SU396368A1 - METHOD OF OBTAINING METALLIZED WELLS - Google Patents

Description

one

The invention relates to the field of direct iron production.

A known method for producing metallized pellets prepared from a mixture of ore with a reducing agent and a flux, with metal coagulation during the burning process, in which the reduced metallic iron coagulates, creating an outer metallic shell, and the oxides of the empty rock constitute an internal core.

However, with such a structure of metal pellets, it is difficult to separate iron from slag by magnetic separation, because with a low degree of metal carbonization, the pellets are poorly crushed (ductile iron), and with significant carbonizing, inevitably strong development of the liquid phase and fusion of granules into a solid conglomerate.

The purpose of the invention is to improve the conditions for the subsequent separation of metal and slag, but not obtained double-layer pellets with a metal core and a slag shell.

For this, pellets or granules with a particle size of 3-20 mm, prepared from ore or concentrate with an additive as a binder and a reducing agent up to 10% of mazut and, if necessary, flux, are burned in a layer of solid (O-3 mm) solid reducing agent (coking , semi-coke, brown or stone

coal) so that each pellet is surrounded by a reducing agent, first at 1100–1250 ° C to an iron reduction level of 85–100% and then at 1300–1500 ° C until the metal coagulates inside the pellet.

A layer of reducing agent can be rolled on the pellets. Coagulation of the metal inside the pellet is ensured by the removal of surface tension. The preservation of the shape of the pellet during the softening of the slag component of the charge is also provided by surface tension forces operating under conditions when the pellet is surrounded by a wettable medium (carbonaceous reducing agent).

After calcination, the metallized pellets have a nut-like structure with a metal in the inner cavity. The separation of the metallized pellets from the reducing agent is achieved by screening or magnetisation. The pellets may be cooled in air due to the fact that the molten slag shell prevents the metal from oxidizing. When crushing cooled pellets, the slag shell is easily cracked and separated from the metal, which is otmashshchivatsya. The structure of such double-layered metallised pellets makes it possible to more easily and more completely separate the metal from the slag. Example. The raw material from the Serovskoye deposit (39–44% Fe total 0.3–0.4% Ni) is used as the source material. The coating mixture contains 10% fuel oil. Palletizing is done in a drum pelletizer. Pellets with a diameter of 8-20 mm are used in the experiments. Restoration is carried out in a resistance furnace with a graphite heater. Raw pellets, immersed in a layer of crushed coke with a size of 2-3 mm, are placed in a furnace preheated to 1100-1150 ° C and kept at this temperature for 1 hour. Then the temperature in it rises to 1500 ° C. The pellets are cooled in air. Separating them from the coke is done by screening, and no sticking of the coke pieces to the surface of the pellets occurs. When crushing the okat5 10 15 20 slag necks, the shell easily separates from the metal core. The composition of the metal phase,%: C 0.93; Ni 0.89. The composition of the slag phase,%: FeO 3,5; Ni 0.057. The subject of the invention is a method for producing metallized pellets prepared from a mixture of ore or co-concentrate with black oil and flux, with metal coagulation in the firing process, characterized in that, in order to improve the conditions for the subsequent separation of metal and slag, to obtain two-layer pellets with a metal core and slag shell, they are calcined under the conditions of each pellet with a solid reducing agent at 1100–1250 ° C until iron reduction is 85–100%, and then at 1300–1500 ° C until D1 metal coagulates inside the pellet.