Modified spherical sponge iron for wastewater treatment and preparation method

Abstract

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.

Description

technical field [0001] The invention relates to a modified spherical iron sponge for water treatment and a production process, belonging to the technical field of metallurgical production. Background technique [0002] With the advancement of science and technology, the discharge of industrial pollutants is increasing day by day, and a large amount of heavy metals and organic pollutants enter the environment, which brings great pressure to environmental protection. At present, sewage treatment mainly adopts physical and chemical methods, phytoremediation and biological methods. Among them, the traditional physical and chemical methods have problems such as large amount of water treatment agents used and uncontrollable reactions; Strong; bioremediation technology needs to control the suitable living environment of microorganisms, which is greatly restricted in the process of large-scale application, and cannot treat highly toxic wastewater. [0003] After the 1990s, domestic...

AI Technical Summary

Problems solved by technology

The patent application "A Spherical Sponge Iron for Water Treatment and Its Preparation Method" (Application No.: 200710139300.8) is researched and developed on the basis of carbon-based direct reduction to produce sponge iron, and its product spherical sponge iron crystal grains can reach below 10μm , has the characteristics of high specific surface energy and strong reducibility, but the problems are as follows: 1. The reducing agent in the preparation process of spherical sponge iron is charcoal, according to the charcoal gasification reaction (C+CO 2 =2CO), the temperature of the reduction reaction is relatively high and needs to be controlled above 900°C, which requires high reduction equipment, high energy consumption, and high product preparation costs; 2. Due to the high reduction temperature, the iron crystal There is a process of continuous growth of sponge iron grains, so the iron grains are relatively large, and the specific surface area and activity of sponge iron are affected to a certain extent.

3. The sponge iron is prone to secondary oxidation in the air. In order to prevent secondary oxidation, the sponge iron needs to be specially preserved, which brings great difficulties to storage and application, and greatly weakens the practical application of spherical sponge iron. Operability