476 Intelligence and Miscellaneous Articles. 



"5 



it immediately becomes olive-green, and hence it may be concluded 

 that pechblende is not identical with the olive-green oxide. 



The pechblende from Joachimstal in Bohemia, when treated with 

 hydrochloric acid, yields at first carbonic acid gas, afterwards hydro- 

 sulphuric acid, and eventually dissolves almost entirely, leaving only 

 a little gelatinous silica, entirely soluble in potash. The filtered so- 

 lution was found to contain lead, iron, manganese, lirne, magnesia, 

 and a small quantity of soda. When pechblende is heated in a cur- 

 rent of dry chlorine it yields only chloride of sulphur. Pechblende 

 acted on by chlorine is partly soluble in water, and leaves a yellow 

 residue of urinate of lime and magnesia ; the solution contains neither 

 antimony, bismuth, arsenic, copper, or zinc. 



To analyse pechblende it was treated with nitric acid ; the silica 

 was separated by evaporating the solution to dryness ; the residue 

 was treated with hydrochloric acid and filtered. The lead was se- 

 parated by hydrosulphuric acid, converted into sulphate and esti- 

 mated ; to the solution after the separation of the lead hydrosulphate 

 of ammonia was added, which precipitated the uranium, iron and 

 manganese ; the method by which these three metals were separated 

 will be presently stated. The solution from which they were pre- 

 cipitated was boiled, then treated Avith oxalate of ammonia, the 

 oxalate of lime converted into sulphate and estimated. The filtered 

 solution was evaporated to dryness, and the residue heated to redness 

 to expel the ammoniacal salts, sulphuric acid was then added, and the 

 sulphates of magnesia and soda were obtained ; the alkali was sepa- 

 rated from the magnesia by means of acetate of barytes. 



The sulphur was determined by a separate experiment, and its 

 quantity was exactly proportional to that of the lead ; the carbonic 

 acid was expelled by nitric acid, and its quantity determined by that 

 of the carbonate which it precipitated from barytes water. 



The water is readily separated by heat ; it was obtained by heating 

 the pechblende in azotic gas, and absorbing it by chloride of calcium. 



The uranium was separated from the iron and manganese by the 

 following means : — the solution of carbonate of uranium in carbonate 

 of ammonia is not rendered turbid by the addition of hydrosulphate 

 of ammonia ; and this fact, which has not been before noticed, allows 

 of the separation of uranium from several metallic oxides slightly 

 soluble in carbonate of ammonia, such as those of manganese, cobalt, 

 nickel and zinc, which hydrosulphate of ammonia completely preci- 

 pitates from this solution : this separation of uranium from the 

 above-named oxides is rendered very simple by this process. 



In the present case the uranium, manganese and iron having been 

 precipitated by hydrosulphate of ammonia, were redissolved in dilute 

 aqua regia, and the liquor supersaturated with carbonate of ammonia, 

 precipitated peroxide of iron mixed with some manganese ; hydro- 

 sulphate of ammonia added to the filtered liquor separated a little 

 sulphuret of manganese, and it was then boiled till colourless ; the 

 precipitate obtained is greenish, owing to the partial reduction of the 

 oxide of uranium by the hydrosulphate ; it was obtained in the state 

 of green oxide by calcination ; the iron and manganese were sepa- 

 rated by succinate of ammonia. 



