Characteristic of Zinc Concentrates and Products of their Roasting in ZGH Boleslaw

摘要

The paper presents the results of research into the primary and secondary physical and chemical properties of zinc concentrates and products of their roasting at the fluidization process in industrial conditions in ZGH Boleslaw S.A (Poland). The properties of the materials were tested in ambient and high-temperature conditions. The following analyses were conducted in ambient conditions: chemical, grain size analysis, structural as well as X-ray phase micro-analysis. High-temperature tests were conducted using the TG method, differential thermal analysis (DTA) and the Bunte-Baum method. Based on the tests it has been established that there are significant differences in the properties of the raw materials from different sources as regards their physical, chemical and structural properties. The macro- and microscopic tests made it possible to observe hollow spaces inside the roasted ore grains, which was interpreted as being the effect of inflating the grains in the roasting process of some types of concentrates and to formulate a hypothesis as to their formation. The temperature critical for the formation of zinc ferrites, whose presence has an adverse effect on the zinc yield in the leaching process, was determined to be approx. 920 °C based on the DTA tests. This value is consistent with the results of the thermodynamic calculations.