Technical indicators and application of hydrochloric acid

[Technical index] GB/T622-2006 chemical reagent hydrochloric acid

[Application] Hydrochloric acid is one of the important raw materials in the chemical industry.

The reaction between hydrochloric acid and iron oxide scale is dissolution.

Table 8-1 Cleaning process conditions with hydrochloric acid as the main cleaning agent

5%～6% HCl+1% HF+ corrosion inhibitor can be used to remove carbonate , sulfate, phosphate, silica scale and iron scale in heat exchangers

The heating surface of the power station boiler is in a state of high temperature, high pressure and high heat load for a long time, and it needs to be pickled and descaled regularly

Hu Shurong used hydrochloric acid for the chemical cleaning of silicon wafers

The characteristics of using hydrochloric acid as a cleaning medium and the matters needing attention are as follows

(1) Most metal salts (metal chlorides) of hydrochloric acid are highly water-soluble, so the rate of dissolving scale (except silicate scale) and rust with hydrochloric acid is fast

(2) Hydrochloric acid is a reducing acid.

(3) The price of hydrochloric acid is cheap and the product is easily available

(4) Hydrochloric acid is a volatile acid with large acid mist.

(5) Since hydrochloric acid contains a large amount of chloride ions, it is easy to cause local corrosion of passive metals and stress corrosion cracking of austenitic stainless steel.

To sum up, because hydrochloric acid is the cheapest one of various inorganic acids and has better comprehensive performance, it is the most commonly used pickling medium.