Yagol'nik M. Improvement of metallurgical properties of pellets due to the improvement of technology of their production from a coal iron bearing charge

Dissertation is devoted to research of oxidizing-reduction processes at the high temperature burning of flux iron-ore pellets, got from the charge with addition of solid fuel. It is experimentally shown that the degree of oxidization is multiplied at the increase of tem-perature and concentration of carbon in a charge up to 0,7 %. In the result of researches is set that the expense of carbon in a charge must be 1,4 % for coke breeze. In these terms eventual concentra-tion in pellets is 4-7 %, providing the improvement of durability of pellets at the heat reduc-tion treatment. In dissertation influence of basicity on durability of pellets in a range of 0-2 is investigated. Attention is accented on that part of pellets, which is exposed to annealing (to the reheat). It is the bed laid on a grate bar and near sides. It is experimentally established that in the interval of pellet basicity 0,5-1,5 there is the decline of durability of pellet in the cold state and at restoration-thermal treatment. The improved technology of production of pellets from the charge with additions of solid fuel is offered and developed. As a solid fuel component to the charge a blast furnace dust is added after grinding with a limestone. The expense of blast furnace dust of high furnaces makes about 30 kg/per ton of pellets. Experimental party of burnt pellets in an amount 68878 t, including 23728 t of fluxed and 45150 t - nonfluxed pellets is made. It is necessary to attribute to the basic results the improvement of quality of pellets, increase of productivity on 20,53-25,57 t/h, the decline of ex-pense of natural gas on 2,99-3,63 m3/t.