Question

natural occurrence of thallium, how and where ?

Answer 1

Although thallium is a modestly abundant element in the Earth's crust, it is not generally economically recoverable. It is generally found in association with potassium-based minerals in clays, soils, and granites. It is also found in manganese nodules found on the ocean floor which is again expensive in terms of isolation. It is isolated for practical purposes from the trace amounts that are found in copper, lead, zinc, and other heavy-metal-sulfide ores. Thallium is found in the minerals such as crookesite TlCu₇Se₄, hutchinsonite TlPbAs₅S₉, and lorándite TlAsS₂.It is also found in iron pyrite and is obtained as a by-product of roasting it for the production of sulfuric acid. Thallium can also be obtained from the smelting of lead and zinc ores. it also occurs in nature as complexes of sulfides or selenides that primarily contain antimony, arsenic, copper, lead, and/or silver.