Also known as slaked lime or hydrated lime, calcium hydroxide is an inorganic compound with many industrial uses. Chemists produce calcium hydroxide by mixing calcium oxide, or lime, with water. While rare, a natural mineral form of calcium hydroxide called portlandite sometimes forms in metamorphic, plutonic and volcanic rocks, as well as in some burning coal dumps.
Identification
Calcium hydroxide can take the form of a white powder or a colorless crystal. Odorless under normal conditions, calcium hydroxide will emit caustic fumes if heated to 580 degrees C. Fine particles of calcium hydroxide may be combined with water to form an emulsion called milk of lime, which is cloudy in appearance.
Significance
Naturally alkaline, calcium hydroxide's base properties make it effective in a number of commercial and environmental endeavors. Among its many uses, calcium hydroxide removes impurities from water, maintains proper pH to stabilize sewage sludge, alkalizes acidic planting soil, treats industrial waste, and plays an important role in steel manufacturing, paper production and leather tanning.
Location
Available in most hardware stores and garden centers, calcium hydroxide can be found in various industrial cleaners and solvents, ranging from floor strippers to brick cleaners and other construction products. Calcium hydroxide also serves as an ingredient in cement thickening agents, plaster applications and garden fertilizers.
Considerations
Calcium hydroxide should be kept in an air-tight container and stored in a cool, dry place with ample ventilation. Protective gloves, aprons and other clothing should be worn to prevent skin exposure. Safety goggles should also be worn to guard the eyes from splashing or harmful dust particles. In case of accidental spills, ventilate the area and don protective clothing before attempting to reclaim the spilled powder, taking care to use a method that won't encourage dusting. Any residual calcium hydroxide may be diluted with water.
Warning
According to the Material Safety Data Sheet, inhaling calcium hydroxide may cause severe irritation to the respiratory tract, with symptoms including coughing and shortness of breath. Calcium hydroxide touching exposed skin may cause serious burns and blistering if left in contact for an extended period of time. Contact with the eyes can be even more serious, leading to ulceration or even blindness in extreme circumstances. Accidentally ingesting calcium hydroxide can lead to severe abdominal pain, vomiting, diarrhea, difficulty swallowing and collapse. Calcium hydroxide poisoning can prove fatal without receiving immediate medical attention.
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