APPLICATION OF THE DRI TECHNOLOGY FOR PRODUCTION OF COMPOSITE PELLETS IN THE UTILIZATION OF METALLURGICAL PRODUCTION WASTE

Abstract

The article considers possible ways of utilization of iron-containing waste of metallurgical industries. Currently, the disposal of iron-containing and carbon-containing wastes of metallurgical production is a very difficult and urgent problem for most metallurgical enterprises. It was established that the main problems in the way of disposal of metal-containing waste are the increased moisture content in the slag, which leads to difficulties in sintering the agglomerate and a decrease in the productivity of the sintering belt when the proportion of slag in the waste mixture is 60–70%, as well as a decrease in the iron content in the agglomerate, which inevitably affects the loss of productivity and the increase in the cost of coke equivalent of the blast furnace. In the conditions of a gradual transition to new technological schemes of steel production, with the aim of more economical and environmentally friendly operation of enterprises, in which there will be partially or completely no agglomeration, and in the future no blast furnace and no coke chemical production. It has been determined that, in addition to sintering production, the production of direct iron reduction products from these materials, such as high-strength, low-metallized pellets for blast furnace production and highly metallized pellets for steelmaking production with relatively low strength, can be promising. It was determined that during the production of low-metallized pellets for the blast furnace process, the hematite bond is destroyed during reduction and is partially replaced by a metal bond. In order to enhance the strength properties of the pellet, it is possible to implement a number of measures, including the incorporation of bentonite in an increased amount of 4–5% of the mass of the charge, the elevation of the sintering temperature and the prolongation of the sintering time. One of the key issues in the disposal of iron-containing waste is the increased moisture content in the waste. Consequently, prior to the sintering of the metallized pellet, the moisture content should be at the lowest possible level. In order to achieve a yield of greater than 90%, the moisture content of the pellet prior to sintering should be no greater than 2%.