JP2006272237A - Iron removal device and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an iron removal device and its method removing iron ions and iron powders in an oil-dispersed aqueous solution. <P>SOLUTION: This iron removal device 10 is provided with an iron powder removing means 12 adsorbing and removing iron powders in the oil-dispersed aqueous solution 11, and a positive ion removing means 13 adsorbing iron ions in the oil-dispersed aqueous solution 11, to remove iron powders and iron ions in the oil-dispersed aqueous solution 11. Thus, iron content in the oil-dispersed aqueous solution 11 is kept low, allowing reuse of the solution 11. The oil-dispersed aqueous solution 11 may be filtered to remove coarse particles in advance, before removing iron powders in the solution 11 by the iron powder removing means 12, thereby the treatment efficiency can be enhanced without imparting burden on the iron powder removing means 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an iron removing apparatus and an iron removing method for removing iron in an oil dispersion aqueous solution.

Oil-dispersed aqueous solution, for example, rolling oil coolant for cold rolling of steel sheet contains 85 to 98 vol% water, 2 to 15 vol% rolling oil as a lubricating component, and additives such as surfactants. It is. The rolling oil coolant cools the steel sheet during cold rolling, reduces rolling power (load) on the lubricated surface (roll and steel plate surface), and relieves frictional heat. However, the rolling oil coolant is used when the used rolling oil coolant (hereinafter also simply referred to as “used coolant”) is reused due to wear powder generated from the steel plate and roll during cold rolling. The abrasion powder contained in the coolant causes problems such as deterioration of the steel sheet surface quality and roll breakage. Therefore, a magnetic separator that has a maximum length contained in the wear powder of, for example, 100 μm or more is removed by filtering, and iron powder less than that is adsorbed by a magnetic force to be removed (for example, Patent Document 1).

Japanese Patent Laid-Open No. 5-212310

However, in the magnetic separator of patent document 1, the iron ion contained in a used coolant cannot be removed, and when reusing the rolling oil coolant processed with the magnetic separator, the concentration of iron in the rolling oil coolant There was a problem of rising. In the present invention, the iron ion is a divalent or trivalent iron ion, and this iron ion includes a hydrated ion hydrated with a water molecule or an iron hydroxide ion combined with a hydroxide ion. included. In addition, iron ions contained in the used coolant react with surfactants and oil to produce metal soap, which dissolves or disperses in the oil dispersion aqueous solution or at the oil interface, degrading the quality of the processed rolling oil coolant. There was also a problem of making it happen.

This invention is made | formed in view of this situation, and it aims at providing the iron removal apparatus and the iron removal method which remove the iron ion and iron powder in oil dispersion aqueous solution.

The iron removing apparatus according to the first invention that meets the above-mentioned object is an iron removing apparatus comprising iron powder removing means that adsorbs and removes iron powder in an oil-dispersed aqueous solution.
Furthermore, a cation removing unit capable of adsorbing iron ions in the oil-dispersed aqueous solution is provided to remove iron powder and iron ions in the oil-dispersed aqueous solution.

As a cation removing means used in water, for example, a filter provided with a cation adsorbent such as a cation exchange resin or a cation exchange membrane having a sulfonic acid group, a carboxylic acid group, or a phosphonic acid group. However, even if this is used as it is, the ion-exchange capacity cannot be sufficiently exhibited in the oil-dispersed aqueous solution due to adhesion of oil to the cation adsorbent, dissolution of the cation adsorbent in oil, and the like. Therefore, as a cation removing means that can be used in an oil-dispersed aqueous solution, a cellulose derivative that has a functional group capable of adsorbing a cation and that can prevent adhesion of oil and does not dissolve in oil is suitable.
Here, the oil-dispersed aqueous solution is an aqueous solution in which oil droplets are dispersed (present) in water, and the amount of oil in the oil-dispersed aqueous solution is, for example, about 1% by volume to 30% by volume. is there.

Further, as the iron removing means, for example, an oil dispersion in which the magnetic body arranged in the cylinder is magnetized by an exciting coil installed around the cylinder formed of a non-magnetic material and supplied to the cylinder. A magnetic separator that adsorbs iron powder in an aqueous solution can be used (see Patent Document 1). In this case, the iron powder adhering to the magnetic material can be separated from the magnetic material by demagnetizing the exciting coil.

An iron removing device according to a second invention is the iron removing device according to the first invention, wherein the oil-dispersed aqueous solution is a rolling oil coolant used in cold rolling.
The rolling oil coolant for cold rolling is a mixture of 85 to 98% by volume of water and 2 to 15% by volume of rolling oil as a lubricating component, and further contains an additive such as a surfactant to emulsify. is doing. In addition, the used coolant includes ferromagnetic wear powder (coarse particles and iron powder) that is generated from the steel plate and roll during rolling and can be removed by the iron powder removing means, and the wear powder in the water in the used coolant. It contains weakly magnetic iron ions and iron hydroxide that are dissolved and are difficult to remove by the iron powder removing means. In many cases, the iron ions react with the surfactant contained in the used coolant to produce a weak magnetic metal soap that cannot be removed by the iron powder removing means.

The iron removing apparatus according to a third aspect is the iron removing apparatus according to the first and second aspects, wherein the oil-dispersed aqueous solution has a pH adjusted to 7 or more and 9 or less.
When the pH of the oil-dispersed aqueous solution is less than 7, iron ions adsorbed by the cation removing means are easily desorbed. When the pH exceeds 9, the basicity of the used coolant is increased and the oil component is hydrolyzed. It becomes easy to proceed and the chemical stability is poor and it is difficult to handle.

The iron removing apparatus according to a fourth invention is the iron removing apparatus according to the first to third inventions, wherein the cation removing means is a cation adsorbent comprising a cellulose derivative in which a hydroxyl group of cellulose is converted to a carboxyl group. And the iron ions are adsorbed by the carboxyl group.
When cellulose composed of 1-4 bonds of β-D-glucose is oxidized, the second, third, and sixth carbons of the glucopyranose ring, which is a structural unit of cellulose (specifically, cellulose molecular chain) The three hydroxyl groups bonded to are changed to carboxyl groups.

In order to maintain the mechanical strength of the cellulose derivative, the hydroxyl group of the sixth carbon (C-6) of the glucopyranose ring is oxidized, and the upper limit of one carboxyl group per glucopyranose ring of the cellulose derivative is preferably 1 Is preferably one carboxyl group per six glucopyranose rings, and the lower limit is preferably 0.1 per glucopyranose ring. This prevents the cleavage of the cellulose molecular chain (part of 1-4 bond of β-D-glucose) and the opening of the glucopyranose ring (oxidation of the second and third carbons) due to oxidation of the hydroxyl group of cellulose. it can.

The iron removing apparatus according to a fifth aspect of the present invention is the iron removing apparatus according to the fourth aspect of the present invention, wherein the cation adsorbent is a non-woven fabric as an aggregate of fibers using the cellulose derivative as a basic shape.
As the cellulose fiber (hereinafter, also referred to as “cellulose fiber”), regenerated cellulose long fibers capable of suppressing fiber dropping and elution from the fibers during the adsorption treatment are preferably used.

In the iron removal method according to the sixth aspect of the invention, the iron powder in the oil dispersion aqueous solution is adsorbed and removed by the iron powder removal means, and then the iron ions in the oil dispersion aqueous solution from which the iron powder has been removed are removed by the cation removal means. Adsorb and remove.

An iron removal method according to a seventh invention is the iron removal method according to the sixth invention, wherein iron powder (for example, particles having a maximum length of less than 100 μm) in the oil-dispersed aqueous solution is removed by the iron powder removal means. Before this, the oil-dispersed aqueous solution is filtered in advance to remove coarse particles (for example, particles having a maximum length of 100 μm or more).

In the iron removing device according to any one of claims 1 to 5, since the cation removing means capable of adsorbing iron ions in the oil dispersion aqueous solution is provided, not only iron powder in the oil dispersion aqueous solution but also iron ions are removed. The amount of iron in the oil-dispersed aqueous solution can be kept low, and the oil-dispersed aqueous solution can be reused.
In particular, in the iron removing apparatus according to claim 2, the dispersion aqueous solution is a rolling oil coolant used in cold rolling, and iron ions in the rolling oil coolant are removed. Generation of metal soap due to the reaction can be suppressed, an increase in iron concentration in the rolling oil coolant can be suppressed, and the life of the rolling oil coolant can be extended.
In the iron removing apparatus according to claim 3, since the pH of the oil dispersion aqueous solution is adjusted to 7 or more and 9 or less, the iron ions are efficiently removed without desorbing the iron ions adsorbed to the cation removing means. Can be removed.

In the iron removing device according to claim 4, since the cation removing means has a cation adsorbent made of a cellulose derivative obtained by converting a hydroxyl group of cellulose into a carboxyl group, iron ions are adsorbed by the converted carboxyl group. Can be removed. In addition, since the cation adsorbent is produced from cellulose, it is superior in oil resistance and heat resistance to the conventional ion exchange material and is inexpensive.
In the iron removing apparatus according to the fifth aspect, since the cation adsorbing material is a non-woven fabric whose basic shape is a fiber using a cellulose derivative, it can be used as a filtering material and is easy to handle. In addition, when a non-woven fabric is used as a filter medium, the non-woven fabric has a fine mesh shape, so that not only iron ions but also iron ions or iron hydroxide is adsorbed to remove oil particles whose maximum diameter is increased. be able to.

In the iron removal method of Claim 6 and 7, the iron powder in oil dispersion aqueous solution is adsorbed and removed by an iron powder removal means, and the iron ion in oil dispersion aqueous solution is adsorbed and removed by a cation removal means. Therefore, the iron content in the oil-dispersed aqueous solution can be kept low, and the oil-dispersed aqueous solution can be reused.
In particular, in the iron removing method according to claim 7, since the coarse particles in the oil-dispersed aqueous solution are previously removed, the processing efficiency can be improved without placing a burden on the iron powder removing means.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 is an explanatory diagram of an iron removing device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of a magnetic separator of the iron removing device, and FIG. 3 is an explanatory diagram of a filter of the iron removing device. FIG. 4 is an explanatory view of a cellulose derivative used for the cation adsorbent of the iron removing device.

With reference to FIGS. 1-4, the iron removal apparatus 10 which concerns on one embodiment of this invention is demonstrated.
The iron removal device 10 is an example of an oil dispersion aqueous solution, and removes iron powder and iron ions in a used rolling oil coolant 11 (hereinafter also referred to as “used coolant”) used in cold rolling, and re-applied. It is to be made available. The iron removing device 10 includes a magnetic separator 12 (trade name HIGAMS manufactured by Nippon Magnetic Sorting Co., Ltd.), which is an example of an iron powder removing means that adsorbs and removes iron powder, and a cation removing means that adsorbs iron ions. It has the filter 13 which is an example. This will be described in detail below.

As shown in FIG. 1, a cold rolling mill 14 used in cold rolling is a facility that rolls a material to be rolled (steel plate or steel strip) 15 with rolls 16 and 17 arranged above and below at room temperature. . During cold rolling, enormous heat is generated due to friction between the workpiece 15 and the upper and lower rolls 16 and 17, so that the rolling oil coolant 19 stored in the coolant tank 18 is rolled via the pump 20. The product 15 is supplied to the top and bottom of the object 15 for cooling. The rolling oil coolant 19 includes an additive such as a surfactant in a mixture of 85 to 98% by volume of water and 2 to 15% by volume of rolling oil.

The used coolant 11 used for the cold rolling is not limited to the components of the rolling oil coolant 19, and the maximum length generated by the rolling from the workpiece 15 and the upper and lower rolls 16, 17 is, for example, a rough value of 100 μm or more. Abrasion powder and iron ions having grains and iron powder less than that are mixed and stored in the waste liquid tank 21. Usually, the used coolant 11 has a pH of 7 or more and 9 or less, but when it is outside the range, for example, an alkali agent such as an aqueous sodium hydroxide solution or an acid agent such as hydrochloric acid is supplied to the waste liquid tank 21 and used. The spent coolant 11 is adjusted to a predetermined pH. The used coolant 11 is supplied from the waste liquid tank 21 to the iron removing device 10 via the pump 26.

The iron removing apparatus 10 includes a coarse filter 27 having a filter (not shown) that can remove coarse particles in the used coolant 11. The used coolant 11 from which coarse particles have been removed by the coarse filter 27 is stored in the standby tank 44. The used coolant 11 stored in the standby tank 44 is supplied to the magnetic separator 12 via the pump 29. Since the coarse particles are removed from the used coolant 11, it is effective that the magnetic separator 12 removes fine iron powder having a maximum length of less than 100 μm.

As shown in FIG. 2, the magnetic separator 12 includes a cylindrical body 30 formed of a non-magnetic material such as stainless steel to which the used coolant 11 from which coarse particles have been removed is supplied from below, and around the cylindrical body 30. One or a plurality of, for example, four exciting coils 31 wound around and one or two or more that are arranged in the cylindrical body 30 and are magnetized by the exciting coil 31 to attract the iron powder in the used coolant 11 by magnetic force. (Multiple) spherical magnetic bodies 32 are provided.

The magnetic body 32 differs depending on the type of raw material (rolled oil coolant), but is usually selected to have a diameter of about 3.2 to 32 mm, and a certain gap is generated even if the cylinder 30 is filled densely. ing. A direct current is supplied to the exciting coil 31 to magnetize the magnetic body 32 inside the cylindrical body 30, and a cooling fan is provided on the side of the exciting coil 31 to cool the heat generated by the exciting coil 31. 33 is provided.

When the magnetic separator 12 demagnetizes the magnetic body 32 and detaches the iron powder from the magnetic body 32, a separate pipe (not shown) for supplying a cleaning liquid from above into the cylinder 30 to wash away the iron powder, It is provided in communication with the cylindrical body 30. In addition, a vibrator 35 connected to a vibration device (not shown) is disposed inside the cylindrical body 30, and the vibrator 35 is vibrated when being cleaned in the cylindrical body 30, and is adsorbed (attached) to the magnetic body 32. It is easy to remove the iron powder. Instead of the vibrator 35, it is possible to attach a vibration motor to the lower part of the cylindrical body so as to vibrate the entire cylindrical body.

As shown in FIG. 3, the filter 13 that adsorbs iron ions is arranged in a cylindrical casing 37 to which the used coolant 11 from which iron powder has been removed by the magnetic separator 12 is supplied, and the casing 37. One end of the casing 37 is attached to one end thereof, the other end is closed, and a cylindrical net 39 having a large number of through holes 38 on the side surface is disposed around the net 39. And a cation adsorbent 40 capable of adsorbing iron ions in the used coolant 11.

The cation adsorbent 40 is a non-woven fabric, and is made of, for example, a fiber 41 (hereinafter referred to as “cellulose fiber”) 41 made of long-fiber regenerated cellulose produced by a copper ammonia method, as shown in FIG. The non-woven fabric was immersed in 1.7% by mass of hydrogen peroxide (an example of an oxidizing agent) at 20 ° C. for 100 hours to convert the hydroxyl group of the cellulose fiber 41 into a carboxyl group, and 0.017 mol / liter hydrochloric acid It is manufactured by washing with an aqueous solution, followed by washing with water and then with an aqueous sodium hydroxide solution having a pH of 9.

As shown in FIG. 4, the cellulose fiber 41 is converted into a cellulose derivative 42 by oxidizing a part of the hydroxyl group of the glucopyranose ring, which is a component thereof, to a carboxyl group by the above-described treatment. Iron ions are adsorbed on the carboxyl groups in the cellulose derivative 42. In addition, the cellulose derivative is a combination of one or more of ultraviolet irradiation, exposure to an oxidizing agent other than hydrogen peroxide (eg, acidic solution of potassium dichromate in hydrochloric acid), and electrolysis in the solution. It can be produced from cellulose by the method described above.

Since the hydroxyl group of the glucopyranose ring constituting the cellulose fiber 41 is structurally more easily oxidized by the primary hydroxyl group (sixth carbon), in the cellulose derivative 42, the primary hydroxyl group of the cellulose fiber 41 is oxidized. And the hydroxyl group of the third carbon may be oxidized. In addition, although the hydroxyl group of a glucopyranose ring is three, in order to maintain the mechanical strength of the cellulose fiber 41, the upper limit is one carboxyl group per glucopyranose ring, and one carboxyl group per six glucopyranose rings. Is more preferable.

As shown in FIGS. 1 and 3, the regenerated coolant 43 from which iron ions have been removed from the used coolant 11 by the filter 13 is stored again in the standby tank 44. Thus, the used coolant 11 in the standby tank 44 is circulated to the standby tank 44 via the pump 29, the magnetic separator 12, and the filter 13. The standby tank 44 is connected to the coolant tank 18 via the on-off valve 45. The regenerated coolant 43 has substantially the same composition as that of the rolling oil coolant 19 by removing coarse particles, iron powder, and iron ions in the used coolant 11. When the rolling oil coolant 19 in the coolant tank 18 becomes low, the on-off valve 45 is opened and the regenerated coolant 43 in the standby tank 44 is supplied to the coolant tank 19.

Next, a method for removing iron in the used coolant 11 using the iron removing device 10 will be described.
When rolling by the cold rolling mill 14, the rolling oil coolant 19 stored in the coolant tank 18 is supplied via the pump 20 between the workpiece 15 and the rolls 16 and 17 disposed above and below the workpiece 15. Cool down. The used coolant 11 used at this time is stored in the waste liquid tank 21. When the pH of the used coolant 11 is not a predetermined value, an alkali agent or an acid agent is supplied to the waste liquid tank 21.

The used coolant 11 in the waste liquid tank 21 is supplied to the coarse filter 27 via the pump 26 to remove the coarse particles in the used coolant 11 and stored in the standby tank 44. It is supplied from the standby tank 44 to the magnetic separator 12 via the pump 29. The iron powder in the used coolant 11 supplied to the magnetic separator 12 is attracted and removed by the magnetic body 32 magnetized by the exciting coil 31. Further, the used coolant 11 from which the iron powder has been removed by the magnetic separator 12 is supplied to the filter 13, and iron ions in the used coolant 11 are adsorbed by the carboxyl groups of the cation adsorbent 40 of the filter 13. Remove. The regenerated coolant 43 from which the iron ions have been removed by the filter 13 is again stored in the standby tank 44.

After filtering the used rolling oil coolant to remove coarse particles, the iron powder was removed with the magnetic separator 12, and further the iron ions were removed with the filter 13, thereby obtaining a regenerated coolant.
(Comparative example)
The used rolling oil coolant was filtered to remove coarse particles, and then the iron powder was removed by the magnetic separator 12 to obtain a treated coolant.

The regenerated coolant treated according to the example contains 0 mg / L of coarse particles, 1125 mg / L of iron powder, and 0 mg / L of iron ions, and the treated coolant treated according to the comparative example contains 0 mg of coarse particles. / L, 1325 mg / L of iron powder, and 4.45 mg / L of iron ions were included. As described above, the wear powder and iron ions in the used rolling oil coolant can be removed by the iron removing apparatus and the iron removing method of the present invention, and the iron content in the regenerated coolant can be set to a predetermined amount or less. it can.

The present invention is not limited to the above-described embodiment, and can be changed without changing the gist of the present invention. For example, a part or all of the above-described embodiment and modification examples are combined. Thus, the case where the iron removing apparatus and the iron removing method of the present invention are configured is also included in the scope of the right of the present invention.

For example, in the iron removing apparatus of the above-described embodiment, the iron powder is removed using a magnetic separator as the iron powder removing means, but an apparatus capable of removing coarse particles and iron powder may be used. In the above embodiment, the cation adsorbent is disposed on the downstream side of the magnetic separator, and the used rolling oil coolant from which the iron powder has been removed is treated with the cation adsorbent. It may be arranged in the cylinder of the magnetic separator, and iron powder and iron ions may be adsorbed and removed simultaneously in the cylinder, and a cation adsorbent is arranged upstream of the magnetic separator and iron ions You may process the used coolant which removed this with a magnetic separator. In addition, as a cation adsorbent, an oil-resistant or oil-resistant cation exchange resin (including a membrane) can also be used.

It is explanatory drawing of the iron removal apparatus which concerns on one embodiment of this invention. It is explanatory drawing of the magnetic separator of the iron removal apparatus. It is explanatory drawing of the filter of the iron removal apparatus. It is explanatory drawing of the cellulose derivative used for the cation adsorption material of the iron removal apparatus.

Explanation of symbols

10: Iron removal device, 11: Used rolling oil coolant, 12: Magnetic separator, 13: Filter, 14: Cooling mill, 15: Rolled material, 16, 17: Roll, 18: Coolant tank, 19 : Rolled oil coolant, 20: Pump, 21: Waste liquid tank, 26: Pump, 27: Coarse-grain filter, 29: Pump, 30: Tube, 31: Excitation coil, 32: Magnetic body, 33: Cooling fan, 35 : Vibrator, 37: casing, 38: through-hole, 39: network, 40: cation adsorbent, 41: cellulose fiber (cellulose molecular chain), 42: cellulose derivative, 43: regenerated coolant, 44: standby tank 45: Open / close valve

Claims (7)

In the iron removing device provided with iron powder removing means that adsorbs and removes iron powder in the oil-dispersed aqueous solution,
Furthermore, an iron removing device is provided, wherein a cation removing means capable of adsorbing iron ions in the oil-dispersed aqueous solution is provided, and iron powder and iron ions in the oil-dispersed aqueous solution are removed. The iron removing apparatus according to claim 1, wherein the oil-dispersed aqueous solution is a rolling oil coolant used in cold rolling. The iron removing apparatus according to any one of claims 1 and 2, wherein the oil-dispersed aqueous solution has a pH adjusted to 7 or more and 9 or less. The iron removal apparatus according to any one of claims 1 to 3, wherein the cation removal means includes a cation adsorbent made of a cellulose derivative obtained by converting a hydroxyl group of cellulose into a carboxyl group, and An iron removing apparatus that adsorbs the iron ions. 5. The iron removing apparatus according to claim 4, wherein the cation adsorbent is a non-woven fabric as an aggregate of fibers using the cellulose derivative as a basic shape. The iron powder in the oil-dispersed aqueous solution is adsorbed and removed by the iron powder removing means, and then the iron ions in the oil-dispersed aqueous solution from which the iron powder has been removed are adsorbed and removed by the cation removing means. Removal method. 7. The iron removing method according to claim 6, wherein before the iron powder in the oil dispersion aqueous solution is removed by the iron powder removing means, the oil dispersion aqueous solution is filtered in advance to remove coarse particles. Removal method.

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