發(fā)布時間：2018-05-13 19:44

  本文選題：磷石膏 + 重金屬　； 參考：《成都理工大學》2015年碩士論文

【摘要】：我國磷礦資源儲量大,以海相沉積型為主,富含有高含量的鈾、釷和重金屬元素。近年來,隨著農用磷肥、復合肥需求的遞增,其副產物磷石膏數量急劇上升。研究表明,磷礦石中重金屬元素大部分積存在磷石膏中。龍門山地區(qū)磷礦及相關化工企業(yè)眾多,磷石膏大量堆積沱江流域兩岸,嚴重危害當地的生態(tài)環(huán)境。磷石膏影響區(qū)中重金屬元素的含量和賦存形態(tài)特征,尚不清楚。本論文依托國家自然科學基金“富磷水系中鈾的賦存形式與分配研究”,通過石亭江流域典型磷石膏堆影響區(qū)內的水、土壤、水系沉積物調查與分析,查明區(qū)內重金屬含量與賦存形態(tài)的分布特征;利用地質累積指數法、潛在生態(tài)危害指數法等方法,對研究區(qū)重金屬元素污染現狀進行評價,結果表明:(1)磷石膏堆是研究區(qū)內重金屬元素重要富集源區(qū)。宏達磷石膏堆中Cd、U元素含量分別超過當地土壤平均值9倍、6倍,金河磷石膏堆中Cd、U元素含量分別超過當地土壤平均值3倍、6倍,磷石膏堆中的重金屬元素含量可能存在隨儲積時間增加而減少的趨勢。(2)石亭江水體中除U元素出現局部高值外,其他重金屬元素As、Cr、Cu、Zn、Cd平均含量均未超過國標Ⅲ類水質標準,未見顯著污染。受沿岸磷石膏堆影響,石亭江中As、Zn、Cu、U元素含量出現較高值,總體來說,下游的重金屬含量分布表現出逐漸升高的趨勢。(3)石亭江水系沉積物中Cd的平均含量為0.34mg/kg,超過土壤環(huán)境質量二級標準。Cd、Cr、Pb、U元素在宏達磷石膏堆旁出現異常高值,As、Zn元素在鎣峰磷石膏堆旁出現異常高值,磷石膏堆可能是引起附近水系沉積物中重金屬元素含量升高的主要原因。(4)磷石膏影響區(qū)土壤中Cd污染較重,Cd平均含量為0.77mg/kg,超過土壤環(huán)境質量二級標準。受鎣峰磷石膏堆、宏達磷石膏堆影響,土壤中重金屬元素含量增加,并隨著距磷石膏堆距離的增加而逐漸減小。(5)磷石膏影響區(qū)水系沉積物中各重金屬元素主要以殘渣態(tài)為主,酸提取態(tài)、可還原態(tài)、可氧化態(tài)含量較低。鎣峰磷石膏堆、宏達磷石膏堆處,重金屬酸提取態(tài)、可氧化態(tài)顯著增加。水系沉積物中Cd、Cu、Ni元素的遷移性相對強于Cr、U、Pb、Zn、As元素。(6)磷石膏影響區(qū)土壤中重金屬元素主要以殘渣態(tài)為主,酸提取態(tài)、可還原態(tài)、可氧化態(tài)所占比例較小。受上游硫酸廠影響,附近土壤中重金屬元素可氧化態(tài)顯著增加,殘渣態(tài)明顯減小。土壤中Cd、Zn、Pb元素的遷移性相對強于Cr、Cu、As、Ni、U元素的遷移性。(7)通過地質累積指數法評價,石亭江水系沉積物中As元素污染程度為無-中度污染,Zn、U、Cd、Pb、Cu、Cr、Ni元素總體無污染。通過潛在生態(tài)危害指數法評價,Cd元素潛在生態(tài)危害為中等生態(tài)危害,其它元素的潛在生態(tài)危害均為輕微生態(tài)危害,磷石膏堆附近沉積物中重金屬生態(tài)危害較大,潛在生態(tài)危害程度由高到低依次為:CdAsCuPbCrZn。
[Abstract]:The phosphate rock resources in China are rich in uranium, thorium and heavy metals with large reserves, mainly marine sedimentary type and rich in high content of uranium, thorium and heavy metals. In recent years, with the increasing demand of agricultural phosphate fertilizer and compound fertilizer, the amount of phosphogypsum, the by-product, increased sharply. The results show that the heavy metals in phosphate rock are mostly accumulated in phosphogypsum. There are many phosphorite and related chemical enterprises in Longmen Mountain area, and phosphogypsum accumulates on both banks of Tuojiang River basin, which seriously endangers the local ecological environment. The content and occurrence of heavy metals in phosphogypsum affected areas are unclear. Based on the National Natural Science Foundation of China, "study on the form and Distribution of uranium in Phosphorus-rich Water system", through the investigation and analysis of the water, soil and water system sediment in the typical phosphorous gypsum heap in Shiting River Basin, To find out the distribution characteristics of heavy metal content and occurrence form in the study area, to evaluate the present situation of heavy metal element pollution in the study area by means of geological accumulation index method and potential ecological hazard index method, etc. The results show that the phosphogypsum stack is an important source of heavy metal enrichment in the study area. The content of CDU in Hongda phosphogypsum is 9 times higher than that in the local soil, and that in Jin He is 3 times or 6 times higher than that in the local soil. The content of heavy metal elements in phosphogypsum heap may decrease with the increase of storage time. (2) except for the local high value of U element, the average content of other heavy metal elements, As-Cr-Cr-CuCuZn-Zn ~ (+) CD, does not exceed the national standard type 鈪，

本文編號：1884543