| 摘要 |
PURPOSE:To pickle stably a steel strip and to prevent generation of sludge in a pickling soln. by charging continuously fresh acid to a specified amt. of the pickling soln. circulated between a pickling tank and a circulation tank and withdrawing continuously the pickling soln. exceeding the specified amt. therefrom. CONSTITUTION:The fresh acid in a storage tank 14 is supplied by a metering pump 16 into a circulation tank 6 and at the same time water for adjusting concn. is supplied through a water feed pipe 20 into the tank 6. The ratio between the fresh acid and water in this case is determined from the target acid concn. and the total amt. of the fresh acid and water is determined by the prescribed equation. The pickling soln. in the tank 6 adjusted to the prescribed concn. in the above-mentioned way is pumped 7 through a heat exchanger 13 into a pickling tank 1. The pickling soln. used for pickling of a steel strip 2 in the tank 1 has some carry-over by the evaporation and the strip 2 but is mostly returned through an overflow pipe 12 into the tank 6. While the pickling soln. is circulated in such a way, the fresh acid and water are replenished into the soln. in the tank 6 and therefore only the soln. equiv. to the difference between the increase and the decrease in the tank 1 is stored temporarily in a waste acid tank 24 through an overflow pipe 26.
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