pH Control and neutralization
Hydrochloric acid can be used to regulate the basicity (pH) of solutions.
OH− + HCl → H2O + Cl−
In industry demanding purity (food, pharmaceutical, drinking water), high-quality hydrochloric acid is used to control the pH of process water streams. In less-demanding industry, technical-quality hydrochloric acid suffices for neutralizing waste streams and swimming pool treatment.[5]
Regeneration of ion exchangers
The use of high-quality hydrochloric acid is the regeneration of ion exchange resins. Cation exchange is widely used to remove ions such as Na+ and Ca2+ from aqueous solutions, producing demineralized water.[3]
Na+ is replaced by H3O+
Ca2+ is replaced by 2 H3O+
Ion exchangers and demineralized water are used in all chemical industries, drinking water production, and many food industries.[1][3]
Other applications
Hydrochloric acid is a fundamental chemical, and as such it is used for a large number of small-scale applications, such as leather processing, household cleaning, and building construction.[5] In addition, a way of stimulating oil production is by injecting hydrochloric acid into the rock formation of an oil well, dissolving a portion of the rock, and creating a large-pore structure. Oil-well acidizing is a common process in the North Sea oil production industry.
Many chemical reactions involving hydrochloric acid are applied in the production of food, food ingredients, and food additives. Typical products include aspartame, fructose, citric acid, lysine, hydrolyzed (vegetable) protein as food enhancer, and in gelatin production. Food-grade (extra-pure) hydrochloric acid can be applied when needed for the final product.[
