Magnesium traditional methods

Traditional methods for producing magnesium by processing hydromineral sources fail to satisfy the newer ecological standards. Consequently, new, alternative technologies, based on sorption methods are being considered despite the profitability of earlier methods. 

Magnesium is the sixth most abundant metal in the earth s crust, but is exceedingly reactive. It finds wide use as a light alloying material, and is extensively used in the aircraft industry. Although traditionally produced by electrolytic methods, it requires between 8 and 9kWh of electricity per pound of metal. Thermal methods are now widely used. 

Traditionally, aldol reactions were carried out under protic conditions, such that the enolate was formed reversibly (see Volume 2, Chapter 1.5). An added measure of control is possible if one uses a sufficiently strong base that the enolate may be quantitatively formed prior to addition of the electrophile. The renaissance that has occurred in the aldol reaction in the last two decades has been mainly due to the development of methods for the formation and use of preformed enolates. The simplest enolates to prepare are those associated with lithium and magnesium, and there now exists a considerable literature documenting certain aspects of lithium and magnesium enolate aldol chemistry. This chapter summarizes the aldol chemistry of preformed enolates of these Group I and Group II metals. Other chapters in this volume deal with boron enolates, zinc enolates, transition metal enolates and the related chemistry of silyl and stannyl enol ethers. 

The pinacol coupling reaction, traditionally carried out with active metals such as sodium, magnesium, or aluminum, can also be accomplished with SmU [29]. Since the initial contribution describing intermolecular pinacolization reactions, several variants have been described [30]. Although many of these papers outline adaptations of the reaction in which additives and catalytic methods have been introduced to improve the reactivity and the economics of the reaction, few of these have adequately addressed the lack of stereoselectivity typically observed in these processes [30a, 31]. 

The majority of wet-chemical analysis is for the silica-aluminosilicate-alumina range, and this is used to illustrate the methods used. The oxides determined are the normal eight (those of silicon, titanium, aluminum, iron, calcium, magnesium, potassium, and sodium). In ceramics, it is traditional to refer to the elements as their oxides. Eor the analyst, this has the advantage of providing an analytical total to cross-check the accuracy of the analysis. 

The determination of common inorganic anions (fluoride, chloride, nitrite, bromide, nitrate, phosphate, and sulfate) and cations (sodium, potassium, magnesium, and calcium) was traditionally carried out using wet chemical methods such as gravimetry, titration, photometry, tmbi-dimetry, and colorimetry. 

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