322 M. Berzelius un Vanadiwn. 



nitrt; and carbonate of soda, in the proportions of one part 

 of cinder, one of nitre and two parts of carbonate ; this mix- 

 ture is strongly calcined for an hour. The soluble portion of 

 the powdered mass is dissolved by boiling water, the solution 

 is filtered, and the excess of alkali saturated with nitric acid 

 and afterwards precipitated with muriate of barytes or acetate 

 of lead. The precipitate is vanadate of barytes or lead, con- 

 taining also some phosphate of barytes or lead, silica, zircon, 

 and alumina. Whilst it is still moist, it is to be decomposed 

 by concentrated sulphuric acid; the solution immediately be- 

 comes of a deep red colour, and after having digested the mix- 

 ture for half an hour, alcohol is added to it, and it is again 

 digested ; a?ther is then formed, and the vanadic acid is re- 

 duced to the state of salifiable oxide, the solution of which is 

 blue ; and when it begins to assume a syrupy consistence, 

 it is mixed in a platina crucible with a little fluoric acid to 

 separate a portion of silica, which it is almost impossible to 

 get rid of in any other manner ; the evaporation is continued 

 over the naked fire, and the sulphuric acid is at last expelled 

 at a red heat. The residue is impure vanadic acid. It is 

 fused with nitre, added in small portions at a time. The va- 

 nadic acid combines with the potash and expels the nitric 

 acid, and nitre is added until it is found that on cooling a 

 small portion of the mass it ceases to be red. The alkaline 

 carbonates may be employed ; but when nitre is used, the zir- 

 con and alumina remain less acted upon, when the vanadate 

 of potash is dissolved. The mass is afterwards dissolved in 

 water, and after filtration the residue is slightly washed ; it still 

 contains vanadium, and ought not to be thrown away. A piece 

 of sal ammoniac, larger than can be dissolved by it, is to be 

 put into the filtered liquor. As this salt dissolves, a white 

 pulverulent precipitate is formed, which is vanadate of am- 

 monia, insoluble in a saturated solution of sal ammoniac. 

 The phosphate of ammonia remains dissolved ; but when the 

 solution is alkaline, which happens when a carbonate is em- 

 ployed to dissolve the vanadic acid, insoluble subphosphate 

 of ammonia always precipitates. The vanadate of ammonia 

 ought to be washed, first with a solution of sal ammoniac, 

 and afterwards, to remove the sal ammoniac, with alcohol of 

 0'S6. It is to be again dissolved in boiling water, mixed with 

 a little ammonia, filtered and left to crystallize. It is from 

 this salt that vanadic acid and oxide are afterwards obtained, 

 by heating it gently in open vessels to procure the former, and 

 in closed vessels to prepare the latter. 



The residue which has been mentioned is a compound of 

 vanadic acid, alumina, zirconia and silica. Tiie vanadium is 



extracted 



