JP5435364B2 - Processing method and processing system for harmful substances generated in casting line - Google Patents

Description

  The present invention relates to a processing method and a processing system for harmful substances generated in a casting line, and more particularly, to a processing method and a processing system for insolubilizing harmful substances such as heavy metals and halogens contained in dust collection dust in a casting line. Is.

  Conventionally, mold sand used in foundries has been reused as a mold raw material through a predetermined treatment process, and waste sand containing dust collection dust has been reused as a cement raw material and a roadbed material raw material. However, due to the recent tightening of environmental cleanup regulations including soil, it is necessary to implement insolubilization treatment to prevent hazardous substances such as heavy metals and halogens from the Ministry of the Environment Notification No. 46 from exceeding the elution standard value of the soil environment standard. Has arisen.

  For example, Patent Document 1 discloses a technique for performing an insolubilization process by adding an additive containing magnesium oxide or the like as a main component to fluorine-contaminated soil and performing a mixing process. .

JP 2005-324083 A

  However, in order to apply the above-mentioned processing method to a casting line to insolubilize harmful substances such as heavy metals and halogens contained in dust collection dust, it is necessary to provide an insolubilization treatment facility 1 as shown in FIG. As a result, the equipment cost increases, and there is a problem that a new installation site for the processing equipment has to be prepared.

  Therefore, the present invention does not require a separate insolubilization processing facility outside the casting line, and performs the insolubilization processing of harmful substances such as heavy metals and halogens contained in the dust collection dust by adding only a few facilities in the casting line. An object of the present invention is to realize a method and a system for treating harmful substances generated in a casting line that can reduce equipment costs, reduce the plane space for equipment installation.

The method for treating harmful substances generated in the casting line of the present invention to achieve the above object is a method for treating harmful substances for insolubilizing harmful substances in dust collection dust generated in the casting line. The casting line includes a mold breaking process for casting a mold after pouring into the mold, a sand recycling process for reclaiming the mold sand discharged from the mold breaking process, and a mold sand regenerated in the sand recycling process. A recycle process for reusing the mold sand, including a kneading process for kneading with unused foundry sand, additives, etc., and supplying it to a molding machine as a kneaded product used for mold molding. transport step between equipment performing a feature that sends a collected dust generated from at least one step of the mold shakeout process and sand reclamation process to the kneading step, the insolubilized by kneading the casting sand along with the insolubilizing agent Is shall.

Incidentally, it is possible to adjust and insolubilization of the mold sand in the kneading step. In addition, the hazardous substance is at least one of cadmium, hexavalent chromium, mercury, selenium, lead, arsenic, fluorine, boron, etc., and at least one of the second class specified hazardous substances regulated by the soil pollution control law. It is.

  In addition, a system for treating harmful substances generated in the casting line of the present invention, which has been made to achieve the above-mentioned object, provides a harmful substance for insolubilizing harmful substances in dust collection dust generated from a casting line for producing castings. In the processing system, the casting line is regenerated by a mold separation facility that performs mold separation after pouring into the mold, a sand regeneration facility that regenerates loose sand generated in the mold separation facility, and a sand regeneration facility. A kneading facility for kneading the cast sand with unused foundry sand, additives, etc., and supplying it to a molding machine as a kneaded product used for mold molding, and a facility for sending dust collection dust to the kneading process, Is characterized by comprising an insolubilizing agent addition facility for adding the insolubilizing agent together with dust collecting dust to the mold sand.

  According to the present invention, the dust collection dust generated from the casting line is sent to the kneading step, and kneaded in the foundry sand together with the insolubilizing agent to perform insolubilization treatment. For this reason, a dedicated facility for insolubilizing hazardous substances such as heavy metals and halogens contained in the dust collection dust is not required. For this reason, equipment cost can be made small and the plane space for equipment installation can also be made small. Further, when the foundry sand treated according to the present invention is reused as a cement raw material or a roadbed material raw material, no harmful substances are eluted and there is no possibility of exceeding the elution standard value of the soil environment standard.

It is a flowchart which shows embodiment of this invention. It is a flowchart which shows a prior art example.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
In the casting line shown in FIG. 1, reference numeral 10 denotes a kneading process equipped with a kneading facility, and kneading the mold sand conveyed from the sand regeneration process 11 and unused casting sand and auxiliary materials to be used for mold molding. It is a thing. The auxiliary material is a binder such as clay and resin, and kneading adjustment is performed with a predetermined amount of water, and the kneaded mold sand is sent to the molding step 12. In the molding process 12, a mold is molded using the mold sand, and then in the pouring process 13, a molten metal is poured into the mold to perform casting.

  The mold cooled after the pouring process 13 is sent to a mold spreading process 14 equipped with a mold spreading facility, and the cast product and the mold sand are separated. The separated mold sand is sent to a sand regeneration process 11 equipped with a sand regeneration facility, and the separation of iron pieces and the like by a magnetic separator, separation of the binder from the sand surface, sieving of fine powder, and cooling by a sand cooler are performed. Recycle the mold sand. As described above, the mold separation step 14, the sand regeneration step 11, and the kneading step 10 constitute a reuse step for reusing the mold sand.

  In addition, the foundry sand adhering to the surface of the cast product separated in the mold separating process 14 is separated in the cast-with-sand cleaning process 15 and sent to the sand recycling process 11. On the other hand, the cast product from which sand has been removed in the casting casting process with sand 15 is shipped through a finishing process 16, an inspection process 17, and the like.

  As described above, dust containing harmful substances such as heavy metals and halogens is generated in the above-described casting line, so that dust collection by the dust collector 20 is performed. The dust generation site is each process and the transfer process between the facilities that perform each process. However, a large amount of dust is generated particularly in the mold separation process 14 and the sand recycling process 11, so at least one of these processes collects dust. Dust is done.

  The dust collected by the dust collector 20 is cadmium, hexavalent chromium, mercury, selenium, lead, arsenic, fluorine, boron, etc., and the soil environment standards are stipulated in the Soil Contamination Countermeasures Law. Contains at least one of the species-specific hazardous substances. In the present invention, the dust collecting dust containing such harmful substances is sent to the kneading step 10 by the dust conveying means 21 such as a belt conveyor or a transport pipe. The dust transfer means 21 preferably has a sealed structure so that dust collection dust does not scatter during transfer.

  The kneading step 10 is provided with an insolubilizing agent addition facility for adding the insolubilizing agent to the mold sand together with dust collection dust. As the insolubilizer, magnesium oxide, magnesium oxide-containing agent and ferric chloride, calcium chloride, alkali metal silicate, calcium oxide and calcium aluminate, calcium aluminate and calcium silicate, and the like can be used.

  Fluorine and its compounds, which have particularly strict environmental standards, and magnesium oxide-based insolubilizers are suitable for insolubilizing boron and its compounds. In this embodiment, a magnesium oxide-based insolubilizing agent is added in a powder state. It is preferable that the insolubilizing agent addition facility has a structure capable of supplying a constant amount of the insolubilizing agent from the tank.

  In this way, if dust collection dust containing harmful substances is sent to the kneading step 10 and kneaded together with the mold sand and the insolubilizing agent, the harmful substances that have reacted with the insolubilizing agent are fixed in a state where they are not eluted into the mold sand. This mold sand can be used as a mold as it is. In addition, even when reusing as waste sand as cement raw material or roadbed material raw material, hazardous substances such as heavy metals and halogens shown in Ministry of the Environment Notification No. 46 do not exceed the elution standard value of the soil environment standard.

  Further, according to the present invention, in the existing casting line equipped with the dust collector, it is only necessary to add the dust transport means 21 for transporting the dust collection dust to the kneading step 10 and the insolubilizing agent addition equipment, and the insolubilization processing equipment is separately provided. Since there is no need to provide the equipment, the equipment cost is low, and there is no need to prepare a new place for installing the treatment equipment.

DESCRIPTION OF SYMBOLS 1 Insolubilization processing equipment 10 Kneading process 11 Sand reproduction process 12 Molding process 13 Pouring process 14 Mold casting process 15 Casting cleaning process with sand 16 Finishing process 17 Inspection process 20 Dust collector

Claims (4)

A method for treating harmful substances for insolubilizing harmful substances in dust collection dust generated in a casting line,
The casting line is
A mold spreading process for casting mold after pouring into mold,
A sand regeneration process for regenerating the mold sand discharged from the mold separation process;
Reusing mold sand, including kneading the mold sand regenerated in the sand reclamation process with unused foundry sand, additives, etc., and supplying it to the molding machine as a kneaded product used for mold molding With a process,
Transport step between equipment performing each step and each process sends a collected dust generated from at least one step of the mold shakeout process and sand reclamation process to the kneading step, the kneading to insolubilized to sand along with the insolubilizing agent A method for treating harmful substances generated in a casting line. The method for treating harmful substances generated in a casting line according to claim 1, wherein in the kneading step, the mold sand is adjusted and insolubilized.   The hazardous substance is at least one of the Specified Hazardous Substances of the second kind specified in the soil pollution control law, such as cadmium, hexavalent chromium, mercury, selenium, lead, arsenic, fluorine, boron, etc. The method for treating harmful substances generated in a casting line according to claim 1. A hazardous substance processing system for insolubilizing harmful substances in dust collection dust generated from a casting line for producing castings,
The casting line is
A mold disassembly facility that performs mold disassembly after pouring into the mold,
Sand reclamation equipment for reclaiming loose sand generated in the mold bulk equipment;
A kneading facility for kneading mold sand regenerated in the sand recycling facility with unused foundry sand, additives, etc., and supplying it to a molding machine as a kneaded product used for mold molding;
Equipment to send dust collection dust to the kneading process,
The said kneading | mixing equipment is equipped with the insolubilizing agent addition equipment which adds an insolubilizing agent to mold sand with dust collection dust, The processing system of the harmful | toxic substance generate | occur | produced in the casting line characterized by the above-mentioned.

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