1918] SOILS FEETILIZERS. 123 



North Carolina, Tennessee, and Arkansas, with particular reference to the 

 amount and solubility of their potash contents. 



The descriptions and analyses indicate that the best greensands are in New 

 Jersey and Delaware. The deposits in places have a maximum thickness of 

 20 or 30 ft., though as a rule it is less, and a horizontal extent of many 

 miles. The quantity varies both in different parts of the section of the bed at 

 the same place and from place to place. In the main these beds outcrop at the 

 surface and have a cover as a rule not more than their own thickness. Locally 

 they carry more than 7 per cent of potash, and over large areas they carry 

 from 5 to 7 per cent of potash. Many of the deposits are close to transportation 

 and so situated that they could be mined by dredge or steam shovel readily and 

 cheaply. The deposits examined south of Delaware are of lower grade. It is 

 considered probable, however, that all of those examined have a sufficient extent 

 for commercial use, if a cheap method of obtaining the potash can be found. 



With reference to the solubility of the potash " experiments were made in 

 dissolving the potash of the greensand in a solution of carbon dioxid. An auto- 

 matic agitator was used and the tests lasted several hours. The solution con- 

 tained such a small amount of potash, however, as to indicate that the process 

 was not commercially feasible. Similar experiments, with like results, were 

 carried on with sulphur dioxid, which could be obtained as a by-product from 

 the smelters, and dilute hydrochloric acid also failed to give results of 

 value. . . . The results obtained do not lend hope to the successful use of such 

 methods. . . . The advantage of greensand over feldspars lies in its abundance 

 and possible low first cost, exclusive of freight." 



An article is included on methods of analysis of greensand by W. B. Hicks 

 and R. K. Bailey. 



Manufacture of potash from feldspar {Jour. Bd. Agr. [London], 23 {1911), 

 No. 11, pp. 1087-1091).— Tests with two British feldspars and a Swedish feld- 

 spar of the so-called Rhodin process for rendering the potash of feldspar 

 soluble in water are reported. It was found that by this process 75 per cent 

 of the potash content of certain feldspars can be obtained in soluble form, while 

 the insoluble residues can be made into a white or nearly white cement, valuable 

 for decorative purposes. 



The recovery of potash as a by-product in the cement industry, W. H. Ross, 

 A. R. Merz, and C. R. Wagnee {U. S. Dept. Agr. Bui. 572 {1917), pp. 22).— 

 " Analysis of samples of raw mix and of cement from 113 cement mills in the 

 United States and Canada shows that the potash in the raw mix varies from 

 0.2 to 1.16 per cent, and that the percentage of potash volatilized in the different 

 plants varies from 24.5 to 95.9 per cent. From the results thus obtained it has 

 been calculated that the potash escaping from the kilns of these plants ranges 

 from 0.35 to 5.14 lbs. per barrel of cement produced, with an average for the 

 plants of this country of 1.93 lbs. On the basis of an average production of 

 90,000,000 bbls., the total potash escaping from the cement plants of this country 

 amounts to about 87,000 tons annually. It has been demonstrated commercially 

 that 90 per cent of the potash escaping in the dust is recoverable, and from 

 experiments made in this laboratory it would appear that 95 per cent of the 

 recoverable potash is, or may readily be made, available. . . . Assuming, in the 

 light of results that have already been obtained, that it would be practicable to 

 increase the percentage of potash volatilized to at least 65 per cent for all 

 plants, then the available recoverable potash would amount to more than 

 100,000 tons annually, or to nearly one-half of the normal consumption of potash 

 in this country. 



40111°— 18— No. 2 3 



