Study of the degree of restoration of two-component self-healing briquettes based on iron- and carbon-containing waste

Abstract

The recycling of iron and carbon-containing wastes in the metallurgical cycle is an urgent task in the Russian Federation and the world as a whole. Various wastes during storage occupy large areas (in the Russian Federation ‒ up to 4 million hectares) and are a source of adverse effects on the environment and the health of the population of nearby territories. In the Russian Federation, only waste from metallurgical enterprises has accumulated about 1 billion tons and its amount continues to grow. In addition, due to storage at waste disposal sites, this technogenic raw material falls out of production chains. Prolonged waste disposal leads to a decrease in the content of valuable components. The utilization of iron- and carbon-containing wastes requires its preliminary preparation, in particular, the agglomeration of finely dispersed materials. One of the methods of agglomeration is briquetting. Briquetting allows the creation of self-healing metallurgical briquettes, consisting only of waste as iron-containing material, reducing agent and binder. The important characteristics of self-healing briquettes are the degrees of its reduction to Femet and Fe+2. In this paper, two-component briquettes were studied, consisting of a waste from metallurgical production ‒ dust from an electric steel-smelting shop (dust from an electric furnace shop) as an iron-containing material and a waste from sugar production ‒ molasses acting simultaneously as a reducing agent and a binder. The content of molasses in two-component briquettes was 5, 10, 15, 20 % wt. The briquettes were calcined in an oxidizing atmosphere at temperatures of 700 and 1100°C until gassing was completed (about 15–20 min.). The degrees of iron reduction for all briquette variants were higher at 1100 °C. The highest reduction degree was obtained when the content of molasses in a two-component briquette was 20 % wt. and amounted to 10.75 % wt. for Femet, and the reduction degree to Fe+2 was 76.82 % wt. The obtained results do not allow us to recommend such briquettes for use in steelmaking, however, its can be considered as an additive to the blast-furnace charge in the presence of an available raw material base. Changing the temperature and time regime and the gas atmosphere during the reduction of briquettes can expand the possibilities of its application in metallurgical production