JPS6187801A - Milling and washing method of fine metallic grain - Google Patents

Abstract

PURPOSE:To strip away the impurity layer on the surface of fine metallic grains in a short period by charging said grains together with media made of a magnetosensitive material into a cylindrical vessel and rotating the grains at a high speed while exerting load thereto from above then washing the grains. CONSTITUTION:The fine metallic grains such as steel balls having the impurity layer on the surfaces are charged together with the media 5 made of the magnetosensitive material into the cylindrical vessel 1. A drop cap 2 is imposed thereon and the load is exerted thereto from above by a heavy material. A vertical revolving shaft 3 is rotated at a high speed to rotate the metallic grains and media 5 at a high speed by a plate-shaped rotating vane 4. Powerful impact force is thereby exerted to the fine metallic grains and the impurity layer sticking thereto is stripped away. The cap 2 and the load are removed upon ending of the milling stage. A required washing liquid is then fed through a lower supply port 6 and the vane 4 is gently rotated while the liquid is made to overflow from an upper overflow port 7. Electricity is conducted to an electromagnet 8 to take out the stripped impurities.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for grinding and cleaning fine metal particles whose surfaces are covered with a layer of oxides and other impurities.

For example, fine metal particles recovered from various types of slag and dust, shot that has been left for a certain period of time, etc. have oxides and other substances attached to their surfaces, so it is necessary to remove the surface impurity layer. Conventionally, methods for removing this kind of impurity layer include a method of chemically eluting the surface layer and a method of physically grinding, but the former requires complicated selection of treatment liquid and post-treatment of treated waste liquid, and Problems also remain in the post-treatment of chemically treated material surfaces, and most conventional techniques cannot effectively remove the adhesion surface layer when the object becomes microscopic, such as less than 1 pus. The current situation is that it has not been removed.

In view of the above-mentioned current situation, the present invention is capable of sufficiently removing the surface impurity layer of even a very fine object, and subsequently separating the impurity layer peeled off by grinding from the metal product. The purpose is to provide a method for grinding and cleaning fine metal grains whose surfaces are covered with oxides and other impurity layers, and to grind and clean the fine metal grains by placing them in a magnetically sensitive medium. At the same time, the fine metal particles and the media are charged into a storage container made of a cylindrical body with a built-in rotating blade, and while an external load is applied to the fine metal particles and the media from above the storage container,
The impurity layer on the surface of the fine metal particles is peeled off by rotating the rotating blade at high speed, and then the external load is removed, and the cleaning liquid is supplied from the lower part of the side wall of the storage container and overflows from the opening at the upper part, while the rotating blade is rotated. This is a method of grinding and cleaning fine metal particles characterized by slow rotation and cleaning, and a method of disposing an electromagnet on the outside (lower side) of the bottom of the storage container to apply magnetic force during cleaning.

The method of the present invention will be described in detail below with reference to the drawings.

As shown in FIGS. 1 and 2, for example, the device used in the present invention includes a storage container (1) provided with a drop lid (2) that can be moved up and down in a loose manner within the container. The drop lid is connected to the rotating vertical shaft (3), and a required number of plate-shaped rotating blades (4) are attached to the lower surface of the drop lid, and the interior of the storage container (1) is A large number of magnetically sensitive media (5) such as steel balls are charged into the storage container (1).
) is provided with a wash water supply port (6) in the lower part of the side wall, and an overflow port (7) in the upper opening.

In another type of device, a storage container (1
) A lower electromagnet (8) is arranged on the outside (lower side) of the bottom plate.

In the method of the present invention, fine metal particles M as a raw material are charged into a storage container (1), and the required pressure is applied from above the drop lid (2).
That is, by rotating the rotating vertical shaft (3) at high speed while placing an object of a certain weight or applying additional pressure, the fine metal particles M are transferred to the magnetically sensitive medium (4).
It is rotated at high speed while being magnetically attached to the surface of. Therefore, the fine metal particles collide with each other with a stronger collision force than when only the fine metal particles M collide with each other, that is, the fine metal particles M are attached to the surface of the media (5), which is considerably heavier than the fine metal particles M. Moreover, although the media (5) are strongly pressed against each other through the drop lid (2) and are difficult to move, they are rotated at high speed, so the weight of the media (5) and the media (5) themselves are Alternatively, due to strong friction with the inner wall of the storage container (1) and rotation, the surface adhesion layer F of oxides etc. adhering to the surface of the fine metal particles M is better peeled off and removed. It is. This grinding may be carried out in a dry manner or may be carried out in a wet manner in which water or necessary oil is interposed as much as possible to achieve an appropriate pulp concentration.

In this way, the plate-shaped rotating blade (4) passes through the rotating vertical shaft (3).

(4) When the grinding process of rotating . While letting the cleaning liquid overflow from the upper overflow port (7), by gently rotating the plate-like rotating blades (4), (4), etc., only the peeled off adhered layer, which is a lightweight object, will flow out. At the same time, the heavy metal particles overflow and remain in the storage container. At this time, while slowly rotating the plate-shaped rotating blades (4), (4), -..., the lower electromagnet (8) disposed on the outside of the bottom plate of the storage container (1) is energized and energized. As a result, the fine metal particles M, which are magnetized objects, become electromagnets (8)
Because of the adsorption force of the electromagnet (
8) It does not receive the adsorption force or only receives it weakly, so the two are distinguished by their light and heavy weight, and the flaked deposits are pushed upward together with the washing water flowing from the bottom to the top, and eventually reach the upper overflow port. It is overflowed from (7).

A series of experiments that led to the development of the method of the present invention and their results will be described below.

The fine metal grains used as the raw material in this experiment were obtained by removing the extremely fine parts from converter dust (hereinafter referred to as coarse grain dust).
The particle size distribution is shown in Table 1, and the chemical composition is shown in Table 2.
Each is shown in the table.

The following experiment was conducted using the apparatus shown in Table 2 (wt%) and FIG. The size of the storage container (1) was 146 mm in diameter and 225 mm in height, and 61T1mf media and the above-mentioned raw materials were charged into it, 6 kg and 2 kg each, and the pulp concentration of the raw materials was set to 90%. The grinding process was carried out for 2 minutes with the rotational speed of the rotary blade (4) being 300 rpm and various external loads.

The raw material after such grinding treatment is taken out and 350
After sieving with a mesh, the sieved material was passed through a magnetic separator at 300 Gauss, and the MFe grade and M4e recovery rate were determined for the magnetically separated material. The MFe grade was 9412% to 9636%, and the MFe recovery rate was It was 8973% to 8486%.

After the above-mentioned grinding process, with the raw material still in the storage container (1) and without applying any external load from the top of the drop lid (2), the amount of washing water was increased to 8/min. The rotating blade (3) was rotated at a low speed of 200 rpm for 3 minutes of cleaning, and then applied to a 300 Gauss magnetic separator to determine the MFe grade and MFe recovery rate for the magnetic material. In comparison, when changing the rotation speed or changing the valve concentration [Fe grade increases by about 15%, M
A decrease of approximately 45% was observed in the Fe recovery rate.

Further, after performing the above-mentioned grinding treatment, an external load is applied to the raw material while it remains in the storage container (1),
The amount of washing water is 8J/min and the rotating blade (4) is 200r.
After washing for 3 minutes at a low speed of
The results shown in Tables 3 and 4 below were obtained.

As described above, according to the method of the present invention, the fine metal particles, which were difficult to grind sufficiently with the conventional method, are collided and polished together with the media, and moreover, the above-mentioned By applying an external load, the grinding effect is further increased, and the process can be completed in an extremely short time.Furthermore, subsequent cleaning can be done as part of the work in the same container.In particular, when cleaning B, the magnetic force is applied from below the container. As shown in Tables 3 and 4, the method has the effect of significantly improving the yield without substantially reducing the M-Fe grade.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an example of the apparatus used in the method of the present invention, FIG. 2 is a plan view of the same, and FIG. 3 is a partially cutaway perspective view showing another example. In the figure, (1) Storage container (2) Drop lid (3) Rotating vertical shaft (4) Plate rotating blade (5) Magnetically sensitive media (6) Cleaning water supply port (7)/Overflow port ( 8)・Electromagnet

Claims (1)

[Claims] 1. A method for grinding and cleaning fine metal particles whose surface is covered with an oxide or other impurity layer, wherein the fine metal particles are mixed with a magnetically sensitive medium and equipped with a rotating blade. The fine metal particles and media are charged into a storage container made of a cylindrical body, and while an external load is applied to the fine metal particles and the media from above the storage container, the rotary blade is rotated at high speed to remove the impurity layer on the surface of the fine metal particles. Polishing of fine metal particles is carried out by removing the external load, supplying a cleaning liquid from the lower part of the side wall of the storage container, and causing the cleaning liquid to overflow from the opening at the upper part of the storage container, while slowly rotating a rotary blade. Crushing and cleaning method. 2. A method for grinding and cleaning fine metal particles whose surface is covered with a layer of oxides and other impurities, wherein the fine metal particles are stored together with magnetically sensitive media in a cylindrical body with a built-in rotating blade. While applying an external load to the fine metal particles and media from above the storage container, the rotary blade is rotated at high speed to peel off the impurity layer on the surface of the fine metal particles. Cleaning is carried out by removing the load on the storage container, feeding the cleaning liquid from the lower part of the side wall of the storage container, causing it to overflow from the upper opening, and slowly rotating the rotary blade while applying a magnetic force from outside the bottom of the storage container. Grinding of fine metal particles,
Cleaning method.