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The Procedures for Neutralizing Muriatic Acid

Brick and stone masons, swimming pool owners and leather workers all use hydrogen chloride suspended in water. This suspension is called spirits of salt, hydrochloric acid or muriatic acid. Muriatic acid is a strong chemical that can damage clothes, contaminate water, corrode metal, injure respiratory passages and burn skin. Fortunately, neutralizing muriatic acid is a relatively simple process.

  1. In-Use Neutralization

    • The standard suspension of muriatic acid is 31.45 percent acid to 68.55 percent inert liquid -- mainly water. Before it is used, the acid solution is diluted further by simply adding more water, usually one part acid to 10 parts water. When the acid solution is used in masonry, it reacts with stone and cement -- that have alkaline surfaces -- and changes into an inert residue of calcium carbonate. This residue is safe and can be washed off with plain water, leaving a clean, shiny surface on the masonry.

    Alkaline Materials

    • Leftover muriatic acid is neutralized with alkaline materials, especially powders. Acids react with alkaline materials dramatically, appearing to fizz and boil. This process releases carbon dioxide and renders the product of the reaction inert. Children experiment with this reaction by mixing baking soda with vinegar to make "volcanoes" in water glasses. Bicarbonate of soda is the most commonly used substance used to neutralize acids, but other materials, such as garden lime and soda ash, can also be used.

    Accidental Spills

    • The chance of a muriatic acid spill is a good reason to keep an alkaline substance on hand in an emergency. Garden lime is a good choice for spill neutralization because it is inexpensive and comes in large sacks. If there is a muriatic acid spill, immediately sprinkle generous quantities of the alkaline powder on the spill site. The acid and base mix will begin fizzing and bubbling. Keep adding the alkaline neutralizer until the fizzing stops. Then you can safely clean up the spill area.

    Intentional Disposal

    • Muriatic acid should never be dumped, poured down a drain or put in a trash receptacle. It should be dropped off for recycling or neutralized. You can neutralize the acid by first pouring a gallon of plain water into a 5-gallon bucket then adding 4 cups of lime or baking soda to the water then stirring it up. Slowly add the acid solution until the fizzing stops then dispose of the contents as you would dispose of dirty water.

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