Discovery of potassium chloride in the sintering dust by chemical and physical characterization

Abstract

Sintering plant dust arrested by electrostatic precipitator (ESP dust) in an integrated iron and steel company is perceived as a precious secondary material to steelmaking process, due to the presence of important elements to the industry such as, Fe and C with an attractive concentration. However, some hazardous elements such as, K, Na, Zn, Pb, seriously destroying normal working of the blast furnace, are enriched meanwhile. Therefore, it becomes very important to know how to separate these elements from Fe and C before reusing the dust. The aim of this work Is to carry out a chemical, physical, structural and morphological characterization of the sintering dust. The dust was subjected to granulometry analysis, chemical analysis, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy via SEM (EDS), X-ray mapping analysis via SEM and X-ray diffraction. With the help of these analysis ways and some comparison made between characterization of the dust before and after water leaching, an encouraging conclusion was drawn: KCl was identified in the sintering dust with a content percentage up to 30%. Considering serious lack of potassium fertilizer in China, it is necessary to recover KCl from the sintering dust. In addition, endanger of K to the steelmaking process is restricted at the same time. © 2008 ISIJ.