JPS5853926B2 - Jikibunrihouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic separation method used for removing heavy metal ions, etc. from wastewater.

Specifically, the present invention relates to a magnetic filter for generating a steep gradient magnetic field used in a steep gradient magnetic separation device.

In recent years, recovery of metal ions from wastewater has become an important issue in terms of wastewater pollution and effective use of resources.

One of the methods is the steep gradient magnetic separation method (High Gradient Magnetic Separation), which uses a large magnetic field gradient to separate metal particles, etc.
ient Magnetic 5 separation (hereinafter abbreviated as HGMS) is attracting attention.

HGMS research is Dirac Magnetic Mo
It originated from research on nop-ohe, but has developed into industrial applications.

What is currently being put into practical use industrially is the removal of iron-based impurities from kaolin used in the paper industry.

Recently, studies have been underway to apply this technology to wastewater treatment.

First, the principle of HGMS will be explained.

At a magnetic field strength H1 and a magnetic field gradient dH, the magnetic force F acting on a magnetic particle of volume V and magnetization M is expressed by the following equation.

H F OCM, V, - x Therefore, if the magnetic particles are large and ferromagnetic, the force F exerted on the magnetic particles is sufficiently large to cause no problem.

If the particles are small and may be paramagnetic, a large magnetic field gradient is required to increase the F acting on the particles.

It is known to insert fine metal fibers into a magnetic field as a means of generating a large magnetic field gradient.

In place of the above-mentioned fine fibers, the present invention provides a metal porous body having a three-dimensional foam structure having continuous pores with a porosity of 90% or more as shown in FIG. 3 as a material for generating a magnetic field gradient.

The characteristics of the present invention are that a porous body with a three-dimensional foam structure having interconnected pores with a porosity of 90% or more is used, so the flow resistance of the liquid is extremely small. It has good contact with the skeleton that forms the structure, and the adhesion efficiency of fine particles is high.

Note that the thickness of the skeleton forming the mesh can be arbitrarily changed and can be arbitrarily selected according to the characteristics of the treated particles.

In general, a porous body made of fine fibers has a small porosity, so that treated particles are adsorbed only on the surface of the porous body, resulting in a short interval for desorption treatment of the adsorbed particles.

The porous body having a three-dimensional foam structure with continuous pores of the present invention has a structure as shown in Fig. 3, so it has the characteristic that it is not only adsorbed on the surface but also uniformly on the inside. It has the characteristics that the increase in fluid flow resistance due to particles is small, the desorption treatment interval is long, and it is industrially effective.

Furthermore, as shown in Fig. 3, the porous body of the present invention has a one-piece structure, so it has high mechanical strength and is easy to handle. , with freely selectable characteristics.

In FIG. 1, a magnetic field is generated in a tank 2 by an air-core coil 1 for generating a magnetic field.

The tank 2 is filled with a porous body 3 having a three-dimensional foam structure with continuous pores as shown in FIG.
A magnetic field gradient is generated by the skeleton 5 within a distance range comparable to the thickness of the skeleton 5.

By flowing a liquid containing fine particles 4 through the tank 2, the fine particles 4 are adsorbed onto the skeleton 5 of the porous body.

The magnetic particles contained in wastewater are removed according to the principle described above.

However, the object to be removed from wastewater is not necessarily magnetic.

In this case, various studies are being conducted on methods of imparting magnetism to non-magnetic materials.

The present invention is not limited to these methods described above.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram illustrating the principle of the present invention. FIG. 2 is an enlarged view of a part of the filter. FIG. 3 is an external view of a porous body having a three-dimensional foamed structure with communicating pores used in the filter.

Claims (1)

[Claims] 1. A magnetic separation method characterized by installing a magnetic filter having a three-dimensional foam structure made of metal with communicating holes in a magnetic field and removing magnetic suspended matter in a liquid using a large magnetic field gradient.