Análise do desempenho de um processo hidrometalúrgico de separação de óxidos da escória de conversor a oxigênio obtida no processo BSSF a variação dos reagentes HCI e CH3COOH

Abstract

Oxygen converter slags contain high iron oxide content because they are produced under oxidizing conditions, which makes it difficult to apply them to cement production, such as Portland cement. In this work, a sample of oxygen-slag, treated by the Baosteel Slag Short Flow technology (BSSF) process provided by a Brazilian steel industry, was characterized by X-ray fluorescence, and then underwent a previously known hydrometallurgical process of acid leaching for the separation of the oxides from the slag provided. The separation takes place as follows: The acid during leaching attacks the bulk phase of the slag separating into two products: A residue with high content of iron oxide that may serve as refrigerant for the oxygen converter, and a supernatant that can be treated later to serve as input to the cement industry. The process was carried out for twelve samples, using hydrochloric and acetic acid as leaching reagents, with six different concentrations for each acid (0.5, 1.0, 2.0, 3.0, 4.0 and 5.0 mol L -1). In each oxidation separation reaction, two products were obtained: a solid fraction with a high iron oxide content and a high calcium oxide liquid fraction, where the liquid fraction had to pass through a later stage to precipitate the white oxide, as the purpose of the work is to analyze the efficiency of each reagent in the reaction route, it was carried out until obtaining the solid and liquid fractions as process products. For each solid fraction sample obtained, the X-ray fluorescence technique was performed, and each liquid fraction obtained was analyzed by qualitative analysis of the supernatant, total iron and calcium analysis. The results of the analyzes were compared with the composition of the starting sample and it was concluded from this study that the molar concentration and type of acid used in the hydrometallurgical process influence the yield of the process, where the best results were for the leached fractions with a concentration of 2M HCl and with 5M concentration of CH3COOH, as they presented a better performance in the separation of the majority phase of the slag in an iron-rich residue and a rich CaO supernatant.