52 



UNITED STATES MINERAL RESOURCES 



also alloyed with copper to give increased corrosion 

 and erosion resistance and a higher annealing tem- 

 perature. 



Potential uses of arsenic include the manufacture 

 of gallium arsenide or gallium arsenide phosphate 

 diodes, improved lead-antimony or lead-tin-antimony 

 alloys, catalysts used in the formation of some 

 organic compounds, and nucleating agents in 

 ceramic manufacture. The potential uses of the ele- 

 ment, however, are not expected to increase its 

 consumption appreciably. 



Arsenic and arsenic compounds are important to 

 the production of certain crops in countries that 

 have developed advanced agricultural technologies — 

 the United States, Canada, the countries of western 

 Europe, Australia, and New Zealand, and to a lesser 

 degree, the U.S.S.R. and the countries of eastern 

 Europe. Industrial-technological-scientific societies 

 have developed only where manpower has been freed 

 from the production of foods and textiles. The ini- 

 tial increases in agricultural productivity resulted 

 from mechanization; later increases resulted from 

 the use of chemical fertilizers and improved seed; 

 and more recent increases resulted from the use of 

 insecticides, pesticides, and herbicides. Insecticides, 

 pesticides, and herbicides play an important role in 

 achieving the standard of living now enjoyed by the 

 advanced nations, and they undoubtedly will play an 

 increasing role in advancing the standard of living 

 of the emerging nations. 



Substitutes have been sought for arsenic com- 

 pounds, not because arsenic is in short supply or is 

 exepnsive, but because it is toxic to humans. In place 

 of inorganic arsenic compounds, a group of chlori- 

 nated hydrocarbons and organic phosphorous com- 

 pounds have been developed which are claimed to 

 have lower toxicities for humans. Substitutes for 

 arsenic used in industrial and metallurgical proc- 

 esses may in part be met by the chemically allied 

 metalloids antimony and bismuth. 



Domestic consumption of arsenic iluctuates from 

 about 20,000 to about 30,000 short tons per year. 

 An estimate for 1968 shows that the United States 

 consumed or stocked the equivalent of 26,200 short 

 tons of arsenic. Of this amount, 2,900 tons (11 per- 

 cent) came from domestic sources and 23,300 tons 

 (89 percent) came from foreign sources, either in 

 arsenic metal and compounds or in ores and con- 

 centrates. Of the imports, Sweden supplied 37 per- 

 cent, Mexico 28 percent, and France 26 percent. 

 Only about 40 tons (about 0.2 percent) came from 

 the Communist world, although in 1967 shipments 

 from this source exceeded 1,000 tons. 



The domestic output of arsenic is insufficient to 



meet current demand, although the United States 

 has both the sufficient arsenic resources and the 

 production facilities to meet demand. The increas- 

 ing reliance on foreign sources, which has taken 

 place over the last 25 years, is chiefly due to eco- 

 nomics. 



EXPLOITATION 



Arsenic, because it is recovered as a byproduct, 

 has had a history of exploitation different from that 

 of most other commodities. It is removed from vari- 

 ous ores during smelting, but its output is dependent 

 upon several factors, including size, grade, and type 

 of deposits, availability of smelter facilities, and 

 price policies at custom smelters. Arsenic-rich seg- 

 regates are refined at smelters with facilities for 

 doing so. Where facilities are lacking or are idle, 

 the segregates are stockpiled and shipped to other 

 processing plants. Supplies have normally exceeded 

 requirements and can be increased when necessary 

 by activiating idle processing plants to recover 

 arsenic from ores not ordinarily so treated. 



Significant arsenic production started around 

 1900 and has increased steadily since then. Arsenic 

 first was produced from arsenical gold deposits and 

 later from other types of deposits. The arsenic-rich 

 B'oliden cooper deposit in Sweden started producing 

 in 1926 and in large part made Sweden the world's 

 foremost producer of arsenic. 



Environmental problems resulting from exploita- 

 tion of arsenic-bearing deposits are similar to those 

 of other deposits. Access roads, mining, milling, 

 and smelting and the disposal of overburden ma- 

 terial, waste rock, mill tailings, and slag all tend to 

 disturb the original environment of any area. At 

 best these disturbances can only be minimized, and 

 then at some cost. With the final cessation of min- 

 ing and allied activity, some operational areas can 

 be restored to approximate original conditions but 

 at considerable cost. 



Where arsenic in sulfide minerals is exposed to 

 the atmosphere, as in the waste dumps of mines, 

 soluble arsenates may be formed which can be a 

 source of stream pollution. Smelters which treat 

 arsenical sulfide ores can lose arsenic to the atmos- 

 phere in the form of arsenic oxides or arsine, 

 AsH„ although most of the arsenic volatilized in 

 smelting and roasting forms a fine ash or dust which 

 is arrested in the smelter stacks or Cottrell precipi- 

 tators. 



GEOLOGIC ENVIRONMENT 



GEOCHEMISTRY 



Arsenic is a relatively rare crustal element, con- 



