Document 4JKBYxYwqkkxv7BebwN6QdQwa

NQNB10L0GIC EFFECTS OF LEAD B. On Glass (Viechnicki) Page 1 Draft - D. J. Viechnicki Concentrations of airborne lead in the air over cities can.reach 4yg/m3 of air or 4 parts per billion (ppb) This is about the same concentration of lead in sea water, I. e., 4-5 ppb. 2 The average con- centration of lead in the earth's crust is 1.6 x 10* ppb. Thus in the minerals used in the manufacture of glass the concentration of lead will be at least 10^ or 10^ times as high as that found in the atmos phere. In fact. Impurities in starting materials used in ceramics re search are given in terms of parts per million (ppm) and starting mater ials used in manufacturing of ceramics are not controlled as closely as those used* in research. Lead is used in the manufacture of glass at much higher concentrations. Decorative and optical glass commonly and incorrectly called "crystal11 contains high concentrations of lead, up 4 to 58 weight %> because of the good optical properties that result in the glass. It may be concluded that glass contains lead at higher con centrations than normally found in the atmosphere, and the small con centration of lead normally found in the atmosphere will have no detrimen tal effects on the glass. Two practical examples of the lack of reaction between lead and glass will be cited. First, glass is not adversely affected by sea water which has a lead concentration of 4-5 ppb; the U.S. Navy is interested in glass as a material for deep submersible vehicles. The second example is that leaded gasoline can be stored in glass with no degradation of the glass. In older cars there was at one time a filter in the fuel line enclosed in a glass bulb which did not degrade. N40685 Chapter 7 Page 2 (Viechnicki) Lead will react with glass at elevated temperatures, >400 It is a problem above these temperatures and at higher concentrations, for example, the hot exhaust from an internal combustion engine impinges upon a glass, and has prevented the use of glass in such items as manifolds. 6*"8 Although reactions occur at high temperatures and at high concentrations * at low temperatures (25 C) and concentrations, airborne lead has no effect on glass. DUP050056022 Chapter 7 D. J. Viechnicki Page 3 References 1, "Surrey of the Concentration of Lead in Air in Three Major Cities," Public Health Bulletin No. 99 AP12, Dept, of HEW, 2, Handbook of Cheraistry and Physics, 50^ Edition, p. F-145* % 3, Ibid. p. F-144. 4* Glass Engineering Handbook. E.B. Shard McGraw - Hill Book Company, N.Y. 1958, p. 4. 5, 'Subsolidus Studies in the System PbO-SiC^," V/.R. Ott and M.G. McLaven, J. Am, Ceram. Soc, 2. (?) P. 374 (1970). s 6, Private communications with Prof. J. Hurt, North Carolina State University, 3 August 1970. 7. Private communications with Dr. D. Mattox, V/estinghouse R&D Center, 3 August 1970. 8. Private communications Y/ith Kir. R, Oldrieve, NASA - Lev/is, 3 August 1970, Incl 1 DUP050056023