WO2010029970A1 - Recycle method, recycle system and recycle system vehicle for release agent waste in an aluminum die-casting machine - Google Patents

Abstract

Provided is a recycle technique, particularly, a vehicle for recycle business capable of easily reusing water glycol-based hydraulic operating oil without taking time and cost to separate and remove the hydraulic operating oil and capable of contributing to a reduction in burden on the global environment by reducing a release agent waste. A recycle system for a release agent waste is provided with a charged coalescer-type oil-water separating device (2) for accelerating oil-water separation by applying voltage between internal electrodes, a power supplying means (8) for supplying driving power to the charged coalescer-type oil-water separating device (2), a pH measuring means (3) for measuring the pH value of the release agent waste, a storage chamber (7) for temporarily storing therein the release agent waste subjected to oil removal processing by the charged coalescer-type oil-water separating device (2), a pH lowering solution supplying device (4) for adding a pH lowering solution for lowering the pH of the release agent waste into the storage chamber, and an addition amount controlling means (92) for controlling the amount of addition of the pH lowering solution by the pH lowering solution supplying device (4) in such a manner that the pH value of the release agent waste is within a predetermined range on the basis of the pH value obtained by the pH measuring means (3).

Description

Reclaiming method, recycling system and recycling system vehicle for release liquid of mold release agent for aluminum die casting machine

The present invention relates to a regeneration method, a regeneration system, and a regeneration system vehicle for a release agent waste liquid of an aluminum die casting machine that uses water glycol hydraulic fluid.

As a recycling system for release liquid of mold release agent for aluminum die casting machine, graphite lubrication mold release agent that solves the problem that graphite dispersibility of graphite lubrication mold release agent deteriorates due to lowering pH and microorganisms grow. As a chemical composition for regeneration, a composition composed of a specific amount of an alkaline preservative and aqueous ammonia is obtained, and this is added to a purification / regeneration liquid of a release agent waste liquid to thereby obtain a dispersion liquid which is an active ingredient in the liquid. It has been proposed to maintain the efficacy, at the same time, extend the life of the preservative and eliminate microbial sterilization and contamination prevention even after repeated regeneration (Patent Document 1). In addition, in a system that collects and reuses mold release agents, the release agent dedicated recovery means that recovers the mold release agent directly under the mold and the concentration of the recovered liquid collected by the release agent dedicated recovery means are automatically set. There has been proposed a release agent regeneration system including an automatic concentration measuring means for measuring and a concentration adjusting means for adjusting the concentration based on the concentration measurement result and sending it again to the mold (Patent Document 2).

However, the release agent for aluminum die-casting machines has not been reused in practice because environmental issues have been raised. This is because water-soluble water glycol hydraulic fluid, which has been widely used in recent years as hydraulic fluid for die casting molds, is mixed in the mold release agent when the mold is operated. This is because the water-glycol hydraulic fluid that has been used causes discoloration of the die-cast product. The water glycol hydraulic fluid is composed of 55% ethylene glycol, 5-10% thickening agent of high molecular polymer with viscosity, and 40% remaining water. It is known to react with metals such as zinc and paints. Incorporation of water glycol hydraulic fluid into the release agent is inevitable, and it is water-soluble and difficult to remove by filtration / separation, which is time-consuming and expensive, so the release agent cannot be reused. It was a cause of increasing waste liquid.

JP-A-61-235036 JP 2005-965 A

In view of the above-mentioned situation, the present invention intends to solve the problem that the water glycol hydraulic fluid is used for the time required for the release liquid of the release agent generated in the aluminum die casting in which the water glycol hydraulic fluid is used. The point is to provide a recycling technology that can be easily regenerated into a liquid that does not cause discoloration without costly separation and removal, reduces the release agent waste liquid, and contributes to reducing the burden on the global environment. Is to provide a recycling business vehicle equipped with such a regeneration system and capable of quickly and efficiently performing a release agent waste liquid regeneration process by visiting factories and the like having an aluminum die casting machine. .

As a result of diligent study to solve the above-mentioned problems, the present inventor performed water-glycol hydraulic operation only by adjusting the pH by filtering and oil-water separation of the release agent mixed with water-glycol hydraulic fluid. Even if it is reused with oil remaining, die cast products will not discolor, and the industry's established discoloration is caused by water glycol hydraulic fluid being an indirect factor rather than a direct factor. As a result, the present invention has been completed.

That is, the present invention relates to a method for reclaiming a release agent waste liquid of an aluminum die casting machine using a water glycol hydraulic fluid, and passing the release agent waste liquid through a charged coalescer type oil-water separator, An oil-water separation step for promoting oil-water separation by applying a voltage between the electrodes in the separation device, a pH measurement step for measuring the pH value of the release agent waste liquid, and the release agent waste liquid based on the measured pH value. and a pH adjusting step for adding a pH lowering solution for lowering the pH. The present invention provides a method for reclaiming a mold release agent waste liquid of an aluminum die casting machine.

Here, before the oil-water separation step, the release agent waste liquid is passed through a charge filter device, and a voltage is applied between the electrodes in the charge filter device to promote filtration of impurity particles in the release agent waste solution. It is preferable to provide a filtration step.

Moreover, it is preferable to provide a component adjustment step for adjusting the component including water supply. In addition, a hydraulic oil concentration measuring step for measuring the concentration of water glycol hydraulic fluid in the release agent waste liquid before the filtration step, and the hydraulic fluid is set to a predetermined threshold based on the measured hydraulic fluid concentration. It is preferable to include a determination step for determining whether or not to stop the reproduction process when the value exceeds.

The present invention also relates to a release agent waste liquid regeneration system for an aluminum die casting machine that uses water glycol hydraulic fluid, wherein the release agent waste liquid is circulated and an internal electrode facing the internal flow path. A charged coalescer type oil / water separator that promotes oil / water separation by applying a voltage therebetween, power supply means for supplying drive power to the charged coalescer type oil / water separator, and a pH value of the release agent waste liquid pH measuring means, a storage chamber for temporarily storing the release agent waste liquid subjected to oil removal treatment by the charged coalescer type oil-water separator, and a pH drop for adding a pH lowering liquid for lowering the pH of the release agent waste liquid into the storage chamber Based on the pH value obtained by the liquid supply device and the pH measuring means, an addition for controlling the amount of pH lowering liquid added by the pH lowering liquid supply device so that the pH value of the release agent waste liquid is within a predetermined range amount Also it provides reproduction system of the releasing agent waste aluminum die cast molding machine, wherein more becomes possible and control means.

Here, the release agent waste liquid is circulated, and a charge filter device is provided to accelerate the filtration of the impurity particles in the release agent waste liquid by applying a voltage between the internal electrodes facing the internal flow path, It is preferable that drive power is supplied to the charge filter device by the power supply means.

Further, it is preferable that the pH measuring means is provided in a flow path between the discharge port of the charged coalescer type oil-water separator and the storage chamber inlet. Further, based on the concentration of the hydraulic oil obtained by the hydraulic oil concentration measuring means and the hydraulic oil concentration measuring means for measuring the concentration of the water glycol hydraulic fluid in the release agent waste liquid, It is preferable to include a determination unit that determines whether to stop the reproduction process when the threshold value is exceeded.

Further, the present invention is a vehicle for reclaiming a release agent waste liquid in a release agent waste liquid storage part of an aluminum die casting machine that uses a water glycol hydraulic fluid and regenerating the release agent waste liquid in the storage part. Vehicle running means having a prime mover and a drive mechanism, suction means for taking in the release agent waste liquid in the release agent waste liquid storage section as a liquid to be treated, and the release agent waste liquid being circulated and internal flow A charged coalescer type oil-water separator that promotes oil-water separation by applying a voltage between the internal electrodes facing the road, power supply means for supplying drive power to the charged coalescer-type oil-water separator, and release agent waste liquid pH measuring means for measuring the pH value, a storage chamber for temporarily storing the release agent waste liquid subjected to oil removal treatment by the charged coalescer type oil-water separator, and a pH lowering liquid for lowering the pH of the release agent waste liquid. Added to Based on the pH value obtained by the pH lowering liquid supply apparatus and the pH measuring means, the amount of pH lowering liquid added by the pH lowering liquid supply apparatus is adjusted so that the pH value of the release agent waste liquid is within a predetermined range. An aluminum die-cast molding machine characterized by comprising: an addition amount control means for controlling; and a delivery means for returning the regenerated treated liquid to the same release agent waste liquid storage section or another storage section. A recycling system vehicle for mold waste liquid is also provided.

The release agent waste liquid is circulated, and a charge filter device is provided that promotes filtration of impurity particles in the release agent waste liquid by applying a voltage between the internal electrodes facing the internal flow path, A vehicle in which driving power is supplied to the charge filter device by power supply means is preferable.

Furthermore, a vehicle in which a power generation device driven by a driving motor constituting the vehicle traveling means is provided as the power supply means is a preferred embodiment.

According to the method and system for reclaiming the release agent waste liquid of the aluminum die casting machine according to the present invention as described above, the waste liquid of the release agent generated in the aluminum die cast molding in which the water glycol hydraulic fluid is used In addition, water glycol hydraulic fluid can be reused efficiently without separating and removing it over time and cost, and it is possible to contribute to the reduction of global environmental load by reducing the release liquid waste liquid as well as cost reduction. In addition, according to the release agent waste liquid regeneration system vehicle equipped with the present regeneration system, it is possible to quickly and efficiently perform the regeneration treatment by visiting factories and the like having aluminum die casting machines.

Explanatory drawing which shows the structure of the mold release agent waste liquid reproduction | regeneration system which concerns on 1st Embodiment of this invention. The flowchart which similarly shows the process sequence of a mold release agent waste liquid reproduction | regeneration system. Explanatory drawing which shows the structure of the mold release agent waste liquid reproduction | regeneration system vehicle which concerns on 2nd Embodiment. Explanatory drawing which similarly shows the structure of the processing service using a mold release agent waste liquid reproduction | regeneration system vehicle.

DESCRIPTION OF SYMBOLS S Release agent waste liquid reproduction | regeneration system 1 Charge filter apparatus 2 Oil-water separator 3 pH sensor 4 Falling liquid supply apparatus 6 Component adjustment means 7 Storage tank 8 Electric power supply means 9 Control apparatus 10 Pump 11 Electromagnetic switching valve 12 Pressure gauge 13 Pressure switch 14 Inlet 15 Stop / recovery port 16 Suction means 17 Delivery means 18 Communication device 19 Storage tank 30 Flow path 31 Pump 41 pH drop liquid tank 42 Solenoid valve 50 Concentration sensor 51 Electromagnetic switching valve 60 Replenishment tank 61 Solenoid valve 70 Stirrer 71 Sending path 72 Electromagnetic on-off valve 73 Integrated flow meter 74 Outlet 80, 81 Load power supply 83 Power generator 91 Replenishment amount control processing unit 92 Addition amount control processing unit 93 Determination processing unit A System vehicle B moving track C Enclosed luggage compartment F1 filter F2 composite filter

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an explanatory diagram showing a configuration of a release agent waste liquid regeneration system S according to the first embodiment of the present invention, and FIG. 3 is a release agent waste liquid equipped with the regeneration system of the first embodiment according to the second embodiment. In the figure, reference numeral 1 denotes a charge filter device, 2 denotes a charged coalescer type oil-water separator, 4 denotes a pH drop liquid supply device, and 7 denotes a storage tank.

The release agent waste liquid regeneration system S of the present invention is a system for reclaiming the release agent waste liquid of an aluminum die casting machine that uses water glycol hydraulic fluid, and as shown in FIG. And a charge filter device 1 that accelerates the filtration of impurity particles in the release agent waste liquid by applying a voltage between the internal electrodes facing the internal flow path, and the charge filter device 1 A charge coalescer type oil / water separator 2 that promotes oil / water separation by applying a voltage between the internal electrodes facing the internal flow path, as well as the charge filter device 1 and the charge coalescer. Power supply means 8 for supplying drive power to the mold oil / water separator 2 and a storage tank 7 that is a storage chamber for temporarily storing the release agent waste liquid that has been subjected to oil removal treatment by the charged coalescer oil / water separator 2. .

The charged filter device 1 removes fine dust, and the charged coalescer type oil-water separator 2 performs an oil-water separation process. As the filtration / oil-water separation processing apparatus, the system already proposed by the same applicant (see the sixth embodiment of Japanese Patent Publication No. 2001-46805) can be used. In particular, the charge filter device 1 is a device that utilizes the physical filtration action by the filter mesh and the aggregation and coarsening phenomenon by neutralization of the zeta potential of oil droplet particles or water molecules. The technique disclosed in the new model registration application No. 1993 No. 98913 and the Japanese application publication No. 1996 No. 210 No. 210 can be used, and the filtration of impurity particles such as solid particles in the liquid to be treated is promoted.

The oil / water separator 2 is a device that utilizes the separation of oil and water by emulsion separation in a coalescer in addition to the aggregation and coarsening phenomenon by neutralization of the zeta potential. A coalescer-type oil / water separator having a composite filter F2 having a filter layer and a coalescer layer, and having both functions of a charge filter device and an oil / water separator, and capturing the impurity particles and oil droplet particles. Or it promotes oil-water separation by agglomeration of water molecules. Both are charged in the filter F1 and the composite filter F2, or placed in an electric field and given potential to the filter and the filter surface, so that the zeta held by impurity particles such as dust and oil passing through them. The repulsive force due to the Coulomb force due to the electric potential is lost, and the impurity particles such as dust and oil are agglomerated and removed from the liquid by using the attractive force between particles acting as a natural force between these impurity particles. is there. If a charged aggregation filter coalescer type oil-water separator is configured as the oil-water separator 2 as in this example, the charge filter device 1 can be omitted.

The inflow side of the charge filter device 1 is connected via a pump 10, an electromagnetic switching valve 11, a pressure gauge 12, and a pressure switch 13, and the discharged liquid is configured to flow into the oil / water separator 2. The charge filter device 1 and the oil / water separator 2 are respectively provided with load power sources 80 and 81, and are supplied with power from the power supply means 8. The discharged liquid from the oil / water separator 2 is supplied to the storage tank 7 through the flow passage 30 provided with the pump 31, and the processing liquid discharged from the storage tank 7 is sent out including the electromagnetic on-off valve 72 and the integrating flow meter 73. It is sent from the channel 71 to the outlet 74.

The storage tank 7 is configured so that moisture or the like can be supplied into the storage tank 7 from the supply tank 60 via the electromagnetic valve 61 as the component adjusting means 6 including supply of moisture of the processed release agent waste liquid. The control device 9 is provided with a replenishment amount control processing unit 91 that automatically controls the replenishment amount by controlling the opening and closing of the electromagnetic valve 61. Similarly, the storage tank 7 is provided with a pH lowering liquid tank 41 and an electromagnetic valve 42 as a pH lowering liquid supply device 4 to be added to a release agent waste liquid described later. Furthermore, a stirring device 70 is provided as a stirring means so that the replenished water and pH lowering agent are stirred, and the processing liquid in the tank is stirred in accordance with the addition of these chemicals and the like. . In addition, the said component adjustment means 6 can also be provided before filtration processing, before oil-water separation processing, before pH value measurement, etc. besides providing in the storage tank 7 like this example.

In the regeneration system S, a pH sensor 3 as a pH measuring means for measuring the pH value of the release agent waste liquid, and a pH lowering solution for lowering the pH of the release agent waste liquid are used as the release agent waste liquid in the storage tank 7. And a pH drop liquid supply device 4 to be added. The control device 9 is configured to control the pH value of the release agent waste liquid within a predetermined range based on the pH value obtained by the pH sensor 3. An addition amount control processing unit 92 is provided as addition amount control means for automatically controlling the addition amount of the pH lowering solution by the falling solution supply device 4. Specifically, the solenoid valve 42 is controlled to be opened and closed by the addition amount control processing unit 92, and the pH lowering liquid supply amount from the pH lowering liquid tank 41 is controlled.

The pH sensor 3 is provided in the flow passage 30 between the discharge port of the charged coalescer type oil / water separator 2 and the inlet of the storage tank 7 in this example, and measures the pH after the oil / water separation process. It is also possible to perform pH measurement before oil / water separation or before charge filtration by providing in a flow path between the filter device 1 and the charged coalescer type oil / water separation device 2 or a flow channel just before the inlet of the charge filter device 1. Is possible. It is also a preferred embodiment to provide the storage tank 7 with a pH sensor 3. In addition, the storage tank 7 is divided into a plurality of components, moisture components and the like are adjusted in the preceding tank, a pH sensor is provided in the flow path from the preceding tank or the preceding tank to the succeeding tank, and the pH drop in the succeeding tank Of course, a liquid may be added.

The regeneration system S further includes a concentration sensor 50 as a working oil concentration measuring means for measuring the concentration of water glycol hydraulic fluid in the release agent waste liquid, and a charge filter for the release agent waste liquid flowing from the inlet 14. An electromagnetic switching valve 51 for switching between the device 1 side and the stop / recovery port 15 side is provided, and the control device 9 has a predetermined threshold value based on the concentration of the hydraulic oil obtained by the concentration sensor 50. A determination processing unit 93 is provided that cancels the regeneration process by automatically switching the electromagnetic switching valve 51 to the stop / recovery port 15 side when it exceeds the limit. This is because if the hydraulic oil concentration in the release agent waste liquid is too high, it will not be possible to prevent discoloration of the die-cast product by adjusting the pH value with the pH lowering agent. This is because the processing can be stopped. The concentration of the hydraulic oil mixed in one molding is about 0.2%, and it has been confirmed that discoloration can be prevented by adjusting the pH value even at 2.5%, so the number of regenerations is limited to about 10 times in advance. If so, such a cancellation determination process is not necessarily required.

The control device 9 is mainly composed of a microprocessor, has a storage unit including a RAM and a ROM (not shown), and has a processing unit for storing programs and processing data for defining various processing operation procedures. Accordingly, the computer is connected to a storage device or the like, and functions of the processing unit include a replenishment amount control processing unit 91, an addition amount control processing unit 92, a determination processing unit 93, and other functions for controlling operations of pumps and valves. These functions are automatically realized by the above program. For example, in the control device 9, the data transmitted from each pressure gauge is stored in a storage device, and if an abnormality is detected, a warning signal is output to a warning light or the like.

The reproduction system of the present embodiment may be attached to an aluminum die casting machine, or a reproduction apparatus having the reproduction system may be separately configured. It is also a preferable example to be mounted on a vehicle as in a second embodiment described later. The inflow port 14 and the outflow port 74 may be provided in the same release agent waste liquid storage unit for circulation treatment, or the outflow port 74 may be stored in a separate storage unit.

Next, a representative example of a process in which the release agent waste liquid is regenerated in the regeneration system S of the present embodiment will be described based on the flowchart of FIG.

First, after the release agent waste liquid of the aluminum die casting machine is taken in by the pump 10 (S1), the concentration of the water glycol hydraulic fluid in the taken release agent waste liquid is measured by a concentration sensor (S2). Based on the hydraulic oil concentration value from the concentration sensor, the determination processing unit 93 of the control device determines that the regeneration process is to be stopped when the hydraulic oil exceeds a predetermined threshold (S3), and operates the electromagnetic switching valve 11. Then, the taken-in release agent waste liquid is discharged from the stop / recovery port 15 without regenerating (S4). If the hydraulic oil concentration does not exceed the threshold value in S3, the release agent waste liquid is filtered through the charge filter device 1 by the electromagnetic switching valve 11 (S5), and the treated liquid is further separated into a charged coalescer type oil-water separator. It press-fits into the apparatus 2 to separate oil and water (S6). At this time, the electromagnetic switching valve 11 adjusts the amount of the release agent waste liquid that is press-fitted into the charge filter device 1 to a constant flow rate. The suction state by the pump 10 is monitored by the pressure gauge 12, and the clogging of the filter of the charge filter device 1 is monitored by the pressure gauge 12.

The liquid to be treated that has entered the oil-water separator enters the composite filter, flows from the inner peripheral surface of the filter toward the outer peripheral surface, and removes impurity particles such as dust and oil due to the charging effect in the process of passing through the filter, Agglomeration and coarsening of oil droplet particles is promoted, and the emulsion state is destroyed. The liquid to be treated containing the coarse oil droplet particles moves up and down the bypass formed by the annular partition plate, and in this process, the oil component floats and separates due to the difference in specific gravity, and a floating oil layer is formed in the upper layer in the container. When the interface level between the floating oil layer and the separated water layer becomes low, an oil / water interface sensor (not shown) that detects this state opens the automatic valve and discharges the separated oil. On the other hand, the treatment liquid (separated water) subjected to the oil / water separation treatment is taken out from the bottom of the container and discharged to the flow passage 30 by the pump 31.

Then, after the pH value is measured by the pH sensor 3 provided in the flow passage 30 (S7), it is temporarily stored in the storage tank 7 (S8). The addition amount control processing unit 92 of the control device controls the addition amount of the pH lowering solution by the pH lowering solution supply device 4 based on the measured pH value (S9). Specifically, the pH lowering liquid supply amount is controlled so that the pH value of the release agent waste liquid that has become alkaline due to the mixing of water glycol hydraulic fluid is in the neutral to weakly acidic range.

Also, in the storage tank, component adjustment including water replenishment is performed along with the pH adjustment (S10). The release agent has a large amount of water evaporated in the process of being used in the molding machine, and it is necessary to adjust the components. Note that this may be performed separately instead of within the playback system. Moreover, you may perform simultaneously with a pH adjustment process. That is, it is also possible to add it mixed with a pH lowering agent. Then, the regenerated liquid processed from the outlet 74 is discharged from the storage tank at an appropriate timing (S11).

Next, a second embodiment of the present invention will be described with reference to FIGS.

In this embodiment, as shown in FIG. 3, a regeneration system vehicle A equipped with the same release agent waste liquid regeneration system S as in the first embodiment is configured. As shown in FIG. Go to factories (factories with aluminum die-casting machines that use water-glycol hydraulic fluids, release agent waste liquid recovery sites, etc.) and recycle the release agent waste liquid stored in the storage tank 19 etc. It is used as a vehicle for providing services.

Similar to the first embodiment, the regeneration system vehicle A includes the charge filter device 1, the oil / water separator 2, the storage tank 7, the power generation device 83 constituting the power supply means, the concentration sensor 50, the pH sensor 3, and the pH drop liquid supply device. 4, component adjustment means 6, a control device 9 comprising a computer having a storage device and an operation unit, and a regeneration system S comprising various electromagnetic valves, flow meters, pumps, etc. It is provided in the loading platform, and in this example, it is installed in the luggage compartment of a van type moving truck B having a box-type luggage compartment C. Of the side plates surrounding the luggage compartment, the left and right lateral side plates and the rear side plate are configured to be openable and swingable around the horizontal axis, and the playback system S can be efficiently operated by opening them individually or entirely. It has a usable structure.

The power generation device 83 may be driven by a prime mover of the vehicle traveling means, or may be provided with a drive unit independent from the prime mover. Although the regeneration system S is driven using the power generation device, the regeneration system S can also be driven using the voltage from the battery of the vehicle A.

In addition, in the regeneration system vehicle A, vehicle traveling means having a prime mover for driving and a driving mechanism, suction means 16 for taking in the release agent waste liquid in the release agent waste liquid storage part of the factory, regenerated recycled liquid It includes a delivery means 17 for returning to the same release agent waste liquid storage section or another storage section, a communication device 18 for performing communication between the vehicle and the sales office, and the like. The inlet 14 and the pump 10 shown in FIG. 1 are provided, and the delivery means 17 is preferably provided with a pump not only in the electromagnetic on-off valve 72 shown in FIG.

Then, at the start of work, the worker inputs the worker ID, customer ID, processing unit price, etc. from the control panel. When the predetermined information input is confirmed, the control device 9 controls the operation of the reproduction system S and releases the mold. Started recycling treatment of waste liquid. When the work is completed, the amount of waste liquid is measured by the integrated flow meter 73 of the delivery path 71 shown in FIG. 1, the sales amount is calculated, work report data is created for each work unit, and this communication device is used as the communication device. The work is completed by sending it to the sales office from 18. This communication between the vehicle and the sales office is performed via a mobile communication network used in, for example, a mobile phone or a simple mobile phone.

The embodiments of the present invention have been described above. However, the present invention is not limited to these examples, and may be implemented in various forms without departing from the gist of the present invention.

Next, a description will be given of the results of a regeneration treatment experiment using the release agent waste liquid actually used in an aluminum die casting machine.

(sample)
First, a sample (pH 9) in which the release agent waste liquid was diluted twice with water and 2.5% of water glycol hydraulic fluid was added was set as Comparative Example 1, and 2.5% of hydraulic fluid was also added. A sample (pH 7) neutralized by adding a pH lowering agent was designated as Example 1. Similarly, a sample (pH 7) was prepared by diluting the release agent waste liquid with water twice, adding 5.0% of water glycol hydraulic fluid and neutralizing it with the addition of a pH lowering agent. 2. Even in cases where the hydraulic hose has been ruptured in the past, the amount of water glycol hydraulic fluid is 1% or less, and the amount of contamination during normal mold operation is 0.2%. It is considered to be about 0.3%, and 2.5% is a level of mixing that is not possible normally, and it cannot be considered to be 5%.

(Experiment)
In the experiment, Example 1 and Comparative Examples 2 and 3 of each sample were each subjected to 10-shot molding, and the degree of discoloration / scumming was observed from the appearance of the die cast product. As a result of the experiment, first, in Comparative Example 1, the discoloration was concentrated on the portion that became the depression of the product and the outer periphery of the product, and the discoloration was seen in many places. Particularly, discoloration of the milling surface was remarkable. As a result, stains (discoloration) of the appearance occurred, and it was determined that there was a problem in appearance quality. On the other hand, in Example 1, the appearance was a normal mass production level, and although it was slightly discolored, it was within an allowable range. In the comparative example 2, the discoloration of the part which becomes a hollow of a product and the outer peripheral part of the product is darker than that of the comparative example 1, and the discoloration of the milling surface becomes more prominent and is rejected.

(Discussion)
In Comparative Example 1, when the water glycol hydraulic fluid is mixed, the die-cast product is discolored and the product is rejected. Conventionally, it is natural that the die-cast product is discolored even at a mixing amount of about 0.2% and the product level is not reached. On the other hand, in Example 1, the product was not discolored at all and passed. The result was completely the same as the new solution. As for Comparative Example 2, it can be seen that even if the pH is adjusted, if 5% of the thickener of water glycol hydraulic fluid is mixed, the pH adjustment can no longer cope. It is thought that the carbon constituting the polymer of the hydraulic oil burned and discolored. From the above experimental results, it can be seen that water glycol hydraulic fluid, which is the industry's established theory, was not a direct factor but an indirect factor. Moreover, since it was confirmed that discoloration can be avoided by adjustment even at 2.5%, it is considered necessary to manage the number of reuses, for example, without having to check the concentration with a hydraulic oil concentration sensor or the like. .

Claims (11)

A method of reclaiming a release agent waste liquid from an aluminum die casting machine that uses water glycol hydraulic fluid,
An oil / water separation step of passing the release agent waste liquid through a charged coalescer type oil / water separator and applying a voltage between electrodes in the oil / water separator to promote oil / water separation;
A pH measurement step for measuring the pH value of the release agent waste liquid;
A pH adjusting step of adding a pH lowering solution for lowering the pH of the release agent waste liquid based on the measured pH value to the release agent waste liquid subjected to the oil / water separation treatment by the oil / water separator. A method of reclaiming mold release liquid from aluminum die casting machines. Before the oil-water separation step, a filtration step of passing the release agent waste liquid through a charge filter device and applying a voltage between the electrodes in the charge filter device to promote filtration of impurity particles in the release agent waste solution. The method for reclaiming a release agent waste liquid of an aluminum die casting machine according to claim 1 provided. The method for reclaiming a release liquid from a release agent for an aluminum die casting machine according to claim 1 or 2, further comprising a component adjusting step for adjusting a component including replenishment of moisture. Prior to at least the oil / water separation step, a hydraulic oil concentration measurement step for measuring the concentration of water glycol hydraulic fluid in the release agent waste liquid, and based on the measured hydraulic oil concentration, The method of reclaiming a release agent waste liquid for an aluminum die-casting machine according to any one of claims 1 to 3, further comprising a determination step of determining whether to stop the regeneration process when the threshold value is exceeded. It is a release agent waste liquid regeneration system for aluminum die casting machines that use water glycol hydraulic fluid,
A charged coalescer type oil-water separator that promotes oil-water separation by applying a voltage between internal electrodes facing the internal flow path, while the release agent waste liquid is circulated,
Power supply means for supplying drive power to the charged coalescer type oil-water separator;
PH measuring means for measuring the pH value of the release agent waste liquid,
A storage chamber for temporarily storing a release agent waste liquid subjected to oil removal treatment by the charged coalescer type oil-water separator;
A pH lowering liquid supply device for adding a pH lowering liquid for lowering the pH of the release agent waste liquid into the storage chamber;
Based on the pH value obtained by the pH measuring means, the addition amount control means for controlling the addition amount of the pH lowering liquid by the pH lowering liquid supply device so that the pH value of the release agent waste liquid is within a predetermined range. A recycling system for a mold release agent waste liquid of an aluminum die casting machine. The power supply is provided with a charge filter device that circulates the release agent waste liquid and applies a voltage between internal electrodes facing the internal flow path to promote filtration of impurity particles in the release agent waste liquid. 6. The regeneration system for a mold release agent waste liquid of an aluminum die casting machine according to claim 5, wherein a driving power is supplied to the charge filter device by means. 7. The release agent waste liquid of an aluminum die casting machine according to claim 5 or 6, wherein the pH measuring means is provided in a flow path between an outlet of the charged coalescer type oil-water separator and an inlet of the storage chamber. Playback system. Based on the hydraulic oil concentration measuring means for measuring the concentration of water glycol hydraulic fluid in the release agent waste liquid, and the hydraulic oil concentration obtained by the hydraulic oil concentration measuring means, the hydraulic oil has a predetermined threshold value. 8. The recycling system for a release liquid of a mold release agent for an aluminum die casting machine according to claim 5, further comprising a determination unit that determines whether or not to stop the regeneration process when exceeding. A vehicle for reclaiming the release agent waste liquid in the storage part, going to the release agent waste liquid storage part of the aluminum die casting machine using water glycol hydraulic fluid,
Vehicle traveling means having a prime mover and a driving mechanism for traveling;
Suction means for taking in the release agent waste liquid in the release agent waste liquid storage section as a liquid to be treated;
A charged coalescer type oil-water separator that promotes oil-water separation by applying a voltage between internal electrodes facing the internal flow path, while the release agent waste liquid is circulated,
Power supply means for supplying drive power to the charged coalescer type oil-water separator;
PH measuring means for measuring the pH value of the release agent waste liquid,
A storage chamber for temporarily storing a release agent waste liquid subjected to oil removal treatment by the charged coalescer type oil-water separator;
A pH lowering liquid supply device for adding a pH lowering liquid for lowering the pH of the release agent waste liquid into the storage chamber;
Based on the pH value obtained by the pH measurement means, an addition amount control means for controlling the addition amount of the pH lowering liquid by the pH lowering liquid supply device so that the pH value of the release agent waste liquid is within a predetermined range;
A recycling system vehicle for a release agent waste liquid of an aluminum die casting machine, comprising: a delivery means for returning the reprocessed processed liquid to the same release agent waste liquid storage unit or another storage unit. The power supply is provided with a charge filter device that circulates the release agent waste liquid and applies a voltage between internal electrodes facing the internal flow path to promote filtration of impurity particles in the release agent waste liquid. 10. The recycling system vehicle for a release liquid of a mold release agent for an aluminum die casting machine according to claim 9, wherein driving power is supplied to the charge filter device by means. 11. The regeneration system vehicle for a release liquid of a mold release agent for an aluminum die casting machine according to claim 9 or 10, wherein a power generator driven by a driving prime mover constituting the vehicle traveling means is provided as the power supply means.

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