24 UNIVERSITY OF COLORADO 



!Now determine the value of the oxalic acid solution in terms 

 of the permanganate solution, as follows: Into a No. 3 beaker run 

 40 cc. oxalic acid solution, add 200 cc. boiling water, then 20 cc. 

 dilute sulphuric acid (1 to 1), and titrate with the permanganate 

 (it is best to make the solutions exactly equal in value, so that 

 1 cc.=l cc). Divide the amount of permanganate solution into the 

 amount of oxalic acid solution, to find its value in terms of oxalic 

 acid, multiply the number of cc.'s of permanganate solution used in 

 the titration by this factor, and subtract from the amount of oxalic 

 acid solution used — in the above case 40 cc.'s — this will give the 

 amount of oxalic acid oxidized by the Mn0 2 obtained from the ore. 



We have previously found (standardizing a solution of potas- 

 sium permanganate) that the ratio of iron to oxalic acid is as 8 to 9. 

 Hence, 



1. Standardize the oxalic acid solution with the permanganate 

 solution and find its equivalent in Fe. Thus, if 1 cc.=l cc. 

 exactly, then 1 cc. oxalic acid=.01 Fe, or, if 1 cc. oxalic acid=.9 cc. 

 permanganate solution, then 1 cc. oxalic acid solution=.009 grams 

 Fe, etc. 



2. Multiply the equivalent in iron by 1.125 to find the value 

 per cc. in oxalic acid, i. e., to find exactly how much H 2 C 2 4 , 2 H 2 

 1 cc. of the oxalic acid solution contains. This amount is then 

 marked on the bottle. 



3. Multiply the amount of oxalic acid oxidized by the MnO, 

 of the ore by .4365 to find the equivalent in Mn, then calculate the 

 i; or the last two may be combined and the value in iron multiplied 

 by (1.125x.4365)=.49106. 



Slags which will not decompose by treatment with acids may 

 be either sintered or fused. 



The sintering is performed (see Furman's Manual) in a small 

 platinum dish by mixing \ gram of the slag with about 1^ (one 

 and one-half) grams sodium carbonate in a small agate mortar; 

 transfer this to the platinum dish, brushing the mixture to a small 

 heap in the center, now place in the muffle and heat until the 

 mass sinters together. Fusion must not take place, since the lead 

 would be reduced and spoil the platinum dish. Remove from the 

 muffle, cool by dipping the bottom of the dish in cold water, then 

 add 2 cc. water and 5 cc. HC1, and proceed as previously directed 

 under silica. 



Fusion, when necessary, is conducted as follows: \ gram of 



