Ahmet Geveci

Investigation of effect of colemanite addition on copper losses in matte smelting slag

Abstract In this study, the aim was to reduce copper losses to slag in copper production by using a boron compound, called colemanite (2CaO.3B2O3.5H2O), as flux, besides silica. In order to achieve this purpose, two different matte–slag couples were used; the flash furnace matte-slag obtained from Eti Copper Inc. (EBİ) and a master matte–slag without copper produced synthetically under laboratory conditions. Chemical analyses of flash furnace slag and synthetic master slag were 0·88%Cu–36·1%SiO2–43·9%FeO–3·7%Fe2O3 and 37·6%SiO2–60·0%FeO–2·4%Fe2O3 respectively. In each experiment, the same amounts of slag and matte were mixed with the addition of predefined amounts of colemanite and melted together at 1250°C for different durations under nitrogen atmosphere in a silica crucible. Results showed that it was possible to decrease the copper losses to about 0·3–0·4% by accelerating the settling rate of matte particles by the addition of colemanite, which was attained by the expected increase in flash furnace slag fluidity and lowering of its liquidus temperature. Dans cette étude, le but était de réduire les pertes de cuivre dans la scorie lors de la production de cuivre en utilisant un composé de bore, appelé colémanite (2CaO.3B2O3.5H2O), comme flux, en plus de la silice. Afin d’atteindre cet objectif, on a utilisé deux couples différents de matte-scorie; la matte-scorie du four éclair obtenu de Eti Copper Inc. (EBİ) et une matte-scorie modèle sans cuivre, produite synthétiquement sous conditions de laboratoire. Les analyses chimiques de la scorie du four éclair et de la scorie synthétique modèle étaient de 0·88%Cu–36·1%SiO2–43·9%FeO–3·7%Fe2O3 et de 37·6%SiO2–60·0%FeO–2·4%Fe2O3, respectivement. Dans chaque expérience, on a mélangé la même quantité de scorie et de matte, avec addition de quantités prédéfinies de colémanite, et fondu ensemble à 1250°C à différentes durées sous atmosphère d’azote dans un creuset de silice. Les résultats ont montré qu’il était possible de diminuer les pertes de cuivre à environ 0·3–0·4% en accélérant la vitesse de sédimentation des particules de matte par l’addition de colémanite, ce qui était atteint par l’augmentation attendue de la fluidité de la scorie du four éclair et par l’abaissement de sa température de liquidus.

Desulphurization Characteristics of Ladle Furnace Slags of a Low Sulphur Steel

Abstract In steelmaking, one of the most important parameters for desulphurization is the oxygen potential of the system which can be expressed either by oxygen activity of the steel or by Fe t O activity of the slag. Removal of sulphur from the steel is enhanced when FetO activity of the slag and thus oxygen activity of the steel decreases. In this paper, ladle furnace slags of a low S steel quality currently produced in Eregli Iron and Steel Works Company (ERDEMIR), Turkey, were studied. Activity coefficients of Fe t O, γ Fe t O were calculated with the relation obtained from the literature. The relation between %Decrease α Fe t O and %DeS (measured) was studied. The percentage of sulphur removal was also investigated using the data of the oxygen activity of liquid steel.

A Study on the Characterization of Nickel Laterites of Central Anatolia

There are mainly three commercial nickel laterites in Turkey: Gordes, Caldag and Sivrihisar. The first two appear in Western Anatolia. The third one, Sivrihisar (Yunusemre) laterites have been found in the first decade of the millennium, in the Central Anatolia region of Turkey. Since then, mining facilities have been continued in Yunusemre. Calcination, prereduction and smelting of Sivrihisar laterites have been extensively studied and published. In the current work, some results of the studies related to characterization of Sivrihisar laterites will be presented.