Method of Agglomerating Iron-Ore-Bearing Materials that Involves Moistening the Charge with Pulp

Abstract

A new method is proposed for agglomerating iron-ore-bearing materials. The method involves moistening the charge with up to 7.5-9% pulp containing dust-sized waste products from the processing of brown iron ores. The ores are ferruginous chlorites (chiefly amesite, chamosite, and penninite). The have a coarseness of 0.074 mm. The ore content of the pulp is within the range 1.5 to 75 wt. %. The chlorites have the following chemical composition (wt. %): Fe 2 O 3 , 41.2, SiO 2 24.0, Al 2 O 3 13.07, FeO 11.23, Cr 2 O 3 3.96, MgO 2.35, CoO 0.86, NiO 0.58, CaO 0.53, MnO 0.06. Sintering of Mikhailovskii ores and concentrates with the use of the pulp under laboratory conditions made it possible to increase the unit productivity of the sintering machine 2.9%, increase the impact strength of the sinter 4.5%, and increase its abrasion resistance 17.1%. Keywords: sinter, impact strength of sinter, abrasion resistance of sinter, unit productivity of sintering machines, vertical sintering rate.The purpose of sintering iron-ore-bearing materials is to prepare them for smelting in blast furnaces. The use of quality sinter can significantly increase the efficiency of the smelting operation and make it more cost-effective.Being a raw material used in blast-furnace smelting, iron-ore-bearing sinter needs to have the following quality characteristics: maximal iron content; stable chemical composition; good mechanical strength at low and high temperatures; low abradability; minimal content of fines (0-5 mm); high initial softening point; narrow softening-point range; good reducibility; a basicity value which ensures the removal of raw limestone from the blast furnace.One quantitative characteristic of the sintering operation is the unit productivity of the sintering machine. In order to perform the sintering operation correctly, it is necessary to optimize the process parameters for the specific composition of the material being sintered. Sinter quality and the unit productivity of the sintering machine are most heavily influenced by the following process parameters: the composition of the material being sintered; the coarseness of that material; the amount of undersize; the material composition, quantity, and coarseness of the various additions that are used; the character of the charging operation and the associated segregation of the charge materials; the quantity, coarseness, and qualitative composition of the fuel added to the charge; the effectiveness of the charge-mixing operation; the moisture content of the charge; the presence of a bed of fines; the bulk density and height of the layer of charge materials; the vacuum created by the exhauster; the initial temperature of the charge.Among the shortcomings of existing methods of sintering are unsatisfactory mixing of the charge materials and the limit on the quantities of dust-sized materials that can be introduced into the charge. This situation results in uneven moistening of the charge as a whole, creates cavities, and reduces gas permeability and vertical sintering rate.Our...