氧化钙沉淀富集低浓度硫酸稀土溶液中稀土的研究
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摘要
氧化钙沉淀富集离子型稀土矿浸出液中稀土的工艺可消除传统碳酸氢铵沉淀过程中存在的氨氮污染,同时补充镁钙复合浸取剂中消耗的钙离子,实现镁钙的有效循环。为此,本文以氧化钙作为沉淀剂,进行了无氨沉淀富集低浓度硫酸稀土溶液中稀土的研究,以期为氧化钙沉淀富集工艺提供数据基础。研究表明,当氧化钙沉淀过程终点pH为9.5时,稀土沉淀率达到99%以上。在最佳沉淀条件下,即温度为45℃、氧化钙消化液浓度为0.5 mol·L~(-1)(以氢氧根计)、加料速度为1.5 ml·min~(-1)、水洗体积为200 ml时,沉淀产物中稀土纯度达83.81%。然而溶液中硫酸根会参与配位沉淀形成碱式硫酸稀土,使得沉淀产物中SO_3含量达12.30%。为了降低沉淀产物中SO_3含量,分别采用乙酸钠、氢氧化钠、丁二酸钠溶液作为洗涤剂对氢氧化稀土滤饼进行搅拌洗涤,利用洗涤剂中阴离子与硫酸根的竞争配位作用,最终获得的沉淀产物中稀土纯度可分别提高至85.83%, 90.40%, 93.09%。可见,通过氧化钙沉淀及氢氧化钠洗涤过程的条件控制,有望获得纯度达标的离子型稀土矿混合稀土氧化物。
The process of rare earth enrichment from the leaching liquor of ion-adsorption type rare earths ore by calcium oxide precipitation could eliminate ammonia nitrogen pollution existing in the traditional precipitation process of ammonium bicarbonate. It couldsupply calcium ions for Mg-Ca compound leaching agent, realizing the effective circulation of magnesium and calcium. Therefore, in order to provide data basis for calcium oxide precipitation process, the calcium oxide was used as precipitant to enrich rare earth from low concentration rare earth sulfate solution. The study showed that the rare earth precipitation efficiency could reach more than 99% when the end pH value was 9.5 in the calcium oxide precipitation process. Moreover, it was determined that the optimum precipitation conditions in 45 ℃, a feeding speed of 1.5 ml·min~(-1), 0.5 mol·L~(-1) calcium oxide slaking solution(C_(OH~-)), 200 ml of washing water, led to 83.81% rare earth purity in the precipitate product. However, the sulfate ions would coordinate precipitation and form the alkaline rare earth sulphate, which made the content of SO_3 in the precipitate product up to 12.30%. In order to reduce the content of SO_3, sodium acetate, sodium hydroxide and sodium succinate were used as washing agentsto agitator washing the rare earth hydroxide cake. With the competitive coordination between the anion and the sulfate, the rare earth purity increased to 85.83%, 90.40% and 93.09%, respectively. Therefore, the qualified mixed rare earth oxide of ion-adsorption type rare earths ore was expected to obtain by controlling the conditions in the calcium oxide precipitation and the sodium hydroxide washing process.
The process of rare earth enrichment from the leaching liquor of ion-adsorption type rare earths ore by calcium oxide precipitation could eliminate ammonia nitrogen pollution existing in the traditional precipitation process of ammonium bicarbonate. It couldsupply calcium ions for Mg-Ca compound leaching agent, realizing the effective circulation of magnesium and calcium. Therefore, in order to provide data basis for calcium oxide precipitation process, the calcium oxide was used as precipitant to enrich rare earth from low concentration rare earth sulfate solution. The study showed that the rare earth precipitation efficiency could reach more than 99% when the end pH value was 9.5 in the calcium oxide precipitation process. Moreover, it was determined that the optimum precipitation conditions in 45 ℃, a feeding speed of 1.5 ml·min~(-1), 0.5 mol·L~(-1) calcium oxide slaking solution(C_(OH~-)), 200 ml of washing water, led to 83.81% rare earth purity in the precipitate product. However, the sulfate ions would coordinate precipitation and form the alkaline rare earth sulphate, which made the content of SO_3 in the precipitate product up to 12.30%. In order to reduce the content of SO_3, sodium acetate, sodium hydroxide and sodium succinate were used as washing agentsto agitator washing the rare earth hydroxide cake. With the competitive coordination between the anion and the sulfate, the rare earth purity increased to 85.83%, 90.40% and 93.09%, respectively. Therefore, the qualified mixed rare earth oxide of ion-adsorption type rare earths ore was expected to obtain by controlling the conditions in the calcium oxide precipitation and the sodium hydroxide washing process.
引文
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[12] Xiao Y F,Feng Z Y,Huang X W,Huang L,Chen Y Y,Liu X S,Wang L S,Long Z Q.Recovery of rare earth from the ion-adsorption type rare earths ore:II.compound leaching [J].Hydrometallurgy,2016,163:83.
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[15] Huang X W,Xiao Y F,Feng Z Y,Chen Y Y,Dong J S,Huang L,Wang L S.A kind of rare earth complex compound containing rare earth hydroxide and rare earth carbonate and its preparation method [P].China Patent:201510036591.2,2015.(黄小卫,肖燕飞,冯宗玉,陈迎迎,董金诗,黄莉,王良士.一种含氢氧化稀土和稀土碳酸盐的稀土复合化合物及其制备方法 [P].中国专利:201510036591.2,2015.)
[16] Huang R P,Wu Y X,Zhong Y M.A rare earth solution precipitator process with calcium oxide [P].China Patent:200810175913.1,2008.(黄日平,邬元旭,钟月明.氧化钙用于稀土溶液沉淀剂的生产工艺 [P].中国专利:200810175913.1,2008.)
[17] Huang X W,Yu Y,Feng Z Y,Zhao N.A method of recovery of rare earth from ionic type rare-earth ore [P].China Patent:201010128302.9,2010.(黄小卫,于瀛,冯宗玉,赵娜.一种从离子型稀土原矿回收稀土的方法 [P].中国专利:201010128302.9,2010.)
[18] Xiao Y F,Huang L,Xu Z F,Yang F L,Ye X Y.A stepwise precipitation method for recovery of rare earth from the leaching liquor of the ion adsorbed rare earth ore [P].China Patent:201510643658.9,2015.(肖燕飞,黄莉,徐志峰,杨凤丽,叶信宇.一种分步沉淀回收离子吸附型稀土矿浸出液中稀土的方法 [P].中国专利:201510643658.9,2015.)
[19] Hulett G A,Allen L E.The solubility of gypsum [J].J.Am.Chem.Soc.,1902,24(7):667.
[20] Meng X L.No-Ammonia Precipitation Enrichment Technology and Process Control of Low Concentration Rare Earth Sulfate Leaching Solution [D].General Research Institute for Nonferrous Metals,2017.37.(孟祥龙.低浓度硫酸稀土浸液无氨沉淀富集技术及过程控制 [D].北京有色金属研究总院,2017.37.)
[21] Dean J A.Lange′s Handbook of Chemistry (15th Edition) [M].New York:McGraw-Hil,1999.258.
[22] Wang J,Burken J G,Zhang X.Effect of seeding materials and mixing strength on struvite precipitation [J].Water Environment Research:A Research Publication of the Water Environment Federation,2006,78(2):125.
[23] GB/T20169-2006.Mixed rare earth oxide of ion-absorbed type rare earth ore [S].Beijing:Bejing Standards Press of China,2006.(GB/T 20169-2006.离子型稀土矿混合稀土氧化物 [S].北京:北京标准出版社,2006.)
[24] Nagy Z K,Jia W C,Fujiwara M,et al.Comparative performance of concentration and temperature controlled batch crystallizations [J].Journal of Process Control,2008,18(3):399.
[25] Li Y X,Li M ,He X B ,Hu P G,Gu Z Y.Precipitation and crystallization process of rare earth carbonate [J].Chinese Journal of Nonferrous Metals,1990,9(1):165.(李永绣,黎敏,何小彬,胡平贵,辜子英.碳酸稀土的沉淀与结晶过程 [J].中国有色金属学报,1990,9(1):165.)
[26] Shen Z,Wang G T.Colloid and Surface Chemistry [M].Beijing:Chemical Industry Press,1997.162.(沈钟,王果庭.胶体与表面化学 [M].北京:化学工业出版社,1997.162.)
[27] Zhu W,Qiu D X,Pei H Y,Zhou X Z,Zhu W C,Li J,Liu Y Z,Li D P,Zhou X M,Li Y X.Precipitation crystallization process of yttrium carbonate and size controlling yynthesis of ytterium oxide particles [J].Journal of the Chinese Society of Rare Earths,2016,34(2):180.(朱伟,邱东兴,裴浩宇,周雪珍,祝文才,李静,刘艳珠,李东平,周新木,李永绣.Y2(CO3)3的沉淀结晶过程与晶粒大小控制 [J].中国稀土学报,2016,34(2):180.)
[28] Men X L,Feng Z Y,Huang X W,Dong J S,Wang L S,Zhao L S.Impurities distributions and removal during the precipitation of rare earth sulfate with calcium oxide [J].Chinese Journal of Rare Metals,http://kns.cnki.net/kcms/detail/11.2111.TF.20170527.1128.002.html.(孟祥龙,冯宗玉,黄小卫,董金诗,王良士,赵龙胜.氧化钙沉淀硫酸稀土过程中杂质的分布与去除 [J].稀有金属,http://kns.cnki.net/kcms/detail/11.2111.TF.20170527.1128.002.html.)
[29] Metal Department of Zhongshan University.Physical and Chemical Constants of Rare Earth [M].Beijing:Metallurgical Industry Press,1978.133.(中山大学金属系.稀土物理化学常数 [M].北京:冶金工业出版社,1978.133.)
[30] Xiao Y F,Xu Z F,Wan Z H,Liao J L,Ni Z C.A method for reducing the content of sulfate in rare earth hydrogen oxide [P].China Patent:201610187379.0,2016.(肖燕飞,徐志峰,万章豪,廖家隆,倪志聪.一种降低氢氧化稀土中硫酸根含量的方法 [P].中国专利:201610187379.0,2016.)
[2] Chi R A,Tian J.Chemical and Metallurgy Process of Weathered Crust Rare Earth Ore [M].Beijing:Science Press,2006.36.(池汝安,田君.风化壳淋积型稀土矿化工冶金 [M].北京:科学出版社,2006.36.)
[3] Ding J Y.Historical review of the ionic rare earth mining:in honor of the 60 anniversary of GNMRI [J].Nonferrous Metals Science and Engineering,2012,3(4):14.(丁嘉榆.离子型稀土矿开发的历史回顾——纪念赣州有色冶金研究所建所60周年 [J].有色金属科学与工程,2012,3(4):14.)
[4] Xiao Y F,Huang X W,Feng Z Y,Liu X S,Huang L,Long Z Q.The environmental impact assessment and prospect for the ion-adsorption type rare earths ore leaching by magnesium salt [J].Journal of the Chinese Society of Rare Earths,2015,33(1):1.(肖燕飞,黄小卫,冯宗玉,刘向生,黄莉,龙志奇.镁盐浸出南方离子型稀土矿的环境影响评价及展望 [J].中国稀土学报,2015,33(1):1.)
[5] Yang X J,Lin A J,Li X L,Wu Y D,Chen Z H.China′s ion-adsorption rare earth resources,mining consequences and preservation [J].Environmental Development,2013,8:131.
[6] Gao Z Q,Zhou Q X.Contamination from rare earth ore strip mining and its impacts on resources and eco-envioronment [J].Chinese Journal of Ecology,2011,30(12):2915.(高志强,周启星.稀土矿露天开采过程的污染及对资源和生态环境的影响 [J].生态学杂志,2011,30(12):2915.)
[7] Tian J,Yin J Q,Tang X K,Chen J,Luo X P,Rao G H.Enhanced leaching process of a low-grade weathered crust elution-deposited rare earth ore with carboxymethyl sesbania gum [J].Hydrometallurgy,2013,139:124.
[8] Qiu T S,Fang X H,Cui L F,Feng Y.Behavior of leaching and precipitation of weathering crust ion-absorbed type by magnetic field [J].Journal of Rare Earths,2008,26(2):274.
[9] Xiao Y F,Huang X W,Feng Z Y,Dong J S,Huang L,Long Z Q.Progress in the green extraction technology for rare earth from ion-adsorption type rare earths ore [J].Chinese Rare Earths,2015,36(3):109.(肖燕飞,黄小卫,冯宗玉,董金诗,黄莉,龙志奇.离子吸附型稀土矿绿色清洁提取技术研究进展 [J].稀土,2015,36(3):109.)
[10] Xiao Y F,Chen Y Y,Feng Z Y,Huang X W,Huang L,Long Z Q,Cui D L.Leaching characteristics of ion-adsorption type rare earths ore with magnesium sulfate [J].Transactions of Nonferrous Metals Society of China,2015,25(11):3784.
[11] Xiao Y F,Feng Z Y,Huang X W,Huang L,Chen Y Y,Wang L S,Long Z Q.Recovery of rare earths from weathered crust elution-deposited rare earths ore without ammonia-nitrogen pollution:I.leaching with magnesium sulfate [J].Hydrometallurgy,2015,153:58.
[12] Xiao Y F,Feng Z Y,Huang X W,Huang L,Chen Y Y,Liu X S,Wang L S,Long Z Q.Recovery of rare earth from the ion-adsorption type rare earths ore:II.compound leaching [J].Hydrometallurgy,2016,163:83.
[13] Tian J,Ying J Q,Chen K H,Rao G H,Jiang M T,Chi R A.Extraction of rare earths from the leach liquor of the weathered crust elution-deposited rare earth ore with non-precipitation [J].International Journal of Mineral Processing,2011,98(3):125.
[14] Xu R G,Zhong H Y,Li Z F.A ion-adsorption type rare earth ore leaching process with non-ammonium salt [P].China Patent:201310424572.8,2013.(许瑞高,钟化云,李早发.离子吸附型稀土矿非铵盐浸取稀土的工艺 [P].中国专利:201310424572.8,2013.)
[15] Huang X W,Xiao Y F,Feng Z Y,Chen Y Y,Dong J S,Huang L,Wang L S.A kind of rare earth complex compound containing rare earth hydroxide and rare earth carbonate and its preparation method [P].China Patent:201510036591.2,2015.(黄小卫,肖燕飞,冯宗玉,陈迎迎,董金诗,黄莉,王良士.一种含氢氧化稀土和稀土碳酸盐的稀土复合化合物及其制备方法 [P].中国专利:201510036591.2,2015.)
[16] Huang R P,Wu Y X,Zhong Y M.A rare earth solution precipitator process with calcium oxide [P].China Patent:200810175913.1,2008.(黄日平,邬元旭,钟月明.氧化钙用于稀土溶液沉淀剂的生产工艺 [P].中国专利:200810175913.1,2008.)
[17] Huang X W,Yu Y,Feng Z Y,Zhao N.A method of recovery of rare earth from ionic type rare-earth ore [P].China Patent:201010128302.9,2010.(黄小卫,于瀛,冯宗玉,赵娜.一种从离子型稀土原矿回收稀土的方法 [P].中国专利:201010128302.9,2010.)
[18] Xiao Y F,Huang L,Xu Z F,Yang F L,Ye X Y.A stepwise precipitation method for recovery of rare earth from the leaching liquor of the ion adsorbed rare earth ore [P].China Patent:201510643658.9,2015.(肖燕飞,黄莉,徐志峰,杨凤丽,叶信宇.一种分步沉淀回收离子吸附型稀土矿浸出液中稀土的方法 [P].中国专利:201510643658.9,2015.)
[19] Hulett G A,Allen L E.The solubility of gypsum [J].J.Am.Chem.Soc.,1902,24(7):667.
[20] Meng X L.No-Ammonia Precipitation Enrichment Technology and Process Control of Low Concentration Rare Earth Sulfate Leaching Solution [D].General Research Institute for Nonferrous Metals,2017.37.(孟祥龙.低浓度硫酸稀土浸液无氨沉淀富集技术及过程控制 [D].北京有色金属研究总院,2017.37.)
[21] Dean J A.Lange′s Handbook of Chemistry (15th Edition) [M].New York:McGraw-Hil,1999.258.
[22] Wang J,Burken J G,Zhang X.Effect of seeding materials and mixing strength on struvite precipitation [J].Water Environment Research:A Research Publication of the Water Environment Federation,2006,78(2):125.
[23] GB/T20169-2006.Mixed rare earth oxide of ion-absorbed type rare earth ore [S].Beijing:Bejing Standards Press of China,2006.(GB/T 20169-2006.离子型稀土矿混合稀土氧化物 [S].北京:北京标准出版社,2006.)
[24] Nagy Z K,Jia W C,Fujiwara M,et al.Comparative performance of concentration and temperature controlled batch crystallizations [J].Journal of Process Control,2008,18(3):399.
[25] Li Y X,Li M ,He X B ,Hu P G,Gu Z Y.Precipitation and crystallization process of rare earth carbonate [J].Chinese Journal of Nonferrous Metals,1990,9(1):165.(李永绣,黎敏,何小彬,胡平贵,辜子英.碳酸稀土的沉淀与结晶过程 [J].中国有色金属学报,1990,9(1):165.)
[26] Shen Z,Wang G T.Colloid and Surface Chemistry [M].Beijing:Chemical Industry Press,1997.162.(沈钟,王果庭.胶体与表面化学 [M].北京:化学工业出版社,1997.162.)
[27] Zhu W,Qiu D X,Pei H Y,Zhou X Z,Zhu W C,Li J,Liu Y Z,Li D P,Zhou X M,Li Y X.Precipitation crystallization process of yttrium carbonate and size controlling yynthesis of ytterium oxide particles [J].Journal of the Chinese Society of Rare Earths,2016,34(2):180.(朱伟,邱东兴,裴浩宇,周雪珍,祝文才,李静,刘艳珠,李东平,周新木,李永绣.Y2(CO3)3的沉淀结晶过程与晶粒大小控制 [J].中国稀土学报,2016,34(2):180.)
[28] Men X L,Feng Z Y,Huang X W,Dong J S,Wang L S,Zhao L S.Impurities distributions and removal during the precipitation of rare earth sulfate with calcium oxide [J].Chinese Journal of Rare Metals,http://kns.cnki.net/kcms/detail/11.2111.TF.20170527.1128.002.html.(孟祥龙,冯宗玉,黄小卫,董金诗,王良士,赵龙胜.氧化钙沉淀硫酸稀土过程中杂质的分布与去除 [J].稀有金属,http://kns.cnki.net/kcms/detail/11.2111.TF.20170527.1128.002.html.)
[29] Metal Department of Zhongshan University.Physical and Chemical Constants of Rare Earth [M].Beijing:Metallurgical Industry Press,1978.133.(中山大学金属系.稀土物理化学常数 [M].北京:冶金工业出版社,1978.133.)
[30] Xiao Y F,Xu Z F,Wan Z H,Liao J L,Ni Z C.A method for reducing the content of sulfate in rare earth hydrogen oxide [P].China Patent:201610187379.0,2016.(肖燕飞,徐志峰,万章豪,廖家隆,倪志聪.一种降低氢氧化稀土中硫酸根含量的方法 [P].中国专利:201610187379.0,2016.)