Release Regularity of Heavy Metals of Ion-type Rare Earth Ore Under Leaching Conditions
Ion-type rare earth deposits,which are abundant in medium and heavy rare earth elements,constitute strategic mineral resources predominantly located in Jiangxi,Fujian,Guangxi,and several other southern provinces and regions.In these deposits,rare earth elements are adsorbed onto clay minerals as hydrated cations or hydroxyl hydrated cations.Due to this specific mode of occurrence,conventional mining and beneficiation techniques are ineffective for their extraction.Consequently,the in-situ leaching method is recommended for the efficient recovery of these elements.During the leaching process,an electrolyte solution is introduced into the mineral soil to facilitate ion exchange leaching.Concurrently,heavy metal ions present in the mine soil are mobilized and transported to adjacent farmland and water bodies along with the leaching solution.This migration poses a significant environmental impact on the surrounding areas of the mine.The resultant heavy metal contamination in the soil at the leaching site severely hinders the sustainable development of ion-type rare earth resources.During the in-situ leaching process,the leaching solution engages in an ion exchange reaction with rare earth cations.Concurrently,this process displaces certain heavy metal ions,leading to the mobilization of these metals within the soil.Consequently,this mobilization can result in the contamination of both soil and groundwater with heavy metals.In this study,simulated leaching experiments of ion-type rare earth elements were conducted using three different concentrations of MgSO4 solutions(3%,6%,9%).The objective was to elucidate the impact of leaching solution concentration on the release of ion-type rare earth heavy metals,specifically Cu,Zn,Pb,and Tl.The content and influencing factors of these heavy metals were analyzed through correlation analysis and multiple linear regression analysis.The findings indicate that,under the influence of varying concentrations of MgSO4,the typical heavy metals exhibit a longitudinal migration trend.A negative correlation was observed between the concentrations of Cu,Pb,and Tl and the concentration of MgSO4,while no significant correlation was found between Zn and MgSO4 concentration.Cu was predominantly enriched in the middle soil strata,Zn in both the middle and lower soil strata,and Pb and Tl primarily in the lower soil strata.Additionally,a significant negative correlation was identified between soil pH and Eh values.Furthermore,correlations were noted between soil pH and Eh values and the concentrations of typical heavy metals.The results of this study provide a theoretical basis for the prevention and control of heavy metal pollution and green mining in the mining area.
ion-type rare earthin-situ leachingsoil environmentheavy metal pollutioncorrelation analysismultiple linear regression analysis
万方数据
维普
