The refined HCl gas (in the packed tower or membrane absorber) can be absorbed with water to produce industrial grade hydrochloric acid, which is the method adopted by most enterprises. These hydrochloric acid can be used for metal cleaning, acidification of oil Wells, hydrometallurgy (e.g. processing clay, kaolin or carbon-bearing shale to produce alumina, processing ilmenite instead of sulfuric acid to produce titanium dioxide, hydrometallurgy to produce precious metal chloride, etc.), replacing sulfuric acid to react with sodium chlorate to produce chlorine dioxide, acidizing phosphate to produce fertilizer grade phosphate, and manufacturing of inorganic substances (e.g

Coal gangue is treated with hydrochloric acid to produce crystalline aluminum chloride and polyaluminum chloride water treatment agent. The crystalline aluminum chloride and polyaluminum chloride are 10,000 t/a respectively, consuming industrial hydrochloric acid 50,000 t/a, organic synthesis (such as esterification of aromatic acid), etc. In addition, the hydrochloric acid produced by heating - desorption - condensation - filtration - adsorption can be used to obtain high yield, high purity hydrogen chloride, so that it is more widely used.