Packaging steel strip system of hydrochloric acid pickling process

Packaging steel strip system of hydrochloric acid pickling process of hydrochloric acid pickling, pickling speed increase with acid concentration and temperature rise faster, but the volatile nature of hydrochloric acid, acid concentration and temperature increase is limited. In pickling tank, the hydrogen chloride gas evaporation, temperature rise and increased dramatically, also increased with the increase of concentration of hydrochloric acid, also along with the rise of ferrous chloride content in acid increased, but the biggest impact of the temperature. In hydrochloric acid content is not big, ferrous chloride has a good solubility. Figure 2 - 9 shows hydrochloride in ferrous chloride and ferrous sulfate in sulfuric acid solubility curve. Visible their solubility with the increase of concentration of hydrochloric acid. Figure 2 - 10 shows temperature in the 20, 40, 60 ℃ respectively when pickling time relationship with the ferrous chloride. In different concentrations of acid, with the increase of ferrous chloride, pickling time reduced, the shortest pickling time is lower than the saturated value of 4 - by in its content By about 8%, when the pickling time after more than the minimum ACTS up, so when the ferrous chloride content in the pickling time longest while approaching saturation values. So do not use in the production of ferrous chloride concentration close to the saturated state of acid solution, lest the pickling time extended. When higher concentration of hydrochloric acid, ferrous chloride is very easy to reach saturation state, the acid concentration shoulds not be too high. In the pickling process, while the acid concentration is reduced, but ferrous chloride content increased, due to these two factors, on the other hand, in a certain period of time offset each other, so in a long time in the pickling, pickling speed to remain the same. According to the above, in order to avoid the ferrous chloride saturated state affect pickling time, in order to avoid high temperature cause excessive volatile hydrochloric acid, hydrochloric acid pickling process system is generally 20 - acid concentration 130 g/L, the temperature is 70 - 45-90 ℃, Fe++ ion concentration 145g/L。