66S NEW YOEK STATE MUSEUM 



phosphorus slag is formed which is known as the Thomas phos- 

 phate. 



Ammonium sulfate 



In the manufacture of aqua ammoniae from ammonium sulfate 

 lime is used to form sulfate of lime and thus liberate the am- 

 monia, sufficient quantity being required to convert all the sulfuric 

 acid in the sulfate and about one third more. 



The lime is added in nearly every instance in the form of 

 milk of lime, caustic of lime being employed in rare cases with 

 a view to utilizing the heat evolved during the slaking, as in the 

 Solvay process. This is not to be recommended, however, owing 

 to the uncertainty which exists as to the time required by the 

 lime to slake; for, if the latter is slow slaking, a temporary 

 shortage of lime results, followed by a momentary excessive 

 reaction, and, if any stoppage of the apparatus occurs, explosion 

 may, and indeed at times does, result."^ 



The lime milk should be free from unslaked particles or sand 

 grains, and magnesia is undesirable from the fact that it retards 

 the distillation if ammonium chlorid or sulfate is present in the 

 gas liquor, since it forms a double salt with them which can not 

 be decomposed except at high concentration. 



Contents of 1 liter of lime milk 

 Degrees BaumS ^ "^JJamT^^^ g^iTs Water grams Pe-f* 



10 1258.6 133.3 1125.3 10.6 



15 1345 179.7 1165.3 13.2 



20 1436 224.3 1211.7 15.68 



25 : 1478 258.3 1219.7 17.52 



30 1490 276.7 1213.8 18.67 



35 1495.4 289.1 1206.3 19.43 



40 1499 297.9 1201.1 19.88 



45 1501.2 303.7 1197.5 20.22 



50 1503.2 308.3 1194.9 20.48 



55 1504.6 311.9 1192.7 20.7 



60 1505.8 314.7 1191.1 20.89 



65 1507 317.2 1189.8 21.05 



1 rrascli. Mm. iud. 7: 45. 



