Spring 2000

ME/IE 8773-8774

HIGH-TEMPERATURE SOLAR METALS REDUCTION: RECENT RESEARCH ZN-H2 CYCLES PRIMARY ALUMINUM PRODUCTION
by

Jean P. Murray, Ph.D.
Visiting Research Professor
Engineering Division
Colorado School of Mines
Golden, Colorado 80401

Wednesday, February 16, 2000
3:35 - 4:25 p.m.
Room 108 ME
Broadcast on UNITE Channel A
Coffee will be available in 152 ME following the seminar

The production of the metals zinc and aluminum by reduction of their oxides, either directly or with carbon is a technical challenge. The temperatures required for a primary aluminum process based on the direct reduction of the oxide with carbon, in the range 2100Ð2300¡C, is too high for practical process heat addition from a combustion source alone. Zinc is of interest as an energy carrier that can produce hydrogen cleanly by splitting water. Its production directly from the oxide without using carbon is the ultimate goal of intense research worldwide. In industry, an electric arc or plasma arc furnace is used for high-temperature production of metals, but then only a fraction of the energy contained in the fuel used to generate electricity enters the process. Thus the energy cost dominates the cost of the final product. By contrast, highly-concentrated solar energy is capable of supplying large amounts of process heat at very high temperatures, and may have real advantages for metals reduction processes. The primary aluminum industry now uses nearly 10% of the electricity generated globally to produce primary aluminum, and about half comes from coal-fired generation stations. It is thus a major source of climate-altering gases. A solar-thermal process would drastically reduce the emission of climate-altering gases, reduce this industryÕs reliance on electricity, and might be a critical factor in making a direct thermal route from the ore to metal possible.

Jean Murray received her BS degrees in Physics and Mechanical Engineering at the University of Minnesota. After working 5 years for Rosemount, Inc. in Product Design and Development, during which time she received a patent for a magnetic flowmeter, she returned to the University of Minnesota to work for a Ph.D. with Professor Edward FletcherÕs high-temperature solar research team on the use of solar energy to split hydrogen sulfide for hydrogen recovery, and the production of synthesis gas from cellulose steam gasification in a fluidized-bed reactor using high-temperature solar process heat. She is currently working with Alcoa on demonstrating the feasibility of using solar process heat for primary aluminum production. Dr. Murray is currently the Department of EnergyÕs US representative to the International Energy Agency for the field of solar chemistry research, referred to by the IEA as Solar PACES (Power and Chemical Energy Systems) Task II: www.solarpaces.org provides links to participating research laboratories in this area.

Faculty Host: Prof. Edward A. Fletcher