Chemical Engineering October 2011 - 11

Edited by Gerald Ondrey
October 2011
U.S. production is scheduled
for a critical metal
C
hina produces about 98% of the
world's electrolytic manganese metal
(EMM), a vital ingredient used in specialty
steels, aluminum and electronics.
In contrast, the U.S. produces no EMM,
says Nick Weir, an executive with U.S.
American Manganese Inc. (AMY; White
Rock, B.C., Canada; www.american
manganeseinc.com). AMY plans to
change that by using a patented hydrometallurgical
process to extract the
metal from its Artillery Peak Manganese
Properties in northwestern Arizona. The
company expects to produce EMM for
$0.44/lb, versus $0.98/lb in China.
Like the Chinese processes, AMY's
method is a modified and updated version
of technology developed by the U.S.
Government in World War II. The Arizona
deposit consists of low-grade oxide
material (2-7 wt.% Mn) that contains
pyrolusite (MnO2), psilomelane and
other four-valent Mn oxides. High-grade
oxide ore is typically subjected to hightemperature
roasting to render the Mn
leachable by sulfuric acid for electrolysis,
Mn
resource
Sulfurous
acid
Sodium
carbonate
Sodium
sulfate
Mix
tank
Pregnant
leach
solution
Clean
tailings
but this is not economical for
lower-grade material, says Weir.
No roasting is required for
Precipitation
tank
Sodium
sulfate
solution
Chiller /
nanofilter
Clean
water
Manganese
carbonate
Sulfuric
acid
Mn solution
mix tank
AMY's process, in which ore
is leached in sulfurous acid
(rather than sulfuric) in a
stirred tank, followed by the
removal of impurities. Aluminum, arsenic,
most of the iron and silica are precipitated
from the solution by raising
the pH above 6, then zinc is removed by
sulfide precipitation in a second purification
stage. Mn is precipitated from
the pregnant solution as manganese
carbonate (MnCO3) by mixing sodium
carbonate with the solution. The MnCO3
is then dissolved in recycled sulfuricA
new approach to maintaining tubular heat exchangers
A
t the 2nd Annual ChemInnovations
Conference and Expo (Houston; September
13-15), Hemi-O Technologies LLC
(Corpus Christi, Tex.; dixonengineering@
gmail.com) introduced its patent-pending
technology that enables external access to
individual tubes in a heat exchanger while
the exchanger is in service and operating
at full capacity. The so-called Hemi-O (heat
exchanger maintenance and inspection -
online) allows safe and leak-free physical
isolation of, and external access to, each
and every tube, thereby enabling tube I.D.
cleaning, tube inspection and testing; and
plugging of failed or failing tubes - all performed
online using conventional methods
for cleaning, inspecting and plugging.
" This technology will allow an end-user to
be far more proactive in maintaining their
exchangers from both a heat transfer perspective
and from a condition monitoring
perspective, says president Chris Dixon,
who invented the technology. Conventional
maintenance is normally performed off line,
which requires waiting for a plant turnNote:
For more information, circle the 3-digit number
on p. 78, or use the website designation.
Mn
solution
Electrolytic
cell
Manganese
metal
acid electrolyte for electrowinning.
In laboratory tests the process has
obtained EMM of greater than 99% purity,
says Weir. He adds that most of the
water used in the process is recycled by
precipitation and nanofiltration. AMY
has started up a pilot plant of undisclosed
capacity, which will operate until
the late fall. Commercial production is
scheduled to start sometime in 2014.
around or - for severe fouling - can lead
to an unscheduled shutdown and associated
costs. Benefits of online servicing include
improved heat-exchanger efficiencies, reduced
energy consumption and lower operating
costs, says Dixon.
The Hemi-O technology can be applied
to most tubular heat exchangers, such as
shell-and-tube and air-fin heat exchangers
and surface condensers. The technology centers
around the installation of a modified
exchanger end plate (or channel cover) that
is designed to have penetrations through it
with integral valves and seal assemblies.
The valve and seal systems allow for leakfree
insertion of tubular isolation lances
that mate-up with each of the tube ends
at the tubesheet, while the heat exchanger
is online and operating normally. Once the
lances are engaged and sealed at either
end of the tube, then that tube can be depressured
and de-inventoried to a safe location.
Once de-pressured and de-inventoried,
the lance end valves, which are outside the
(Continues on p. 12)
Renewable jet fuel
Houston-based bioenergy
company Terrabon Inc. (www.
terrabon.com) has been
awarded a $9.6-million, 18month
contract from Logos
Technologies (Arlington, Va.;
www.logos-technologies) to
produce 6,000 L of renewable
jet fuel for the Defense
Advanced Research Products
Agency (DARPA; Arlington,
Va.; www.darpa.mil) using its
MixAlco biorefining process.
The MixAlco process converts
nonsterile, nonfood biomass
to organic acids, alcohols,
ketones and other chemicals
that can be further processed
into renewable hydrocarbon
fuels. The customized production
process, to be constructed
at Terrabon's Bryan,
Tex. demonstration facility,
employs proprietary Terrabon
technology that allows the
non-sterile anaerobic diges(Continues
on p. 13)
CHeMICAL engIneeRIng www.CHe.CoM oCToBeR 2011 11
http://www.american http://www.manganeseinc.com http://www.terrabon.com http://www.logos-technologies http://www.darpa.mil http://www.CHe.CoM
Chemical Engineering October 2011

Table of Contents for the Digital Edition of Chemical Engineering October 2011
