本文選題：離子型稀土　切入點(diǎn)：地下水污染　出處：《中國地質(zhì)大學(xué)(北京)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：稀土可廣泛用于軍事、冶金、石油化工等各個(gè)方面,是具有重要戰(zhàn)略意義的產(chǎn)品。我國南方離子型稀土礦現(xiàn)行開采工藝為原地浸礦開采法,生產(chǎn)中采用高濃度硫酸銨做浸礦劑使土壤吸附大量的銨態(tài)氮,因此開采過程中氨氮對(duì)環(huán)境造成的污染十分嚴(yán)重。為解決氨氮污染,需先了解氨氮的吸附機(jī)理及其在土壤中的賦存情況,在此基礎(chǔ)上采取淋洗手段解吸土壤的銨態(tài)氮。論文采取室內(nèi)實(shí)驗(yàn)方法,根據(jù)實(shí)際工況對(duì)采集到的原礦進(jìn)行了土樣對(duì)氨氮的吸附實(shí)驗(yàn),研究了開采工況下氨氮吸附的機(jī)理,并對(duì)吸附飽和的土樣進(jìn)行了解吸附實(shí)驗(yàn),確定了不同形態(tài)銨態(tài)氮所占的比例及含量。另外研究了不同淋洗方案的可行性,并通過柱實(shí)驗(yàn)對(duì)實(shí)際工況進(jìn)行了模擬,應(yīng)用Cl-濃度為250mg/l的KCl溶液淋洗方案,研究了實(shí)際可行性。主要的結(jié)論如下:1)動(dòng)力學(xué)結(jié)果同顆粒內(nèi)擴(kuò)散模型和Elovich方程擬合均較好。土體對(duì)氨氮的吸附平衡時(shí)間為3小時(shí),在開采工況下土體對(duì)氨氮的飽和吸附量約為770mg/kg。通過Langmuir Freundlich方程的參數(shù)得到土體對(duì)氨氮的理論最大飽和吸附量為970mg/kg。2)批實(shí)驗(yàn)中吸附飽和的土體所含的銨態(tài)氮中,能被去離子水解吸的部分約占總銨態(tài)氮的33%,1M的KCl溶液可解吸的部分占總銨態(tài)氮的60%,剩余存在礦物晶格中的部分約占6%。3)現(xiàn)行清水淋洗措施效率低且無法解吸交換態(tài)銨態(tài)氮,而Cl-濃度為250mg/l的KCl溶液可快速且有效地浸提土中殘存銨態(tài)氮,適宜應(yīng)用在實(shí)際生產(chǎn)中。4)模擬實(shí)際的柱實(shí)驗(yàn)中吸附平衡的土體中水溶態(tài)銨態(tài)氮比例上升至53%,交換態(tài)銨態(tài)氮所占比例降至47%,不存在固定態(tài)銨態(tài)氮或存在量極小。
[Abstract]:Rare earths can be widely used in military, metallurgical, petrochemical and other fields. High concentration ammonium sulfate is used as leaching agent to absorb a large amount of ammonium nitrogen in the soil in production, so the pollution caused by ammonia nitrogen during mining is very serious. In order to solve the pollution of ammonia nitrogen, It is necessary to understand the adsorption mechanism of ammonia nitrogen and its occurrence in soil, on the basis of which the leaching method is adopted to desorb the ammonium nitrogen in soil. According to the actual working conditions, the adsorption experiments of ammonia nitrogen were carried out on the soil samples, the mechanism of ammonia nitrogen adsorption under mining conditions was studied, and the adsorption experiments were carried out on the saturated soil samples. The proportion and content of different forms of ammonium nitrogen were determined. In addition, the feasibility of different elution schemes was studied, and the actual conditions were simulated by column experiments. The leaching scheme of KCl solution with Cl-concentration of 250 mg / l was used. The practical feasibility has been studied. The main conclusions are as follows: (1) the kinetic results fit well with the particle diffusion model and the Elovich equation. The adsorption equilibrium time of the soil for ammonia nitrogen is 3 hours. Under mining condition, the saturated adsorption capacity of ammonia nitrogen is about 770 mg / kg. The theoretical maximum saturated adsorption capacity of soil for ammonia nitrogen is 970 mg / kg 路2 through the parameters of Langmuir Freundlich equation. The part that can be desorbed by deionized water accounts for about 331M of total ammonium nitrogen. The desorbed part of KCl solution accounts for 60% of total ammonium nitrogen, and the remaining portion of mineral lattice is about 60.3.The current clean water elution measures are inefficient and cannot desorb exchangeable ammonium nitrogen. The KCl solution with a concentration of 250 mg / l can rapidly and effectively extract residual ammonium nitrogen from the soil. It is suitable for application in practical production .4) in the actual column experiment, the proportion of water-soluble ammonium nitrogen in the soil adsorbed in equilibrium rises to 53 and the proportion of exchangeable ammonium nitrogen decreases to 47, and there is no fixed ammonium nitrogen or minimal amount of ammonium nitrogen in the soil.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X53;X753

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

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本文編號(hào)：1574261