Research conducted and presented in this paper have sought to reduce the pollution of the environment by harnessing the red sludge, waste ferrous powdered alumina factories existing areas. The red mud is a waste derived from the production of alumina due to the fact that the raw material bauxite contains besides Al2O3 and other minerals such as: hematite, quartz, calcite, rutile titanium dioxide, clay, and shows the red color due to hematite, the whose content can reach up to 45-50% (or 31-35% Fe). Because mineral constituents, containing red mud and water of constitution (approximately 10%). The valorification of red mud in metallurgy is not resolved so far appropriately in terms technical-economical, due primarily to the high content of arsenic than the limit allowed to minerals, which leads to storing it in ponds or throwing by some manufacturers in the sea. This waste has been processed along with other ferrous scrap, are still able powdery or petty, but having a content almost double iron (powder steel mill, mill scale, sludge from agglomeration - furnaces) in order to increase the concentration of iron and decrease the concentration of arsenic by-product.

In this paper are presented the results of some desulphurization trials in the ladle carried out at industrial scale for steels with low carbon, low alloyed and aluminum killed, using basic slag and argon bubbling. The main variables of treatment have been established on the basis of a thermodynamic model that includes parameters as sulphur capacity of the slag, optical basicity of oxides and of the slags, the activities of oxides in the slags and activities of elements in the liquid steel. Sulphur contents at the end of treatment, are close to the values predicted by the model. Low sulfur levels achieved in the process, facilitate the subsequent treatment with calcium to modify the inclusions. Finally an evaluation is presented concerning the effects resulting from the reoxidation of the melt on the main indicators, showing the efficiency of the applied treatment for desulphurization. KeywordsDesulphurization; Slag; Thermodynamic model; Sulphur capacity; Reoxidization.La eficiencia a escala industrial de un modelo termodinámico para eliminar el azufre en los aceros calmados con aluminio utilizando escorias del sistema CaO-MgO-Al 2 O 3 -SiO 2 ResumenEn este trabajo se presentan los resultados de algunos ensayos de desulfuración en cuchara, llevados a cabo a escala industrial, para aceros con bajo contenido en carbono, de baja aleación y calmados con aluminio, utilizando escorias basicás y corriente de argón. Las principales variables del tratamiento se han establecido sobre la base de un modelo termodinámico que incluye parámetros como la capacitad de captación de azufre por las escorias, la basicidad ópti-ca de los óxidos y de las escorias , las actividades de los óxidos en las escorias y las actividades de los elementos en el acero liquido. Los contenidos de azufre al final de tratamiento están cerca de los valores predichos por el modelo. Los bajos niveles de azufre alcanzados en el proceso, facilitan el posterior tratamiento con calcio para modificar las inclusiones. Se presenta, finalmente, una evaluación de los efectos derivados de la reoxidación del fundido sobre los principales indicadores que muestran la eficiencia del tratamiento de desulfuración aplicado. Palabras claveDesulfuración; Escoria; Modelo termodinámico; Capacidad de captación de azufre; Reoxidación.

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Present in the metallurgical industry one of the most frequently problem is the presence of Fe and his compound in secondary aluminum melting. This problem appears when using chip inadequate technologies. This work makes a survey on the problems which can appear because of the presence of Fe and his compound in aluminum. Two systems, Al-Si and Al-Si-Li, are analyzed, by taking into consideration metallographies, as well as the systems mechanical properties. The end presents metallographic evidence of the problems which Fe and his compound can cause in secondary aluminum meltings.

The present paper refers to the remelting of light waste. The research aims to provide a substantial decrease of the oxidation losses and a decrease of the noxious expulsion resulting from the production of aluminium alloys. The fundamental solution found consists in achieving a stable flux layer. For this the wastes are introduced directly in the metallic bath, without a previous preparation. Data about oxidation losses, the content of gases and the correlation between the casting properties and the quality of remelting secondary alloys are presented. Several samples are analysed in order to point out the quality of the alloy and the relationship between the chemical composition, the content of gases and the free linear contraction of the alloy.