Environmental Engineering Reference
In-Depth Information
TABLE 11.2
(Continued)
Metal
Ore Mineral
Composition
Percent Metal
Tin
Cassiterite
Stamnite
SnO
2
Cu
2
S FeS SnS
2
78
27
Nickel
Pentlandite
Garnierite
(Fe, Ni)S
H
2
(Ni, Mg)SiO
3
H
2
O
22
Chromium
Chromite
FeO Cr
2
O
3
68
Manganese
Pyrolusite
Psilomelane
Braunite
Manganite
MnO
2
Mn
2
O
3
(OH)
2
3Mn
2
O
3
MnSiO
3
Mn
2
O
3
H
2
O
63
39
71
81
Aluminium
Bauxite
Al
2
O
3
2H
2
O
39
Antimony
Stibnite
Sb
2
S
3
71
Bismuth
Bismuthianite
Bi
2
S
3
81
Cobalt
Smaltite
Cobaltite
CoAs
2
CoAsS
28
35
Mercury
Cinnabar
HgS
86
Molybdenum
Molybdenite
Wulfenite
MnS
2
PbMoO
4
60
39
Tungsten
Wolfanite
(Fe Mn)WO
4
76
Minerals can consist of a single element such as diamond or native gold. More often minerals are in the form of combi-
nations of two or more elements, and about 3,000 minerals species are known. Only 50 of them are rock forming.
Rocks
To the geologist, rock is any substantial portion of Earth, whether solid or loose. In the
geological sense, rock also includes glaciers and sometimes even water bodies, which after
all, are only liquid ice. To most of us, however, rock includes only solid materials that can-
not be excavated by hand. Scientii cally, rocks are a composition of mineral assemblages.
Rocks are classii ed in various ways, the most common being according to their mode of
formation. A few rocks consist of only one mineral, such as quartzite or limestone, but
these are the exceptions to the rule. A mineral assemblage is a mixture of any number of
minerals and elements. The composition of rock, of course, varies widely, but minerals can
be separated by physical means, a key characteristic exploited in ore processing. Unlike
minerals, rock retains the properties of its main constituents.
There is the i nal point that to the exploration geologist, a mineral is anything that is
commonly considered as such. Thus coal, limestone, or other rocks are not truly miner-
als, but they certainly are mineral resources, as is petroleum, which is neither mineral
nor rock.
Minerals can be separated
by physical means, a key
characteristic exploited in ore
processing.
Search WWH ::
Custom Search