DETERMINATION OF TUNGSTEN AND MOLYEDENUiM IN SEA WATER 819 



The results obtained are shown in Table I, Nos. 10-16 



TABLE I 

 Recovery of Mo and W 



♦ Residual molybdenum. 



The recoveries of molybdenum and tungsten in this procedure are 

 both about 90%. 



3. Determination of Molybdenum and Tungsten in Sea Water 

 About 50 1. of the sample water was taken, and acidified with 6 ml. 

 of nitric acid; 400 mg. of ferric iron was added as ferric nitrate and 

 thoroughly mixed. To the solution, 200 ml. of hexamine nitrate was 

 added and thoroughly mixed. To the solution, 200 ml. of hexamine 

 solution (containing 100 gr. of hexamine) ^v^s treated as above men- 

 tioned, and the amounts of tungsten and residual molybdenum were 

 determined. 



Molybdenum sulfide in the filter was ashed at low temperature and 

 dissolved in sodium hydroxide. Then the amount of molybdenum was 

 colorimetrically determined by the dithiol method. 

 The results obtained are shown in Table II. 



