基于PHREEQC模拟分析Na_(2)S_(2)O_(4)对退役铀矿山采区地下水生态的修复  

Ecological Restoration of Groundwater in Decommissioned Uranium Mining Area by Na_(2)S_(2)O_(4)Based on PHREEQC Simulation

作　　者：王晓玭[1] WANG Xiaopin(College of Science and Technology,Nanchang University,Nanchang 330000,China)

机构地区：[1]南昌大学科学技术学院,南昌330000

出　　处：《有色金属（冶炼部分）》2024年第4期94-101,共8页Nonferrous Metals（Extractive Metallurgy)

基　　金：江西省教育厅科学技术研究项目(191558);江西省高等学校教学改革研究课题(JXJG-21-30-5)。

摘　　要：酸法原位地浸采铀作为回收铀资源首选工艺,不可避免会存在部分铀进入地下水污染生态环境,而采用还原剂Na_(2)S_(2)O_(4)将游离的铀还原固定可高效解决此类问题。为此,针对某酸法地浸采铀退役铀矿山地下水铀污染,采用PHREEQC模拟分析Na_(2)S_(2)O_(4)还原固定地下水中可溶性铀的机制,讨论NaHCO_(3)在Na_(2)S_(2)O_(4)还原固定可溶性铀的影响。模拟结果表明:1)该区域地下水中铀以U(Ⅵ)为主,其中UO_(2)SO_(4)、UO_(2)^(2+)和UO_(2)(SO_(4))_(2)^(2-)为优势物种,分别占63.60%、32.35%和3.89%;2)Na_(2)S_(2)O_(4)还原固定可溶性铀时,会降低地下水Eh值和Fe(Ⅲ)浓度,增强地下水还原性,促进沥青铀矿和黄铁矿沉淀,但会造成地下水酸化和高SO_(3)^(2-)浓度;3)NaHCO_(3)+Na_(2)S_(2)O_(4)在还原固定可溶性铀时,减轻了地下水酸化,增强了对U(Ⅵ)和SO_(3)^(2-)的去除,对Na_(2)S_(2)O_(4)还原固定可溶性铀的影响较小,在Na_(2)S_(2)O_(4)和NaHCO_(3)浓度比为1∶1至1∶1.5时修复效果最佳。Acid in-situ leaching of uranium is the preferred process for recovering uranium resources,some uranium will inevitably flow into groundwater and pollute the ecological environment.However,the reduction and fixation of free uranium with the reductant Na_(2)S_(2)O_(4)can effectively solve this problem.Therefore,the mechanism of Na_(2)S_(2)O_(4)reduction and fixation of soluble uranium in the groundwater of a decommissioned uranium mine in the acid leaching method was simulated and analyzed using PHREEQC,and the influence of NaHCO_(3)on Na_(2)S_(2)O_(4)reduction of fixed soluble uranium was discussed.The simulation results show that:1)U(Ⅵ)is the dominant uranium in the groundwater of this area,in which UO_(2)SO_(4),UO_(2)^(2+)and UO_(2)(SO_(4))_(2)^(2-)are the dominant species,accounting for 63.60%,32.35%and 3.89%respectively.2)The reduction of fixed soluble uranium by Na_(2)S_(2)O_(4)can reduce the Eh value and Fe(Ⅲ)concentration of groundwater,enhance the reducibility of groundwater,and promote the precipitation of uraninite and pyrite,but cause acidification and high SO_(3)^(2-)concentration of groundwater.3)When reducing fixed soluble uranium,NaHCO_(3)+Na_(2)S_(2)O_(4)alleviates groundwater acidification,enhances the removal of U(Ⅵ)and SO_(3)^(2-),and has little effect on the reduction of fixed soluble uranium by Na_(2)S_(2)O_(4).The optimum remediation effect is achieved when the concentration ratio of Na_(2)S_(2)O_(4)to NaHCO_(3)is between 1∶1 and 1∶1.5.

关 键 词：退役铀矿山 Na_(2)S_(2)O_(4) 还原固定铀 PHREEQC 反应路径模拟 

分 类 号：X52[环境科学与工程—环境工程] X591