The amount of wash water to be consumed in an electrodeposition coating facility and the amount of used wash water to be discharged that requires post-treatment are reduced. To achieve this object, an electrodeposition coating facility that includes a degreasing process section A, a post-degreasing rinse section B, a chemical conversion process section C, a post-chemical-conversion rinse section D, an electrodeposition coating section E, and a post-electrodeposition rinse section F is provided with a filtration process apparatus 4 and a wash water recycling line 5. The filtration process apparatus 4 performs a filtration process on wash water W after being used to wash an object to be coated 1 in the post-electrodeposition rinse section F. The wash water recycling line 5 feeds, to the post-chemical-conversion rinse section D, the wash water W after being subjected to the filtration process in the filtration process apparatus 4 as wash water W to be used to wash an object to be coated in the post-chemical-conversion rinse section D.

An electrodeposition coating method includes a degreasing/cleaning step, a chemical conversion step, and an electrodeposition coating layer formation step. The degreasing/cleaning step includes a degreasing step of ultrasonically vibrating a degreasing solution in which a target object is immersed, using an ultrasonic vibrator. The electrodeposition coating layer formation step includes: a first electrodeposition step; a first rinsing step; a rinse water removal/reduction step of removing or reducing rinse water on a rinse water stagnating surface of the target object; a thermal flow step of allowing the first electrodeposition coating film to thermally flow so that the first electrodeposition coating film formed on a portion of the target object near a first counter electrode has a higher electrical resistance than the first electrodeposition coating film formed on a portion of the target object far from the first counter electrode; and a second electrodeposition step.

An electrodeposition bath, water-washing baths, a first filtration membrane which feeds filtrate and concentrated-solution obtained by filtering electrodeposition-solution in the electrodeposition bath to the water-washing bath in a last stage and the electrodeposition bath, a feed system that feeds filtrate-water obtained by performing ultrafiltration or microfiltration on water after water-washing in the water-washing bath, a second filtration membrane which feeds filtrate and concentrated-solution obtained by filtering the filtrate-water fed by the feed system to the water-washing bath in the last stage and one of the electrodeposition bath and a water-washing bath other than the water-washing bath in the last stage, respectively, and a flow rate adjustment unit that adjusts a feed amount of each of the filtrate obtained by filtration by the first filtration membrane and the filtrate obtained by filtration by the second filtration membrane to the water-washing bath in the last stage are included.

An electrodeposition bath, water-washing baths, a first filtration membrane which feeds filtrate and concentrated-solution obtained by filtering electrodeposition-solution in the electrodeposition bath to the water-washing bath in a last stage and the electrodeposition bath, a feed system that feeds filtrate-water obtained by performing ultrafiltration or microfiltration on water after water-washing in the water-washing bath, a second filtration membrane which feeds filtrate and concentrated-solution obtained by filtering the filtrate-water fed by the feed system to the water-washing bath in the last stage and one of the electrodeposition bath and a water-washing bath other than the water-washing bath in the last stage, respectively, and a flow rate adjustment unit that adjusts a feed amount of each of the filtrate obtained by filtration by the first filtration membrane and the filtrate obtained by filtration by the second filtration membrane to the water-washing bath in the last stage are included.

Methods for recovering manganese etchant solutions are provided wherein a process solution used to rinse or neutralize a nonconductive substrate after etching the substrate is collected and evaporated to provide a concentrated process solution that is fed back into the manganese etchant solution or acid rinse.

In an electrodeposition system, the final quality of a coating is prevented from being degraded due to a coating material-containing aqueous solution flowing out of a steel plate mating portion during a drying process, while derivative problems such as an increase in the size of the system, an increase in the initial costs and the running costs, and a decrease in reliability are avoided. A washing zone that is subsequent to an electrodeposition zone in which an object to be coated is immersed in a coating material solution for electrodeposition so that a coating is formed on a surface of the object to be coated is provided with: a hot water washing tank in which the coated object is washed by being immersed in high-temperature washing water in the tank; and a spray washer that sprays a steel plate mating portion of the coated-object with high-temperature washing water, subsequent to washing in the hot water washing tank.

In an electrodeposition system, the final quality of a coating is prevented from being degraded due to a coating material-containing aqueous solution flowing out of a steel plate mating portion during a drying process, while derivative problems such as an increase in the size of the system, an increase in the initial costs and the running costs, and a decrease in reliability are avoided. A washing zone that is subsequent to an electrodeposition zone in which an object to be coated is immersed in a coating material solution for electrodeposition so that a coating is formed on a surface of the object to be coated is provided with: a hot water washing tank in which the coated object is washed by being immersed in high-temperature washing water in the tank; and a spray washer that sprays a steel plate mating portion of the coated-object with high-temperature washing water, subsequent to washing in the hot water washing tank.

Methods for recovering manganese etchant solutions are provided wherein a process solution used to rinse or neutralize a nonconductive substrate after etching the substrate is collected and evaporated to provide a concentrated process solution that is fed back into the manganese etchant solution or acid rinse.

An installation for coating objects, in particular vehicle wheels, has a dipping trough which is filled with a coating liquid into which the objects can be dipped. In order to reduce the complexity of the piping, there is provided a combined recirculation and filtration circuit for recirculating and filtering the coating liquid, wherein the recirculation and filtration circuit includes a pump, at least one recirculation outlet, arranged in the dipping trough, for the coating liquid, and a filtration device having a residue connection and a filtrate connection, wherein the residue connection is connected to the at least one recirculation outlet in the dipping trough.

An installation for coating objects, in particular vehicle wheels, has a dipping trough which is filled with a coating liquid into which the objects can be dipped. In order to reduce the complexity of the piping, there is provided a combined recirculation and filtration circuit for recirculating and filtering the coating liquid, wherein the recirculation and filtration circuit includes a pump, at least one recirculation outlet, arranged in the dipping trough, for the coating liquid, and a filtration device having a residue connection and a filtrate connection, wherein the residue connection is connected to the at least one recirculation outlet in the dipping trough.