448 Gooch and Eddy — Separation of Magnesium. 



Table III. 



o a ~ 



n 



CD 



J g 



cS 



a 



CD 



B 



MgO 



weighed 



grm. 



o° P 

 u be P 



H§ 3= 



A 

 + 0-0011 



CD 



eg 



Id . 



bC 1 ^ 



S4 



cd M 



"is P 



«W 1 



o p 



CD .2 



3 B 



*0 

 O cc 



o» 

 ■3 3 



TO O 

 1 



O CD 



H3 



CD r£ 



a * 



fP CO 

 O 



o 1 



|| 



Volume of solu- 

 tion used in 

 washing — cm 3 



° a 



CD 15 



cc 



0-1444 





o-i 



.. 



0-1455 



o-oooo 



1-2 





100 



50 



over 



0-1444 



o-i 



-- 



-- 



0-1446 



+ 0-0002 



o-oooo 



1-2 



--- 



100 



50 



night 







1444 





o-i 





0-1445 



B 

 + 0-0001 



o-oooi 



50 



50 



50 



50 



20 min. 







1444 





o-i 





0-1444 



o-oooo 



o-oooi 



50 



50 



50 



50 



20 " 







1444 



o-i 









0-1445 



+ 0-0001 



0-0002 



50 



50 



50 



50 



20 " 







1444 



o-i 









0-1449 



+ 0-0005 



o-oooi 



50 



50 



50 



50 



20 " 







1444 



0-2 







0-1449 



+ 0-0005 



0-0002 



50 



50 



50 



50 



20 " 







1444 





0-2 





0-1461 



+ 0-0017 



o-oooo 



50 



50 



50 



50 



20 " 







1444 









3 



0-1444 



o-oooo 



o-oooi 



50 



50 



50 



50 



20 " 



0-1444 



-- 



-- 



3-0 



0-1447 



+ 0-0003 



0-0002 



50 



50 



50 



50 



20 " 



0-1444 



0-2 







0-1446 



C 

 + 0-0002 



0-0002 



50 



50 



50 



50 



20 min. 







1444 



-- 



0-2 





0-1442 



— 0-0002 



0-0002 



50 



50 



50 



50 



20 " 



The results of each method of treatment are plainly very 

 good, but it is more convenient to add alcohol to a water solu- 

 tion than to evaporate a solution and then treat the residue. 

 Reprecipitation is shown to be advisable when large amounts 

 of the alkalies are present. For amounts comparable to those 

 which we have handled, the procedure is very rapid and simple. 

 The solution containing the salts of magnesium and the alkalies 

 is brought to a volume of about 50 cm3 and an equal amount of 

 absolute alcohol is added, precipitation is made by addition of 

 50 cm3 of the saturated ammoniacal ammonium carbonate solu- 

 tion containing 50 per cent alcohol, and the mixture is allowed 

 to stand twenty minutes with stirring for five minutes. If the 

 amount of alkali salt originally present is small, the precipi- 

 tate may be collected on asbestos in a j)erforated crucible, 

 washed with the precipitant, dried, ignited, and weighed as 

 magnesium oxide. When the amount of alkali salt originally 

 present is large, the precipitate may be freed from traces of the 

 alkali salt by pouring off the supernatant liquid through the 

 prepared asbestos filter, dissolving the precipitate, and pre- 

 cipitating ammonium magnesium carbonate as at first. This 

 second precipitate, collected upon the filter originally used, 

 leaves upon ignition practically pure magnesium oxide. 



