Behavior of sulfate in preparation of single light rare earth carbonate by Mg(HCO_(3))_(2) precipitation method

作     者：Meng Wang Xiaowei Huang Zongyu Feng Chao Xia Deliang Meng Zonghe Yu Meng Wang;Xiaowei Huang;Zongyu Feng;Chao Xia;Deliang Meng;Zonghe Yu

作者机构：National Engineering Research Center for Rare Earth MaterialsGRINM Group Co.Ltd.Beijing 100088China GRIREM Advanced Materials Co.Ltd.Beijing 100088China General Research Institute for Nonferrous MetalsBeijing 100088China Rare Earth Functional Materials(Xiong'an)Innovation Center Co.Ltd.Baoding 071700China 

出 版 物：《Journal of Rare Earths》 (稀土学报（英文版）)

年 卷 期：2021年第39卷第7期

页      面：850-857,I0004页

核心收录：

学科分类：081702[工学-化学工艺] 0709[理学-地质学] 0819[工学-矿业工程] 08[工学] 0817[工学-化学工程与技术] 0708[理学-地球物理学] 0703[理学-化学] 

基　　金：Project supported by the National Natural Science Foundation of China(51674037,51674036) Guangxi Science and Technology Major Project(Guike-AA18242022)。 

主　　题：Rare earth sulfate Magnesium bicarbonate Rare earth carbonate Sulfate ion Complex salt 

摘      要：The precipitation of the water-leaching solution of Baotou mixed rare earth(RE) concentrate roasted with sulfuric acid using ammonium bicarbonate for producing RE carbonate produces a mass of ammonia-nitrogen wastewater because of the relatively low solubility of rare earth sulfate.To solve the serious problem of ammonia-nitrogen pollution,new precipitators need to be developed urgently so as to meet the requirements of environmental protection and impurities content of the product(SO_(4)^(2-)1.8 wt% in RE carbonates products).In this paper,we studied the effects of feeding modes on the behavior of SO_(4)^(2-) during the preparation of light RE carbonate(RE=La,Ce,Pr,Nd) from their sulfate solutions using Mg(HCO_(3))_(2) as a precipitant.The results indicate that the contents of SO_(4)^(2-) in the La and Ce precipitates using positive feeding mode exceed 16 wt% because of the formation of La_(2)(CO_(3))2.15(-SO_(4))0.85·4 H_(2)O and Ce_(2)(CO_(3))_(2).15(SO_(4))0.85·3H_(2)O,while those of the Pr and Nd precipitates are 4 wt%-5 wt% since they exist in the form of n-carbonate.The precipitates prepared using synchronous feeding mode are all RE carbonate with only 4 wt%-5 wt% of SO_(4)^(2-) enclosed in the precipitation.The content of SO_(4)^(2-) in the RE carbonate obtained using reverse feeding mode is the lowest.Among them,the content of SO_(4)^(2-) in La precipitate is only 1.40 wt%.Both synchronous and reverse feeding modes can effectively reduce the content of SO_(4)^(2-)in RE carbonate,which provides theoretical guidance for the preparation of qualified light RE carbonate products by Mg(HCO3)2 precipitation method.