The Albion process is an atmospheric leaching process for processing
zinc
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic t ...
concentrate
A concentrate is a form of substance that has had the majority of its base component (in the case of a liquid: the solvent) removed. Typically, this will be the removal of water from a solution or suspension, such as the removal of water from fru ...
,
refractory
In materials science, a refractory material or refractory is a material that is resistant to decomposition by heat, pressure, or chemical attack, and retains strength and form at high temperatures. Refractories are polycrystalline, polyphase ...
copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish ...
and refractory
gold
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile ...
.
The process is important because it is the most cost-effective method currently in use for extracting both the zinc and
lead
Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate ...
from concentrates that contain high lead levels (7% or greater). Zinc and lead often occur together and large remaining zinc deposits contain levels of lead that exceed what can be economically extracted through other techniques. The Albion process is not sensitive to the concentration grade and gives favorable recovery with both low grade and dirty concentrates.
Environmental impact is also claimed to be mitigated using this technology because in contrast to other methods,
sulfur dioxide
Sulfur dioxide ( IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic ...
is not emitted and less energy is consumed over all.
History
Development of the Albion process started during the early nineties led by
Mount Isa Mines
Mount Isa Mines Limited ("MIM") operates the Mount Isa copper, lead, zinc and silver mines near Mount Isa, Queensland, Australia as part of the Glencore group of companies. For a brief period in 1980, MIM was Australia's largest company. It ha ...
. It was first patented in 1993.
Several pilot plant projects were conducted in 1994 and 1995 which tested the feasibility of using the technology to process high arsenic gold and copper ore.
[
The Albion Process has been successfully installed in seven projects globally:
* GPM Gold Project (Gold, Armenia)
* Las Lagunas Tailings (Gold, Dominican Republic)
* Sable Copper Project (Copper, Chalcopyrite, Zambia)
* Asturiana de Zinc (Zinc, Spain)
* Nordenham Zinc Refinery (Zinc, Germany)
* McArthur River (Zinc, Australia)
]
Process
The ore concentrate is first introduced into an IsaMill
The IsaMill is an energy-efficient mineral industry grinding mill that was jointly developed in the 1990s by Mount Isa Mines Limited ("MIM", a subsidiary of MIM Holdings Limited and now part of the Glencore Xstrata group of companies) and Netzsch F ...
. This comminution
Comminution is the reduction of solid materials from one average particle size to a smaller average particle size, by crushing, grinding, cutting, vibrating, or other processes. In geology, it occurs naturally during faulting in the upper part ...
step places a high degree of strain on the mineral lattice and causes an increase in the number of grain
A grain is a small, hard, dry fruit ( caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legu ...
boundary fractures and lattice defects of several orders of magnitude. The increase in the number of defects within the mineral lattice "activates" the mineral, facilitating leaching. The rate of leaching is also enhanced, due to the increase in the mineral surface area.
The oxidative leaching stage is carried out in agitated tanks operating at atmospheric pressure. Oxygen is introduced to the leach slurry to assist the oxidation. Leaching is autothermal, not requiring any external heat. Temperature is controlled by the rate of addition of oxygen, and by the leach slurry density.
Chemistry
The general reaction for the leaching process is:
References
{{DEFAULTSORT:Albion Process
Metallurgical processes