發(fā)布時間：2018-02-25 04:06

  本文關(guān)鍵詞： 鈾尾礦 淋浸 污染物 釋放規(guī)律 鈾浸出　出處：《南華大學》2015年碩士論文　論文類型：學位論文

【摘要】：鈾尾礦是一種高容量、低放射性廢物,常堆置于地表形成尾礦庫,在地球化學作用下,其中的放射性核素及其他有毒物質(zhì)將會釋放出來,對庫區(qū)周邊水土造成污染,從而危害人類健康。了解鈾尾礦中污染物的釋放規(guī)律和控制釋放的機制有助于制定對應的防范措施,以減輕鈾尾礦對環(huán)境的不利影響。我國廣東、江西等濕熱地方鈾礦眾多,但是目前國內(nèi)針對這些地方的鈾尾礦放射性核素和有毒重金屬元素的釋放、遷移機理的研究較少,因此,對這些尾礦開展這方面的研究具有重要的實際意義。本文以廣東韶關(guān)某鈾尾礦庫的尾礦為研究對象,分析其物理化學性質(zhì),然后對鈾尾礦進行模擬自然條件下的動態(tài)淋浸實驗,研究鈾尾礦中鈾及其他污染物的釋放規(guī)律,并對各金屬元素的釋放進行動力學分析。論文的主要結(jié)論如下:1.該鈾尾礦粒徑較大,主要分布在0.1-10 mm之間;所含主要元素有硅、鐵、鋁、鉀;主要礦物有石英、微斜長石、高嶺石、石膏、斜綠泥石;尾礦中鈾、鉛、鋅、鎘以殘渣態(tài)為主,鐵、錳主要以鐵錳氧化物/氫氧化物結(jié)合態(tài)為主.2.鈾尾礦動態(tài)淋浸的淋濾液p H值呈上升的趨勢,其變化范圍為3.3-4.84;尾礦中鈾、鐵、錳、鋅、鎘、鉛和硫酸根離子等污染物在淋浸初期釋放較快,后期逐漸變慢,淋浸液中鈾濃度遠大于鈾尾礦庫鈾的排放限值50 ug/L,其他污染物的濃度也超過地下水Ⅲ類水質(zhì)標準的限值。3.幾種金屬的累積浸出量大小為鈾錳鐵鋅鎘鉛,取決于各元素總量及元素在尾礦中存在的形態(tài)。4.浸出液中鈾濃度最高達286.66 mg/L,經(jīng)過2個月淋浸實驗,鈾累積釋放量達158.06 mg/Kg,具有回收價值。5.鐵、錳的釋放可用準二級動力學方程很好的擬合;鉛、鋅、鎘的釋放用拋物線擴散方程擬合較好;鈾的釋放具有階段性,淋浸0-24 h,鈾的釋放符合一級動力學,24 h-1464h,鈾的釋放符合二級動力學方程。
[Abstract]:Uranium tailings are high capacity, low radioactive wastes, often deposited on the surface to form tailings reservoirs. Under geochemical action, radionuclides and other toxic substances will be released, resulting in pollution of water and soil around the reservoir area. Therefore, it is harmful to human health. Understanding the release law of pollutants in uranium tailings and the mechanism of controlling the release will help to formulate corresponding preventive measures to mitigate the adverse effects of uranium tailings on the environment. There are many uranium deposits in humid and hot areas such as Guangdong and Jiangxi in China. However, at present, there are few studies on the migration mechanism of radionuclides and toxic heavy metal elements from uranium tailings in China. It is of great practical significance to study these tailings. In this paper, the physical and chemical properties of the tailings of a uranium tailings reservoir in Shaoguan, Guangdong Province, are analyzed, and the dynamic leaching experiments of uranium tailings under simulated natural conditions are carried out. The release regularity of uranium and other pollutants in uranium tailings is studied, and the release kinetics of each metal element is analyzed. The main conclusions of this paper are as follows: 1. The size of uranium tailings is large, mainly distributed in the range of 0.1-10 mm. Aluminum, potassium; main minerals are quartz, microplagioclase, kaolinite, gypsum, clinopyrite; uranium, lead, zinc, cadmium in tailings are mainly residual, iron, Mn is mainly iron-manganese oxide / hydroxide bound state .2.The pH value of leaching filtrate in dynamic leaching of uranium tailings shows an upward trend, and its variation range is 3.3-4.84, uranium, iron, manganese, zinc, cadmium in tailings, uranium, manganese, zinc, cadmium, uranium, manganese, zinc, cadmium, uranium, manganese, zinc, cadmium, uranium, manganese, zinc and cadmium in tailings. Pollutants such as lead and sulfate ions were released rapidly in the early stage of leaching, and gradually slowed down in the later period. The concentration of uranium in leaching solution is much larger than the limit value of uranium discharge from uranium tailings reservoir by 50 ugL, and the concentration of other pollutants exceeds the limit value of groundwater class 鈪，

本文編號：1532921