發(fā)布時(shí)間：2018-06-26 20:22

  本文選題：離子型稀土 + 稀土離子含量　； 參考：《江西理工大學(xué)》2017年碩士論文

【摘要】：目前,離子型稀土礦山浸取稀土所用的原地浸礦法已相當(dāng)成熟,其具有工藝簡單、出礦快、成本低等優(yōu)點(diǎn),然而在長期實(shí)際運(yùn)用中,浸注過程引發(fā)的環(huán)境、事故問題時(shí)有報(bào)道,如滑坡、水土流失等,嚴(yán)重影響了該方法的推廣。浸礦液浸注過程,礦體內(nèi)部結(jié)構(gòu)受化學(xué)-滲流耦合持續(xù)作用,微觀孔隙結(jié)構(gòu)發(fā)生變化,致使礦體滲透性發(fā)生改變,影響浸礦效果,甚至誘發(fā)礦體滑坡。本文為了研究礦體浸礦過程微觀結(jié)構(gòu)變化與試樣宏觀滲透性之間的關(guān)系,利用浸礦過程滲透系數(shù)測定裝置,完成了浸礦過程稀土礦滲透系數(shù)測定實(shí)驗(yàn),研究了離子交換條件下試樣滲透系數(shù)變化規(guī)律及形成機(jī)理,分析了初始滲透性對滲流規(guī)律的影響。獲得以下主要結(jié)論:(1)浸礦液為純水時(shí)(0-17h),稀土離子含量(REO)在6.5*10-4g/t波動(dòng),根據(jù)公式(3.1)分析,表明此階段重塑土樣內(nèi)部不發(fā)生化學(xué)交換反應(yīng);浸礦液為硫酸銨時(shí)(7-17h),根據(jù)離子含量的變化可將化學(xué)反應(yīng)過程分為三個(gè)階段:初始反應(yīng)階段(7-9h)、強(qiáng)烈反應(yīng)階段(9-14h)、結(jié)束反應(yīng)階段(14-17h),整體呈現(xiàn)先強(qiáng)后弱的變化規(guī)律。(2)浸礦過程中,稀土礦體內(nèi)部微觀孔隙結(jié)構(gòu)受控于溶液滲流和離子交換兩個(gè)過程的耦合影響,其中溶液滲流誘發(fā)礦體內(nèi)部孔隙增多,孔徑增大,微觀結(jié)構(gòu)趨于松散;而離子交換引起顆粒移動(dòng)重組,導(dǎo)致孔徑變小,孔隙數(shù)量減少,微觀結(jié)構(gòu)趨于緊密。(3)浸礦過程的離子交換反應(yīng)在礦體中隨溶液滲流逐層向下進(jìn)行,符合滲流理論的層流規(guī)律;浸礦過程的化學(xué)置換和溶液滲流雙重作用下,浸礦液滲流對礦體微觀結(jié)構(gòu)具有破壞作用,而化學(xué)置換對微觀結(jié)構(gòu)具有一定的修復(fù)作用。(4)純水浸礦過程顆粒運(yùn)移,滲流場穩(wěn)定前有效滲流孔徑增大,試樣滲透系數(shù)逐步增加,滲流場穩(wěn)定后試樣滲透系數(shù)保持不變;硫酸銨溶液浸礦,在初始反應(yīng)階段和強(qiáng)烈反應(yīng)階段試樣滲透系數(shù)呈現(xiàn)下降趨勢,隨著化學(xué)反應(yīng)強(qiáng)度減弱滲透系數(shù)開始增大。(5)純水浸礦過程在穩(wěn)定滲流場形成前各試樣滲透系數(shù)呈現(xiàn)上升的變化趨勢且增加的幅度基本相當(dāng);硫酸銨溶液浸礦過程滲透系數(shù)變化趨勢呈現(xiàn)先下降-后上升,變化幅度隨試樣初始滲透性降低而逐步減弱。因此,建議初始滲透性較差的稀土礦體可采用“先水后硫酸銨溶液”順序浸礦,可達(dá)到最優(yōu)浸礦效果。
[Abstract]:At present, the in-situ leaching method used for leaching rare earths in ion rare earth mines is quite mature. It has the advantages of simple process, quick ore drawing and low cost. However, in long-term practical application, the environment caused by leaching process and accident problems have been reported. Such as landslide, soil erosion and so on, seriously affected the popularization of this method. In the process of leaching, the internal structure of ore body is continuously influenced by the coupling of chemical and percolation, and the microscopic pore structure changes, which results in the change of the permeability of ore body, which affects the leaching effect and even induces the landslide of ore body. In order to study the relationship between the microstructure change of ore body leaching process and the macroscopic permeability of the sample, the experiment of determining the permeability coefficient of rare earth ore during leaching process was carried out by using the apparatus for determining the permeability coefficient of the ore leaching process. The variation law and formation mechanism of the permeability coefficient of the sample under ion exchange conditions were studied and the influence of initial permeability on the seepage law was analyzed. The main conclusions are as follows: (1) when the leaching solution is pure water (0-17 h), the rare earth ion content (REO) fluctuates in 6.5*10-4g/t, according to the formula (3.1) analysis, it shows that there is no chemical exchange reaction in the remolded soil at this stage; When the leaching solution is ammonium sulfate (7-17 h), the chemical reaction process can be divided into three stages according to the change of ion content: initial reaction stage (7-9 h), strong reaction stage (9-14 h), end reaction stage (14-17 h). The micropore structure of rare earth ore body is controlled by the coupling effect of solution percolation and ion exchange, in which the pore size increases and the pore size increases, and the microstructure tends to be loose. However, ion exchange leads to particle movement and recombination, resulting in the decrease of pore size, the decrease of the number of pores and the close microstructure. (3) the ion exchange reaction in the leaching process is carried out layer by layer with the solution percolation, which accords with the laminar flow law of seepage theory. Under the dual action of chemical replacement and solution seepage in leaching process, leaching fluid seepage can destroy the microstructure of ore body, while chemical replacement can repair the microstructure to some extent. (4) the particle migration in pure water leaching process. Before the seepage field stabilizes, the effective percolation pore size increases, the sample permeability coefficient increases gradually, the sample permeability coefficient remains unchanged after the seepage field stabilization, the ammonium sulfate solution leaching ore, At the initial reaction stage and the strong reaction stage, the permeability coefficient of the sample decreased, As the chemical reaction intensity weakens the permeability coefficient begins to increase. (5) the permeability coefficient of each sample increases before the steady seepage field is formed and the increase range is basically the same; The change trend of permeability coefficient in ammonium sulfate solution leaching process is first decreasing and then increasing, and the change range decreases gradually with the decrease of the initial permeability of the sample. Therefore, it is suggested that the rare-earth ore bodies with poor initial permeability can be leached in the order of "first water and then ammonium sulfate solution", and the optimum leaching effect can be achieved.
【學(xué)位授予單位】：江西理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TD865

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