Study On Occurrence,determination And Leaching Of Trace Rhenium In Sandstone-Type Uranium Deposit

Mineral resources are important material basis for the protection of national security and economic sustainable development.With the rapid development of the aerospace industry,the demand for rare and dispersed rhenium is increasing rapidly.Rhenium is one of the most scarce metals on earth.It has attracted high attention of the relevant departments of the state about how to combine mining rhenium and increase the reserves of rhenium.In this paper,a method for the determination of trace Re in sandstone-type uranium deposits by ICP-MS was established.This method effectively eliminates uranium,molybdenum and other matrix elements by using magnesium oxide sintered melting method and 103 Rh as internal standard elements.Under the optimum conditions,the detection limit for rhenium can be as low as 0.0008 ?g/L.The method was validated by a variety of standard samples,and the measured Re contents are in good agreement with the standard values.The relative standard deviation is less than 1.5% for Re contents of0.06~180.57 ?g/g,which meets the requirement of determining trace Re in sandstone type uranium deposite.It studies the redox properties of rhenium(VII)in pyrite surface by cyclic voltammetry system and studies the effects of different contact time,pH and temperature on the redox properties of rhenium,which shows rhenium is hard to be restored in sandstone type uranium deposits.To carry out the study of the adsorption of pyrite and humic acid on rhenium,the results show that pyrite and humic acid on rhenium(VII)have no obvious adsorption capacity.According to the parameters of the main components and contents,temperature,pH and pe and other parameters of the actual acid leaching sandstone type uranium deposits,the results show that the Re is not affected by acidity and ionic strength in the acid leaching sandstone type uranium deposits by using PHREEQC and mainly existes in the form ofReO4-.The presence of U in the leachate is not affected by the concentration of anions(SO42-,Cl-),but is affected by pH,which could vary with the pH of the solution.At the pH of 2.0~5.0,and the main form is UO2SO4.At the pH of 5.0~8.0,and the main form is(UO2)2CO3(OH)3-.To carry out the leaching process experiments of uranium and rhenium in sandstone type uranium deposit,it determines the leaching conditions of 5~10 g/L sulfuric acid and0.8~1.2 g/L hydrogen peroxide.By a large number of experimental data analysis,it shows that concentration range of rhenium in the rhenium-containing leaching sandstone type uranium is the 61~104 g/L.The high proportion of the anion resin can be effective enrichment of rhenium.