SU511143A1 - The method of obtaining iron powder - Google Patents

Description

one

The invention relates to powder metallurgy, in particular to the preparation of iron powders by reduction.

A known method for producing iron powder by restoring scale or 5

ore solid reducing agent, I conclude. The result is that the recoverable material and the reducing agent are placed in crucibles with immiscible layers. The recovery process in tunnel kilns is carried out at about 115 ° C for an hour. The sponge iron obtained after reduction is ground in air.

However, the known method does not provide fire and explosion safety when grinding - jg

sponge iron in drum mills in an atmosphere no different from the environment.

The purpose of the proposed method is to prevent ignition when grinding caustic iron in air. For this purpose, in the proposed method, the reduction is carried out at an isothermal holding of 25 to 30 hours, and the grinding is carried out at the exchange rate of the ground material.

la in relation to the volume of the mill, which is equal to 0.25 3 3 0.5 M; / M: us and kratisyuti exchange votsuha in; drum mills, equal 15О3

300 M / M h with cooling of the crushed material with a temperature of 0.40, 5 times the magnitude of its ignition temperature.

The restoration of scale or ore with a solid smoke reducing agent is carried out at 11OO-12OO C with an isothermal exposure of 25 Oz. which reduces heat generation during grinding of the material by reducing the stock released during the process of rcrystal. lization of the surface energy of the crystalline system as well as due to a decrease in the heat of formation of the oxide film due to the reduction of the surface ma-1

teriala. The prevention of ignition of the comminuted material is achieved by regulating the removal of heat from the discharged N; the crushed material and from the asp p1feygly1 smmeln atsyvozukhy. As a result, heat dissipation during erosion of the material is insufficient to heat the comminuted material to self-ignition temperature.

An example. Restoration of finished rolling р scinna (with a bulk weight of 2.34 g / cm and an average median diameter of

rum particles 173 microns, containing iron 74.8%, manganese J,) are carried out in tunnel kilns. The recoverable material and the reducing agent are placed in non-mixed layers in the capsules.

The grinding is carried out in a rod melnitsa with a drum with a diameter and length of 15OO and ZO90, respectively, with a rod weight of 119OO kg and an engine with 1OO KW engine.

The test results are presented in the table.

Zoo wound 210

0.25

15One turned 300

0.1

i is the maximum temperature of the material during recovery; at

R is the multiplicity of exchange of material in the mill in relation to the beat of the drum of the mill that is free from grinding bodies;

to - the frequency of air exchange in the mill drum}

t is the temperature of the material discharged from the mill;

f is the average median particle diameter of the crushed material. As can be seen from the table, when the droplets with charge materials are heated in the recovery process to IIOO-IISO C with an isothermal holding time of 25 hours, they are crushed at a ratio of exchange of the crushed material relative to the volume free from the rods the drum of the mill is 0.23-0.46 hours and the air exchange rate 15O-ZOO (test 3-6) prevents the spontaneous combustion of the crushed material. The self-ignition temperature of the powder in the 2OO layer (;, and the temperature of the material being fed from the muslars does not exceed

groups of hot particles

Claims (1)

Particular Red-hot Particles Formula of the Invention A method of producing iron powder by reducing a raw material containing iron oxides with a solid reducing agent, followed by grinding the reduced material in an air medium, characterized in that, in order to prevent the powder from igniting during grinding, the reduction is carried out at isothermal exposure 25. -ZO hour, and grinding is carried out at the multiplicity of exchange of the crushed material with respect to the mill type, free from the grinding bodies, avnom 0.25-0.5 m / m h and multiplicity of air exchange in the drum mill 15O300 m / m hour ohlazhoeviem comminuted "material ORI tzo temperature equal to O, 4-O, 5 values of its ignition temperature.