( 95 ) 



Decomposition of Substances by Steam^ and Manufacture of 

 Sulphate and Muriate of Potash. 



The most interesting and probably the most valuable of the pa- 

 tents granted during the last year, under the subject of chemistry, 

 are two which have been granted to an American citizen, now resid- 

 ing in England. One is for the manufacture of sulphate and muriate 

 of potash from feldspar, and the other for decomposing alkaline 

 salts by the action of steam at a high temperature. The latter ap- 

 pears highly interesting, as a purely scientific discovery, apart from 

 its practical value. In this exhibition of the solvent power of 

 steam, we see at once a new, powerful, and most economical chemical 

 reagent. 



In the process of decomposing feldspar, the inventor heats together 

 a potash feldspar, lime, or its carbonate, and the sulphate of either 

 lime, baryta, or strontia, and afterwards lixiviates the mixture with 

 water. The heat is to be kept at or above redness. In obtaining 

 the muriate of potash, the muriate of either soda, lime, or iron is 

 added to the potash feldspar, in place of the sulphate above men- 

 tioned, the modus operandi being substantially the same as in ob- 

 taining the sulphate. 



The process of decomposing salts by steam is so replete with in- 

 terest and novelty, as to warrant the citation in full of its description 

 by the inventor : — 



My invention consists in a method of decomposing the sulphates 

 and muriates of the alkalies and alkaline earths, by exposing them 

 at a high temperature to a current of steam or vapour of water, by 

 which the acid is carried off, and the alkaline base either remains 

 free, or enters into combination with some third substance provided 

 for that purpose. 



To decompose sulphate of lime, and obtain from it sulphuric and 

 sulphurous acids, and free lime, I proceed in the following manner : 

 I have a fire-clay cylinder of close texture, and of any convenient 

 size, placed vertically in a furnace, and provided with openings at the 

 top and bottom, for charging and discharging, which openings are 

 capable of being closed air-tight. To the top of this cylinder I 

 adapt an escape tube of fire-clay, for conveying off the acid vapours ; 

 and to the bottom for the admission of the steam, I adapt another 

 clay-pipe, connected with a steam-boiler, by a series of fire-clay tubes, 

 which are to be kept at a red heat. In order to diminish the corro- 

 sion of the cylinder by the sulphate of lime or the lime itself, I line it 

 with a coating of native carbonate of magnesia, applied in a manner 

 similar to the usual clay-linings of chemical furnaces. I fill the 

 cylinder with pieces of sulphate of lime, about a quarter of an inch 



