258 



Report of the State Geologist. 



lime. This milk of lime is sent to the distilling vessels in the works, where it 

 meets the chloride of ammonia, produced in a later process. The reaction 

 which here takes place, converts the calcium oxide of the milk of lime into 

 calcium chloride, and sets free the ammonia which w as held by the chlorine. 



" In the burning of the limestone in the kilns, carbonic acid gas is produced. 

 This is pumped by suitable pumping engines, and after being washed in 

 w ater, is forced into the carbonating system, where it meets the brine which 

 has been previously supplied with the proper amount of ammonia. The 

 whole ammonia-soda process depends upon the reaction wzhich now takes 

 place. The carbonic acid gas first takes the ammonia and produces a carbonate 

 of ammonia. In the presence of this substance, and the excess of carbonic 

 acid gas, a double decomposition takes place. The carbonate of ammonia 

 takes the chlorine from the salt, and the sodium from the salt takes the car- 

 bonic acid from the" carbonate of ammonia. By these reactions, two new 

 substances are produced, i. e. chloride of ammonia and bicarbonate of soda. 

 The first of these is a liquid and the second a solid. By means of suitable 

 niters, the liquid is separated from the solid, and the solid bicarbonate of soda 

 is roasted in proper furnaces, driving off the excess of moisture, ammonia and 

 carbonic acid gas, and reducing it to the form of mono-earbonate of soda, 

 which is the ordinary soda-ash of commerce. After the necessary grinding 

 and screening, the product of the furnaces is ready for packing 



" The chloride of ammonia in the liquid form is now returned to the distil- 

 ling columns, where it meets the milk of lime produced at the lime kilns, and 

 gives up its chlorine to the lime, thereby releasing the ammonia, which in the 

 form of ,gas is put back again into the process. 



" The chemical reactions of the ammonia-soda process are extremely simple, 

 and together form an almost complete cycle of operations. It only remains 

 to separate the chlorine from the calcium in the waste product, to make the 

 process absolutely perfect. Upon this point, many of the most able chemists 

 of the world are at present engaged. Although the chemical reactions are 

 without complications, the handling of the carbonic acid gas and the ammonia 

 presenl many practical difficulties, which it has cost many years of patient 

 study and experiment to overcome. The apparatus necessary for the proper 

 carrying out of the process has become complicated out of all proportion to 

 the apparent simplicity of the reactions. This, however, is to be accounted 

 for by the fact that the reagents to be handled are largely in a gaseous state. 



" The ammonia-soda process differs radically from the Le Blanc process, 

 which was its predecessor, in that the old process works largely in the dry 



