PREPARATION OF THE CITRIC ACID EXTRACT 2O5 



chemically pure ammonium molybdate are dissolved in about 500 

 cubic centimeters of water. This solution is poured into one liter 

 of nitric acid, 1.19 specific gravity, 400 grams of ammonium 

 nitrate added thereto, and the mixture diluted with water to two 

 liters. The solution is allowed to stand 24 hours at about 35 

 temperature and filtered. 



Fourth. Magnesia Mixture. One hundred and ten grams of 

 crystallized magnesium chlorid and 140 of ammonium chlorid are 

 dissolved in 1300 cubic centimeters of water and 700 cubic centi- 

 meters of ammonia water containing eight per cent, of NH 3 added 

 thereto. After standing several days the solution is filtered. 



Fifth. Citrate-Magnesia Mixture. Two hundred grams of 

 citric acid are dissolved in 20 per cent, of ammonia and the vol- 

 ume made up to one liter with 20 per cent, ammonia. This solu- 

 tion is mixed with one liter of the magnesia mixture described 

 under " fourth." 



Sixth. Iron-Citrate-Magnesia Mixture. One liter of the 

 citrate-magnesia mixture described under "fifth" is mixed with 10 

 cubic centimeters of a 20 per cent, ferrous chlorid solution. 



Preparation of the Basic Slag for Analysis. The basic slag 

 which is intended for analysis is passed through a two 

 millimeter mesh sieve in order to remove any large pieces 

 which may be present. All loss of dust during this operation is 

 to be carefully avoided and to this end the sieve is to be closed 

 with a well fitting cover and nicely adjusted to the vessel receiv- 

 ing the sifted material. Any residue remaining upon the sieve is 

 weighed and is excluded from analysis, but is included in the 

 results on the total sample in order to determine the percentage 

 thereof. Thus prepared the material will yield a typical sample 

 for analysis. 



178. Preparation of the Citric Acid Extract. Five grams of 

 the basic slag, prepared as above, are placed in a half-liter flask 

 into which previously five cubic centimeters of alcohol has been 

 poured and the flask filled with the dilute two per cent, citric acid 

 solution at a temperature of 17.5 the flask closed with a rubber 

 stopper and without delay placed in a revolving shaking apparatus 

 rotating at from 30 to 40 times a minute for 30 minutes. The con- 

 tents of the flask are then immediately filtered. 



