LOW CARBON FOOTPRINT IN
-KHILESH KUMAR BHANDARI
-KRISHNA KUMAR HANSDAH
-BHAGAT LAL TUDU
The total amount of green house gas
produced to directly and indirectly
support human activities , usually
expressed in equivalent tons of carbon
Global-warming potential (GWP) is a relative
measure of how much heat a greenhouse gas traps
in the atmosphere.
For example, the 20 year GWP of methane is 72, which means
that if the same mass of methane and carbon dioxide were
introduced into the atmosphere, that methane will trap 72
times more heat than the carbon dioxide over the next 20 years
The biggest savings are with aluminium where the recycled only takes
6% of the energy, but other pollution is caused in the production both
times.12 kg of CO2 are produced per kg aluminium from bauxite but
only 1.7 kg CO2 from recycled aluminium. Pollution
Kgs of CO2 produced per kg of metal
Aluminium from bauxite 12
Aluminium recycled 1.7
Brass from ores 6.7
Brass recycled 1.7
Steel from ore 2.82
Steel recycled 0.5
Kgs of CO2 produced per kg of metal
Copper from ore 5.5
Copper recycled 1.4-4
Aluminium has the highest CO2 production per kg but it is much lighter
than most metals.
Biohydrometallurgy can be defined as the field of applications resulting
from the control of natural (biochemical) processes of interactions between
microbes and minerals to recover valuable metals.
It is a subfield within hydrometallurgy which includes aspects of
It is used to perform processes involving metals, for example,
microbial mining, oil recovery, bioleaching, water-treatment and
It is mainly used to recover certain metals from sulfide ores.
It is usually utilized when conventional mining procedures are too
expensive or ineffective in recovering a metal such
as copper, gold, lead, nickel and zinc.
Bioleaching is the extraction of metals from their ores
through the use of living organisms. This is much cleaner
than the traditional heap leaching using
cyanide.Bioleaching is used to recover copper, zinc, lead,
arsenic, antimony, nickel, molybdenum, gold, silver, and
Role of microorganisms in mineral bio-oxidation:
•Microbes produce the leaching chemicals.
•Microbes also provide the most efficient reaction
space for bioleaching to occur.
(aq) + 2LH(organic) → CuL2(organic) + 2H+
Because this complex has no charge, it is no longer attracted
to polar water molecules and dissolves in the kerosene, which is then
easily separated from the solution
(aq) + Fe(s) → Cu(s) + Fe2+
The bacterium Paenibacillus polymyxa
grown in the presence of hematite.
BENEFITS OF BIOLEACHING
• Simple and inexpensive process. Substantially lower capex and
opex than in traditional smelting and refining processes
• No sulfur dioxide emissions as in smelters.
• No need for high pressure or temperature
• Leaching residues less active than in physico-chemical processes
• Ideal for low grade sulfide ores – lower cut-off rate possible
Nanoscavengers - a simple approach to
This method, termed the nanoscavenger concept, is based on silica particles and
is an easy, green approach to the collection and concentration of metals for
analysis. The technique is expected to yield both environmental and cost
Analytical chemists regularly need to remove metals from aqueous solutions so
they can be analysed. Extraction into organic solvents is currently the most
popular procedure for doing this.
Howard and Khdary's approach uses chelating organic ligands to modify the
surface of silica spheres with an approximate diameter of 250 nm. These
particles are able to bind to metals temporarily, and can be collected easily
SEM image of the
The concept behind this research is beautifully simple. The nanoscavenger moves
naturally through the solution under examination, binding any metal with which it
comes into contact. This movement, using Brownian motion, means that no physical
agitation is required. Simple filtration removes the metal-bound nanoscavenger
from the solution. Finally, separation of the metal and nanoscavenger allows analysis
of the metal using standard detection methods.
A wide range of organic materials can be extracted on the surface of
nanoscavengers by hydrophobic interaction. This is can be achieved by modifying of
the silica surface with different organic groups. Indeed, large particle size modified
silica has been widely and successfully used for the pre-concentration of drugs and
the technique is environmentally friendly as smaller
volumes of organic solvents are used than with the other
extraction methods and only small quantities of
nanoscavenger (50-200 mg) need to be dispersed.
Large numbers of samples can be quickly and
simultaneously treated, even at the sampling site.
One of the most important physical advantages of this
procedure is less human or mechanical effort is needed as
no mechanical agitation is required.