BORAX 4x7 



acres of rich marsh land near Lake Alvonl in the southern 

 part of Harney county. The total area of the deposit, which 

 is south of the lake, aggregates approximately 10,()()(J acres. 

 The ground is level and treeless, and is incrusted with a layer 

 several inches thick containing in addition to sodium borate 

 numerous other salts of sodium. During the long summer 

 months the loose surface deposit is shoveled into small heaps, 

 and is subsequently replaced w^ith a second incrustation within 

 a comparatively short period of time. The stock of crude 

 material collected during the summer is sufficient to enable 

 the refinery to continue in operation throughout the entire 

 year. The crude mineral, containing from 5 to 20 per cent 

 of boric acid in combination wath a sodium base, is shoveled 

 into tanks containing boiling water to w^hich is added a proper 

 quantity of chlorine gas or sulphuric acid to decompose the 

 alkali salts and thus liberate the boric acid. After a treatment 

 of twenty four hours in the tank the clear supernatant liquor 

 is withdrawn to the crystallizing vats and allowed to cool, which 

 causes the boric acid to separate in the form of crj^stals, leaving 

 a mother liquor, which is used repeatedly until it contains suffi- 

 cient sodium salts to warrant a separate treatment. 



The pruicipal minerals containing boron are as follows: 

 Sassolite, boric acid (H3BO3); borax (tincal), sodium biborate 

 (NaoB^Or.lOHaO); ulexite (boronatrocalcite) (CaNaB,0,.8H3 

 O); colemanite (impure varities, priceite and pandermite), 

 calcium borate (CaoBeOn.SHoO); and boracite (stassfurtite), 

 magnesium borate (2Mg3B80i'^.MgC12) . Boron is also a constit- 

 uent of several common silicate minerals, notably tourmaline 

 and datolite. Borax, sodium biborate (XaoBjOr.lOHoO), is 

 the only important salt derived from boric acid. It occurs 

 native in California, Ceylon, and Thibet, and from the last 

 named place it is obtained in the form of tincal, an imjnire 

 crystaUized borax containing calcium and magnesium sulphates 

 and chlorides and a greasy substance which is adiled presum- 

 ably to protect the cr>'stals from efflorescence and break- 

 age. The tincal is purified by dissolving in warm water 

 and adding limewater and calcium chloride in order to pre- 

 cipitate the grease as a lime soap. After filtering, the pure 



Vol. 6— »7 



