Optimal conditions of sorption concentration of perrhenate-ions with activated carbon have been considered. The possibility of rhenium determination with accompanying element is show

Buynovskiy, A. S.

Kolpakova, Nina Alexandrovna

Melnikova, I. A.

Electronic archive of Tomsk Polytechnic University

REFERENCES1. Slepchenko E.S., Karbainov Yu.A., Slepchenko G.B., AnisimovaL.S. Voltamperometric research of azithromycin dihydrate electrochemical dependence // Izvestiya Vuzov. Khimiya i Khimicheskaya Tekhnologiya. – 2004. – V. 47. – № 9. – P. 6–9.2. ITM – Innovations, technologies, materials. Chemical analysis: voltamperometric complex «STA», [electronic resource]: – Access mode: http://itm.tomsk.ru3. Nigovic Biljana. Adsorptive stripping voltammetric determination ofazithromycin at a glassy carbon electrode modified by electrochemicaloxidation // Analytical Sciences. – 2004. – V. 20. – № 4. – P. 639–643.4. Mayranovskiy S.G. Catalytic and kinetic waves in polarography. –Moscow: Nauka, 1966. – 288 p.5. Success of organic compound electrochemistry / Ed. by S.G. Mayranovskiy. – Moscow: Nauka, 1966. – 115 p.6. Karbainov Yu.A., Karbainova S.N., Mamaeva V.A., Biryukov M.S.,Ivanovskaya E.A., Bobleva Yu.V. Adsorption of sodium humate, cordanum, verapamile at mercuryfilm electrode // Elektrokhimiya. –2002. – V. 38. – № 12. – P. 1438–1500.7. Mayranovskiy S.G., FilonovaKrasnova A.D. Polarographic kineticcurrents limited by interaction rate of σbromo carboxylic acids withelectrode mercury // USSR AS Bulletin. Chemical series. – 1967. –№ 8. – P. 1973–1679.8. Karbainov Yu.A., Puchkovskaya E.S., Karbainova S.N., SlepchenkoG.B. Theoretical justification of voltamperometry method ability forstudying the adsorption of surfaceactive organic substances // Bulletin of the Tomsk Polytechnic University. – 2006. – V. 309. – № 3.– P. 118–119.Received on 18.12.2006Bulletin of the Томsк Pоlytеchnic University. 2007. V. 311. № 384The analysis of geological rhenium samples is not aneasy task owing to its low industrial contents as well as thepresence of tungsten and molybdenum accompanying toit in ores. Rather complete review by the methods of rhenium determination in mineral raw materials is given inpapers [1–3]. As rhenium is distributed nonuniformlyover the analyzed sample then its determination is notpossible without preconcentration. Sorption concentration of perrhenateions (ReO4–) with activated carbon(AC) is one of the most efficient methods of extractingReO4– from solutions with high content of nonferrousand other metals salts. Increase of determination sensitivity is not the only and often not the main reason of concentration use. Concerning the method of Xray fluorescence analysis (XFA) the concentration allows solvingand decreasing acuity of the problem of obtaining calibration characteristics at singletype matrices [4].The aim of the given work was to determine optimalconditions of perrhenateions sorption concentration atactivated carbon and develop the technique of Xrayfluorescence rhenium determination in crude ore.Experimental partTo study sorption characteristics the standard nitricacid solution Re(VII) in 3М HNO3 with concentrationof 100 mg/dm3 was used. After metal rhenium dissolution it is in solution in the form of perrhenateion(ReO4–).Model mixtures containing different quantities ofReO4– ions were prepared by 3М HNO3 dilution on theday of analysis. ReO4– sorption was carried out at activated carbon of BAUA type with total pore water volumenot less than 1,6 cm3/g and iodine adsorption activitynot less than 60 %. For more uniform concentrationsorbent granules were ground to powder in agathic mortar to the size of 50 mkm.Influence of time contact of sorbent with solutionon completeness of sorption of BAUA ions was studiedunder the affect of ultraviolet radiation (UVR) of solutions and without it. Mercury lamp of high pressureDRT220 without filter was used as a source of UVR.Distance from radiation source to the samples is 20 cm.Sorption of perrhenateions was carried out in staticconditions. For this purpose 0,3 g of BAUA was put into solution with volume of 10 ml. After concentrationsorbent with sorbtive were filtered, the remainder wasdried. Quantity of sorbed perrhenateions was determined by the method of XFA [5] using spectrometer«Spectroscan» (SPA «Spectron», SaintPetersburg).The parameters of Xray tube operation with molybdenum anode were as follows: voltage 40 kV, current100 mA, crystallizer LiF. Time of one measurement was200 s. Lα1, Lβ2 served as analytic lines at rhenium determination. Fluorescence radiation intensity at the statedlines was defined by subtracting the magnitude of background intensity.UDC 543.253DETERMINING RHENIUM IN CRUDE ORE BY THE METHOD OF XRAY FLUORESCENCE ANALYSISA.S. Buynovskiy*, N.A. Kolpakova, I.A. MelnikovaTomsk Polytechnic UniversityEmail: nak@anchem.chtd.tpu.ru*Seversk State Technological Academy, SeverskEmail: oep@ssti.ruOptimal conditions of sorption concentration of perrhenateions with activated carbon have been considered. The possibility of rheniumdetermination with accompanying element is shown.Sorption completeness was controlled analyzing filtrate at voltamperometric analyzer ТА1 (SPA «Takhnoanalit», Tomsk) by the method of inverse voltamperometryby the technique [6]. Threeelectrode cell in which mainelectrode represents graphite electrode impregnated bypolyethylene prepared by the technique was used [6]. Saturated chloridesilver electrode served as the referenceone. Platinum electrode was used as an auxiliary one.Results and discussionTaking out the experiments solution pH, process duration, UVR action were varied. As AC is capable of sorbing perrhenateions from acid and alkaline solutions,pH of solutions containing perrhenateions was changed from 0,5 to 13 adding concentrated solutions ofHNO3 and NaOH. Sorbent was researched after sorption by the method of XFA. It was stated that activatedcarbon has a pronounced dependence of sorbent capacity on pH of analyzed solution. Optimal value of pH atwhich static exchange capacity BAUA by perrhenateions achieves maximal value amounts to 1,5...2,5.One more factor influencing the completeness ofperrhenateion sorption with activated carbon is contacttime of sorbent with solution. After treating experimental data it was stated that the most complete sorptionconcentration of perrhenateions at BAU is achievedduring 90 min of sorption. The possibility of intensifyingthe process of sorption due to sorption process carryingout from solutions irradiated by ultraviolet was studied.The data of changing sorption kinetics of perrhenateions from nitroacid solutions of AC of BAUA typewithout solution irradiation and at UVR influence aregiven in Fig. 1. As it is seen from the Figure already after 10 min of radiation perrhenateions are sorbed byAC almost completely 95...99 %. Within the same period of time perrhenateions sorption without UVR does not exceed 80 %. The fact that complete extraction ofRe(VII) by AC is possible without UVR but for longerperiod of time allows supposing that in natural conditions rhenium ion sorption may also occur owing to solution irradiation with light from visible spectrum.Fig. 1. Kinetics of perrhenateions sorption from nitroacid solutions of AC of BAUA type. Solution volume is 10 ml,sorbent mass is 0,3 g: 1) at UVR; 2) without influenceAdsorptive processes coursing at AC may be describedmathematically by different isotherms. Determination ofthe type of adsorptive isotherm allows describing sorptionmechanism, determining sorbent sorption capacity.Sorption isotherm was plotted using solutions withconcentration 50, 100, 150, 200, 250, 300, 350, 400,450 mg/dm3. BAUA batch amounted to 0,3 g. Sorptionwas carried out during 10 min with UVR.To plot sorption isotherm it is necessary to calculateГ adsorption in equilibrium conditions of sorption process. Quantity of sorbed substance was calculated by theformula (1) by the experimental data.(1)where Аэксп is the experimental rhenium adsorption, Сначis the initial rhenium concentration in solution, mg/l,Сравн is the residual rhenium content in solution aftersorption, mg/l, m is AC mass equal to 0,3 g, V is the volume of solution for sorption, l.On the basis of the data calculated by the formula(1) the sorption isotherm was plotted, Fig. 2.Fig. 2. Sorption isotherm of perrhenateions with activated carbonThe character of sorption isotherm given in Fig. 2does not allow indicating definitely the type of adsorptive isotherm. Therefore, the experimental data were treated by the equation of Langmuir and Freundlich intheir linear form.As a result of calculations the Freundlich isothermwas plotted however the Freundlich equation turned outto be not appropriable for describing rhenium sorptionas the dependence is nonlinear.To check out the possibility of describing sorptionprocesses by Langmuir isotherm:where А is the quantity of adsorbed substance; А∞ is thecapacity of monolayer, k is the constant; Сравн is theequilibrium concentration.Let us introduce the notations: then the equation has a form у=ax+b.Isotherm of perrhenateion sorption with AC calculated by the Langmuir equation is given in Fig. 3.ðàâí ðàâí1Ñ ÑÀ k À À∞ ∞= +⋅ðàâí1 1; ; ,Cà b yÀ À k À∞ ∞= = =⋅ðàâí ðàâí1 ,Ñ ÑÀ kÀ À∞ ∞= +00,010,020,030,040,050,060,070,080,090 0,02 0,04 0,06 0,08 0,1C, ?????/??,?????/?íà÷ ðàâíýêñï ,Ñ ÑÀ Vm−= ⋅505560657075808590951000 50 100 150 200 250?????, ???.????????????????????????????????-????, % 12Quantity of sorbed perrhenateion, %Time, min.Сhemistry85Fig. 3. Langmuir isotherm in linear coordinates for rhenium sorptionStatic exchange capacity (SEC) of AC by rheniumА∞=0,0763 millemole/g or 14,2 mg/g was calculated.The obtained experimental data showed that fordescribing sorption of perrhenateion by AC in the range of concentrations of 0,5...100 mg/dm3 the isotherm ofmonomolecular adsorption of Langmuir may be applied.As in ores the main accompanying elements for rhenium are molybdenum, tungsten, aurum, argentum anda number of other metals their influence on the processof sorptive concentration of perrhenateions by AC wasstudied. For this purpose the solutions with content ofdifferent ratios of metals to rhenium were prepared, sorption at AC under UVR was carried out, the obtainedsystems were filtered, rhenium content in sorbent wasmeasured by the method of XFA, Table 1.Table 1. Influence of accompanying elements on the processof sorptive concentration of perrhenateions by ACAs a result of carried out works it was stated that molybdenum, aurum, argentum, copper at their ratio torhenium 100:1, 30:1, 30:1, 30:1 respectively do not influence the determination of perrhenateions by themethod of XFA therefore, rhenium determination bythe method of XFA with these elements is possible.Presence of tungsten influences rhenium determinationthough their analytic lines are not juxtaposed. Tungsteninfluence consists in absorbing rhenium fluorescent radiation and decreasing its analytical signal.Found optimal conditions of rhenium concentration at BAU (рН=1,5...2; sorption time is 10 min;UVR; SEC =14,2 mg/g) allowed developing the technique of roentgen fluorescent determination of rheniumafter its sorptive concentration by AC from nitroacidsolutions irradiated by ultraviolet [7]. The calibratingdiagrams for rhenium determining in the range of concentrations of 0,5...100 mg/l in standard solutions(Fig. 5, а) and determination of rhenium in the range ofconcentrations of 0,25...5,0 mg/l with molybdenumand tungsten were obtained (Fig. 5, b).Plotting the calibrating dependences for determining Re with W the standard solutions in which the ratio of concentration of Re to W amounts 1:50 were prepared. It is seen from Fig. 5, a that at the selectedmethod of recording W influence the calibration equation Re remains linear even at fifty fold excess of W(VI)ions in the range of rhenium concentrations from 0,5 to5 mg/dm3. Re determination at W presence at their ratio 1:1000 is possible according to the given dependence, Table 2.аbFig. 5. Calibrating diagrams for determining Re(VII) andRe(VII) with W(VI) (Solution volume is 10 ml,рН=1,5...2,5, sorbent mass is 0,3 g, sorption time is10 min at UVR influence): а) Re; b) Re with WThe obtained calibrating dependences allowed determining rhenium in real objects, in the given case inaurumgold raw material, Table 3. The method of inversion voltamperometry was the comparison method(TPU, Tomsk).05101520253035400 1 2 3 4 5 6?, ??/?I, ???/?01002003004005006007008009000 20 40 60 80 100C, ??/?I, ???/?Ratio Re:Me1:1 1:30 1:50 1:100IntroducedRe,mg/lFoundRe,mg/lIntroducedRe,mg/lFoundRe,mg/lIntroducedRe,mg/lFoundRe,mg/lIntroducedRe,mg/lFoundRe,mg/lRe : W64,1163,9662,5851,424,21 3,93 2,12 2,044,09 4,02 3,14 2,13Re : Mo65,9965,966,3366,156,23 6,03 6,02 6,036,05 6,2 6,1 6,09Re : Au108,58109,43108,3297,329,14 9,68 7,95 6,949,83 9,05 8,36 7,22Re : Pt109,45109,24107,4995,5910,1 9,76 8,04 5,758,96 9,87 8,06 5,9900,20,40,60,811,21,40 0,02 0,04 0,06 0,08 0,1 0,12?, ?????/??/?, ?/?Bulletin of the Томsк Pоlytеchnic University. 2007. V. 311. № 386Table 2. Validation of Re(VI) determination with W(VI) by themethod of XFAIt is seen from Table 3 that the obtained results coincided satisfactorily with contents found by themethod of TVA that indicates the possibility of applyingthe developed technique for determining rhenium inores with accompanying elements by the method XFA.Table 3. The results of determining Re in ores of differentcompositionDeposit Ore materialXFA С·105, %IV С·105, %Nezhdaninskoe Pyrite 7,12±0,06 7,12±0,05BokoVasilievskoe Sulfoarsenide 10,20±0,02 9,61±0,06Akzhal Sulphidized siltstone 4,18±0,03 4,21±0,03Baladzhal Black shales 0,83±0,04 0,84± 0,04Dzhumba Pyrite 0,95±0,04 0,96±0,03Bakyrchik Sulphidized siltstone 2,04±0,02 1,78±0,03BolshevikPyrite and sulfoarsenides3,16±0,02 3,17±0,05Sukhoy logSiliceouscarbonaceous siltstones0,56±0,05 0,37±0,04Nezhdaninskoe Pyrite 1,07±0,04 0,82±0,04Olimpiadinskoe Black shales 0,63±0,03 0,54±0,02Introduced ReO4–, mg/l Re:W Found ReO4–, mg/l1 1:501,2281,0150,9684 1:1003,9404,1703,9813 1:10002,9122,8762,965Сhemistry87REFERENCES1. Ermakov A.N. Analytical chemistry of rare elements. – Moscow:Nauka, 1988. – 248 p.2. Karpov Yu.A., Kim E.M., Ryazanova L.N., Shiryaeva O.A. Modernmethods of rhenium determination in «weak» products // Zavodskaya Laboratoriya. – 1990. – V. 56. – № 12. – P. 1–14.3. Losev V.N., Buiko E.V., Elsufiev E.V., Belousov O.V., TrofimchukA.K. Platinum and rhenium determination in catalyst on the basis ofaluminium oxide using silica chemically modified by NallylN’propylthiourea // Zavodskaya Laboratoriya. – 2005. – V. 71. – № 2.– P. 16–18.4. Lebedev K.B. Rhenium. – Moscow: Metallurgizdat, 1963. – 208 p.5. Kolpakova N.A., Buynovskiy A.S., Zhidkova I.A. Rhenium determination by the method of Xray fluorescent analysis // Izvestiya Vuzov. Fizika. – 2004. – № 12. – P. 147–149.6. Pat. 2247369 RF. IPC7 G01N 23/223. The way of rhenium determination in ores and ore concentrates by the method of inversion voltamperometry / N.A. Kolpakova, L.G. Goltz, O.V. Avgustinovich.Stated 03.02.2004; Published 27.02.2005, Bull. № 6. – p.: ill.7. Pat. 2272278 RF. IPC7 G01N 23/223. The way of determination ofrhenium, rhenium at molybdenum and tungsten presence by themethod of Xray fluorescent analysis / A.S. Buynovskiy, L.G. Goltz,I.A. Zhidkova, N.A. Kolpakova. Stated 22.11.2004; Published20.03.2006, Bull. № 8. – 6 p.: ill.Received on 26.10.2006

Determining rhenium in crude ore by the method of X-ray fluorescence analysis

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