Lyutyi Igor

Faculty: Physical and Metallurgical
Speciality: Electric Metallurgy

Theme of master's work:

Research of process of reduction by carbon of a ferriferous technogenic waste and design of bases of technology of their recycling for the purpose of use in charge electric arc furnace

Scientific adviser: Timoshenko Sergey

Summary of research and developments

Metallized raw materials production - the most dynamic part of the world charge market for the steel industry. World production of metallized raw materials in 2006 achieved  60mln. t at the next distribution methods and technologies production (Figure 1). The most promising processes is RHF ( "Fastmet", "Fastmelt", "ITMK3"), but their implementation requires considerable investment costs.

Figure 1-World production of metallized raw materials

Figure 2 - The processes in the smelting chamber of the ratary hearth furnace

Relevance

Actual less expensive technology of carbothermic process  briquettes reduction from technological wastes (slag, dust and sludges steel production) using a heating furnace available metallurgical enterprises of Ukraine. Rising prices for competing commodities: scrap metal and pig iron, tainted scrap metal impurities by non-ferrous metals (copper, zinc, tin, lead), which is practically not removed during subsequent processing, the accumulation of anthropogenic iron-containing wastes (roll scale, BF dust and sludges, BOF, and EAF production), which may be partially recycled in the production of metallized raw materials, development concept of mini-mills, with the technological route: metallized raw materials -steel (EAF), all of which are causes of high interest to the metallized raw materials.

Objective

    Investigation of the ore carbothermic reduction  processes, which are intended for use as metall charge for the partial replacement of scrap in the future electric arc furnace smelting industry.

Thermodynamic analysis

Iron formation (briquette metallization) by carbothermic process  obtaining raw materials from the ore-coal briquettes, will occur with the following parameters:

• temperature of briquette must be more than 700 0С, but to achieve a sufficient level of coal gasification requires temperatures more than 1000 Celsius degree;
•  concentration of CO in the gas phase more 60%. According to thermodynamics, this condition is automatically executed when performed first. Therefore, the briquettes temperature factor containing iron oxides and carbon is decisive to the reduction process;
• the dry briquette composition, the best for carbothermic process, with the metallization degree of 0,8 includes,%: concentrate InGOK - 75, coke -14 binder - 11 (InGOK concentrate) and flue dust - 90, binder-10 (briquettes from the flue dust).
   However, thermodynamic analysis can not determine the time frame and the energy cost of carbothermic reduction needed as inputs for the design carbothermic reduction plant for obtaining raw materials from ore-coal briquettes. The answers to these questions provides an analysis of energy and the kinetics of the process, but mainly to the experiment.

The energy balance of the recovery process

Performofed the energy balance of of carbothermic reduction ore-coal briquettes in a pusher-type furnace. On the basis of it determine blast furnace and coke gases flow.

Briquette heating

Maked a calculation of heating briquettes duration in  furnace.  Heat to temperature 1000 Celsius degree occurs for 15-20 min (Fig. 3)

Figure 3 - The dynamics of briquettes heating in a furnace. time (tau) dependence temperature (Celsius degree), t axis (x = 0), half the thickness (x = 0,5 S) and the briquette surface

(x = S) (tau), pp.

Figure 4 - The model pusher-type furnace

Literature

1.  Fastmet, Fastmelt and ITmk3: development of new coal-based ironmaking
processes/Direct from Midrex. Special report. Winter 2007-2008.

2.  Nagata K., Kojima R., Murakami T., Susa M., Fukuyama H. Mechanism of
pig-iron making from magnetite ore pellets containing coal at low
temperatures // ISIJ. - Vol. 41 (2001), № 11, р. 1316 – 1323.

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