SOURCES AND PREPARATION OF MAGNESIA. 



157 



TABLE 65. 

 ANALYSES OF HIGHLY MAGNESIAN LIMESTONES, U. S. 





1. Morrisville, Calhoun County, Ala. W. F. Hillebrand. analyst. Bulletin 60, U. S. Geol. 



Survey, p. 159. 



2. S. 16, T. 7, R. 7, E. Talladega County, Ala. J. B. Britton, analyst. Rep. Ala. Geol. Survey 



for 1875, pp. 149, 150. 



3. Inyo Marble Co., Inyo, Calif. 20th Ann. Rep. U. S Ge*ol. Survey, pt. 6, p. 359. 



4. East Canaan, Conn. 20th Ann. Rep. U. S. Geol. Survey, pt. 6, p. 370. 



5. Canaan, Conn. J. S. Adams, analyst. 20th Ann. Rep. U. S. Geol. Survey, pt. 6, p. 370. 



6. Jasper, Ga. W. H. Emerson, analyst. Bulletin No. 1, Ga. Geol. Survey, p. 87. 



7. Cockeysville, Md. J. E. Whitfield, analyst. Bulletin 60, U. S. Geol. Survey, p. 159. 



8. Ossining, N. Y. H. Ries, analyst. Bulletin 44, N. Y. State Museum, p. 829. 



9. Tuckahoe, N. Y. Ledoux, analyst. 20th Ann. Rep. U. S. Geol. Survey, pt. 6, p. 427. 

 10. Gates, Monroe County. N. Y. D. H. Newland, analyst. Bulletin 44, N. Y. State Museum,, 



p. 706. 



Extraction of magnesia from magnesian limestone. Two principal 

 processes have been suggested for extracting magnesia from magnesian 

 limestone. 



Scheibler process. The mixture of lime and magnesia left by burn- 

 ing magnesian limestone is made into a thick milk by adding suffi- 

 cient water. Into this solution is poured water containing 10 to 15 

 per cent, by volume, of molasses, and the mixture is mechanically 

 stirred. In a few moments saccharate of lime is formed, which re- 

 mains in solution while the magnesia is precipitated. On putting 

 through a filter-press the magnesia remains behind, while the saccha- 

 rate of lime passes through. The composition of the magnesia so 

 obtained at a German plant was: 



Silica (SiO 2 ) } 



Alumina (A1 2 O 3 ) \ 1 .47 per cent 



Iron oxide (Fe 2 O 3 ) J 



Lime (CaO) 2.18 " " 



Magnesia (MgO) 95.99 " " 



The saccharate of lime which passed through the filters is now treated' 

 for recovery of its constituents. Carbon dioxide precipitates the lime 

 as carbonate, after which it is filtered and the lime carbonate precipi- 



