Study On Uranium Extraction From Saline Lake Brine

Uranium is one of the most important element in nuclear science and can be used as a strategic resource in both military and civil affairs.With the fast development of nuclear power supply,increased uranium need come across with the limited uranium reservation.There are 4.5 million tons of uranium in seawater.However,the uranium concentration in seawater was so low?about 3.5mg/L?that it is very hard and expensive to extract uranium form seawater.According to the previous research,uranium concentration in saline lake slain is 100 times higher than uranium in seawater which makes salt lake slain becomes another idea resource for uranium.There are many saline lake in our country,hence,it is meaningful to explore the uranium resource in saline lake.The object of present work was to extract mg order of uranium from the Gasikule lake water.The concentration change of uranium in different saline lake brine development phase were analyzed and brines from the potassium fertilizer production process was determine to be the optimum resource for uranium extraction.Amidoximated mesoporous silica was prepared by grafting and co-condensation method in this work,respectively.The materials were characterized by fourier transform infrared spectroscopy?FTIR?,scanning electron microscopy?SEM?,X-ray photoelectron spectroscopy?XPS?and physisorption apparatus.The effects of pH,adsorption time,initial uranium concentration,adsorbent amount and coexisting ions on uranium adsorption by amidoximated mesoporous silica were investigated.The experiments showed that the uranium adsorption ratio and capacity were improved after modification by amidoxime group.It can be deduced that uranium adsorption was the results of the N atoms of oximido-and amido-in amidoximated mesoporous silica.On this basis,the adsorption of uranium from saline lake brine on amidoximated mesoporous silica was studied.The results show that the uranium adsorption capacity can reach to 3.5 mg/g using amidoximated mesoporous silica,which was prepared by co-condensation method.Hence,amidoximated mesoporous silica can be a prospect adsorbent in extracting of uranium from saline lake brine.In order to improve the uranium adsorption,imidazole mesoporous silica was also prepared and as adsorbent to investigate in this work.This experiment offers a basic data for amidoximated imidazole mesoporous silica as absorbents in extracting of uranium from saline lake brine.Since the extremely high concentration of inorganic salts in the actual saline lake brine samples,it is unavoidable to adsorb the impurity elements even though the good selectivity of the adsorbent.To get uranium products of high purity from the actual saline lake brine samples,a technological process which containing the adsorptive preconcentration and extraction purification steps was sesigned.In this process,the mesoporous silica was used as the adsorbent,the adsorption time,the kinds and amounts of desorbents were also optimized.Tri-Butyl-Phosphate?TBP?was used to purify the uranium products.Based on the above technological process,60 mg uranium products was goy from 200 liters saline lake brine samples and the main component was analyzed as Uranyl-Nitrate Hexahydrate?UO₂?NO₃?₂·6H₂O?.