The Development Of Fundamental And Applied Research In The Sphere Of Ferro Alloys In South Africa PDF Download

The growth of the ferro-alloy industry in South Africa has been accompanied by developments in electric-furnace technology and an increase in furnace capacity. It soon became clear that stricter control of furnace operation was necessary, especially in the larger furnaces, if optimum production was to be achieved. In 1974 a research team set up by the Council for Mineral Technology (formerly the National Institute for Metallurgy) and a large ferro-alloy producer started investigating the control of a large submerged-arc electric furnace, their objectives being to install a computer system, to increase their understanding of the process, to devise strategies to improve the furnace operation, and, in the long term, to optimize the process. An account is given of the first system installed - a minicomputer system that was responsible for the acquisition and storage of data on the status of the furnace at all times, and for the development of off-line programmes for metallurgical control of the process. As the project developed, it became clear that control of the raw-material feed and electrode-hoist position were unsatisfactory. The analogue system for the batching of raw materials was changed to a system that controls the automatic feeding of raw materials according to a preset recipe, controls the dry mass of the reducing agent, and compensates for any errors that occurred during the previous batching. Electrode control was achieved through a system that depends on phase resistances, which are calculated from reliable measurements made in the furnace. Both these controllers were designed and developed as stand-alone microcomputer units. Although there is still much room for improvement in the production of ferro-alloys in South Africa, a lack of skilled manpower will probably delay the implementation of computer control on the whole plant operation as has been achieved overseas.