19201 SOILS — FERTILIZERS. 629 



Tlie production of phosphoric acid by smelting phosphate rock in a fuel- 

 fed furnace, W. H. Waggaman and T. B. Tuiu.ey (Jour. Indus, and Engin. 

 Chem., 12 {1920), No. 7, pp. G'iC-G.'jO, figs. S).— The results of preliiuinary ex- 

 periments on the production of pliosphoric acid by smelting phosphate rock in 

 a fuel-fed furnace. coiuUicted by the Bureau of Soils of the U. S. Department 

 of Agriculture, are reported. 



Preliminary work in the laboratory showed that the nearly complete evolu- 

 tion of phosphoric acid from a charge of calcium phosphate, carbon, and quartz 

 Hour was perfectly feasible if reducing conditions were maintained until a 

 fusible slag was produced and a temperature of approximately 1,500° C. was 

 continued throughout the operation. The addition of small amounts of alumina 

 to the charge seemed to aid the fusion somewhat. 



Further experiments on a larger scale, in which a fire-brick furnace fitted 

 with two oil burners was used, showed that in order to make the process eco- 

 nomically practicable the full calorific power of the fuel must be utilized, which 

 can be done only by heating the charge directly in the flame. The plan of spray- 

 ing the phosphatic charge into the furnace along with the fuel was also tested, 

 but the vast bulk of material was carried out of the furnace along with the gases 

 of combustion and lost. 



Tests on briquetting the phosphate charge showed that a charge containing 

 from 20 to 25 per cent of finely divided material classed as clay can be formed 

 into very satisfactory briquettes. The furnace was modified so that a portion 

 of the flames and hot gases of combustion from the oil burners would play up 

 through the central shaft and thus heat the charge of briquettes directly. 

 While the results obtained with this furnace were not entirely satisfactory, it 

 appeared that by exposing the charge to a high temperature for a sufficient 

 length of time nearly complete evolution of the phosphoric acid can be brought 

 ai)out. This process is said to show a considerable economic advantage over the 

 ordinary method of obtaining soluble phosphoric acid. 



Making phosphate available with bisulphate, B. Neumann and K. Kley- 

 LEiN (Ztschr. Angcw. Vhem., 33 (1920), No. 26-27, Aufsatzt., pp. 7J,-77, figs. 3).~ 

 Laboratory experiments are reported on the substitution of sodium bisulphate 

 for a part of the sulphuric acid in the process of treating raw phosphate for 

 the production of superphosphate. It was found when working with sulphuric 

 acid of different concentrations that the concentration of the acid was increased 

 by additions of bisulphate up to 47.5° Baume, beyond which the concentration 

 was decreased. The bisulphate was found to be a practical substitute only 

 when working with an acid of 30° Baura6 or lower. 



Phosphorite, superphosphate, and tetraphosphate, A. Quartaroli (Staz. 

 Sper. Agr. Ital., 52 (1919), No. 7-9, pp. 416-^35).— The author reviews the re- 

 sults of work by others, and reports studies to show that tetraphosphate does 

 not have a higher content of easily soluble phosphate than ordinary rock 

 l>linsphate. 



Phosphoric acid utilization, with special reference to conditions in 

 Bavaria, II. Fisiiieu (Landio. Jahrb. liayern, 9 (1919), No. 3, pp. 1(11-169). — • 

 The author reviews a number of studies by himself and others on the ways in 

 which phcKsphoric acid is placed in available condition in soils, particularly those 

 of Bavaria. 



He takes up especially the unlocking of soil phosphates by soil acids, chemical 

 action and mass action of soil amendments, and heat and soil bacteria. With 

 reference to the action of soil amendments, it is believed that liming has a 

 favorable effect upon the solubility of soil phosphates owing to its precipitating 

 action OH solutit)ns of iron salts. This is thought to explain the relatively 



