ALUMINUM ALUMINUM ALUMINUM ALUMINUM ALUMINUM 
Project Fact Sheet 
BENEFITS 
APPLICATIONS 
POTLINING ADDITIVES 
ü Potential energy savings of about 
two trillion British thermal units (Btu) 
annually by increasing cell efficiency 
in the U.S. by 2010 
ü Potential energy cost savings of 
$23 million annually by 2010 [about 
$5,000 per year for a 150 kiloampere 
(kA) production cell] 
ü Improved pot operation and 
extended cell life leading to a 
potential non-energy cost savings of 
one million dollars annually by 2010 
ü Significant reduction of the cyanide 
in spent potliners, leading to lower 
cost options for environmentally 
sound disposal 
Boron oxide additions to potlining are 
expected to promote smoother and 
more energy efficient cell operation due 
to wetting of the carbon by the metal 
product, enhance pot life due to 
reduced intercalation, and suppress 
cyanide formation. This technology can 
be applied whenever small amounts of 
titanium are acceptable in the metal 
product, in new or retrofitted cells. 
 yyyy 
BORON OXIDE ADDED TO POTLINING WILL INCREASE ENERGYEFFICIENCY 
AND OPERATIONS IN PRIMARY ALUMINUM PRODUCTION 
Since the invention by Hall and Héroult more than a century ago, aluminum has 
been produced by electrolysis of aluminum oxide dissolved in a fluoride melt. 
Although there has been continuous progress to increase affordability, smelting 
remains as the most energy-intensive process in aluminum production. 
Preliminary research results obtained by EMEC Consultants (which yielded a 
U.S. Patent) indicates that cell operation, cathode performance, and options for 
the disposal of spent potlining will be improved by additives to potlining. The 
addition of boron oxide to potlining especially has been considered a promising 
way to suppress cyanide formation. This project is designed to further examine 
the potential benefits derived from the addition of boron oxide to potlining used in 
primary aluminum production cells. It addresses a high-priority topic of the 
Primary Products Sector related to research and development (R&D) for improving 
the Hall Héroult process in the Aluminum Industry Technology Roadmap. 
A relatively inexpensive bulk chemical, boron oxide not only suppresses cyanide 
formation, but also may inhibit sodium intercalation and, above all, promote, in 
the presence of some titanium, wetting of cathode carbonaceous material by the 
metal pad, thus reducing ohmic cell resistance and sludge formation. Improvements 
in energy consumption, waste disposal and overall economics of the 
process are projected. 
INDUSTRIAL CELL 
Cathode  yyyy 
Block y yyy 
Impregnation of a cathode block with boron oxide. 
Vacuum 
Water-Cooled Top 
Heating Element 
Inconel or Stainless Steel 
Steel Liner 
Boron Oxide 
OFFICE OF INDUSTRIAL TECHNOLOGIES 
ENERGY EFFICIENCY AND RENEWABLE ENERGY ü U.S. DEPARTMENT OF ENERGY
Project Description 
Goals: Establish the technical feasibility and performance data of adding boron oxide to 
the carbonaceous components of the lining of aluminum electrolysis cells and research 
the effects and potential benefits that can be derived from additives to the potlining of 
traditional aluminum reduction cells. 
Laboratory testing and commercial scale testing will investigate parameters that are 
important for the commercial application. Tests in industrial cells will complement laboratory 
testing. This experimentation is scheduled for the first year. Carbonaceous potlining 
components added with boron oxide will be incorporated in industrial cells in later phases 
of the program, providing results in the first year are positive. Partial installation is 
planned for the second year, equipping full cells with blocks containing boron oxide for the 
third phase of the program. In this third phase, performance of the material will be 
examined as well as cell operating data established. Following a validation of the concept 
in the laboratory, tests will be conducted in the industrial environment of the participating 
companies. 
Progress and Milestones 
The project will be conducted in three phases. Phase I includes laboratory studies and 
tests of samples in industrial cells of two participating primary aluminum producers. In 
case of a positive go/no-go decision towards the end of Phase I, material will be prepared 
in Phase II to be installed in industrial cells, which will be operated for six months and 
then inspected. Carbon blocks to equip two full cells will be impregnated with boron oxide 
in Phase III; cell operational data will be gathered to assess achieved improvements. 
(1) Verification and Quantification of Effects (Fall 1999) 
(2) Partial Tests in Industrial Cells (Fall 2000) 
(3) Testing of the Concept in an Entire Industrial Cell (Fall 2002) 
Commercialization Plan 
If industrial testing is successful, the additive should quickly become commercially viable. 
Using the new additives is expected to be more economical than current practice. Market 
introduction of boron oxide as a potlining additive is anticipated in the near-term time 
frame. 
PROJECT PARTNERS 
Century Aluminum of West Virginia, Inc. 
Ravenswood, WV 
EMEC Consultants 
Export, PA 
NSA Division of Southwire Company 
Hawesville, KY 
SGL Carbon Corporation 
Charlotte, NC 
FOR ADDITIONAL INFORMATION, 
PLEASE CONTACT: 
Sara Dillich 
Office of Industrial Technologies 
Phone: (202) 586-7925 
Fax: (202) 586-1658 
sara.dillich@ee.doe.gov 
http://www.oit.doe.gov/IOF/aluminum 
Please send any comments, 
questions, or suggestions to 
webmaster.oit@ee.doe.gov. 
Visit our home page at 
www.oit.doe.gov 
Office of Industrial Technologies 
Energy Efficiency 
and Renewable Energy 
U.S. Department of Energy 
Washington, D.C. 20585 
January 1999