The Le Châtelier process for the extraction of ... - ACS Publications

The Le Châtelier process for the extraction of alumina. George B. Kauffman. J. Chem. Educ. , 1991, 68 (3), p 270 ... Abstract. The Bayer process...
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LETTERS The Le ChYeller Process for the Extraction of Alumina To the Editor:

The "chemically feasible" but "commercially unlikely" reprecipitation of hydrated aluminum hydroxide from a sodium aluminate solution by carbon dioxide cited in the "Textbook Forum" feature by Colin H. L. Kennard [1989, 66,3131 is indeed not a step in the Bayer process ( I ) for the extraction of alumina from bauxite. However, it is a step in the older Le Chitelier process (1855), developed by Louis Le Chitelier (1815-1873, a French mining engineer who was the French Inspector General of Mines and the father of the chemist Henri Le Chitelier (1850-1936) of Le ChBtelier's principle fame (2). Charles Martin Hall's (1863-1914) Pittsburgh Reduction Company, which became the Aluminum Company of Americain 1907, continued touse the Le Chhtelier process until 1911, when Karl Josef Bayer's (1847-1904) US. patent, issued in 1894, expired. Alcoa thereafter used the more economical Bayer process (3). George 6. Kaufiman California State University. Fresno Fresno. CA 93740

Literature Cited

However, you will not succeed properly in the teaching of science a t high school until you metricate. As i t stands now, an American child lives for 15 years in pints, pounds, and feet, then he or she meets in one fell swoop the concepts of force. weiaht, mass, and density, and the metric system. No wonder wLy the children can't cope and why so many don't like science! Everything about i t is contrary t o their everyday experience: gallonfliter; ouncelgram; yardlmeter; weightlmass; caloriesljoules. The language of the supermarket and the home is completely different from that of the science laboratory. I t shouldnot he. T o confusematters further, in California distance is measured in units of time ("only 20 minutes awav"). and meed is measured in units of length ("speed limi; 3b; miles';). There is, thus, a massive gap hitween what is seen and done in the real world of everyday life and what is said and taught in science courses at school. The pupil is alienated. Things will he corrected only when all of American society measures in liters, grams, and meters and when in the high school chemistry curriculum the students learn about the chemistry of the world around them: of water purification, soap, car batteries, fertilizers, and swimming pools, to name only a few topics. Those electron pairs in their plasticwrapped budgie boxes can safely he left to theuniversities to worry about. Throw caution to the winds andholdlv advance hv stepping backward 30 years. Teach the deicriptive chemistry that was in the hieh school and freshman texts of the 1950's. It's worth a try. l&oducing the metric system nationwide is a separate and much bigger task.

To the Editor:

Mlchael Lalng University of Natal Durban. South Anica

George B. Kauffman's letter clearly shows that although errors are not tolerated in the scientific literature, they are easily propagated in teaching texts. The reference to the Bayer process occurs in the brand new edition of a U. S. text currently being used in first year a t this university. Colln H. L. Kennard University of Queensland Brisbane QLD 4067 Au~halla

Revisit Descriptive Chemistry, Please! To the Editor:

Your editorial comments in the November 1988 issue [1988,65,935] together with the article by W. S. Richardson and J. E. Teeeins about the measurement of densitv. (DD 1013-1014) me to write. In my biased opinion, your chemistry prohlems started with the takeover of high school chemistry by CHEMSTUDY. As a result, old-fashioned down-to-earth dull (?) reality was replaced by glorious principles. Many of the high school texts are still this way, hut fortunately the writers of the freshman texts have seen the problem and have finally put back industrial processes, qualitative analysia, and descriptive inorganic chemistry. The one American high school text that has stood its ground over the years and kept the real world in the book is Modern Chemistry by Metcalfe, Williams, and Castka. ~~

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Journal of Chemical Education

An "Old" New ldea To the Editor:

In an article in the current issue of the Journal of Chemical Education 11989. 66. 3101. R. W. Parsons proposes to have developed; new schemefor applying the Aufbau princinle in writine electronic configurations for atoms. 1 agree with Parsons &at the scheme he cites is simple for students to remember and apply. However, I have been using this scheme for over 20 years in my classes. The scheme did not originate withme hut was conceived and published by one of my professors, Reino W. Hakala, over 40 years ago [J.Chem. Educ. 1948,25,229]. I have always been puzzled that only a few texts have quoted Hakala's scheme. (See L. N. Ferguson, Electron Structures of Organic Molecules; Prentice-Hall: New York, 1952; p 12.) Leroy Chauffe Callfornla State University Hayward. CA 94542

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Editor's Not.:

While we check far duplication of Ideas, we are occasionally surprised to find out how " o l d a "new' ldea is.