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Every Drop Counts
Drinking Acid Mine Water
Research Project
The philosophy of Professor Alison Lewis, Director of the Crystallization and Precipitation Research Unit, is that
researchers need to consider both water and its contaminants as resources, and to design processes that recover both.
With this in mind, she and her team have devised a
means of treating acid mine water so that it is ‘good
enough to drink’, and are taking one step closer to
achieving the goal of water security, one of the most
significant challenges facing the country. In her
technique, known as Eutectic Freeze Crystallization
(EFC), the contaminated waste stream is frozen to a
point where both ice and salt are formed – ice is the
form in which water is recovered. For this reason, it
is important that the ice formed is pure to ensure
that good-quality water is obtained. The process,
which is both environmentally friendly and cost-
effective, also allows for usable salts to be extracted
from the toxic acid mine water. It can, furthermore,
be used in a broad range of industrial sectors that
produce wastewater.
Master’s student Michael Kapembwa won an award for the
Outotec “Sustainability in Mineral Industry” best paper
presentation at the Southern Africa Institute of Mining
and Metallurgy-SAIMM MinProc 2012 workshop for his
paper
Ice growth mechanisms in electrolyte aqueous
solutions
. Michael was born in Luanshya, a small mining
town in Zambia, and completed his primary and secondary
education in Livingstone. In 2009 he graduated with a
bachelor’s degree in Metallurgy and Mineral Processing
from the University of Zambia. After working at different
mines in mineral processing and hydrometallurgy and in a
full-time job with Non-Ferrous Africa Mining Cooperation
as a Metallurgist (Foreman), he decided to join the
Crystallization and Precipitation Research Unit to further his
studies in chemical engineering with a focus on wastewater
and mining brine treatment.
Master's student Michael Kapembwa