Solution to world's largest waste stream: Make sand
Date:
April 12, 2022
Source:
Universite' de Gene`ve
Summary:
After water, sand is the most exploited natural resource on
the planet.
However, its extraction from seas, rivers, beaches and quarries
has an impact on the environment and surrounding communities. A
new study has found that a step-change in mineral processing could
drastically reduce mineral waste -- the world's largest waste
stream -- while creating a sustainable source of sand. Coined
'ore-sand' this material has the potential to address two global
sustainability challenges simultaneously.
FULL STORY ========================================================================== After water, sand is the most exploited natural resource on the planet.
However, its extraction from seas, rivers, beaches and quarries has an
impact on the environment and surrounding communities. A new study by researchers from the University of Geneva (UNIGE) and the University
of Queensland's Sustainable Minerals Institute (SMI) has found that a step-change in mineral processing could drastically reduce mineral waste
-- the world's largest waste stream - - while creating a sustainable
source of sand. Coined "ore-sand," this material has the potential to
address two global sustainability challenges simultaneously, according
to the report ''Ore-sand: A potential new solution to the mine tailings
and global sand sustainability crises."
========================================================================== Concrete, asphalt, glass, electronic chips: sand has many applications.
Composed of small mineral particles, this granular material comes from sensitive dynamic environments such as seas, beaches, lakes and rivers
or, from static land-based environments such as ancient river deposits
and rock quarries. It is estimated that 50 billion tons of sand are
used each year. Over the past two decades demand has tripled primarily
due to urbanisation and population growth, a trend which is expected to continue with aggregates use reaching beyond 50 Bt per year by 2030.
In addition to the risks of local shortages, the extraction of such a
volume of sand has environmental and societal consequences. For example,
it is leading to erosion in river banks, which significantly increases
the risk of flooding. In some countries, sand mining has caused loss of livelihoods in communities.
Two sustainability challenges with one solution Researchers from the
University of Geneva (UNIGE) and from the Sustainable Minerals Institute
at the University of Queensland (UQ), Australia, have researched the
potential of a viable alternative to naturally occurring sand.
This material, presented in a recent report published by the two
universities, has been coined ''ore-sand''.
UNIGE's Adjunct Professor at Department F.-A. Forel for environmental
and aquatic sciences of the Faculty of Science, Pascal Peduzzi said
that "ore-sand has the largest potential in volume for reducing the
amount of sand taken in the natural environment. By using what has
been so far considered as ''left over'' material, the project gives an important impetus towards a more circular economy." The production of
ore-sand can help reduce the production of mineral mining waste and thus
the further build-up of mine tailings. Mineral wastes from the mining
of ores currently represents the largest waste stream on the planet,
estimated between 30-60 billion tonnes per year. These residues come
from crushing operations to extract certain metals from the rock.
========================================================================== SMI's Development Minerals Program Leader Professor Daniel Franks
said ore-sand has the potential to address two global sustainability
challenges simultaneously. "Separating and repurposing these sand-like materials before they are added to the waste stream would not only significantly reduce the volume of waste being generated but could also
create a responsible source of sand." Reduction of carbon emissions The 12-month study independently sampled and investigated sand produced from
iron ore mining, pioneered by Vale S.A in Brazil, which has previously experienced tailings dam failures. After an analysis of the chemical
properties and some refining operations, the researchers were able to demonstrate that part of the material stream which would otherwise end
up as mining residues could be used as a substitute for construction and industrial sand, in the same way as recycled concrete and steel slag. "If
these results can be replicated with other types of mineral ores there is potential for major reductions in global mine tailings." "By mapping
mining locations worldwide and modelling global sand consumption,
we discovered that almost a third of mine sites can find at least
some demand for ore-sand within a 50 km range. This could contribute
to at least 10% reduction in the volume of tailings generation at each
site. Simultaneously, almost half of the global sand market (by volume)
could find a local source of ore-sand. For example, ore-sand could
potentially substitute 1 billion metric tons of sand demand in China,"
explains Daniel Franks.
In addition, the life cycle assessment of ore-sand, based on the Vale
case, shows that substituting naturally sourced sand with ore-sand
could potentially lead to net reductions in carbon emissions during
sand production. The carbon emissions by transport is however a key consideration.
==========================================================================
A benefit for mining companies "Considering the co-production of ore-sand
is a significant advantage for mining companies: it reduces the large
tailings which hinder operational mining activities, while at the same
time can generate additional revenues. Ore-sand is a step towards a "no tailings mine'', explains Pascal Peduzzi. Developing countries have fewer options for using recycled aggregate materials, given their more recent infrastructure. However, many have mining operations that can generate
ore-sand as a by-product." Some of the next steps are to collaborate
with aggregate market players to demonstrate this substitute material's ease-of-use, performance and sourcing process. Findings from the study
were presented at the 5th United Nations Environment Assembly. A new UNEA resolution (UNEP/EA5/L18/REV.1) on ''Environmental aspects of minerals
and metals management'' calls for strengthened scientific, technical
and policy knowledge with regard to sand to support global policies and
action regarding its environmentally sound extraction and use.
Citation: Golev, A., Gallagher, L., Vander Velpen, A., Lynggaard, J.R.,
Friot, D., Stringer, M., Chuah, S., Arbelaez-Ruiz, D., Mazzinghy, D.,
Moura, L., Peduzzi, P., Franks, D.M. (2022). Ore-sand: A potential
new solution to the mine tailings and global sand sustainability
crises. Final Report. Version 1.4 (March 2022). The University of
Queensland & University of Geneva.
========================================================================== Story Source: Materials provided by Universite'_de_Gene`ve. Note:
Content may be edited for style and length.
==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/04/220412161611.htm
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