鈾礦冶地域土壤中鈾污染特征及其環(huán)境有效性研究
發(fā)布時(shí)間：2018-07-25 14:42
【摘要】：鈾(U)礦冶過(guò)程中產(chǎn)生了大量鈾尾礦和鈾廢石。尾礦中易殘留大量的化學(xué)雜質(zhì),其中包括大量的放射性元素鈾。鈾尾礦雖然做了相應(yīng)的防護(hù)措施,但污染問(wèn)題仍不斷被報(bào)道。鈾廢石通常認(rèn)為其放射性核素含量低,大多沿山谷露天自然堆放,一般不對(duì)堆場(chǎng)做防滲漏處置,故對(duì)鈾廢石堆產(chǎn)生的潛在環(huán)境影響尚未引起重視。本文以湖南某尾礦庫(kù)和廣東某花崗巖型鈾礦山的廢石堆周邊土壤為研究對(duì)象。在尾礦堆表層取四個(gè)尾礦樣,并在尾礦壩外的上下游分別采集了2條剖面(視作背景土壤)和3條剖面(視作潛在U污染土壤)。在廢石堆采集四個(gè)廢石樣,同時(shí)在上、下游分別采集了2條剖面(視作背景土壤)和4條剖面(視作潛在U污染土壤)。簡(jiǎn)單分析和探討了尾礦及廢石中鈾的釋放能力;通過(guò)剖面間U分布特征的對(duì)比,定量估算了受污染土壤中外源U的輸入通量;根據(jù)富集因子評(píng)價(jià)了土壤的污染程度;結(jié)合逐級(jí)化學(xué)提取技術(shù),分析了U在土壤剖面的賦存形態(tài)(包括六個(gè)相態(tài):可交換態(tài)(Ⅰ);碳酸鹽結(jié)合態(tài)(Ⅱ);有機(jī)質(zhì)結(jié)合態(tài)(Ⅲ);無(wú)定型鐵錳氧化物/氫氧化物結(jié)合態(tài)(Ⅳ);晶質(zhì)鐵錳氧化物/氫氧化物結(jié)合態(tài)(Ⅴ);殘?jiān)鼞B(tài)(Ⅵ))及其環(huán)境有效性(活性態(tài)(可交換態(tài)+碳酸鹽結(jié)合態(tài));潛在活性態(tài)(有機(jī)質(zhì)結(jié)合態(tài)+無(wú)定型鐵錳氧化物/氫氧化物結(jié)合態(tài));惰性態(tài)(晶質(zhì)鐵錳氧化物/氫氧化物結(jié)合態(tài)+殘?jiān)鼞B(tài)));探討了U與pH、有機(jī)質(zhì)、常量元素的相關(guān)性;通過(guò)本研究為鈾礦冶區(qū)域安全評(píng)價(jià)提供參考,同時(shí)為土壤中放射性元素的監(jiān)測(cè)和治理提供理論依據(jù)。結(jié)果表明:一、鈾尾礦及鈾廢石中U含量普遍高于本底基巖,活性鈾與潛在活性鈾之和所占的比例都在60%以上(鈾尾礦活性與潛在活性U所占的比例65.92%~96.02%,廢石中的比例為65.99%~84.36%)。鈾在鈾尾礦及鈾廢石中釋放能力相當(dāng),活性鈾與潛在活性鈾在一定條件下容易發(fā)生遷移,威脅周邊的生態(tài)環(huán)境。二、根據(jù)富集因子對(duì)鈾礦冶地域周邊土壤進(jìn)行評(píng)價(jià),鈾尾礦及鈾廢石堆對(duì)周邊土壤均產(chǎn)生了顯著的放射性污染(如近尾礦堆的Wp2土壤剖面中鈾的平均含量在65.96μg.g-1,是背景剖面的17.36倍;廢石堆周邊土壤剖面Fp1中U含量平均值達(dá)4848μg.g-1,是背景剖面的660.5倍)。三、根據(jù)外源鈾通入量及風(fēng)化土壤中U的質(zhì)量遷移系數(shù)表明:土壤中鈾污染主要來(lái)自于污染源輸入的外源鈾。四、總體來(lái)看,鈾尾礦及鈾廢石周邊污染剖面距污染源由近及遠(yuǎn)鈾含量呈明顯減小趨勢(shì)。污染較重的土壤剖面中,鈾隨著深度增加有減小的趨勢(shì),并在土壤中部易出現(xiàn)峰值。周邊土壤活性鈾距污染源由近及遠(yuǎn)土壤中活性態(tài)U所占比例增大,潛在活性態(tài)U所占比例降低。隨著深度的增加不同土壤剖面活性鈾有遞減的趨勢(shì),而潛在活性鈾有增加的趨勢(shì)。五、鈾尾礦及鈾廢石周邊污染剖面中活性鈾所占的平均比例均高于背景剖面,潛在活性鈾除了污染最重的Fp1所占平均比例高于背景剖面外其余均低于背景剖面。六、總體來(lái)看,鈾尾礦與廢石堆周邊土壤距污染源愈近,土壤中外源U的輸入通量愈大,在近源區(qū),大量的外源U優(yōu)先在土壤表層聚集,隨著遠(yuǎn)離污染源,逐漸轉(zhuǎn)變?yōu)閮?yōu)先在土壤剖面的深部淀積。七、本文研究的7條污染剖面中,尾礦周邊土壤剖面平均活性鈾在40%以上,加上潛在活性鈾近90%以上;廢石堆周邊土壤近半及以上的U為活性態(tài),加之潛在活性態(tài),近90%及以上。土壤在被污染的同時(shí)也變成了新的更具活性的污染源,對(duì)生態(tài)環(huán)境產(chǎn)生的影響應(yīng)引起充分重視。八、土壤中U與pH、有機(jī)質(zhì)、常量元素(SiO2、TFe2O3、P2O5等)有較好的相關(guān)性。
[Abstract]:A large amount of uranium tailings and uranium waste rocks have been produced in the process of uranium (U) mining and metallurgy. A large number of chemical impurities are easily retained in the tailings, including a large number of radioactive elements. Although the uranium tailings have been protected, the pollution problem is still reported. The potential environmental impact on the uranium waste rock pile has not been paid much attention to. In this paper, the soil surrounding the waste rock pile in a tailings reservoir in Hunan and a granite type uranium mine in Guangdong is studied. Four tailings are taken on the surface of the tailings pile and 2 sections are collected in the upper and lower reaches of the tailings dam. Background soil) and 3 sections (regarded as potential U contaminated soil). Four waste rock samples were collected from the waste rock pile. At the same time, 2 sections (as background soil) and 4 sections (regarded as potential contaminated soil) were collected in the lower reaches. The release capacity of uranium in tailings and waste rocks was briefly analyzed and discussed, and the comparison of U distribution characteristics between the sections was determined. The input flux of the source U in the contaminated soil was estimated. The degree of soil contamination was evaluated according to the enrichment factor. In combination with the step by step chemical extraction technology, the occurrence patterns of U in the soil profile (including six phases: exchangeable state (I), carbonate bound state (II), organic matter binding state (III), and amorphous iron manganese oxide / hydroxide junction) were analyzed. Combined state (IV); crystalline ferromanganese oxide / hydroxide bound state (V); residue state (VI)) and its environmental effectiveness (active state (exchangeable + carbonate binding state); potential active state (organic matter binding state + amorphous iron manganese oxide / hydroxide binding state); inert state (crystalline ferromanganese oxide / hydroxide bound state + residue)); The correlation between U and pH, organic matter and constant element, provides a reference for the safety evaluation of uranium mining and metallurgy, and provides a theoretical basis for the monitoring and control of radioactive elements in the soil. The results show that the content of U in uranium tailings and uranium waste rocks is generally higher than that of the base rock, and the proportion of the active uranium and the potential active uranium is 60. Above% (the proportion of uranium tailings activity and potential activity U is 65.92%~96.02%, the proportion of waste rocks is 65.99%~84.36%). Uranium is released in uranium tailings and uranium waste rocks, and the active uranium and potential active uranium are easily migrated under certain conditions and threaten the surrounding ecological environment. Two, according to the enrichment factor, the surrounding soil of uranium mining and metallurgy is on the soil. It is evaluated that uranium tailings and uranium waste piles have produced significant radioactive pollution to the surrounding soil (for example, the average content of uranium in the Wp2 soil profile of the near tailing pile is 65.96 mu g.g-1, 17.36 times the background profile; the average value of U content in the soil profile around the waste rock pile is 4848 mu g.g-1, 660.5 times of the background section). Three, according to foreign uranium The mass transfer coefficient and the mass transfer coefficient of U in the weathered soil show that the uranium pollution in the soil mainly comes from the exogenous uranium input from the source of pollution. Four. In general, the pollution sources of uranium tailings and uranium waste rocks are obviously decreasing from the near and far away from the pollution sources. In the middle of the soil, the peak value of the active uranium in the surrounding soil is increased, the proportion of the active state of the active state of U is increased, the proportion of the potential active U is reduced. With the increase of depth, the active uranium in different soil profiles has a decreasing trend, and the potential active uranium has an increasing trend. Five, uranium tailings and the surrounding pollution profiles of uranium waste rocks. The average proportion of active uranium is higher than the background section. The average proportion of potential active uranium, except the most polluted Fp1, is lower than the background section. Six. In general, the soil around the uranium tailings and the waste rock pile is closer to the source of pollution, the greater the input flux of U in the soil source, and a large amount of exogenous U in the near source area. In the 7 polluted sections, the average active uranium in the surrounding soil section of the tailings is over 40%, and the potential active uranium is over 90%, and the U around half and above the soil around the waste rock pile is active, and the potential activity is in addition to the potential activity. Seven The soil has become a new and more active source of pollution at the same time, and the impact on the ecological environment should be paid full attention to. Eight, the soil U and pH, organic matter, constant elements (SiO2, TFe2O3, P2O5, etc.) have good correlation.
【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)】：X53;X75
本文編號(hào)：2144142
[Abstract]:A large amount of uranium tailings and uranium waste rocks have been produced in the process of uranium (U) mining and metallurgy. A large number of chemical impurities are easily retained in the tailings, including a large number of radioactive elements. Although the uranium tailings have been protected, the pollution problem is still reported. The potential environmental impact on the uranium waste rock pile has not been paid much attention to. In this paper, the soil surrounding the waste rock pile in a tailings reservoir in Hunan and a granite type uranium mine in Guangdong is studied. Four tailings are taken on the surface of the tailings pile and 2 sections are collected in the upper and lower reaches of the tailings dam. Background soil) and 3 sections (regarded as potential U contaminated soil). Four waste rock samples were collected from the waste rock pile. At the same time, 2 sections (as background soil) and 4 sections (regarded as potential contaminated soil) were collected in the lower reaches. The release capacity of uranium in tailings and waste rocks was briefly analyzed and discussed, and the comparison of U distribution characteristics between the sections was determined. The input flux of the source U in the contaminated soil was estimated. The degree of soil contamination was evaluated according to the enrichment factor. In combination with the step by step chemical extraction technology, the occurrence patterns of U in the soil profile (including six phases: exchangeable state (I), carbonate bound state (II), organic matter binding state (III), and amorphous iron manganese oxide / hydroxide junction) were analyzed. Combined state (IV); crystalline ferromanganese oxide / hydroxide bound state (V); residue state (VI)) and its environmental effectiveness (active state (exchangeable + carbonate binding state); potential active state (organic matter binding state + amorphous iron manganese oxide / hydroxide binding state); inert state (crystalline ferromanganese oxide / hydroxide bound state + residue)); The correlation between U and pH, organic matter and constant element, provides a reference for the safety evaluation of uranium mining and metallurgy, and provides a theoretical basis for the monitoring and control of radioactive elements in the soil. The results show that the content of U in uranium tailings and uranium waste rocks is generally higher than that of the base rock, and the proportion of the active uranium and the potential active uranium is 60. Above% (the proportion of uranium tailings activity and potential activity U is 65.92%~96.02%, the proportion of waste rocks is 65.99%~84.36%). Uranium is released in uranium tailings and uranium waste rocks, and the active uranium and potential active uranium are easily migrated under certain conditions and threaten the surrounding ecological environment. Two, according to the enrichment factor, the surrounding soil of uranium mining and metallurgy is on the soil. It is evaluated that uranium tailings and uranium waste piles have produced significant radioactive pollution to the surrounding soil (for example, the average content of uranium in the Wp2 soil profile of the near tailing pile is 65.96 mu g.g-1, 17.36 times the background profile; the average value of U content in the soil profile around the waste rock pile is 4848 mu g.g-1, 660.5 times of the background section). Three, according to foreign uranium The mass transfer coefficient and the mass transfer coefficient of U in the weathered soil show that the uranium pollution in the soil mainly comes from the exogenous uranium input from the source of pollution. Four. In general, the pollution sources of uranium tailings and uranium waste rocks are obviously decreasing from the near and far away from the pollution sources. In the middle of the soil, the peak value of the active uranium in the surrounding soil is increased, the proportion of the active state of the active state of U is increased, the proportion of the potential active U is reduced. With the increase of depth, the active uranium in different soil profiles has a decreasing trend, and the potential active uranium has an increasing trend. Five, uranium tailings and the surrounding pollution profiles of uranium waste rocks. The average proportion of active uranium is higher than the background section. The average proportion of potential active uranium, except the most polluted Fp1, is lower than the background section. Six. In general, the soil around the uranium tailings and the waste rock pile is closer to the source of pollution, the greater the input flux of U in the soil source, and a large amount of exogenous U in the near source area. In the 7 polluted sections, the average active uranium in the surrounding soil section of the tailings is over 40%, and the potential active uranium is over 90%, and the U around half and above the soil around the waste rock pile is active, and the potential activity is in addition to the potential activity. Seven The soil has become a new and more active source of pollution at the same time, and the impact on the ecological environment should be paid full attention to. Eight, the soil U and pH, organic matter, constant elements (SiO2, TFe2O3, P2O5, etc.) have good correlation.
【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)】：X53;X75
【參考文獻(xiàn)】
相關(guān)期刊論文 前2條
1 巫聲揚(yáng);王德生;;川北陸相砂巖型鈾礦床成巖與成礦過(guò)程中有機(jī)質(zhì)對(duì)鈾的富集作用[J];鈾礦地質(zhì);1991年05期
2 孫賽玉;周青;;土壤放射性污染的生態(tài)效應(yīng)及生物修復(fù)[J];中國(guó)生態(tài)農(nóng)業(yè)學(xué)報(bào);2008年02期
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