Zinc Minerals and Deposits
Zinc in the Earth's crust is about 65 g/t (0.0065%). Zinc usually occurs as the sulphide, mostly deposited from hydrothermal solutions and simic and sialic magmas. Zinc deposits can be classified as follows:
Deposits
- Simic vulcanogenic –sedimentary deposits that sometimes occur as massive ore bodies and sometimes as impregnations (ore from this kind represent about 60% of total world reserves). There are several mining of this type such as Mount Isa and Broken Hill (Australia),Kidd Creek and Anvil Mine (Canada) ,Rammelsberg and Meggen (Germany),Bleiberg (Austria) and…..
- Simic- hydrothermal or marine sedimentary deposits(ore from this kind represent about 30 % of total world reserves).There are some mining of this kind such as Kipishi (Zaire),Kabwe (Zambia),Tsumed South-West Africa ,New Zinc Belt and Old and New Lead Belt( USA) and …
- Sialic lodes (impregnation and replacement deposits) ore from this kind represent about 10% of total world reserves. There are in some country deposits from this kind like, Bad Grund (Germany),western U.S. states such as Idaho, Colorado and Utah and ……. Cd,Ag Pb and Cu are important by product of Zinc.
Minerals
Zinc Minerals are summarized in table1:
| Mineral | Formula | % Zn | Crystal system | Density,g/cm3 |
| Zinc blende or Sphalerite | ZnS | 67.09 | tetrahedral | 3.9-4.1 |
| Wurzite | ZnS | - | Hexagonal | 3.98 |
| Simthsonite | ZnCO3 | 52.14 | trigonal | 4.30-4.45 |
| Hemimorphite | Zn2SiO4.H2O | 54.3 | Rhombic pyramidal | 3.4-3.5 |
| Willemite | Zn2SiO4 | 58.68 | rhombohedral | 4.0 -4.2 |
| Franklinite | (Zn,Fe,Mn)O.(Fe2,Mn2)O3 | 21%ZnO 59%Fe2O3 | Cubic | 5.0-5.1 |