This paper demonstrates the results of experiments for the determination of the composition of gases during the dehydration of sulfates (Na-jarosite, melanterite, and chalcanthite) collected at the surface of pyrometallurgical waste heaps. The volatilization of various elements, and vapor–gas phase transport from three sulfate groups were investigated by stepwise laboratory heating at 45, 55, and 65 °C. The sample of yellow efflorescence mainly consisted of Na-jarosite, the white efflorescence contained melanterite as the major mineral, and the blue efflorescence sample consisted of chalcanthite. These all contained a few impurities up to 5 %. The highest total dissolved solids (TDS) was found in the gas condensates from melanterite (59 mg/L), followed by chalcanthite (29 mg/L) and Na-jarosite (17 mg/L). It was determined that major and trace elements in the condensate can be trapped by water vapor and can migrate with the vapor phase during the desorption and dehydration of hydrous sulfates. X-ray diffractograms showed that Na-jarosite remained stable throughout the temperature range, whilst the separation of melanterite’s structural water occurred at 40 °C, and chalcanthite completely lost two water molecules at 50 °C. The gas condensates contained acetates and formates, which could be the fermentation products of bacterial communities. Some of the strains—Micrococcaceae sp., Bacillus sp., and Microbacteriaceae sp.—were cultivated.
On a défini expérimentalement les régions du soudage à l'aide de l'explosion pour obtenir une série de joints bimétalliques à la solidité non moindre que celle du matériau le plus faible. Pour la construction correcte des régions du soudage on a exploré l'influence des faits suivants: la dépendance de l'indice de polytropie des produits de l'explosion visa -vis de la vitesse de la détonation; l'influence de la pression résiduelle des produits de la détonation; les distortions périphériques au moment du lancement de la plaque; l'influence de la résistance des matériaux sur la géométrie de l'impact des plaques. On a proposé des rapports mathématiques pour le calcul de la limite inférieure des régions du soudage, la pression optimum résiduelle des produits
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