Download BIOHYDROMETALLURGY of IRON ORE

BIOHYDROMETALLURGY of IRON ORE
Present methods
 Pulverising iron ore to fines
 Agglomerating them to pellets ( temp upto 1200
degrees)
 Reheating in blast furnaces(1500 degrees)
these process are energy intensive
 to date there has been no practical technique
for hydrometallurgical extraction of iron
 Hydrometallurgy methods require huge amts of
reagents (acids)
 The problems in iron extraction by this means have
been:


The standard leaching method is dissolution of fully-oxidized
ore by acid.
Electrolysis of Fe+3 solution to produce metallic iron is
inefficient
HYDROMETALLURGY
 Hydrometallurgy is part of the field of extractive
metallurgy involving the use of aqueous chemistry
for the recovery of metals from ores, concentrates,
and recycled or residual materials. Hydrometallurgy
is typically divided into three general areas:



Leaching
Solution concentration and purification
Metal recovery
Leaching
 In general, leaching is the extraction of certain
materials from a carrier into a liquid
Leaching (Cont.)
 In the leaching process, oxidation potential,
temperature, and pH of the solution are important
parameters, and are often manipulated to optimize
dissolution of the desired metal component into the
aqueous phase.
 The three basic leaching techniques are



In-situ leaching
Heap leaching
Vat leaching
Alternative solution (Back ground)
 Since iron is a necessary nutrient for most
organisms, it can only be made biologically available
if it is chemically reduced, and so the iron-reducing
bacteria serve a critical role in the cycling of iron in
the ecosystem
Alternative solution (Observation)
 Certain bacteria (for
example, Geobacter
metallireducens and
Shewanella
putrefaciens) reduces
Fe+3 to Fe+2 under
anaerobic conditions, as
a part of their
metabolism
BIOHYDROMETALLURGY
These microorganisms actually gain energy
by breaking down minerals into their
constituent elements.
Bioleaching by microorganisms takes place
owing to destruction of a crystal lattice of
minerals, composing solid.
This shakes of a lattice are causes the
destruction of a mineral.
The process
Merits
 Using microorganisms, costs are reduced
 Eco-friendly method
 Low grade dumps are effectively leached
 Uses organic waste (sawmill chips and dust,
papermaking sludges, miscellaneous biomass, waste
carbohydrates, or even sewage sludges) as a feed for
bacteria
Thank you