GB433174A - Methods for the manufacture of inflammable metals of a semi-pyrophoric nature - Google Patents

Abstract

Metals in semi-pyrophoric form (i.e. metals in such a state that their ignition temperature lies between 50 DEG C. and 300 DEG C.) are manufactured by the reduction of metal compounds by thermal decomposition in the presence of an inert gas or gases, or by chemical reduction of metal compounds by hydrogen at raised temperature, the temperature and reaction conditions being maintained throughout the reaction intermediate those required to produce non-pyrophoric metals and those to produce pyrophoric metals. For chemical reduction, oxides, nitrates, carbonates, sulphates, oxalates, tartrates or citrates may be employed; for thermal decomposition, oxalates, tartrates or citrates. Alternatively, metal compounds may be reduced in such manner as to produce pyrophoric metals, the latter being then cooled in a current of hydrogen and when cold treated in inert gases, air being excluded. For example, semi-pyrophoric iron may be produced by heating the oxide for an hour at 390 DEG C. in a hydrogen current and then cooling it in hydrogen or semi-pyrophoric nickel may be produced by heating the nitrate in hydrogen for 50-60 minutes at 340-360 DEG C. Specifications 14971/08, [Class 1], 233,029, [Class 82 (i)], 372,958 and 433,117 are referred to.