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[en] The operation principles, construction flowsheet, and electronic control circuit of a gradient elution device are described. The device was used for the separation of rare earth elements, (Lu, Yb, Tm, Er, Ho, Y, Dy, Tb, Gd, Eu, Sm, Nd, Pr, Ce and La) on a polystyrene sulfonic acid cation exchanger by elution with hydroxyisobutyric acid. The gradient elution device was easy to operate reliable and could be used continuously for a long period of time

[en] Rare earth elements were separated by anion exchange resin(Amberlite CG 400, 200-400 mesh) using the mixture solution of methanol and nitric acid as an eluent. The mixture solution of 95% CH₃OH + 5% of 0.1M HNO₃ was used for the separation of Y³⁺, 80% CH₃OH + 20% of 0.5M HNO₃ for Sm³⁺ and Pr³⁺, 85%CH₃OH + 15% of HNO₃ for Pr³⁺ and Ce³⁺, 80% CH₃OH + 20% of 0.5M HNO₃ for Ce³⁺ and La³⁺, the flow rate was 1.0ml/min. MTB(Methyl Thymol Blue) was added into 10 ml effluent and measured the absorbance at 610nm. The detection limit of the rare earths was about 1 ppm. (Author)

[en] Known trace-matrix-separation and enrichment procedures for the refractory metals Mo and W use very time-consuming batch-techniques. This paper presents the application of a quasicontinuous liquid chromatographic (LC) technique as a step towards automated ultratrace separation. The anionic peroxo complexes from Mo(VI) and W(VI) are used for the trace-matrix-separation. Optimization of the peroxide concentration permits a complete removal of all cationic analyte traces on the HPLC-suitable cation exchanger Nucleosil SA. The high chromato-graphic efficiency also allows a direct ion chromatographic separation of the removed traces. This leads to conclusions about the contribution of the analyte traces on the trace-matrix-separation column and the limits of determination. (author). 13 refs.; 12 figs.; 5 tabs

[en] The present work concerns ion chromatrography (IC) with conductometric detection as analytical technique for controling several materials of nuclear interest by determining the chemical elements present in them. Priority has been given to the individual determination of the lanthanide elements and yttrium. Complexing agents were used as eluents for the elements studied. Several experiments were performed in which the eluent composition as well as its pH were varied, so obtaining the eluent's iso-pH and iso-concentration values for each of the lanthanide and yttrium. The importance of the presence of the ethylenediamine ion on the separation and elution of the rare-earths was investigated. The determination of the alkaline metals and ammonium ion, alkaline-earth elements, fluoride, chloride, nitrate and phosphate anions in several solutions and in different materials that are involved in the chemical processes belonging to the fuel cycle was carried out. Single column ion chromatography technique was applied for determining all the lanthanide elements as well as yttrium, magnesium, calcium, strontium and barium and the sensibility of the measurements determined. A rapid chromatographic method for determining gadolinium in urania-gadolinia matrix is also proposed. Quantitative data on the separation of the lanthanide elements and yttrium from large amounts or other ions, rare earths for example, are presented. (author)

[en] Coagulation-Flocculation is an unavoidable stage in water treatment. It permits to reduce the color and the turbidity, normally caused by the organic and inorganic contaminants to acceptable levels for drinking water or for wastewater. The used coagulants can be organic or inorganic nature. The main goal of this work is to make the follow-up of water quality parameters and the optimization of the clarification stages in the drinking waters treatment station, by determination of the break point in the stage of the prechloration and optimization of the coagulant (aluminum sulphate) proportion. The determination of the anions concentration by means of the ionic chromatography before and after coagulation-flocculation shows that the stability and the solubility of the aluminum species are strongly affected by the presence of these anions. Consequently, the content of the anions affects the process of coagulation and must be taken into account in the optimization of this process. We present in this communication, the results of the pH, concentration of the coagulant, time of coagulation effect on the coagulation process .These factors show optimum values. The research of residual aluminum in the two water studied during this work shows that the aluminum content is lower than 200 g/L at the pH optimum.

[en] High-pressure ion exchange chromatography, used first for nucleic acid separations, was applied to the production of the heavier actinides, particularly the transcurium elements. Its use at the TRU plant is described. Future developments are considered briefly

[en] The determination of fluoride, nitrate, sulphate and phosphate ions in crude phosphoric acid by means of ion chromatography is described. A previous separation of interferent cations was made by using a cationic resin or EDTA complexation. The last alternative allowed more reproductible results. The technique described is very quick and is being applied for the simultaneous determination of impurities in phosphoric acid and its own phosphospate concentration. The method is quick and has good reprodutibility. (author)

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