The distinction between pickling with hydrochloric acid and sulfuric acid

Benefits and disadvantages of marinading hydrochloride

(1) Advantages of pickling with HCl

Although the pickling solution can be either sulphuric acid or hydrochloric acid, hydrochloric acid is mainly used in pickling line production. Due to the fact that the pickling operation can be performed at room temperature, hydrochloric acid has strong chemical solubility to metal oxides, and can successfully pickle a range of metals.

Under the greenhouse, the dissolving pickling of the iron matrix of steel workpiece with hydrochloric acid is much faster than sulfuric acid, and the pickling time is much shorter, so it is simple to manage the pickling procedure efficiently. Therefore, making use of hydrochloric acid to marinade steel workpieces is less most likely to cause "extreme deterioration" and "hydrogen embrittlement".

At room temperature, the surface of the workpiece after marinading is less residue, the surface area quality is greater.

Improve the quality of hydrochloric acid concentration is one of the procedures to enhance the speed of pickling, hydrochloric acid marinading less hydrogen precipitation, so the "hydrogen embrittlement" phenomenon is lighter.

For numerous oxides of iron, the solubility in hydrochloric acid is little, and the solubility in sulfuric acid is relatively large, therefore, using hydrochloric acid is much easier to manage the iron ion content variations, so regarding preserving a greater pickling speed.

For the exact same concentration and temperature level of hydrochloric acid and sulfuric acid, the marinading speed of hydrochloric acid is 1.5 to 2.0 times faster than that of sulfuric acid.

(2) Disadvantages of marinading with HCl

Utilizing hydrochloric acid production expenses are high, unstable, corrosive fog must be installed with the excellent effect of the slander gas equipment, waste acid treatment, and resource recycling procedure are really complex. And sulfuric acid is cheap, simple to transport and store, high concentration of product acid, in a really high pickling temperature level, almost no steam. This is because there are trusted commercial treatment methods for waste acid and wastewater, so before the 1960s, continuous pickling of strip steel was nearly inevitably made with sulfuric acid.

Benefits and downsides of sulfuric acid pickling

(1) Advantages of marinading with sulfuric acid

The production expense of sulfuric acid pickling is lower, and at the same time, it is easier to recycle the waste acid of sulfuric acid than hydrochloric acid

Raising the temperature level can extend the pickling efficiency of sulfuric acid, which is conducive to reducing acid intake and production expenses.

The storage and transportation of focused sulfuric acid do not require the use of acid-resistant materials.

(2)Disadvantages of pickling with Sulfuric acid.

Sulfuric acid in the pickling process of the workpiece iron base of the engraving big, easy to produce hydrogen embrittlement. When the temperature level is expensive, it is simple to trigger "over rust" of the iron matrix and increase the possibility of "hydrogen embrittlement", for that reason, it is necessary to add a corrosion inhibitor to control it.

In order to improve pickling performance, it is required to perform heating and warming operations.

After the workpiece has been marinaded with sulfuric acid, a layer of dark black iron salts remains on the surface, which is not easy to tidy.

Concentrated sulfuric acid can quickly trigger chemistry, so unique care needs to be taken when managing and utilizing it.