qiáng)度，即 應(yīng)currency1，拉應(yīng)currency1和剪應(yīng)currency1極 態(tài)計(jì)算。 考，動(dòng)態(tài) 效應(yīng) 能是 強(qiáng)度的重要實(shí)踐 分，尤 是在疲勞問題上。重復(fù)常常產(chǎn)生 縫， 增長緩慢直發(fā)生故障。為重要的就是在實(shí)室規(guī)模的礦石破碎使 工業(yè)加工的 利性和經(jīng)濟(jì)性。在任何破碎和研磨設(shè)備產(chǎn)品 貴重細(xì)磨礦石就被 制例如釋放大小， 磨性“ 定， 粗 細(xì)比例“。顎式破碎機(jī)在礦山和采石 于破碎巖石 。提供河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文了在重 破碎機(jī)設(shè)計(jì)的新技術(shù)， 實(shí)現(xiàn)產(chǎn)量、更大的進(jìn) 口、分 大 機(jī)、回轉(zhuǎn)度、 滿足安裝要求的顎式破碎機(jī) 架和 撐腳定位。 破碎機(jī)是為了異常重連續(xù)運(yùn)行 巖石強(qiáng)度性能影響佳效 操 和長壽命設(shè)計(jì)的。巖石強(qiáng)度性能的影響 能導(dǎo)致顎式破碎機(jī)設(shè)計(jì) 規(guī)定功能的喪失。 強(qiáng)度 的主要特征就是巖石 強(qiáng)度的定量方法。” 于在巖土工程實(shí)踐 確定巖石強(qiáng)度 “。巖石巖性分為般fl和確定 個(gè)fl別的轉(zhuǎn)換因子。 使得完整的巖石強(qiáng)度的“ 將提供巖土工程“分 與實(shí)證巖分fl 統(tǒng)，例如煤礦頂板”。粉碎是礦 加工工