164 § 94. SPECIAL METHODS OP ANALYSIS. 



5. Fourth Filtrate. {From the 2^i'ecip. hy BaCl.) Eemove excess 

 of Ba with (NH4)2 CO3, evaporate filtrate to dryness, ignite, treat with 

 IlaCoOi, (see G, 2), ignite, exliaust with water, and treat this solution for 

 the estimation of the alkalies, as directed for the treatment of the cor- 

 responding solution in G, 3. 



6. Dissolve the residue thai has been exJiausted hy water as above, in di- 

 lute HCl, filter if necessary, and precipitate Mg in the filtrate with NajH 

 PO, (§ 50, a). 



VI. 



TO DETERMINE ALL EXCEPT MANGANESE, W^ITHOUT DIVIDING THE 

 SOLUTION. 



Proceed as under V, except that the evaporation to dryness, ignition, and 

 treatment with Ci for the estimation of Mn, are to be omitted. 



VII. 



TO DETERMINE ALL EXCEPT MANGANESE AND PHOSPHORIC ACID, WITH- 

 OUT DIVIDING THE SOLUTION. 



Proceed as under VI, except that no FcsCle need be added, and that one 



portion of the solution of the precipitate by NH4C2H3O0 is to be used for 



the estimation of the sum of the Fe and Al only, and the other portion 



for the determination of Fe. (A.) 



VIII. 



TO DETERMINE ALL EXCEPT ALUMINIUM AND MANGANESE WITHOUT 

 DIVIDING THE SOLUTION. 



Proceed as under VI, except that one portion of the solution of the pre- 

 cipitate by NH4C2H3O2 is to be used for the esthnation of Fe, and the 

 other for that of P2O5. (A, H.) 



IX. 



DETERMINATION Or ALL, AND ELIMINATION OF PHOSPHORIC ACID BY 

 THE TIN PROCESS. 



Divide the filtrate from tjie silica iu tw^o parts, a and b. 



a. 



1. Precipitate 

 SO3 with BaCl, 

 and filter. (E.) 



2. Eliminate K 

 and Na as chlo- 

 rides. (See 



Scheme I, a, 3.) 



b. 



1. Treat the concentrated nitric-acid solution with 

 Sn, this precipitate by NH4HS,and the solution so ob- 

 tained with magnesia mixture (B). 



2. First Filtr.' (From the precip. by Sn.) Precipi- 

 tate Fe and Al by NallO and NaCoHgOo, dissolve the 

 precipitate in HCl, divide solution in two equal purts, 

 precipitate one part by NH4HO to get total Al and Fe, 

 and determine Fe in the otlier part (A). 



3. Second Filtr. (From the ])reci]). by NaC2H302.) 

 Treat tliis for the estimation of Mn, Ca, and Mg, as in 

 Scheme I, under c-, 3, 3 and 4. 



