CHANGES OF PROCESS MINERALOGY OF PYRITE AND THE IMPACT ON IN-SITU NEUTRAL LEACHING EFFICIENCY FROM THE MENGQIGUER U-RANIUM DEPOSIT
Pyrite is one of the most prevalent minerals in sandstone-type uranium deposits.Investigating the mineralogy of pyrite before and after CO2+O2 neutral leaching holds significant importance for deter-mining uranium leaching parameters and evaluating the prospect of uranium leaching exploitation.Focu-sing on the Mengqiguer sandstone-type uranium deposit in the Yili Basin,this study conducts a neutral(CO2+O2)pressure stirring test on ore-bearing samples from the deposit.The technological mineralogy characteristics of pyrite before and after leaching are analyzed using TIMA and SEM-EDS.The findings reveal that pyrite in the raw ore exhibits a relatively complete crystalline form and is associated with quartz and coffinite.Post-leaching,pyrite undergoes dissolution,resulting in a decrease in its content from 0.46％to 0.01％.Furthermore,the proportion of pyrite particles smaller than 20 pm increases signifi-cantly from 21.77％to 55.89％.The percentage of pyrite with a dissociation degree exceeding 50％de-creases from 58.54％to 26.25％,leaving only a small amount of uranium in the pores within quartz,feld-spar,and other mineral particles.This indicates that the pyrite present in the Mengqiguer uranium deposit is conducive to in-situ leaching of uranium.However,the divalent sulfur in pyrite is prone to reacting with oxygen,consuming a considerable amount of oxygen,resulting in the sluggish dissolution of pyrite and an increase in oxygen consumption during uranium leaching.Therefore,the development of an oxidizer that can selectively react with pyrite in actual in-situ leaching is crucial to reduce the cost of in-situ leaching and enhance uranium leaching efficiency.
Mengqiguer sandstone type uranium depositprocess mineralogyneutral leachingpyrite
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