ECOLOGICAL PROBLEMS OF IRONMAKING (BASED ON PROCEEDINGS OF THE FOURTH EUROPEAN COKE AND IRONMAKING CONGRESS)

摘要

Technological processes of preparing raw materials for the blast-furnace process - the production of sinter and pellets - are among those most polluting the environment. Although the presence of a sintering plant at an integrated metallurgical plant solves the problem of utilizing many metallurgical wastes, reducing the plant's harmful effect on he environment, the sintering plant itself is a source of air and water pollution. In accordance with the requirements of regional authorities on matters of environmental protection, the Corus firm in Emeiden has developed an emission optimizing system at a sintering plant and a wastewater treatment system at a pellet production plant (report of T. Leuwerink and A. van der Panne). The emission optimizing system was first constructed in 1994 on the first sintering machine and received quite hopeful results with respect to reducing emissions of SO_2, NO_x, and dioxins. Works continued in the direction of trapping dioxins, furans, and dust. Improved emission optimizing systems were installed on two other sintering machinesin 1995. Furthermore, a wastewater treatment facility was constructed at a pellet production plant. The reduction of emissions at the sintering plant after installing the system was by elements, percent: SO_2 - 28, NO_x - 39, dust - 55, dioxins and furans - 63, C_xH_y - 42, HCl - 15. The attained level of harmful emissions with respect to all parameters is below the maximum allowable concentration (MAC), which is seen from Table 1. Analogous data on the content of harmful elements in wastewaters of the sintering plant and pellet production plant are given in Tables 2 and 3. Specialists of the firm are working on a further reduction of emissions, especially with water and NO_x.