Platinum Metals Review - Volume 30, Issue 4, 1986

The cathodic protection of steel reinforcing bars in concrete to prevent their corrosion, brought on principally by de-icing salts used on roadways, is at the interesting stage where technology is barely keeping pace with practical demand. It already seems likely that platinum and other noble metals, used in conjunction with titanium and niobium, will play a vital role in several of the protection systems that appear to be the forerunners in a rapidly developing industry.

The principles of the design and operation of a new variable high pressure, large diameter experimental ammonia oxidation test facility built by Johnson Matthey Metals Limited are described. The layout and arrangement of the plant are illustrated in some detail and examples of its use with platinum catalysts are given. The design of the plant is such that the operating conditions of any current, or likely future, commercial undertaking can be reproduced.

Increasingly the energy needs of society will have to be met from renewable resources. The use of these is limited at present by their location, the technologies available to harness them and the major problems associated with their storage. One possible solution to these difficulties has now been demonstrated, and is described here, while further development wcrk is continuing. Hydrogen produced by any convenient means is used as a medium for energy storage and transmission. Close to its production site the hydrogen is catalytically reacted with toluene to yield methylcyclohexane; this is transferred safely by pipeline or container to the point of energy requirement where it is catalytically dehydrogenated. The hydrogen released is then available for use in a wide variety of ways, while the toluene is returned to the source for further hydrogenation, and the cycle is repeated.

When a metallic powder is subjected to a sufficiently high pressure a certain amount of adhesion takes place between individual particles. If this compact is then sintered the bond is improved by diffusion and intergranular grain growth. The earliest known platinum objects were fabricated by such a powder metallurgical process, and when European scientists first addressed the problem of manufacturing platinum bars they also used powder metallurgy to overcome their inability to melt the metal. Now powder metallurgical methods are widely used for fabricating a variety of materials, and this paper reviews studies made of the sintering of refractory metals when this process is promoted by the addition of a minor amount of a platinum group metal activator.

This year marks the twentieth anniversary of the death of Academician A. A. Grinberg who, fifty years ago, founded a new field of science to study the chemistry of co-ordination compounds of the platinum metals at the Lensoviet Institute of Technology in Leningrad. His academic life was devoted to this subject and his many contributions continue to form a source of inspiration to his successors.