本文選題：鈾尾礦 + 鈾元素��； 參考：《南華大學(xué)》2015年碩士論文

【摘要】：鈾尾礦中鈾元素的釋放受粒徑影響非常大。酸法提鈾過(guò)程中,鈾元素的提取率與粒徑有很大關(guān)系,與尾礦中鈾的殘留量更是有直接關(guān)聯(lián);水是尾礦中鈾釋放最主要的動(dòng)力之一,而粒徑是影響尾礦與水接觸面積的關(guān)鍵性因素。在我國(guó)南方降雨豐沛、地下水系運(yùn)動(dòng)復(fù)雜的地理?xiàng)l件下,研究粒徑對(duì)鈾元素釋放的影響很有必要。本論文采用靜態(tài)浸泡實(shí)驗(yàn),模擬自然環(huán)境中,粒徑對(duì)浸泡在地下水層的尾礦中鈾元素釋放的影響;采用動(dòng)態(tài)淋浸實(shí)驗(yàn),模擬自然環(huán)境中,粒徑對(duì)受到降水淋浸作用的淺層尾礦中鈾元素的浸出,并對(duì)其動(dòng)力學(xué)特征進(jìn)行探究。通過(guò)實(shí)驗(yàn)得到以下結(jié)論:1.分析了粒徑對(duì)尾礦中鈾釋放過(guò)程的影響。通過(guò)對(duì)我國(guó)南方某鈾尾礦庫(kù)的尾礦樣品進(jìn)行了靜態(tài)浸泡實(shí)驗(yàn)和動(dòng)態(tài)淋浸實(shí)驗(yàn),模擬了庫(kù)區(qū)環(huán)境中,研究不同的尾礦—水共存體系中,粒徑對(duì)鈾元素釋放的影響。實(shí)驗(yàn)結(jié)果表明:(1)靜態(tài)浸泡條件下,不同粒徑鈾尾礦中鈾的釋放過(guò)程類似,粒徑對(duì)尾礦中鈾的釋放過(guò)程影響不大;動(dòng)態(tài)淋浸條件下,尾礦粒徑越小,鈾的釋放過(guò)程進(jìn)展越快。(2)尾礦粒徑越小,鈾元素浸出速率越大。但粒徑越小,靜態(tài)浸泡條件下,尾礦越容易出現(xiàn)板結(jié),影響鈾元素的釋放。(3)尾礦粒徑越小,飽和階段溶液中鈾濃度各個(gè)階段的鈾濃度差距越小,整個(gè)鈾釋放過(guò)程越穩(wěn)定,鈾濃度波動(dòng)越小,更利于長(zhǎng)期貯存。2.對(duì)尾礦中鈾的釋放過(guò)程進(jìn)行了浸出機(jī)制和動(dòng)力學(xué)分析。模擬了實(shí)驗(yàn)過(guò)程中,鈾元素濃度變化現(xiàn)象,運(yùn)用了有限元回歸方法對(duì)實(shí)驗(yàn)數(shù)據(jù)進(jìn)行分析,指出在不同的尾礦—水共存體系中,鈾元素釋放的動(dòng)力學(xué)機(jī)制存在差異。模擬結(jié)果表明:(1)尾礦表面附著的鈾酰離子是導(dǎo)致尾礦中鈾元素快速溶出的主要來(lái)源。(2)靜態(tài)浸泡條件下,尾礦中鈾的釋放符合未反應(yīng)收縮核模型特征;動(dòng)態(tài)淋浸條件下,表面洗脫是尾礦中鈾釋放的主要形式。
[Abstract]:The release of uranium elements from uranium tailings is greatly affected by particle size. In the process of acid extraction of uranium, the extraction rate of uranium is closely related to the particle size and the residual amount of uranium in the tailings, and water is one of the main driving forces of uranium release in the tailings. The particle size is the key factor affecting the contact area between tailings and water. It is necessary to study the effect of particle size on uranium release under the geographical conditions of abundant rainfall and complicated movement of underground water system in southern China. In this paper, static immersion experiment was used to simulate the effect of particle size on uranium release from tailings immersed in underground water layer, and dynamic leaching experiment was used to simulate the natural environment. The particle size was used to elucidate the uranium element in the shallow tailings by precipitation leaching, and the kinetic characteristics of the uranium element were investigated. The following conclusion is drawn from the experiment: 1. The effect of particle size on uranium release process in tailings was analyzed. The static immersion and dynamic leaching experiments were carried out on the tailings of a uranium tailings reservoir in southern China. The effects of particle size on the release of uranium elements in different tailings and water coexistence systems were simulated in the reservoir area. The experimental results show that under the condition of static immersion, the uranium release process in uranium tailings of different sizes is similar, the particle size has little effect on the uranium release process in tailings, and the smaller the particle size of tailings is under dynamic leaching conditions, The faster the process of uranium release is, the smaller the particle size of tailings is, the higher the leaching rate of uranium is. However, the smaller the particle size is, the easier it is for the tailings to appear under the condition of static immersion, and the smaller the particle size of tailings is, the smaller the uranium concentration gap is in each stage of the saturated solution, and the more stable the whole uranium release process is. The smaller the fluctuation of uranium concentration, the more favorable for long-term storage. The leaching mechanism and kinetics of uranium in tailings were analyzed. The variation of uranium concentration was simulated and the experimental data were analyzed by finite element regression method. It was pointed out that the kinetic mechanism of uranium release was different in different tailings and water coexistence systems. The simulation results show that the uranyl ions attached to the tailings surface are the main source of the rapid dissolution of uranium elements in the tailings. Under the static immersion conditions, the uranium release in the tailings conforms to the characteristics of the unreacted shrinking nucleus model, and under the dynamic leaching conditions, the uranium release from the tailings conforms to the characteristics of the unreacted shrinking nuclei model. Surface elution is the main form of uranium release from tailings.
【學(xué)位授予單位】：南華大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X753

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 劉漢彬;鈾尾礦的管理:地球化學(xué)過(guò)程和放射性風(fēng)險(xiǎn)評(píng)價(jià)[J];國(guó)外鈾金地質(zhì);2000年04期

2 招國(guó)棟;吳超;伍衡山;;含銅尾砂的浸出及其動(dòng)力學(xué)研究[J];礦業(yè)研究與開發(fā);2006年05期

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本文編號(hào)：1813338