CS226573B1 - Device for applying chromate coatings - Google Patents

Abstract

The device is intended for the application of chromate coatings on the surface of galvanized steel strips with the regeneration of the chroming solution and solves the problem of the dependence of the operation of the continuous sendzimir galvanizing line on the chroming technology as well as the problem of disposing of the chrome baths by returning the used chroming solution back to the technological process.

Description

226573 2

BACKGROUND OF THE INVENTION The present invention relates to an arrangement for applying chromate coatings to the surface of a zinc-coated steel strip with the regeneration of a chromating solution and solves the problem of the independence of the continuous galvanizing line from the chromating technology as well as the problem of disposal of chromating baths by returning the worn chromating solution to the process.

The solution to the chromating problem in continuous steel zinc galvanizing devices encounters difficulties on the one hand in the first place by the fact that the built-in chromatation device can affect the operation of the continuous galvanizing line on the one hand, and on the other hand, the disposal of the high chromium chromium-containing waste chromate trap. For example, the replacement of a worn chromating solution with a new one in the Czech Republic. AO No. 176,780 is carried out by shutting down the entire galvanizing line, and the spent solution must be disposed of before discharge to neutralization. These drawbacks can affect not only the downtimes resulting from unplanned shutdowns of the continuous zinc-plating line, but also the high consumption of chromium oxide and other components of the chromating solution. When the new chromating solution is poorly prepared or replaced one time, the quality of the chromate coating depicted is considerable.

It should be noted that the worn chromating solution, whose reaction capacity is insufficient to produce a high quality chromate coating, still contains a significant amount of chromium. The functional ability of the chromating solution is reduced by the growth of * 2+ 3+ ballast ions, mainly Zn and Cr. With some attention to these elements, the solution needs to be replaced, although the hexavalent chromium content is still at operating value. Worn chromatation solutions have so far been disposed of in a conventional manner, i.e. by reduction of Cr® + -> - rr ^ +, with sulfites, sulfuric acid and the like. The product of this reduction is a considerable amount of polymetallic sludge, while reducing! other chemicals needed and Pudding.

The above-mentioned drawbacks are solved and the problem is solved by a device for depositing chromate coatings according to the invention, characterized in that it comprises a chromating and regenerating portion, wherein the chromating honor consists of two or more reaction tanks of a chromating solution with its own waist draft system abyc! immersing it at any time in one of two or more reaction vessels. The chromating solution is fed through the nozzle branches located below and above the chromating solution to provide a better reaction capability of the solution. the wringing rollers return the excess chromating solution and the rinse water to sleep in the remaining tanks. The unreacted chromating solution that remains after wiping is removed by rinsing nozzles. After removing excess rinse water after wiping, the chromate coating is dried with air jets. The regeneration part consists of storage tanks of worn and fresh solution, ion exchange column with filter and tanks for elution solution. In particular, the advantages of the invention are to provide an efficient, high-quality chrome-plating without affecting the operation of the continuous galvanizing line and the requirements for the disposal of chromium waste pellets, where the introduction of the strip into the line, its immersion in the reaction tank of the chromating solution and the shift back to the preferred position are simple and quickly.

If the galvanizing line is eventually shut down, the belt can be immediately emptied out of the electrolyte solution to avoid unnecessary dissolution of the zinc coating and enriched, 2+ 3+ solution to Zn and Cr ballast ions. It is also possible to immerse the strip briefly in both reaction tanks in case of poor reaction ability of the solution. Furthermore, it is possible to accelerate the reaction capability of the solution, also by increasing the delivery of the amount of chromating solution to the spray nozzles, while maintaining a constant level of the chromating solution in the reaction tank.

Although the chromating line and the regeneration station form one continuous unit, the efficiency is independent of each other "and a regenerated chromating solution is always available,

Claims (1)

3 226573 which, when added to the initial values, corresponds to the technological requirements. Ion exchange regeneration allows the level of impurities in the solution to be maintained at a desired level, so that the regenerated solutions work more uniformly, which results in a high chromate coating quality and a relatively lower zinc dissolution rate in the solution. Waste products from ionic regeneration of the chromating solution can be utilized in a suitable arrangement of the device. For example, the sulfuric acid, after passing through the ion exchange column, can be collected in the tank, led through the ion exchange column as the once used eluent, and then used in the morphine column. neutralization station. The flushing water can also be advantageously used to cool the chromating solution in the collection tank. An example of an embodiment of the device according to the invention in the Sendzimir line is shown in the accompanying figure 1 in schematic view of the technological flow of the material by marking the functional elements of the device according to their location. The hot-dip galvanized sheet of galvanized sheet 10 is deposited into the line just downstream of the support roll 11 through the wiping rollers 26 of the first 20 and the wiping rollers 36 of the second 30 section, passing through the rinse nozzles 43 and wringing rollers 44 of the rinse zone 40 to follow blowing nozzles 51. 52 of the drying zone 40. The dip of the strip into the chromating solution is carried out by the immersion system either by means of submersible rolls 22 into the reaction tank 21 of the first section 20 or by means of submersible rolls 32 into the reaction tank 31 of the second section 10. The first section consists of a collecting tank 27 of solution and a pump 24, which discharge conduit is connected to a set of spray nozzles 23 with outlet slots directed in the direction of the technological flow of the material and the reaction tank 21. Likewise, the second separation consists of a collecting tank 37 of solution, a heater 35. the spray nozzle sets 33 and the reaction tank 31. The pumps 24 and 34 are connected by both sections to each other. The level of the solution in the reaction tanks is maintained by the overflow at the same level. Advantageously, the overhangs can be formed by the lower position of the transverse edges of the reaction tanks 21 and 31 at the spinning rollers 26 and 36. The ionex regeneration consists of a cooler 63 and a chromating solution preparation tank 64, an ion exchange column 72 protected by a mechanical filter 11. with control tanks 81 and 82. return eluate tanks 91. piping system with pumps 61. ú2. 66. 92 flow meters 12, 22, 21 fittings and control elements. The connection of the chromating apparatus to the regeneration station is ensured by a pipe system, wherein pumps 61 and 62 are connected by suction to the collection tank of chromating solution 27 and 37 and the discharge side to the cooling tank 63. pumps 65 and 66 are connected by suction side to tank 63 and 64 and discharge the side of the reaction tank of the chromating solution 21 and 31. The mechanical filter 71 and the ion exchange column 22 are preferably located above the level of the other tanks of the recovery station with the gravity piping of the chromating solution into the tank 64 and the eluate into the return eluate tank 91.resp. to a tank 82. SUBJECT OF THE INVENTION An apparatus for applying chromate coatings, characterized in that it comprises a chromating portion consisting of at least two (21, 31) chromating solution reaction tanks with its own belt immersion system (22, 32), from a chromating solution supply through nozzle branches (23, 33) below and above the level of the chromating solution, wringing rollers (26, 36) of the chromating solution and wringing rolls (44) of rinse water, rinse (41, 43) and suction (51,52) nozzles, collection tanks of the chromating solution ( 27, 37) and rinse water (45) and a regeneration Sas consisting of an ion exchange column (72), a filter (71), a worn (63) and regenerated (64) chromating solution and an elution solution reservoir (91). 1 drawing i