含铀煤燃烧底灰中铀的形态分布及其影响因素研究
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摘要
以云南临沧的含铀褐煤为研究对象,在实验室模拟燃烧试验,考察了不同温度、时间、原煤粒径和是否加入CaO 4种燃烧控制条件下煤的燃烧过程,并采用逐级提取法分析了燃煤底灰中铀的赋存形态,讨论了不同燃烧条件下燃煤底灰中不同赋存形态铀的含量及其相互转化关系。结果表明:燃煤底灰中铁锰氧化物结合态铀和残渣态铀的含量随燃烧温度的升高而增加,碳酸盐结合态铀的含量随燃烧温度的升高而减小;在600℃、不同条件下的原煤燃烧过程中,燃煤底灰中碳酸盐结合态铀和铁锰氧化物结合态铀的质量随燃烧时间的增加逐渐增加,有机物结合态铀和残渣态铀的质量随燃烧时间的增加逐渐减少;原煤粒径较小时,在燃烧过程中易形成飞灰而降低各种赋存形态铀在燃煤底灰中的含量;在原煤燃烧过程中,加入适量CaO会提高燃煤底灰中除离子交换态铀外的各种赋存形态铀的含量,使燃煤底灰中的铀富集。
Taking the uranium-bearing lignite from Lincang,Yunnan Province as the research object,this paper investigates the combustion process of coal under different temperature,time,particle size of raw coal and the addition of CaO in the laboratory simulation combustion test.The paper adopts the sequential extraction procedures to analyze the species of uranium in the bottom ash and discusses the relationship between the mass of uranium in the bottom ash and combustion conditions.The results show that the mass of uranium bound to Fe-Mn oxides and residual in the bottom ash increases while that of uranium bound to carbonate decreases with temperature increasing.In the process of combustion at 600℃ with different conditions,the uranium mass of carbonate-bound state and iron-manganese oxide-bound state in coal-fired bottom ash increases with time,while the uranium mass of organic matter-bound state and residual state decreases with time.It is easier to form fly ash and reduce the content of uranium in bottom ash in the combustion process when particle size is smaller.Adding an appropriate amount of calcium oxide improves the content of all uranium species except exchangeable uranium,which resultes in the uranium enrichment in the bottom ash.
Taking the uranium-bearing lignite from Lincang,Yunnan Province as the research object,this paper investigates the combustion process of coal under different temperature,time,particle size of raw coal and the addition of CaO in the laboratory simulation combustion test.The paper adopts the sequential extraction procedures to analyze the species of uranium in the bottom ash and discusses the relationship between the mass of uranium in the bottom ash and combustion conditions.The results show that the mass of uranium bound to Fe-Mn oxides and residual in the bottom ash increases while that of uranium bound to carbonate decreases with temperature increasing.In the process of combustion at 600℃ with different conditions,the uranium mass of carbonate-bound state and iron-manganese oxide-bound state in coal-fired bottom ash increases with time,while the uranium mass of organic matter-bound state and residual state decreases with time.It is easier to form fly ash and reduce the content of uranium in bottom ash in the combustion process when particle size is smaller.Adding an appropriate amount of calcium oxide improves the content of all uranium species except exchangeable uranium,which resultes in the uranium enrichment in the bottom ash.
引文
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[22]张仁里.煤灰中铀的化学状态[J].燃料化学学报,1981,9(4):375-383.
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[24]Sun Y,Qi G,Lei X,et al.Distribution and mode of occurrence of uranium in bottom ash derived from high-germanium coals[J].Journal of Environmental Sciences,2016,43:91-98.
[25]Yang J,Liu D,Wang Y,et al.Release and the interaction mechanism of uranium and alkaline/alkaline-earth metals during coal combustion[J].Fuel,2016,186:405-413.
[26]喻亦林.滇西临沧褐煤放射性水平及区域污染分析[J].地球与环境,2007,35(2):147-153.
[27]吕海亮,陈皓侃,李文,等.铁岭煤中重金属元素的赋存形态及其在热解过程中的挥发行为研究[J].燃料化学学报,2004,32(2):140-145.
[28]刘东原,赵永椿,张军营,等.煤中铀及其在燃烧过程中的迁移行为研究进展[J].煤炭科学技术,2016,44(4):175-181.
[29]Zhang Y,Shi M,Wang J,et al.Occurrence of uranium in Chinese coals and its emissions from coal-fired power plants[J].Fuel,2016,166:404-409.
[30]张仁里.含铀煤灰的烧结及其对铀的包裹作用[J].铀矿冶,1986,5(1):7-14.
[31]孙晓,钱枫,魏新鲜,等.添加CaO对燃煤重金属元素富集效果的影响[J].化工环保,2016,36(2):205-210.
[2]孙淑静,刘学敏.我国粉煤灰资源化利用现状、问题及对策分析[J].粉煤灰综合利用,2015(3):45-48.
[3]陈敏敏,刘杰,李莉娜,等.基于全要素监测数据的我国燃煤电厂汞排放分析[J].安全与环境工程,2015,22(6):62-66.
[4]黄文辉,唐修义.中国煤中的铀、钍和放射性核素[J].中国煤田地质,2002(S1):56-64.
[5]Frandsen F,Dam-Johansen K,Rasmussen P.Trace elements from combustion and gasification of coal-An equilibrium approach[J].Progress in Energy&Combustion Science,1994,20(2):115-138.
[6]张卫,郝玉怀,刘普灵,等.粉煤灰和煤矸石再资源化利用中天然放射性及其对环境的影响[J].中国科学院水土保持研究所集刊,1987(6):35-42.
[7]孙中惠,郭建新,冯金仙.粉煤灰对太原市地下水造成的放射性污染[J].华北地质矿产杂志,1996,11(2):199-208.
[8]文湘闽,李建成.煤灰渣利用中对人群所产生辐射影响的评价[J].四川环境,1994(4):32-35.
[9]赵存良.邯邢矿区煤中伴生矿产及微量元素研究[D].邯郸:河北工程大学,2008.
[10]代世峰,任德贻,李生盛.煤及顶板中稀土元素赋存状态及逐级化学提取[J].中国矿业大学学报,2002,31(5):12-16.
[11]王运泉,张汝国,王良平,等.煤中微量元素赋存状态的逐提试验研究[J].中国煤田地质,1997,9(3):23-25.
[12]王起超,邵庆春,康淑莲,等.煤中15种微量元素在燃烧产物中的分配[J].燃料化学学报,1996,24(2):137-142.
[13]Wan X,Wang W,Ye T,et al.A study on the chemical and mineralogical characterization of MSWI fly ash using a sequential extraction procedure[J].Journal of Hazardous Materials,2006,134(1/2/3):197-201.
[14]Dai S,Zhao L,Peng S,et al.Abundances and distribution of minerals and elements in high-alumina coal fly ash from the Jungar Power Plant,Inner Mongolia,China[J].International Journal of Coal Geology,2010,81(4):320-332.
[15]Ito S,Yokoyama T,Asakura K.Emissions of mercury and other trace elements from coal-fired power plants in Japan[J].Science of the Total Environment,2006,368(1):397-402.
[16]高勤芬.煤及煤燃烧中痕量元素砷、溴、碘的分布研究[D].上海:上海师范大学,2008.
[17]姚多喜,支霞臣,王馨.煤及其燃烧产物飞灰和底灰中稀土元素地球化学特征及集散规律[J].地球化学,2003(5):491-500.
[18]徐旭,严建华,葛俊,等.燃煤飞灰中重金属元素分布规律的试验研究[J].热力发电,2002(1):51-53.
[19]秦攀.煤燃烧重金属生成规律的研究[D].杭州:浙江大学,2005.
[20]王馨,姚多喜,冯启言.褐煤燃烧过程中重金属元素分布特征及其对环境影响评价[J].环境科学学报,2013,33(5):1389-1395.
[21]孙晓,钱枫,魏新鲜.燃烧条件对燃煤灰渣中重金属形态分布的影响[C]//2015年中国环境科学学会学术年会论文集(第二卷).北京:中国环境科学学会,2015.
[22]张仁里.煤灰中铀的化学状态[J].燃料化学学报,1981,9(4):375-383.
[23]王馨,冯启言,方婷,等.滇东地区中-高硫煤中放射性元素铀的地球化学特征[J].煤炭学报,2015,40(10):2451-2457.
[24]Sun Y,Qi G,Lei X,et al.Distribution and mode of occurrence of uranium in bottom ash derived from high-germanium coals[J].Journal of Environmental Sciences,2016,43:91-98.
[25]Yang J,Liu D,Wang Y,et al.Release and the interaction mechanism of uranium and alkaline/alkaline-earth metals during coal combustion[J].Fuel,2016,186:405-413.
[26]喻亦林.滇西临沧褐煤放射性水平及区域污染分析[J].地球与环境,2007,35(2):147-153.
[27]吕海亮,陈皓侃,李文,等.铁岭煤中重金属元素的赋存形态及其在热解过程中的挥发行为研究[J].燃料化学学报,2004,32(2):140-145.
[28]刘东原,赵永椿,张军营,等.煤中铀及其在燃烧过程中的迁移行为研究进展[J].煤炭科学技术,2016,44(4):175-181.
[29]Zhang Y,Shi M,Wang J,et al.Occurrence of uranium in Chinese coals and its emissions from coal-fired power plants[J].Fuel,2016,166:404-409.
[30]张仁里.含铀煤灰的烧结及其对铀的包裹作用[J].铀矿冶,1986,5(1):7-14.
[31]孙晓,钱枫,魏新鲜,等.添加CaO对燃煤重金属元素富集效果的影响[J].化工环保,2016,36(2):205-210.