424 A. A. Blair — Chromium and Aluminium in Steel and Iron. 



KC10 3 (when KC10 3 is used instead of KNO s the precipitate 

 must be thoroughly ground in and incorporated with the flux 

 before fusing) dissolving in water, filtering, and determining the 

 Cr0 3 volumetrically. The results obtained in this way are 

 fairly good, but are apt to be a little low. 



Aluminium, nearly always exists as such in steel, and may be 

 estimated with great accuracy by proceeding exactly as in the 

 above method for the determination of chromium, until after 

 filtering and washing the precipitate by BaCO s , which is then 

 dissolved on the filter in dilute HC1 and the solution allowed 

 to run into a small clean beaker. This solution is diluted, 

 boiled, and the barium precipitated bv a sli. 

 H 2 S0 4 ; the BaS0 4 allowed to settle," filtered, washed, and the 

 filtrate evaporated nearly to dryness to get rid of the excess of 

 acid. This solution is then diluted, and the Fe 2 3 , and A1 2 3 

 separated by C 4 H 6 6 , FH 4 HO, and NH 4 HS. If the steel con- 

 tains any chromium it will be with the A1 2 3 , and must be sepa- 

 rated by fusing the residue obtained by running to dryness the 

 filtrate from the FeS and igniting with Na 2 C0 3 , and KNO s ; 

 dissolving in water and, without filtering, adding KC10 3 and 

 HC1, as before in the separation of A1 2 3 , and Cr 2 3 . The A1 2 3 

 . precipitating by (NH 4 ) 2 C0 3 will be contaminated 

 by small amounts of Si0 2 , and CaO (from the C 4 H 6 ? ) from 

 which it can be separated by dissolving on the filter in HC1, 

 after washing free from alkaline chromate, into a small clean 

 beaker, running to dryness to render Si0 2 insoluble, dissolving 

 in HC1, tih- ring the A1 2 3 by NH 4 HO, being 



careful to boil off all smell of NH 4 HO. After filtering and 

 careful washing the precipitate can be dried, ignited, and 

 weighed as A1 2 3 , calculating to aluminium by the factor 

 5331. Atomic weight, 274. 



The great solubility of the Cr of chromium steel in the most 

 dilute HC1 certainly seems to indicate the existence of a true 

 alloy of iron and chromium, and that a large part at least of the 

 chromium exists as such, and not as an oxide or in any inter- 

 mingled slag. Mr. E. Riley,* at a meeting of the Chemical 

 Society, March 15, 1877, presented some specimens of chromium 

 pig-iron containing from six to seven per cent of Cr. He men- 

 tioned the fact, during his remarks, that the Cr had dissolved 

 with the Fe in the course of analysis. The president, Professor 

 Abel, F.R.S., said that he had examined a specimen of the so- 

 >imum steel, but had found a mere trace of chromium 

 in it It was possible however, he said, that the chromium 

 Q the production of the steel, but was elim- 

 inated at some stage in the process, so that it did not appear in 

 the finished steel 



