Hydrochloric Acid or “HCL”, or commonly known as muriatic acid, is used in a wide range of industrial and commercial applications. For people who work in industries where this chemical is used, it is important to understand the common uses for hydrochloric acid, what purposes it serves, and what you need to know to handle it safely and responsibly.
Hydrochloric acid is the liquid version of hydrogen chloride, an acidic gas. It occurs naturally and is also commercially manufactured. Although it can be a corrosive and dangerous liquid, HCL is naturally-occurring within our own bodies. The chemical is used in our digestive system, regulated by mucous in our stomach lining as well as the hormone secretin.
In its liquid form, HCL is corrosive and produces a pungent, irritating odor. The National Fire Protection Association Hazard Identification System categorizes industrial substances based on various risk factors and ranks each area of risk from 0-4. A ranking of 0 means that the material does not post a threat, whereas anything ranked 4 denotes a life-threatening risk. HCL’s NFPA rankings are:
- Health risk: 3 (extreme danger)
- Flammability: 0 (will not burn under normal circumstances)
- Stability: 1 (normally stable but can become unstable at elevated temperatures and pressures)
Anyone who interacts with hydrochloric acid should be aware of these factors because proper protection and containment are vitally important. Keep in mind that proper procedures for handling hydrochloric acid vary from industry to industry, but there are always best industry practices to follow.
So, what are the ways in which HCL is used in various industries?
Poly Vinyl Chloride (PVC) is resistant to hydrochloric acid corrosion, which is one of the main reasons why PVC is used for many aspects of HCL containment and transport. HCL can be used to manufacture the organic compounds that are then used for the production of PVC.
Just as HCL regulates the pH levels in our stomachs, it can also be used to regulate pH levels in consumables and medications. It can contribute to the pH balance of our drinking water, food, and pharmaceuticals.
Hydrochloric acid is one of the chemicals that play a role in keeping pH levels safe for swimmers in public and private pools.
When added to sodium chloride, HCL triggers a purification process that results is safe, useable table salt.
Steelworkers use HCL for the pickling process, which removes rust from steel, both in coil and sheet form.
Hydrochloric acid is one of the substances used in the leather tanning process. Tanneries use HCL to stop the development of bacteria and maintain the proper pH level of leather.
This is an important step in maintaining water safety. Essentially, HCL contributes to the process of removing ionized particles from water. Anyone who has purchased deionized water has benefited from the HCL’s role in the ion exchange process.
In addition to treating drinking water, HCL is used to produce the inorganic compounds that are used in the processing of our wastewater.
HCL is used in the fracking process and in many gases and oil extraction processes to acidify a well to remove carbonate reservoirs, or limestones, from the rock or combined with other materials to dissolve quartz, sand and clay from rocks. Other additives can be introduced to the well to prevent the acid from breaking down steel casings.
Several additives used in the food industry include HCL in the development process. These include fructose, citric acid, and hydrolyzed vegetable protein.
This list demonstrates that HCL can be used for a wide range of purposes that most people would not ever consider. Many of these uses are pretty benign, even though hydrochloric acid itself sounds intimidating. The most important thing is that proper procedures are in place to use HCL in each of these processes.