How to Obtain Arsenic

By Education Editor

How to Obtain Arsenic. Arsenic occurs in elemental form but is much more common in minerals. Most of the world's arsenic is mined in China with most of the remainder coming from Chile, Mexico, the Philippines and Russia. The following steps will describe the more common methods of obtaining this highly poisonous element.

Mine arsenic directly. Deposits of pure arsenic are known to occur naturally although they are too small to mine commercially.

Heat orpiment (As2S3) with soap. This method was described, albeit vaguely, by Albertus Magnus in the 13th century.

Reduce White Arsenic (As2O3), known as arsenolite, with charcoal by heating to get the following reaction: 2As2O3 + 3C + heat -> 4As + 3CO2. This method was clearly described by Johann Schroder in 1649. Arsenic is now prepared in the laboratory with a similar reaction heating arsenious oxide (As4O6) with carbon.

Dig for arsenic ore commercially. Arsenic is found in a number of commercially important minerals such as arsenopyrite, realgar, orpiment and loellingite with arsenopyrite being the most common. These minerals are heated to 700 degrees Celsius in the absence of air. The arsenic sublimates out of the mineral as a gas and it is condensed into solid pure arsenic.

Obtain arsenic as a by-product of mining and refining other metals. Recover the flue dusts produced from copper, nickel and tin, which are high in the arsenides of these metals. Heat them in air to sublimate the arsenic and cool the gas to condense the arsenic back into a solid. This method accounts for most of the arsenic production in the world.