136 B. B. Biggs — Separation of Iron, Manganese and 



The solution of calcium chloride was prepared from calcium 

 carbonate puritied by repeated precipitations, as carbonate, by 

 means of ammonium carbonate. It was free from iron, 

 alumina and alkalies. 



Weight of CaCl, 



Weight of CaO 



Weight of CaO in 



solution taken. 



found. 



100 grams of solution. 



grin. 



grm. 



grm. 



(6.) 20G94 



0-1 133 



0-5638 ) 



(1.) 20-18 



0-1136 



5632 [■ 



(8.) 20-19 



0-1135 



0-5630 ) 



Mean. 

 0-5633 



My experiments began with analyses of solutions containing 

 known quantities of the three substances. From this they 

 grew and though the order may be the reverse of a logical one 

 it had best be followed in giving the results. 



In the first and second series the quantities of iron and cal- 

 cium were constant, the manganese was variable. In a third 

 series, containing only manganese and calcium, the proportions 

 of each were varied. 



The general mode of operating was the following : 



The solutions, containing, in the first and second series, the 

 equivalents of about 0'2 grams of iron and 0*17 grams of cal- 

 cium oxide and quantities of manganese oxide varying from 

 0-03 to 2 grams, were diluted to 350-400 cc - To secure 

 the usual conditions of analysis, and because ammonium salts 

 tend to hold manganese in solution, 10 c - c - of hydrochloric 

 acid were added. The cold solution was neutralized with 

 ammonia containing ammonium carbonate. The precipitate 

 that might be formed was dissolved with as little as possible 

 hydrochloric acid and 5' grams of ammonium acetate* added. 



For the precipitation of the iron and the conversion of the 

 salts of the other elements into acetates, this is an unneces- 

 sary excess and because of its possible reducing action on the 

 iron, such an excess should in general be avoided. But, pre- 

 liminary experiments having been made, it was believed that 

 with proper care the reduction of the iron might be avoided. 

 To further test this opinion and because of the influence off 

 ammonium acetate in holding manganese salts in solution, this 

 excess was added. 



Two acetate precipitations were made. The iron was thrown 

 down a third time with ammonia. In but two cases (!Nob. 14 

 and 17) did the third filtrate contain manganese. In making 

 this separation care was taken not to digest the iron precipi- 



*The ammonium acetate was prepared by neutralizing ammonia with acetic 

 acid and an amount taken which would be equal to about h gr. of the salt. 



f Experiments seemed to show that the influence of ammonium acetate in hold- 

 ing manganese salts in solution, though the solution be ammoniacal, is somewhat 

 greater than that of the chloride of ammonium. 



