Copper Carbonates

Copper Carbonates

 

carbonate salts of copper. Normal copper carbonate has not been isolated yet. Copper carbonate (basic) occurs in nature as the emerald green mineral malachite, CuCO3 · Cu(OH)2, and the sky blue mineral azurite, 2CuCOa. Cu(OH)2. The basic carbonate CuCO3 - Cu(OH)2 · 0.5H2O is obtained by the action of Na2CO3 on CuSO4 in an aqueous solution; upon heating, the carbonate is converted into malachite.

Copper carbonates are unstable and at temperatures above 200°C break down into CuO, CO2, and H2O. They are insoluble in water but can be dissolved in ammonia in the presence of ammonia salts. Azurite is used as a pigment; it is also used in pyrotechnics, metallurgy, and other industries. Both azurite and malachite are used in the fashioning of decorative objects and jewelry.

References in periodicals archive ?
Mining extracted ferruginous silicified slate with copper carbonates (malachite and azurite) passing into cuprite, native copper and minor chalcocite in what appears to be a classic supergene profile.
More recent mining of the oxide zones at the Girilambone, New Cobar and Elura (Endeavor) deposits has exposed a rich diversity of secondary minerals including copper carbonates and phosphates, copper and lead arsenates, and silver minerals.
Metallic copper usually occurs in rock outcrops where the atmosphere and water have oxidized copper sulfides into copper oxides and two copper carbonates, brilliantly colored blue azurite and green malachite.
Copper, with grades shown in Table 2, is mainly contained in chalcopyrite, bornite, chalcocite, and copper carbonates in the oxide zone.
The topic, "Azurite and Other Copper Carbonates," matched the Best of Species mineral.
This stockwork is in marine volcanic rocks which show calcopyrite, specularite and copper carbonates with Gold values from 1 to 5 grams per tonne, silver of 30 to 90 grams per tonne and Copper from 1 percent to 3 percent per tonne.