IV 

 OTHER METHODS OF ANALYSIS 



The methods mentioned previously are those in general use, 

 daily. There remain, however, other methods, designed to meet 

 exceptional cases, and these I shall now take up. 



Manganese. — Volhard's method, the one previously given, is 

 the best for general use. It is well, however, to have another 

 method to check by. 



Pattinson's Method (Modified).* — Weigh into a No. 4 casserole 

 ^ gram of ore, treat with HN0 3 , and HC1, according to require- 

 ments, i. e., if an oxidized ore, little or no nitric acid will be 

 required; if a sulphide, from 5 to 8 cc. will be required. Evaporate 

 to dryness, dissolve in 15 cc. strong HC1, dilute with 100 cc. boiling 

 water, add an emulsion of oxide of zinc until the solution turns 

 red, then a slight excess; now add from 20 to 50 cc. strong bromine 

 water, according to the amount of manganese present, 50 cc. being 

 sufficient to ppt. about 40$ Mn, boil until all the excess Br has 

 been expelled, and filter through a large filter, washing by decanta- 

 tion, until free from chlorides and bromides. Remove the filter 

 and its contents carefully from the funnel, open it against the side 

 of a No. 3 beaker; wash the ppt. into the beaker with boiling water, 

 cleaning the filter paper as thoroughly as possible. 



Fill a burette with a volumetric solution of oxalic acid (see 

 table on page 1); from this burette run into the casserole 10 cc. 

 of the solution, add 20 cc. dilute sulphuric acid (1 to 1) and a little 

 boiling water. Dissolve all the Mn0 2 , etc., adhering to the cas- 

 serole with this mixture, and then pour it over the filter in the 

 beaker, to remove what still sticks to it; wash the filter with boil- 

 ing water and remove it from the beaker. Now add to the mixture 

 in the beaker about 30 cc. more of the oxalic acid solution (an 

 excess is required), and 200 cc. boiling water. If everything does 

 not dissolve, heat until it does and the solution becomes clear. 

 Titrate with the volumetric solution of potassium permanganate 

 until just pink. 



♦Assay Notes, Colorado School of Mines. 



