RU1811980C - Method of ferrous powder production from iron-containing waste products - Google Patents

Abstract

The essence of the invention lies in the fact that the material, which is a waste of shot blasting of forged products and extracted from a shot blasting machine, is sieved on a sieve with a 250 micron mesh. A feed product containing 39.5% metallic iron and 60.5% dross is passed through a magnetic separator with simultaneous air supply. After separation, the waste contains 10-30 wt.% Scale. The waste is then subjected to reductive annealing at 950-1050 ° C. The method is simple to implement and provides a powder with improved compressibility. 1 C.p. f-crystals, 1 tab.

Description

ate

with

The invention relates to the field of metallurgy, in particular powder metallurgy, and can be used to produce iron powder from ferrous metal wastes.

The purpose of the invention is to simplify the process and increase the compressible ™ powder.

The essence of the proposed method is as follows.

Shot blasting waste for the forged products, which is a powder with a particle size of mainly less than 250 microns and consisting on average of 40% of ground steel shot and 60% of fine scale, is subjected to magnetic separation. The separation of metal and scale by the magnetic method is based on the difference in their magnetic properties. After separation, a product is obtained containing 70 ... 90% metallic iron and 10 ... 30% dross. Dross is represented by iron oxides, mainly FeO. Thus, it is not an extraneous impurity, since it can be reduced to metallic iron during processing in a reducing medium. Moreover, in the process of cleaning forged products from scale, the latter is crushed to fine fractions to a greater extent than shot, and during reductive annealing of fine scale, coating the metal particles with a shell, it is welded to them, roughening their outer surface. This phenomenon helps to increase the compressibility of the powder.

The absence of coolant and abrasive material simplifies the process, since there is no need to remove moisture and oil, calcining in an atmosphere of hydrogen, and repeating operations such as recovery twice

U 00

about

innovative annealing, crushing, magnetic separation.

Wastes of shot blasting of forged products after a one-stage magnetic separation are subjected to regenerative annealing at a temperature of 950-1050 ° С. The need for reductive annealing is dictated by the presence in the material of excess oxygen bound in the iron oxides present in the scale.

Material recovered from the shot blasting machine was sieved on a sieve with a 250 μm mesh. A feed product containing 39.5% metallic iron and 60.5% dross was passed through a laboratory magnetic separator (such as a Davis tube) while air was introduced into it to more effectively separate the low magnetic fraction. After separation, the material contained THAT ... 30 wt.% Dross. In each experiment in a tubular electric furnace, resistances at the appropriate temperature were reduced with hydrogen 1 kg of the specified material; hydrogen flow rate was 0.32 m3 / h. After

0

5

0

reductive annealing, the powder was cooled in an argon atmosphere to 40 ° C and crushed to a fraction of less than 250 microns. The resulting powder was analyzed to determine its main process characteristics.

The most significant characteristics are given in the table.

Claims (2)

The proposed method is more economical in comparison with the known. SUMMARY OF THE INVENTION 1. A method of producing iron powder from iron-containing wastes, including magnetic separation and reductive annealing at temperatures up to 1050 ° C, characterized in that the waste materials are shot blasting forged products and the magnetic separation is carried out until contained in the powder 10-30% of scale. 2. The method according to claim 1, characterized in that the reduction annealing is carried out 25 at a temperature of 950-1050 ° C.