Abstract: The invention relates to a method of producing a graphite die for use in continuous casting of non-ferrous metals. The die has wearing surfaces which, in accordance with the invention, are coated, using either plasma-combustion flame or liquid-spraying techniques, with a first layer consisting of a metal or a metal plus a ceramic material and then with a second layer of ceramic material. The coating materials are applied as a suspension in a liquid medium by painting or spraying techniques or they must be applied by plasma or combustion flame spraying techniques.The first layer may comprise one or more of the following substances: silicon, iron, nickel, chromium, molybdenum, tungsten or their alloys or any other metal which can be subsequently carburized by heating with graphite in an inert or reducing atmosphere.Alternatively the first layer may be either aluminium, an aluminium alloy, an aluminium-metal composite or a mixture of the metal(s) and alumina and the second layer is preferably alumina.

Abstract: Control of emission from coke ovens during charging. A bank of coke ovens is provided with two gas mains. The first of the gas mains is connected to each of the individual ovens in turn during charging. The second of the gas mains is connected to the bank of ovens during coking. A fluid energized venturi ejector maintains a predetermined level of vacuum at the head of each individual coke oven during charging. Means are provided to automatically reduce the suction provided by the ejector if the level of vacuum exceeds said limit. This means consists of a valve operated by changes in the level of vacuum at the head of the individual oven during charging. The valve connects the second main to the first, thus increasing the gas pressure applied at the throat of the venturi ejector in turn decreasing the degree of vacuum provided by the venturi ejector. The energy for the ejector may be provided by flushing liquor or by a compressible fluid such as steam, air or an inert gas.

Abstract: Method of hardening powdered titania (titanium dioxide) so as to make it attrition-resistant and to enhance its properties as a catalyst carrier. The method involves thoroughly dispersing powdered titanium dioxide in water, removing the excess water, drying and then calcining the product at a temperature between 650.degree.C and 900.degree.C. Preferably a large excess of water is used, at least 37% to effect dispersion; and dispersion may be aided by use of a surfactant, a water soluble organic compound or a highly polar inorganic compound. The excess water may be removed by filtration or the use of flocculants.The resultant powdered material is particularly useful as a carrier for oxidising ortho-xylene to phthalic anhydride.