The invention relates to a modified sphere-shaped
sponge iron used for
sewage treatment and a preparation method thereof, and belongs to the technical field of metallurgical production. The modified sphere-shaped
sponge iron is used for reducing
crystal grains in the sphere-shaped
sponge iron and improving the specific surface area and the stability of the sphere-shaped sponge iron in air. The modified sphere-shaped sponge iron is characterized in that the modification sphere-shaped sponge iron has a porous structure, the
diameter of a sphere ranges from 1 to 10mm, while the
diameter of an internal elementary iron
crystal grain is less than 1 micron, and the specific surface area is 0-50m<2> / g; the
surface layer of the sponge iron is
cementite with the thickness between 10 nanometers and 100 nanometers. The process of the invention includes material blending, sphere making, oxidizing
roasting, direct deoxygenizing and
carburizing of the sphere-shaped sponge iron, etc. In the invention, H2 is chosen as a reductant, thereby ensuring low temperature in the preparation of the sponge iron and ensuring the reductive sponge iron finer; the process of the
carburizing of the sphere-shaped sponge iron is increased so as to ensure the
surface layer of the sponge iron to be attached by a
carburizing layer with the thickness between 10 nanometers and 100 nanometers and the sponge iron is not easy to undergo secondary oxidization. Compared with the prior art, the modification sphere-shaped sponge iron has the advantages of low production cost, high efficiency of
stain removing, uneasy hardening and convenient storage and usage, etc.