硫酸化焙烧-水浸处理废稀土荧光粉工艺
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摘要
针对当前废稀土荧光粉综合回收利用率低、不当处理造成环境污染严重等问题,采用硫酸化焙烧-水浸法处理废稀土荧光粉,考察了焙烧温度对物料形态的影响及焙烧温度、浓硫酸添加量对稀土氧化物浸出效果的影响,并对该工艺进行了初步环保评估。结果表明,在焙烧温度300℃、时间120 min、浓硫酸与废粉质量比为1.85及浸出温度25℃、时间120 min、液固质量比2:1的条件下,4种稀土氧化物的回收率分别为Y2O3 98.82%, Eu2O3 97.39%, CeO2 96.58%和Tb4O7 98.77%。硫酸化焙烧可使稀土分解为可溶性的硫酸盐和磷酸盐,并保证渣为环保的低放渣。浓硫酸添加量对4种稀土氧化物浸出率影响较大,焙烧温度对CeO2和Tb4O7浸出效果影响显著,在浓硫酸与废粉质量比1.85、浸出温度25℃、时间均为120 min的条件下,CeO2和Tb4O7的浸出率分别由焙烧温度200℃时的40.18%和37.18%提高至300℃时的96.58%和98.77%。稀土荧光粉在300℃下焙烧不会产生SO2和SO3等有害气体,焙烧过程中放出的气体主要为水蒸气和挥发的硫酸,物料失重约为10%。该工艺避免了焙烧过程中产生大量含硫、含氟、强酸性废气及难溶解的焙烧废渣,同时减少了环境污染及部分稀土资源浪费,具有广阔的工业应用前景。
At present, in view of the existing problems in waste phosphor, such as lower comprehensive utilization and serious environmental pollution caused by improper handling, the method of sulfation-roasting-leaching was used to pre-treatment waste phosphor according to its problems to explore the effect of roasting temperature on the form of materials, roasting temperature and concentrated sulfuric acid addition on rare earth leaching. A preliminaryenvironmental assessment of the process was carried out. The results showed that with the optimum leaching conditions which were roasting temperature of 300℃, roasting time of 120 min, concentrated sulfuric acid-waste phosphor mass ratio of 1.85, leaching temperature of 25 ℃, leaching time of 120 min and liquid-solid mass ratio of 2:1, the sulfationroasting-leaching rate of rare earth oxides were Y2 O3 98.82%, Eu2 O3 97.39%, CeO2 96.58% and Tb4 O7 98.77%. The material after sulfation-roasting-leaching indicated that sulfation-roasting can decompose rare earth into soluble sulfate and phosphate, and ensure that the slag was environmentally friendly and low slag. Concentrated sulfuric acid addition gave greater impact on the leaching of four kinds of rare earth, while roasting temperature brought larger influence on the leaching of CeO2 and Tb4 O7, leaching rates increased from 40.18% and 37.18% at 200 ℃ to 96.58% and 98.77% 300 ℃, respectively. Waste phosphor calcined at 300 ℃ will not produce harmful gases such as SO2 and SO3 through the discussion of the emission of gas during the roasting process, the main gases released during roasting were water vapor and volatile sulfuric acid, and the material loss was about 10%. This process avoided the production of a large amount of sulfur-containing, fluorine-containing, strongly acidic waste gas and refractory roasting waste residue in the roasting process, and reduced environmental pollution and waste of rare earth resource, the new process has good prospects for industrial applying.
At present, in view of the existing problems in waste phosphor, such as lower comprehensive utilization and serious environmental pollution caused by improper handling, the method of sulfation-roasting-leaching was used to pre-treatment waste phosphor according to its problems to explore the effect of roasting temperature on the form of materials, roasting temperature and concentrated sulfuric acid addition on rare earth leaching. A preliminaryenvironmental assessment of the process was carried out. The results showed that with the optimum leaching conditions which were roasting temperature of 300℃, roasting time of 120 min, concentrated sulfuric acid-waste phosphor mass ratio of 1.85, leaching temperature of 25 ℃, leaching time of 120 min and liquid-solid mass ratio of 2:1, the sulfationroasting-leaching rate of rare earth oxides were Y2 O3 98.82%, Eu2 O3 97.39%, CeO2 96.58% and Tb4 O7 98.77%. The material after sulfation-roasting-leaching indicated that sulfation-roasting can decompose rare earth into soluble sulfate and phosphate, and ensure that the slag was environmentally friendly and low slag. Concentrated sulfuric acid addition gave greater impact on the leaching of four kinds of rare earth, while roasting temperature brought larger influence on the leaching of CeO2 and Tb4 O7, leaching rates increased from 40.18% and 37.18% at 200 ℃ to 96.58% and 98.77% 300 ℃, respectively. Waste phosphor calcined at 300 ℃ will not produce harmful gases such as SO2 and SO3 through the discussion of the emission of gas during the roasting process, the main gases released during roasting were water vapor and volatile sulfuric acid, and the material loss was about 10%. This process avoided the production of a large amount of sulfur-containing, fluorine-containing, strongly acidic waste gas and refractory roasting waste residue in the roasting process, and reduced environmental pollution and waste of rare earth resource, the new process has good prospects for industrial applying.
引文
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[16]唐永波,朱宪忠,王海波,等.BaMgAl10O17:Eu蓝色荧光粉的研究进展[J].材料导报,2006,20(专辑VI):335-338.Tang Y B,Zhu X Z,Wang H B,et al.Progress in research on barium magnesium aluminate[J].Materials Review,2006,20(VI):335-338.
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[18]李解,王少炳,李保卫,等.微波辅助硫酸低温焙烧稀土精矿试验研究[J].稀土,2013,34(6):45-50.Li J,Wang S B,Li B W,et al.Microwave-assisted decomposition of rare earth concentrate with sulfuric acid at low temperature[J].Chinese Rare Earths,2013,34(6):45-50.
[19]王秀艳,李梅,许延辉,等.包头稀土精矿浓硫酸焙烧反应机理研究[J].湿法冶金,2006,25(3):134-137.Wang X Y,Li M,Xu Y H,et al.Study on decomposition mechanism of rare earth concentrate by concentrated sulfuric acid[J].Hydrometallurgy of China,2006,25(3):134-137.
[2]朱凯,侯仰龙.稀土永磁纳米材料的控制合成及其磁学性能[J].稀有金属,2017,41(5):466-474.Zhu K,Hou Y L.Controllable synthesis of rare-earth based permanent magnetic nanomaterials and their magnetic properties[J].Chinese Journal of Rare Metals,2017,41(5):466-474.
[3]廖春发,曾颜亮,焦芸芬.从废旧稀土荧光粉中回收稀土的研究现状[J].稀有金属与硬质合金,2013,41(6):7-12.Liao C F,Zeng Y L,Jiao Y F.The latest development of rare earth recovery from waste rare eareh phosphors[J].Rare Metals and Cemented Carbides,2013,41(6):7-12.
[4]李雨,徐欣欣,雷鹰,等.机械活化浸出废荧光粉中稀土氧化物实验研究[J].稀土,2016,37(5):72-78.Li Y,Xu X X,Lei Y,et al.Research on the mechanical activation leaching of reos from waste fluorescent powder[J].Chinese Rare Earths,2016,37(5):72-78.
[5]赵卓,徐桂丽.废弃荧光粉中稀土元素的回收技术现状与发展趋势[J].中国稀土学报,2015,33(6):641-649.Zhao Z,Xu G L.Present situation and development trend of technology of rare earth elements in waste phosphor[J].Journal of the Chinese Socity of Rare Earths,2015,33(6):641-649.
[6]李宏煦,王帅,李超.稀土元素回收技术及其生命周期循环分析[J].稀有金属,2016,40(9):945-954.Li H X,Wang S,Li C.Recycling and life cycle analysis of rare earth elements[J].Chinese Journal of Rare Metals,2016,40(9):945-954.
[7]Hirajima T,Bissombolo A,Sasaki K,et al.Floatability of rare earth phosphors from waste fluorescent lamps[J].International Journal of Mineral Processing,2005,77(4):187-198.
[8]Mei G,Rao P,Matsuda M,et al.Separation of red(YO:Eu),blue(BaMgAlO:Eu)and green(CeMgAlO:Tb)rare earth phosphors by liquid/liquid extraction[J].Journal of Wuhan University of Technology(Materials Science Edition),2009,24(4):603-607.
[9]Otsuki A,Mei G,Jiang Y,et al.Solid-solid separation of fluorescent powders by liquid-liquid extraction using aqueous and organic phases[J].Resources Processing,2006,53(3):121-133.
[10]Hirajima T,Sasaki K,Bissombolo A,et al.Feasibility of an efficient recovery of rare earth-activated phosphors from waste fluorescent lamps through dense-medium centrifugation[J].Separation and Purification Technology,2005,44(3):197-204.
[11]申星梅,李辽沙,武杏荣,等.废弃CRT荧光粉中稀土的提取工艺与技术[J].化工学报,2015,66(4):1498-1505.Shen X M,Li L S,Wu X R,et al.Recovery of rare earth from waste CRT phosphor[J].CIESC Journal,2015,66(4):1498-1505.
[12]李洪枚.从废稀土荧光粉中酸浸回收稀土的研究[J].稀有金属,2010,34(6):110-116.Li H M.Recovery of rare earths from phosphor sludge by acid leaching[J].Chinese Journal of Rare Metals,2010,34(6):110-116.
[13]吴玉锋,贾平平,王维,等.从废弃CRT荧光粉中熔浸稀土元素的研究[J].中国稀土学报,2013,31(6):723-727.Wu Y F,Jia P P,Wang W,et al.Leaching of rare earth elements from waste fluorescent powder of cathode ray tube by molten salts[J].Journal of the Chinese Socity of Rare Earths,2013,31(6):723-727.
[14]张兆雪,王瑞祥,熊家春,等.碱熔预处理对废旧稀土荧光粉中稀土提取的影响[J].有色金属科学与工程,2016,7(6):129-135.Zhang Z X,Wang R X,Xiong J C,et al.Effect of alkaline fusion pretreatment on extraction rate of rare earth from waste rare earth fluorescent powder[J].Nonferrous Metals Science and Engineering,2016,7(6):129-135.
[15]章启军,吴玉锋,程会强,等.稀土荧光粉回收利用技术研究现状与发展趋势[J].环境污染与防治,2013,35(8):79-83.Zhang Q J,Wu Y F,Cheng H Q,et al.Research status and developing tendency of the recycling technologies of rare earth phosphors[J].Environmental Pollution and Control,2013,35(8):79-83
[16]唐永波,朱宪忠,王海波,等.BaMgAl10O17:Eu蓝色荧光粉的研究进展[J].材料导报,2006,20(专辑VI):335-338.Tang Y B,Zhu X Z,Wang H B,et al.Progress in research on barium magnesium aluminate[J].Materials Review,2006,20(VI):335-338.
[17]马莹,许延辉,常叔,等.包头稀土精矿浓硫酸低温焙烧工艺技术研究[J].稀土,2010,31(2):20-23.Ma Y,Xu Y H,Chang S,et al.Study on the decomposition of Baotou rare earth concentrate[J].Chinese Rare Earths,2010,31(2):20-23.
[18]李解,王少炳,李保卫,等.微波辅助硫酸低温焙烧稀土精矿试验研究[J].稀土,2013,34(6):45-50.Li J,Wang S B,Li B W,et al.Microwave-assisted decomposition of rare earth concentrate with sulfuric acid at low temperature[J].Chinese Rare Earths,2013,34(6):45-50.
[19]王秀艳,李梅,许延辉,等.包头稀土精矿浓硫酸焙烧反应机理研究[J].湿法冶金,2006,25(3):134-137.Wang X Y,Li M,Xu Y H,et al.Study on decomposition mechanism of rare earth concentrate by concentrated sulfuric acid[J].Hydrometallurgy of China,2006,25(3):134-137.