The work objective is to study the effect of the temperature lime burning conditions in a rotary kiln on the quality indices of the industrial lime used in the steelmaking. The methodology for stud-ying the heat transfer conditions and the temperature behavior of the bulk material under the heat passage and temperature-waves propagation in the semibounded space of a rotary kiln is offered. It is shown that a system of equations describing boundary condi-tions of the limestone heating by the radiant heat flux becomes increasingly complicated in the case of the parallel convective heat transfer. To simplify the calculations, it is suggested to reduce the combined radiant and convective heat transfer to the convective one (in form) using the known criterial dependences. The investigation results of the heat transfer in the ‘flame – limestone’ system with testing apparent and optimum temperatures in the burning zone are presented. The thermal effect in the rotary kiln on the lime quality indices is specified experimentally under the laboratory and plant conditions. Conditioning of the slag adjustment by the lime con-sumption during the steel electrosmelting in an arc furnace is de-fined. Conclusions on the effect of the furnace thermal perfor-mance on the principle processes of the carbonate raw materials kilning in the industrial lime manufacturing are formulated. The optimal furnace temperature conditions for manufacturing quality lime with more than 90% CaO are specified.
burning conditions, rotary kiln, industrial lime, quality, heat flux, criterial dependences, heat exchange, steel industry, electrosmelt-ing, arc furnace, slagging
Введение. Получение стали стандартно-высокого качества обеспечивается технологиями плавки соответствующего уровня [1]. Шлакообразование в сталеплавильных печах и при наведении шлака в ковшах во время внепечной обработки жидкой стали аргоном или азотом требует использования промышленной извести [2]. При этом основные технико-экономические показатели производства стали [3] во многом зависят от технологических решений по оптимизации расхода извести в процессе наведения шлака, а также от качества промышленной извести, используемой в сталеплавильном производстве. Эти показатели во многом зависят от температурных условий обжига известняка во вращающейся печи. Таким образом, исследование указанных условий, установление оптимальных режимов представляется важной научно-технической задачей
1. Karabasov, Y. S., ed. Stal´ na rubezhe stoletiy. [Steel at the turn of the century.] Moscow: MISSiS, 2001, 664 p. (in Russian).
2. Bakhayev, D. A., Kochetov, A. I., Kem, A. Y., Ansimov, A. A Issledovanie roli izvesti pri shlakoobrazovanii i vnepechnoy obrabotke stali inertnymi gazami. [Investigation of the role of lime under slagging and inert-gas secondary steel refining.] Vestnik of DSTU, 2013, no. 7/8(75), pp. 35-42 (in Russian).
3. Kem, A. Y., Kazartsev, V. O., Merker, E. E., Kharlamov, D. A. K voprosu ob optimizatsii vyplavki stali v dugovoy pechi i ee vnepechnoy obrabotki v agregate «kovsh-pech´». [Optimization of steelmaking in electric arc furnace and ladle treatment in the ladle-furnace] Vestnik of DSTU, 2014, vol. 14, no. 2(77), pp.66-71 (in Russian).
4. Nekhlebayev, Y. P. Ekonomiya topliva pri proizvodstve izvesti. [Fuel saving in lime manufacturing.] Moscow: Metallurgiya, 1987, 136 p. (in Russian).
5. Berghaus, A. L., Rosenfeld, E. I. Povyshenie effektivnosti sgoraniya topliva v pechakh. [Improving the furnace fuel efficiency.] Leningrad: Nedra, 1984, 175 p. (in Russian).
6. Merker, E. E., Kharlamov, D. A., Ansimov, A. A. Sovershenstvovanie metodiki kontrolya parametrov rezhima szhiganiya topliva vo vrashchayushchikhsya pechakh. [Improving the parameter checking technique of fuel combustion conditions in rotary kilns.] Chernaya metallurgiya. NTI Bull., 2011, no. 7, pp. 78-81 (in Russian).
7. Antonov, G. L. Osobennosti ekspluatatsii korotkikh vrashchayushchikhsya pechey obzhiga izvestnyaka. [Special operation features of short rotary lime-burning kilns.] Steel, 2008, no. 9, pp. 97-99 (in Russian).
8. Gamey, A. I. Освоение технологии обжига известняка во вращающихся печах. [Development of limestone burning technology in rotary kilns.] Chernaya metallurgiya. NTI Bull., 2002, no.6, pp. 3-5 (in Russian).
9. Fokin, V. M., Boykov, G. P., Vidin, Y. V. Osnovy energosberezheniya v voprosakh teploobmena. [Fundamentals of heat energy saving issues.] Moscow: Mashinostroenie, 2005, 143 p. (in Russian).
10. Merker, E. E, Agarkova, T. V., Gubin, V. V. Povyshenie effektivnosti szhiganiya topliva vo vrashchayush-chikhsya pechakh obzhiga izvesti. [Improving the furnace fuel efficiency in rotary lime-burning kilns.] Chernaya metallurgi-ya. NTI Bull., 2005, no. 5, pp. 28-30 (in Russian).
