本文選題：浮選 + 葉輪轉(zhuǎn)速�。� 參考：《太原理工大學(xué)》2015年碩士論文

【摘要】：煤炭洗選是實(shí)現(xiàn)煤潔凈利用的第一步，煤炭通過洗選，可以提高煤炭質(zhì)量，，減少燃煤污染物的排放；提高煤炭利用效率，節(jié)約能源。在礦物的加工和分選中，浮選是眾多煤炭洗選方法中的一種，在國內(nèi)外應(yīng)用廣泛，同時(shí)也是處理細(xì)粒級(jí)煤泥最有效的方法。本文以小于1.0mm的粗煤泥為研究對(duì)象，對(duì)試樣進(jìn)行按粒度按密度分級(jí)，通過實(shí)驗(yàn)室單元浮選試驗(yàn)以及窄粒級(jí)浮選動(dòng)力學(xué)試驗(yàn)的方法，精細(xì)的研究了葉輪轉(zhuǎn)速和充氣量對(duì)寬粒級(jí)煤泥及浮選動(dòng)力學(xué)常數(shù)的影響，系統(tǒng)的進(jìn)行了相關(guān)分析。結(jié)合理論分析和實(shí)驗(yàn)數(shù)據(jù)進(jìn)一步探討和論證了葉輪轉(zhuǎn)速和充氣量以及煤泥的密度、粒度對(duì)浮選過程的影響。用MATLAB對(duì)試驗(yàn)條件與浮選速率常數(shù)進(jìn)行了回歸分析。通過FLUENT流體動(dòng)力學(xué)模擬軟件模擬浮選槽內(nèi)部的氣液兩相流場及湍流度，解釋了葉輪轉(zhuǎn)速以及浮選槽充氣量對(duì)粗煤泥浮選的影響。 通過實(shí)驗(yàn)室自制的充氣攪拌式浮選機(jī)，規(guī)格為1L。進(jìn)行了相關(guān)實(shí)驗(yàn)室單元浮選試驗(yàn)，考察了充氣量以及葉輪轉(zhuǎn)速對(duì)粗煤泥產(chǎn)率以及可燃體回收率的影響，結(jié)果表明：在葉輪轉(zhuǎn)速一定的條件下。精煤產(chǎn)率隨著充氣量的增大而增加，并在充氣量到400L/h時(shí)，各個(gè)轉(zhuǎn)速情況下的精煤產(chǎn)率到達(dá)最大。葉輪轉(zhuǎn)速對(duì)浮選行為影響也較為明顯，隨著葉輪轉(zhuǎn)速的增大，精煤的可燃體回收率和產(chǎn)率也會(huì)增加，但是，過大的葉輪轉(zhuǎn)速不利于浮選。相對(duì)于充氣量對(duì)浮選指標(biāo)的影響，葉輪轉(zhuǎn)速對(duì)浮選精煤的產(chǎn)率和可燃體回收率影響更為顯著�？梢�，葉輪轉(zhuǎn)速是浮選效果好壞的決定性因素之一 通過實(shí)驗(yàn)可知，實(shí)驗(yàn)所用窄粒級(jí)煤泥的浮選過程符合一級(jí)動(dòng)力學(xué)方程。浮選機(jī)葉輪轉(zhuǎn)速對(duì)細(xì)粒級(jí)、低密度級(jí)煤泥的浮選速率常數(shù)k影響巨大。當(dāng)葉輪轉(zhuǎn)速增加時(shí)，浮選速率常數(shù)會(huì)增大；如果葉輪轉(zhuǎn)速過大，浮選速率常數(shù)的數(shù)值反而會(huì)下降。但是，較高的葉輪轉(zhuǎn)速會(huì)提高大密度、大粒度顆粒的浮選速率常數(shù)。故在浮選過程中，并不是葉輪轉(zhuǎn)速越大越好。另外，煤泥顆粒對(duì)浮選速率常數(shù)也有較大的影響，當(dāng)煤泥顆粒增大時(shí)，浮選速率常數(shù)會(huì)逐漸減小。 通過實(shí)驗(yàn)結(jié)果可以看出，浮選速率常數(shù)k受顆粒的粒度、密度以及浮選機(jī)的葉輪轉(zhuǎn)速的影響。試驗(yàn)數(shù)據(jù)通過數(shù)值計(jì)算軟件MATLAB分析并建立了浮選速率常數(shù)k與這些參數(shù)之間的多元線性模型。同時(shí)，從流場的氣液兩相湍流度的角度分析了浮選槽中葉輪轉(zhuǎn)速和通氣量對(duì)浮選過程的影響。通過流體動(dòng)力學(xué)軟件FLUENT模擬了浮選槽內(nèi)部的流場，直觀的表現(xiàn)出浮選槽內(nèi)部的湍流度和氣液兩相云圖。從模擬云圖以及試驗(yàn)數(shù)據(jù)可知，過大的充氣量會(huì)加大浮選槽液面的湍流度，對(duì)粗顆粒而言，會(huì)降低其附著概率，不利于粗顆粒的浮選。當(dāng)葉輪轉(zhuǎn)速增大時(shí)，轉(zhuǎn)子區(qū)域的湍流度會(huì)大幅增大，但是過大的轉(zhuǎn)速，會(huì)使浮選槽內(nèi)湍流度過大。因此，合適的葉輪轉(zhuǎn)速將會(huì)提高顆粒的碰撞和附著概率，這也會(huì)有利于增大顆粒和氣泡的礦化概率。 浮選動(dòng)力學(xué)的特性分析表明，在其他變量不變時(shí)，在相對(duì)較大的葉輪轉(zhuǎn)速（800r/min）以及較低的充氣量（400L/h）有利于提高粗煤泥的回收率和可燃體回收率。通過數(shù)值模擬軟件，建立起浮選速率常數(shù)的模型，并通過這個(gè)模型，揭示了浮選速率常數(shù)與葉輪轉(zhuǎn)速以及煤泥的密度、粒度之間的關(guān)系。
[Abstract]:Coal washing is the first step to realize the clean utilization of coal. Through washing, coal can improve the quality of coal, reduce the emission of coal pollution, improve the efficiency of coal utilization and save energy. In the mineral processing and selection, flotation is one of the many methods of coal washing, which is widely used at home and abroad, and is also the treatment of fine grained slime. The most effective method. In this paper, taking the coarse slime less than 1.0mm as the research object, the influence of the impeller speed and the inflating volume on the dynamic constant of the wide grain grade slime and flotation is carefully studied by the laboratory unit flotation test and the narrow particle flotation dynamic test. Correlation analysis. Combined with theoretical analysis and experimental data, the effects of impeller speed and volume, density of slime and particle size on the flotation process were further discussed and demonstrated. The regression analysis of the test conditions and the rate constant of flotation was carried out by MATLAB. The gas-liquid two phase flow field inside the flotation tank was simulated by FLUENT fluid dynamics simulation. And turbulence intensity, which explains the effect of impeller speed and the amount of aeration of flotation cell on coarse slime flotation.
The laboratory unit floatation test was carried out by a laboratory self-made aerated and stirred flotation machine. The effect of gas volume and impeller speed on the yield of coarse slime and the recoverable rate of the flammable body was investigated by 1L.. The results showed that the yield of refined coal increased with the increase of inflating volume and inflated under the condition of a certain impeller speed. When the speed of the impeller is measured to 400L/h, the yield of the refined coal reaches the maximum at every speed. The influence of the impeller speed on the flotation behavior is also obvious. With the increase of the impeller speed, the recoverable rate and the yield of the combustible body will increase. However, the oversize impeller speed is not favorable to the flotation. The yield of clean coal and the recovery rate of combustibles are more significant.
The experiment shows that the flotation process of the narrow particle slime used in the experiment is in accordance with the first order kinetic equation. The impeller speed of the flotation machine has great influence on the flotation rate constant k of the fine particle and low density grade slime. When the impeller speed increases, the flotation rate constant will increase; if the impeller speed is too large, the value of the flotation rate constant will drop. However, the higher impeller speed will increase the large density and the rate constant of large particle particles, so in the process of flotation, the higher the impeller speed is, the better the better. In addition, the slime particles have a great influence on the rate constant of the flotation. When the slime particles increase, the number of the flotation rate will gradually decrease.
The experimental results show that the flotation rate constant k is affected by the particle size, density and the impeller speed of the flotation machine. The experimental data is analyzed by the numerical software MATLAB and the multiple linear model between the flotation rate constant K and these parameters is established, and the floating rate is analyzed from the angle of the gas and liquid turbulent flow. The effect of impeller speed and aeration on the flotation process is simulated by the fluid dynamics software FLUENT. The flow field inside the floatation tank is simulated, and the turbulence in the flotation tank and the gas-liquid two phase cloud are displayed intuitively. From the simulated cloud chart and the experimental data, it is known that the excessive volume of gas will increase the turbulence of the floatation tank and the coarse particles. When the impeller speed increases, the turbulent degree of the rotor will increase greatly, but the excessive speed will make the turbulent flow in the flotation tank too large. Therefore, the appropriate impeller speed will increase the particle collision and the attachment probability, which will also help to increase the particles and the gas bubbles. Probability of transformation.
The characteristic analysis of the flotation kinetics shows that the relatively larger impeller speed (800r/min) and the lower gas volume (400L/h) are beneficial to the improvement of the recovery rate and the recovery rate of the flammable body when the other variables are constant. Through the numerical simulation software, a model of the constant number of floatation rate is established, and the flotation rate is revealed through this model. The relationship between constant and impeller speed and density and particle size of slime.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TD94

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