A Study of the Extraction of Potash from Orthoclase 

 Feldspar by Carbon Dioxide and Sulphur Dioxide. 

 Thesis submitted by Earle Forrester Whyte, B. A., to 

 the Faculty of Dalhousie College for the Degree of Master 

 of Arts. March 19, 1921. 



(Read 9 May. 1921) 



Introduction. — The term potash usually includes any simple 

 compound of potassium from which the metal or any particular 

 salt can be easily obtained. Such deposits of potash are of re- 

 markably rare occurrence, insomuch that the world has been 

 dependent on one or two sources for almost its entire supply 

 of this indispensable substance. 



The largest deposit, and the one which has supplied practically 

 all demands since 1860, is that in Northern Germany known as 

 the Stassfurt Deposit. The next largest bed of potassium 

 salts is in Alsace, and the fact that this country has recently 

 changed ownership will introduce an element of competition 

 in the potash trade. Another large deposit has been found in 

 Spain, and smaller deposits in Galicia and California, while a 

 certain percentage of these salts is obtained from the nitre beds 

 of Chili, and a further small quantity is recovered from a few 

 industries, as cement mills, niolasses distillery slop, and beet- 

 sugar refineries. 



But while potassium in suitable form occurs only in a few 

 places, yet it is widely distributed as a component of rocks and 

 soil, and is also found in vegetable and animal substances. In 

 1914 the supply of potassium salts from Germany was cut off, 

 and it became necessary to discover some other source from which 

 to obtain the potash required by the industries. As orthoclase 

 is a mineral of very common occurrence, and in unlimited quan- 

 tity, and contains from 9% to 1 4% K2 O, a great deal of research 

 work has been done on it in the endeavor to extract its potash 

 content. 



Historical. — Though it was during the period of the Great War 

 that attention was more particularly focussed on felspar as a 

 possible source of potash, yet attempts have been made to ex- 

 tract it from orthoclase since the middle of the 19th century. 

 Patents for the recovery of the potash content of felspars have 

 been issued in the United States, Canada, and Great Britain 



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