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[en] After separation of valuable metals from the leaching solution of ores or secondary resources, the recovery of inorganic acids from the raffinate is important. Therefore, the possibility of recovering inorganic acids, such as HCl, H_2SO_4 and HNO_3, by extraction with Tris 2-ethylhexyl amine (TEHA) was investigated. The solvent extraction reaction of acid by TEHA was identified by applying a slope analysis method to the extraction data. The extraction efficiency of the acids by TEHA was in the order HNO_3 > HCl > H_2SO_4, which corresponds well to the variation in the electric charge densities of the anions of each acid. The loading capacity of TEHA for HNO_3, HCl and H_2SO_4 was determined and the extraction behavior of the acid seemed to be affected by the acid concentration in the organic phase. It was possible to strip all the HCl and H_2SO_4 by using distilled water at room temperature, while the stripping percentage of HNO_3 at the same conditions was very low.
[en] A two-step process is described for dissolving plutonium metal, which two steps can be carried out sequentially or simultaneously. Plutonium metal is exposed to a first mixture containing approximately 1.0M--1.67M sulfamic acid and 0.0025M--0.1M fluoride, the mixture having been heated to a temperature between 45 C and 70 C. The mixture will dissolve a first portion of the plutonium metal but leave a portion of the plutonium in an oxide residue. Then, a mineral acid and additional fluoride are added to dissolve the residue. Alteratively, nitric acid in a concentration between approximately 0.05M and 0.067M is added to the first mixture to dissolve the residue as it is produced. Hydrogen released during the dissolution process is diluted with nitrogen. 2 figs
[en] Titanium ion polymerization and hydrolysis in acid solutions is studied. Results of developed experiences with titanium (III) and (IV) were presented. (L.M.J.)
[pt]Estuda-se a hidrolise e polimerizacao do ion titanio em solucoes acidas. Resume-se o que se publicou sobre titanio (III) e (IV) e apresenta-se resultados de experiencias desenvolvidas. (L.M.J.)
[en] Complete text of publication follows. Sample preparation is usually the most time-consuming step in the analytical chain, besides it also has an enormous impact on the accuracy of the subsequent analysis. Moreover, modern analytical labs have to cope with a variety of different analytical tasks, thus requiring sample preparation techniques just as versatile. Scientifically accepted already for years, microwave-assisted sample preparation has been developed over time into an indispensable tool to bridge the gap between sample and spectrometer in research and industry. Very powerful instrumentation and methods for high performance acid digestion is state of the art. Just recently the scope of applications has been drastically extended. Previously conventionally heated reactions like oxygen combustion procedures for halide determination or UV-assisted treatment of liquid samples for trace metal determination at very low element concentrations have been successfully transformed into microwave heated processes. Economic benefits, application examples and figures of merit will be presented for those new approaches to microwave-assisted sample preparation beyond acid digestion.
[en] This book deals with synthetic rubber in the first part: Poly norbornene rubber, Polysulfide rubber, FKM, Fluoridated rubber, BR, CR, Syndiotactic 1,2 - Polybutadiene, Silicone rubber, IR, IIR, ACM, Liquid rubber, SBR, EVA, Co, NBR, TPE, SBC, TPVC, TPO, TPU, TPAE, TPEE, Urethane rubber, CSM, and propylene oxide rubber. The second part describes organic rubber chemical carbon black, processing aid, zinc salts of fatty acids, Exton L-2, Exton k-1, and vulcanizing agent.
[en] The results of researches conducted in Nuclear and Radiation Safety Agency of Academy of Sciences of the Republic of Tajikistan were considered in present monograph. This book is devoted to reprocessing of uranium production wastes and to decomposition of uranium ores by mineral acids.