| Rubidium,cesium and its compounds have a wide range of applications,and China has a wealth of brine（salt lake brine,underground brine,oil and gas field water）resources,which contains rubidium and cesium with mining value.In order to resolve a difficult problem that is analyse and recovery rubidium,cesium from brine.Firstly,a new analytical method for the simultaneous determination of rubidium and cesium in high salt brine by inductively coupled plasma-optical emission spectrometry（ICP-OES）was developed in this thesis.Secondly,the seperation of rubidium and cesium from brine by saponified extraction system "t-BAMBP+D80 oil solvent" was researched,then the experiment of extracting-washing-back extraction was carried out.The relevant technological parameters were obtained,and the main conclusions presented in this work were summarized as follows:（1）the analysis of trace rubidium and cesium in high salinity brine by inductively coupled plasma-optical emission spectrometer（ICP-OES）was carried out in this work.Results showed that there isn’t obvious spectral interference for cesium at 894.347 nm,while a strong argon interfering spectral line exists for rubidium at 780.027 nm,and this interference can be well solved by proper spectral line calibration.Co-existing Na+,K+,Ca2+and Mg2+ions in brine had serious positive interference for rubidium and cesium determination by ICP-OES.Based on the fitting equations of co-existing ions on the interference of rubidium and cesium measurement,the addition of moderate NaCl into the standard series solutions can well match the co-existing NaCl,KCl,CaCl2 and MgCl2 in brine,by which it can realize the quick and accurate determination of trace rubidium and cesium in brine by standard curve method.The analysis of underground brine samples from Dazhou,Sichuan.Results showed that the recoveries for rubidium and cesium were at the range of 106.7%～112.8%and 108.0%～112.5%,the relative standard deviation were respectively 1.46%and 2.47%,and the detection limits were respectively 0.013 mg/L and 0.018 mg/L.（2）The saponified extraction system "t-BAMBP+D80" with NaOH solution was used to separate and extract rubidium and cesium from brine,meanwhile separation of rubidium and cesium with extraction and back-extraction in simulated brine（Rb+0.8 g/L,Cs+0.2 g/L）were carried out.Under the preferable optimum extraction conditions（organic phase composition 30%t-BAMBP+70%D80,saponifier concentration of NaOH 0.6 mol/L,saponification mole ratio=4/1,extraction phase ratio（O/A）=3/1,reverse extractant concentration of HC1 0.2 mol/L,back-extraction phase ratio（O/H）=5～6/1）.The conclusions were as follows,the single-stage extraction rate of rubidium and cesium reached 85.05%and 98.78%,respectively.Meanwhile,the single-stage back-extraction rate was 86.19%and 82.75%,respectively.According to this research,the better extraction and back-extraction results of rubidium and cesium were obtained.The presence of potassium ions in brine will bring a certain influence to extract rubidium and cesium,consequently,the elution of potassium ions must be carried out in the loaded organic phase after extraction.The presence of calcium and magnesium ions makes it necessary to adjust the pH of brine about 5.0 before extraction,so as to avoid precipitation during extraction.（3）The seperation of rubidium and cesium with solvent extraction were carried out for the underground brine in Dazhou,Sichuan.Firstly,cesium separation with extraction,water washing,back-extraction was conducted.Under the optimum extraction conditions（brine pH=5.0,organic phase composition 30%t-BAMBP+70%D80,saponifier concentration of NaOH 0.5 mol/L,saponification ratio（O/OH）=1/1,extraction phase ratio（O/A）＝1/1,water washing phase ratio（O/A’）=2/1,water washing stage 2,reverse extractant concentration of HC1 0.1 mol/L,back-extraction phase ratio（O/H）=5～6/1）.The conclusions were as follows,single-stage extraction rate of cesium reached 72.78%,it reduced 26.00%compared with the simulated brine system（Rb+0.8 g/L,Cs+0.2 g/L）,while rubidium and potassium was 12.06%and 7.33%,respectively.The separation coefficient of cesium and potassium were 33.80.the elution rates of rubidium and potassium were 111.67%and 106.84%,respectively,while cesium was 13.70%after the second-stage water washing.the single-stage back-extraction rate of cesium was 47.00%.Secondly,rubidium separation with extraction,alkali washing,back-extraction was conducted.Under the better extraction conditions of rubidium after extracted cesium（brine pH=5.0,organic phase composition 30%t-BAMBP+70%D80,saponifier concentration of NaOH 0.8 mol/L,saponification phase ratio（O/OH）=1/1,extraction phase ratio（O/A）=2/1,alkali washing concentration 0.1 mol/L NaON solution,alkaline washing phase ratio（O/A ’）=3/1,alkaline washing stage 3,reverse extractant concentration of HC1 0.1 mol/L,back-extraction phase ratio（O/H）=5～6/1,back-extraction stage 3）.The conclusions were as follows,single-stage extraction rate of rubidium was 47.44%,which was lower than the simulated brine system about 37.61%.The single-stage extraction rate of potassium was kept at a low level of 4.33%,the separation coefficient of rubidium and potassium was 19.96.the third—stage elution rate of potassium was 111.43%and rubidium was 18.58%.the third-stage back-extraction rate of rubidium was 77.31%.potassium ions will effect the extraction of rubidium and cesium,the elution of potassium ions must be carried out in the loaded organic phase after extraction.Through the above experimental research,the separation and extraction of rubidium and cesium in brine can be realized,which is of great significance to the comprehensive utilization of brine. |
