【摘要】：本文針對目前高梯度強磁選設備的工業(yè)應用現(xiàn)狀,分析了不同類型聚磁介質(zhì)工業(yè)應用中存在的優(yōu)勢與不足,設計了一種用于強化細粒級弱磁性鐵礦物回收的強磁選用聚磁介質(zhì),借助于有限元仿真模擬對單一介質(zhì)體及復合介質(zhì)體交互作用體系下的磁場特性進行了數(shù)值分析,詳細地考查了鏡鐵礦單礦物在介質(zhì)表面的磁吸附率及幾種赤鐵礦礦石的高梯度分選效果,系統(tǒng)地驗證了數(shù)值模擬對物料分選行為的預測規(guī)律,從而確定了凸極介質(zhì)的最佳參數(shù)。通過采用X射線衍射分析、化學分析、鐵物相分析及顯微鏡下查定等多種分析檢測手段,對不同粒級鏡鐵礦單礦物開展了礦物種類的查定、鐵含量的測定、含鐵的礦物類型的確定及相應鐵分布率的標定等工作,結果表明：鏡鐵礦單礦物試樣中鐵礦物主要為α-赤鐵礦,其鐵分布率占所有含鐵礦物量的99%,粒度較粗的物料中赤鐵礦的礦物含量相對較低,并查明了各粒級單礦物中鐵礦物的解離狀態(tài)。通過化學分析、粒度篩析、鐵物相分析等檢測手段,對寶鋼集團梅山礦業(yè)公司選礦廠強磁掃選尾礦、東鞍山燒結廠強磁給礦及強磁尾礦、海南石碌鐵尾礦等多種礦石的物料性質(zhì)進行了查定,弄清了物料的粒度分布情況、不同粒級鐵的分布率、鐵礦物的存在類型及相對含量,結果表明：幾種弱磁性鐵礦石試樣中主要含鐵礦物均為赤鐵礦,原礦物料粒度小于0.043mm的粒級均占80%以上,說明幾種弱磁性鐵礦石中待回收鐵礦物均為赤鐵礦且集中于細粒級物料中。采用Ansoft三維磁場模擬技術對輔助凸極聚磁介質(zhì)的單一介質(zhì)體及多介質(zhì)體復合體系的磁場特性進行仿真研究,探明了介質(zhì)體表面輔助凸極的尖端形狀、角度、凸極間距等結構參數(shù)對單元介質(zhì)體周圍磁場分布的影響規(guī)律,揭示了多介質(zhì)體復合體系介質(zhì)間感應磁場的交互影響機制,預測了不同介質(zhì)的磁場特性對分選過程產(chǎn)生的可能影響,研究結果表明：凸極介質(zhì)較之等徑圓棒介質(zhì)在介質(zhì)表面磁感應強度和磁場不均勻程度上均有提高,尤其在背景磁感應強度較低時這種情況更為突出；凸極尖角過大或過小均不利于分選,確定適宜凸極尖角角度為60。：在凸極間距為2mm或4mm時,尖端高磁感應強度和凹部低磁感應強度交替出現(xiàn)的頻率高,沿介質(zhì)體軸向介質(zhì)表面磁場的不均勻程度提高,預測分選效果較好；相鄰介質(zhì)中心距越小,介質(zhì)間的磁感應云疊加效果越顯著,介質(zhì)表面凸極尖端及周圍空隙的磁感應強度越大,隨介質(zhì)中心距增大,介質(zhì)表面磁感應強度逐漸減弱,但中心距增大到一定程度時,介質(zhì)間的磁感應交互影響已弱化且等同于單一介質(zhì)體時的磁感應分布。在水平磁場和垂直磁場下分別進行了印度細粒赤鐵礦、廣東英德褐鐵礦強磁尾礦及寶鋼集團梅山礦業(yè)公司選礦廠強磁掃選尾礦的不同介質(zhì)的分選試驗,初步明確了凸極介質(zhì)體表面凸極棱角突出強化了磁場梯度作用,進而增強介質(zhì)對磁性礦物顆粒的磁力作用,可提高鐵精礦回收率,通過探索試驗證實了改變介質(zhì)表面結構特征是強化磁場梯度作用進而增大磁場力的有效途徑。在一定范圍內(nèi)較大棒徑的介質(zhì)可通過適當降低棒(絲)間隙及提高介質(zhì)充填率的方式取得與較小介質(zhì)相當?shù)姆诌x效果。此外,較大棒徑的介質(zhì)雖表面磁感應強度較高,但介質(zhì)表面積減小,有效吸附磁性物面積降低；棒徑小的介質(zhì)磁場梯度較大,介質(zhì)表面積大,但充填率降低,磁損耗增加,因此針對不同待分選物料應確定適宜分選的介質(zhì)棒徑與充填率。通過不同粒級鏡鐵礦單礦物的磁吸附試驗,考察了凸極介質(zhì)的排布方式、脈動水流作用對不同粒級單礦物磁吸附行為的影響,揭示了介質(zhì)參數(shù)對弱磁性單礦物的捕獲行為,找出了粒度特征對單礦物磁吸附作用體系的作用機制,驗證了三維磁場模擬的預測結果,研究結果表明：交錯排列的介質(zhì)對鏡鐵礦單礦物的磁吸附率高于平行排列介質(zhì)的相應值,當給料粒度減小時,交錯排列與平行排列介質(zhì)磁性物吸附率的差值逐漸增大；增加脈動作用(脈動沖程為11.4mm,沖次為150次/min)較之無脈動作用時,相同間隙的不同凸極間距介質(zhì)對物料的磁性物吸附效果差異性更明顯；凸極間距為1.Omm時的凸極介質(zhì)的磁性物吸附能力最佳。在相同間隙下,凸極介質(zhì)較之光滑圓棒介質(zhì)對鏡鐵礦單礦物的磁力作用更大,回收率更高。通過對東鞍山強磁給礦、東鞍山強磁尾礦、海南石碌鐵尾礦開展系統(tǒng)的磁分離試驗,詳細考察了介質(zhì)結構參數(shù)變化對分選效果產(chǎn)生的差異性,確定了適宜強化弱磁性細粒鐵礦物顆�；厥盏木鄞沤橘|(zhì)結構參數(shù),分析了介質(zhì)對弱磁性物料的分選行為,揭示了介質(zhì)結構參數(shù)與介質(zhì)體系特征參數(shù)對磁性產(chǎn)物粒度分布的作用規(guī)律等問題,并對凸極介質(zhì)和圓棒介質(zhì)的在相同背景磁場強度下的指標進行了對比,研究結果表明：凸極間距為1.Omm,介質(zhì)體間隙為3mm的介質(zhì)參數(shù)對東鞍山強磁給礦的分選效果最好；凸極間距為0.5mm,介質(zhì)體間隙為2mm的介質(zhì)參數(shù)對東鞍山強磁尾礦和海南石碌鐵尾礦的分選效果最好；凸極介質(zhì)較之圓棒介質(zhì),其磁性產(chǎn)物粒度回收下限有所降低,同時其回收率的提高主要源自細粒級顆粒的回收,達到了強化細粒級弱磁性礦物回收的目的。凸極介質(zhì)與圓棒介質(zhì)達到相同磁性產(chǎn)物回收率的情況下,凸極介質(zhì)所需的背景磁感應強度平均低于圓棒介質(zhì)背景磁感應強度約0.2T,為強磁選設備的節(jié)能降耗起到較大的作用。本文的研究成果為強化弱磁性鐵礦物顆粒的強磁選回收提供了新的技術思路,為聚磁介質(zhì)的開發(fā)與改進奠定了理論基礎,同時也為改善高梯度強磁選處理難選鐵礦資源的技術指標提供重要的技術積累。
[Abstract]:Aiming at the present industrial application situation of high gradient high intensity magnetic separation equipment, this paper analyzes the advantages and disadvantages of different types of magnetic concentrating media in industrial application, designs a kind of magnetic concentrating medium which is used to enhance the recovery of fine-grained weak magnetic iron ore, and uses finite element simulation to simulate the interaction between single medium and composite medium. The magnetic field characteristics under the action system are numerically analyzed. The magnetic adsorption rate of the single mineral on the surface of the medium and the high gradient separation effect of several hematite ores are examined in detail. The prediction law of the material separation behavior by numerical simulation is systematically verified, and the optimum parameters of the salient medium are determined. By means of radiation analysis, chemical analysis, iron phase analysis and microscopic examination, the determination of mineral types, iron content, types of iron-bearing minerals and the calibration of corresponding iron distribution rate of single mineral specimens of Specularite with different grain sizes were carried out. As a kind of alpha-hematite, its iron distribution rate accounts for 99% of all iron-bearing minerals, and the mineral content of hematite in coarse-grained materials is relatively low. The dissociation state of iron ore in single mineral of each grain size has been found out. The material properties of tailings, high-intensity magnetic tailings and high-intensity magnetic tailings from Donganshan Sintering Plant, and Shilu iron tailings from Hainan Province were investigated. The particle size distribution, distribution rate of iron with different grain sizes, existing types and relative contents of iron ores were found out. The results show that the main iron minerals in the samples of several weak-magnetic iron ores are iron ores. In hematite, the particle size of raw material is less than 0.043 mm, accounting for more than 80%, indicating that the iron ore to be recovered from several weak magnetic iron ores is hematite and concentrated in fine-grained materials. The influence of structure parameters such as tip shape, angle, salient spacing and so on on magnetic field distribution around the unit dielectric body is studied. The interaction mechanism of induced magnetic field between the media of multi-dielectric composite system is revealed. The possible influence of magnetic field characteristics of different media on the separation process is predicted. The results show that the magnetic induction intensity and the magnetic field inhomogeneity of the salient medium are higher than that of the equal-diameter rod medium, especially when the background magnetic induction intensity is lower; too large or too small salient tip angle is not conducive to sorting, and the suitable salient tip angle is 60. At 4mm, the frequency of alternating high magnetic induction intensity at the tip and low magnetic induction intensity at the concave is high, and the magnetic field inhomogeneity along the axial direction of the dielectric surface is improved, and the predictive sorting effect is better; the smaller the center distance between adjacent media, the more remarkable the magnetic induction cloud superposition effect between the media, and the magnetic induction intensity at the salient tip and the surrounding gap of the dielectric surface. With the increase of the center distance, the magnetic induction intensity on the surface of the medium decreases gradually, but when the center distance increases to a certain extent, the magnetic induction interaction between the media has weakened and is equivalent to the distribution of magnetic induction in a single medium. Magnetic tailings and separation tests of different media for high intensity magnetic sweeping tailings in Meishan Mining Company of Baosteel Group have been made clear preliminarily that the prominence of the prominent edges and corners on the surface of the prominent medium strengthens the magnetic field gradient effect, and then enhances the magnetic force of the medium on the magnetic mineral particles, which can improve the recovery of iron concentrate. The experimental results show that the change of the magnetic gradient on the surface of the prom The surface structure of the medium is an effective way to strengthen the magnetic field gradient and increase the magnetic field force. In a certain range, the medium with larger rod diameter can achieve the same separation effect as the medium with smaller diameter by reducing the gap between rods and wires and increasing the filling rate of the medium. However, the surface area of medium decreases with the decrease of the surface area of medium, and the magnetic field gradient of medium with small rod diameter is larger than that of medium with large surface area, but the filling rate decreases and the magnetic loss increases. Therefore, the suitable diameter and filling rate of medium rod should be determined according to different materials to be sorted. The distribution of salient medium and the effect of pulsating flow on the magnetic adsorption behavior of single mineral with different particle size have been studied. The trapping behavior of medium parameters on weak magnetic single mineral has been revealed. The mechanism of particle size characteristics on the magnetic adsorption system of single mineral has been found. The predicted results of three-dimensional magnetic field simulation have been verified. The magnetic adsorption rate of the medium to the single mineral of Specularite is higher than that of the parallel arrangement medium, and the difference between the magnetic adsorption rate of the staggered arrangement and the parallel arrangement medium increases gradually when the feed particle size decreases, while the pulse action (the pulse stroke is 11.4 mm and the pulse time is 150 times/min) is higher than that of the non-pulse action. The magnetic properties of the salient medium with 1.Omm salient pole spacing are the best. At the same gap, the salient medium has more magnetic effect on the single mineral of Specularite and higher recovery than the smooth rod medium. A systematic magnetic separation experiment was carried out in Shilu iron tailings of Hainan Province. The difference of separation effect caused by the change of medium structure parameters was investigated in detail. The structure parameters of magnetic concentrate suitable for strengthening the recovery of weak magnetic fine iron ore particles were determined. The separation behavior of medium for weak magnetic materials was analyzed. The medium structure parameters and medium bodies were revealed. The results show that the medium parameters with 1.Omm salient interval and 3 mm medium interval have the best separating effect on Donganshan high-intensity magnetic feeding ore. 0.5mm, 2 mm interval of medium medium parameters on the Donganshan strong magnetic tailings and Hainan Shilu iron tailings separation effect is the best; salient medium than the round rod medium, the magnetic product size recovery lower limit has been reduced, and its recovery rate mainly from the recovery of fine particles, to strengthen the fine-grained weak magnetic mineral return. The average background magnetic induction intensity of salient medium is lower than that of round medium about 0.2T under the condition that salient medium and round rod medium achieve the same recovery rate of magnetic products, which plays an important role in saving energy and reducing consumption of strong magnetic separation equipment. It provides a new technological idea for separation and recovery, lays a theoretical foundation for the development and improvement of magnetic concentrating medium, and also provides an important technical accumulation for improving the technical index of high gradient high intensity magnetic separation for refractory iron ore resources.
【學位授予單位】：東北大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：TD924;TD951

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本文編號：2235147