The Chemical Engineering Division

The story of the Chemical Engineering Division begins with Dr. Stephen Lawroski, who was its original Division Director. Dr. Lawroski received a doctorate in chemical engineering in 1943 from Pennsylvania State University.

While doing his graduate work, he was employed as a Research Assistant at the Petroleum Refining Laboratory at State College, Pennsylvania, where he was one of the principal staff members working on high-efficiency packing materials for distillation and solvent-extraction equipment. He spent two years at the University of Chicago Metallurgical Lab (Met Lab, where work on the Manhattan Project was conducted) from 1944 to 1946 on loan from the Standard Oil Development Company (later named the EXXON Research and Engineering Company). There, he directed a group engaged in the development of solvent-extraction processes for the recovery and purification of uranium and plutonium from Hanford plutonium production reactors. This group, under his leadership, was highly productive and its work led to the Redox process.

In 1946, he returned to the Standard Oil Development Company as Assistant Section Chief of the Manufacturing and Process Section of the Research Division. In September of that year, however, his company recommended him for atomic energy training as an Advanced Professional Trainee at the Clinton Laboratory, where he remained until June 1947. This assignment offered the opportunity to study reactor and separations technology, including the solvent-extraction pilot plant that had been built to test the large-scale Redox process for the Hanford facility. From Argonne’s standpoint, one of the most valuable results of this assignment was that Dr. Lawroski, in part due to his gregarious personality, made many friends among the other engineers, scientists, and trainees. Later on, he persuaded some of these people (Hal Feder, Milt Levenson, Walt Rodger, Les Coleman, and Les Burris) to come to work at Argonne. He also became acquainted with a number of other people who later became important contacts in the Atomic Energy Commission and the other national nuclear establishments.

When Dr. Lawroski returned to the Chicago area in July 1947, he accepted employment as head of the Process Development Section and Associate Director of Argonne's Chemistry Division and the section under Herbert Hyman became one of his responsibilities. Early in 1948, Argonne's director, Dr. Walter Zinn, Argonne’s first director and a pioneer in nuclear physics and reactor development, approached Dr. Lawroski with the proposal that Argonne should establish a Chemical Engineering Division with him as director. Thus, the Chemical Engineering Division was born in February 1948. Soon thereafter, Zinn presented him with an interesting choice. As the Laboratory was moving to its present DuPage County site, the Chemical Engineering Division was given the option of moving to the new site within about a year if it were willing to move into military-type Quonset buildings. Alternatively, if the division preferred to wait another year, it could have new buildings built specifically to meet its requirements. That was the genesis of Building 205, which today still houses the Chemical Engineering Division.

Dr. Lawroski's Vision

When the Division was formed, Dr. Lawroski made a policy decision that probably had a more profound effect than any other single factor on the nature of the Chemical Engineering Division's future work. He believed that process development should be an integrated effort from the test tube to plant design. Thus the major programs often included basic and applied lab-scale research, basic engineering studies, equipment development, engineering design, materials development, pilot plant or semiworks testing, conceptual plant design, and some economic evaluations. With this type of organization, team efforts could include whatever particular talents were needed at any stage of process development, and much of the work could be done in parallel instead of sequentially. It also expedited feedback of problems for further work. The basic chemistry and engineering studies, although directed toward solutions of practical problems, were most often performed with the care and scope necessary to produce quality publications in the basic scientific and engineering journals. At the same time, these resources were available for troubleshooting on problems arising in the process development work.

As a first step in implementing this policy, Dr. Lawroski, in order to complement his own training and experience as a chemical engineer, hired a highly qualified chemist to serve as the Associate Division Director. The man he selected was Dr. Charles Stevenson, who had earned a Ph.D. in organic chemistry at Pennsylvania State University and then worked as a research chemist at the Standard Oil Development Corporation and the Diamond Glass Company. Lawroski and Stevenson had been colleagues and personal friends both at Penn State and at Standard Oil. Charlie was a highly competent, affable individual, and he brought a new dimension to the Division.

The Division Takes Shape

The core personnel of the new Chemical Engineering Division were basically those from the Process Development Section of the Argonne Chemistry Division plus new hires, including those from the Clinton Laboratory at Oak Ridge. People who were at the Met Lab in the early days and in the Chemical Engineering Division after it was formed include Elton Turk (1942), Milt Ader (1944), George Bernstein (1944), Phil Fineman (1944), John Schraidt (1944), Les Coleman (1946), Harold Evans (1946), and John Natale (1946). Milt, George, John, and Phil were members of SED (Special Engineering Detachment) of the U.S. Army during part of the time. Don Webster, who joined the Division much later and served as an Associate Division Director, had also spent a short time at the Met Lab in 1942-43. Marvin Tetenbaum spent some time at the Met Lab in 1942, returned to New York to obtain a Ph.D., worked at Columbia University for a time, and came to the Chemical Engineering Division several years later. The people from Oak Ridge (Hal Feder, Walt Rodger, Milt Levenson, and Les Burris) brought with them a great deal of practical experience in radiochemistry and hot pilot-plant operations. In 1949, Richard Vogel, who had received a Ph.D. in physical chemistry at Harvard University and was on the faculty of the Illinois Institute of Technology, was hired as a Senior Chemist, and was destined to succeed Dr. Lawroski as the Division Director several years later.

Once the Division was established, it expanded rapidly, both in manpower and in the scope of the work. Nearly all of the work during 1948 and 1949 continued to be directed toward solvent-extraction processes. A large program under Walt Rodger was concerned with the use of acid-deficient solvent-extraction flowsheets that had been proposed by Oak Ridge and later by Hanford. Some of the studies were done with extraction columns and others with two 20-stage mixer-settler units in which all the stages could be sampled simultaneously to obtain equilibrium data. These were especially useful in constructing equilibrium diagrams for various operating conditions. Individual studies were conducted on the precipitation of plutonium oxalate in columns, the behavior of neptunium, and the possibility of volatilizing ruthenium from solutions by oxidation to RuO₄ with oxygen-ozone mixtures.

Because the breeder reactor concept had become popular both at Argonne and within the Atomic Energy Commission, interest began to develop in the reprocessing of breeder reactor fuel. Recovery of Experimental Breeder Reactor and Materials Test Reactor fuels had been demonstrated in the Oak Ridge pilot plant. One such Argonne program, headed by Les Burris, was the development of a simpler tributyl phosphate (TBP)-methylcyclohexane process for the recovery of highly enriched uranium from experimental cores of the Experimental Breeder Reactor (EBR). This process proved capable of achieving the requisite fission product removal (a decontamination factor of 105) and uranium recovery (>99.9%) in a single solvent-extraction cycle. Sixteen runs with active feed material from Hanford that were conducted in the shielded columns in the high bay section of Building 205 showed that the process could meet the requirements. While this work was still in progress, however, the Atomic Energy Commission issued an edict that the bulk of the EBR fuel would be processed at the Idaho site, and the TBP process would be used at Argonne only for analytical samples and cleanup operations.

Some work was performed on the recovery of simulated Mark I naval reactor fuel, which was an enriched uranium-zirconium alloy. A Redox-type process seemed to be the best choice for this type of fuel, but it could not be dissolved in nitric acid because of its high zirconium content. Hydrofluoric acid with aluminum nitrate proved later to be the most promising solvent for this alloy. One of the early processes initiated in the late 1940s and developed by the Division was of considerable import for recovery of tritium from irradiated lithium-aluminum alloy. Tritium was needed for the development of thermonuclear weapons (H-bombs). Tritium (hydrogen-3) is generated by irradiation of lithium-6 with neutrons, which results in the alpha reaction:

 ₃Li⁶ + ₀n¹ → ₁H³ + ₂He⁴

Bernie Abraham of the Chemistry Division had proposed the use of lithium-aluminum alloy for this purpose. The tritium and helium recovery process consisted of heating the irradiated alloy to just below its melting point (about 600°C) at which temperature the gases, principally hydrogen-3 (tritium), helium-3, and helium-4, are released. The gases were pumped off, passed over uranium turnings at 800°C to remove any gaseous contaminants such as oxygen or moisture, and then through a palladium barrier to separate the helium isotopes from the tritium. The palladium barrier, a disc in the line maintained at a temperature of several hundred degrees Celsius, was permeable by the tritium, but not by the helium. This process was installed at Hanford and later in the Savannah River production plant where it has been used for many years.

Development work was also initiated on the fluoride volatility process, in which uranium in the fuel was fluorinated to form uranium hexafluoride (UF₆). The UF₆ is volatile and can be separated from the other fuel constituents by vaporization or distillation. The rationale behind this process was that the decontaminated uranium product is in the form of a fluoride, which is directly suitable for reconversion to the metal, and the fission-product wastes would be a small volume of solid fluorides.

The idea of recovering uranium and plutonium by volatilization of the hexafluorides was not new. As early as 1942, Harold Urey had suggested the possibility of volatilizing uranium as the hexafluoride to separate it from plutonium. That same year Harrison Brown and Orville Hill at the Met Lab fluorinated the tetrafluorides of uranium and plutonium completely to the hexafluorides and suggested the procedure as a method for separating them from fission products. Fluorination studies continued off and on in the Met Lab for several years. Fluorine research was also in progress, particularly on the plutonium fluorides at Los Alamos. In 1944, Seaborg, in a systematic review of the stabilities of the actinide metal halides, concluded by analogy that plutonium hexafluoride (PuF₆) should be marginally stable, which was borne out by later experimental studies. The use of elemental fluorine as a fluorinating agent for metallic fuels did not work out well because of heat- transfer problems and irregular reaction rates. Joe Katz and Herbert Hyman of the Chemistry Division did some preliminary work on the use of halogen fluorides, such as ClF₃, BrF₃ or BrF₅, which are liquids. Bill Mecham and Milt Levenson conducted an experiment in the Chemical Engineering Division in which 10 g of irradiated uranium metal was dissolved in a BrF₃-BrF₅ mixture. The uranium dissolved smoothly and the UF₆ product was distilled off. The gross gamma decontamination factor was 2,000, and over 97% of the plutonium was in the residue. The only detectable fission-product activity in the UF₆ was tellurium. These results were highly encouraging and the fluoride volatility process became a major program in the 1950s.

Work continued on waste processing as the incinerator proceeded to dispose of radioactive combustible wastes from the entire Laboratory. Some development studies also continued on a process for the recovery of waste aluminum nitrate solutions from the Redox process. By the end of the 1940s, the Chemical Engineering Division had established its identity as a major part of Argonne and had become recognized nationally for the originality and excellence of its contributions to nuclear technology. It had expanded both in personnel and in programs to the stage that larger quarters were necessary. The time was ripe to move on to the new buildings at the DuPage site, including Building 205, which today still houses Argonne's Chemical Engineering Division.