Present and future uses of lithium and its compounds are briefly reviewed. A method for the extraction of lithium from the Dead Sea involving its precipitation as lithium aluminate followed by solvent extraction to separate the lithium from aluminium is described. An economic evaluation of the method is given.

AbstractDifferent laboratory crystal populations of potassium chloride are described and compared with similar types of industrial crystals. Laboratory experiments have shown that the crystal characteristics, i.e. size distribution, crystal habit and degree of agglomeration are strongly affected by the degree of supersaturation at the beginning of crystallisation. Similarity of crystal characteristics indicates similarity of factors governing growth conditions, hence the industrial growth conditions, especially supersaturation in a crystalliser, may be determined by inspection of the final product.

Growth rates of potassium chloride crystals in cooling solutions were measured. Systems with either linear (0.2°C/min) or non-linear profiles and spontaneous nucleation were investigated. The range of the average overall measured growth rates was 0.6−1.5 × 10-7 m s-1. Most crystals were aggregates of several cubes. Crystals <0.5 mm apparently grew faster than those >0.5 mm. The decrease of growth rate could be attributed to attrition which is evident in rounding of corners and edges and presumably breakage of ill fitted aggregates. Crystals grown at initial slow rate of cooling (∽0.01°C min-1) with subsequent fast cooling, were spherical, built around single central cubes. The existence of an analogy was suggested between this mechanism of growth and the sub-microscopic processes in crystallizers where cycling phenomena occur.

A process is proposed for the recovery of potassium from brines by precipitation as potassium perchlorate, followed by conversion to potassium chloride by liquid anion exchange with a tertiary amine in the form of its hydrochloride. Regeneration of the amine salt is effected by means of lime and hydrochloric acid. The process was tested on Dead Sea brine, containing 13 g/l KCl. Precipitation at 30 °C gave a 40% yield of potassium, cooling to 0 °C increased the yield to over 80%. The anion exchanger used was the hydrochloride of trioctylamine dissolved in toluene; this performed satisfactorily and phase separation was easy. A separation factor of 130 was obtained for the ClO4−/Cl− separation. Regeneration of the amine was tested with various bases.

Austenitische Stähle können gegen den Angriff durch Br 2 mit Hilfe von NO 2 geschützt werden. Der erforderliche NO 2 -Gehalt hängt von der Feuchtigkeit des Br 2 ab. Die Wirkung des NO 2 beruht auf der Bildung des Trihydrats von HNO 3 unter Zutritt von H 2 O und auf der Oxidation der anwesenden HBr. Andere Stoffe, die dehydratisierend wirken, zeigen eine ähnliche schützende Wirkung. Der Einfluß des NO 2 auf den Angriff anderer Metalle durch Br 2 wurde gleichfalls untersucht.

The conditions for electrolytic reduction of dilute nitric acid without the formation of ammonia, and without the addition of foreign substances, have been investigated. Dilute nitric acid is reduced at a graphite electrode at controlled potentials, nitrogen dioxide and carbon dioxide being the main products. A mechanism for this reduction is suggested.