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The present work is part of an investigation towards the development of a process route for the extraction of metal values from slag, low grade ores and other oxidic materials such as spent refractories using molten salts in the temperature range 800-950uC. The present paper focuses on the recovery of metal values, primarily Cr and Fe, from electric arc furnace slag and chromite ore. The impact of different factors to the dissolution of slag, such as temperature, holding time, flux content and weight ratio of flux/slag was studied. Based on the optimised experimental factors, the salt bath containing metal values extracted from the slag/ore was electrolysed under an applied voltage of 2?8 V. The cathode deposit was subjected to SEM/EDS and XRD analyses, which confirmed the formation of CrFe alloy. The process was also extended towards the production of CrFe alloy directly from chromite ore. The results show that the molten salt extraction process offers a promising route towards the recovery of metal values from slags and low grade ores.

OverviewMolybdenum and tungsten are refractory metals in the elemental form with the largest production volume in the world. The fabrication of these refractory metals, as well as their alloys and intermetallics, using hightemperature powder metallurgy (PM) is reviewed in this article. The primary focus is on the role of traditional hightemperature PM in producing alloys with tailor-made properties. An insight into the bulk production of molybdenum and tungsten alloys with nano-grains is highlighted.

Powder metallurgical production of fully dense steel such as high-speed steel, tool steel and stainless steel is of large industrial importance. The process route is as follows: melting -inert gas atomization -encapsulation -hot isostatic pressing and subsequently often also hot forming. Final products comprise near-net-shape components, billets and semi-finished parts e.g. rods. The mechanical and functional properties of the PM steels are often superior to those of conventional manufactured steels over casting þ forging with the same chemical composition. The properties of the PM-steels are highly dependant on their oxide contents. There are three types of oxides in PM-steels: exogenous and endogenous slag inclusions and oxides originating from surface oxidation of the atomized particles. The negative effect from the inclusions on the properties of the PM-steels is dependant on their origin. The exogenous inclusions are normally highly detrimental while the endogenous inclusions are harmless. Surface oxides are harmful when present in larger amounts.A special experimental technique was developed to study surface oxidation of powders. Large emphasis was also focused on sampling to enable that the oxygen determination was representative of the bulk powder. The results thus obtained gave most important information on when and how the atomized powder was oxidized during the process. Furthermore, a new methodology was developed based on the experimental results. It is now used world-wide for quality control of atomized steel powders. This method enables the distinction between exogenous þ endogenous inclusions and surface oxides.

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