GB191005382A - Improvements in the Manufacture of Ammonia, and Aluminium Compounds, from Mixtures containing Aluminium Nitride. - Google Patents

Abstract

5382. Johnson, J. Y., [Badische Anilin & Soda Fabrik]. March 3. Ammonia; ammonium salts.-Ammonia and practically pure aluminium compounds are obtained from raw or impure mixtures containing aluminium nitride by treating the mixtures with such limited quantities of acid or alkali, or by carrying out the reaction under such mild conditions, that the aluminium nitride alone is decomposed. The use of mild conditions consists in a suitable choice of concentration of the ingredients, and the temperature and time during which the reaction takes place. The bodies treated are such as are obtained by heating minerals containing aluminium with carbon in a current of nitrogen gas, and the impurities are mainly nitrides, carbides, and oxides of silicon and titanium. When an acid is used, the amount added may be such as to convert the ammonia and the aluminium into the salt of the acid; or a less quantity of acid may be employed, the aluminium salt in this case reacting with more aluminium nitride. Other salts, such as iron chloride, of which the bases are precipitated by ammonia, may be used, and acid salts may be also employed for carrying out the process. Further, carbonic acid, or an acid incapable of forming stable salts with aluminium, may be used. When using an alkaline reagent, the amount used may be such as will form aluminate with the aluminium, although a smaller quantity may be employed. The aluminate solution is filtered off, and any undissolved aluminium compound can be brought into solution by means of an acid, or an alkali. Double salts may be prepared from the raw product thus obtained by adding an acid, or an acid salt, and any alkali. It is advantageous, especially when a limited quantity of alkali is used, to add a neutral salt, which has the effect of increasing the evolution of ammonia, and this addition is particularly advantageous when preparing double salts. The raw nitride may be first treated with steam or water, or it may be purified by any suitable process before being treated with acid or an alkali.