Calcium Chloride Powder: Structure, Properties, and Safe Use

What is Calcium Chloride Powder?

Calcium chloride powder comes from calcium and chlorine. Factories produce it through refining processes involving limestone and hydrochloric acid. The powder looks white or off-white, sometimes even slightly gray. Chemically, calcium chloride holds a formula of CaCl₂ and weighs in at a molecular weight of about 110.98 g/mol. The powder absorbs moisture straight from the air. It does not give off an odor. Because it can pull water in so quickly, the raw material feels damp if left open in a room. Specific density hovers around 2.15 g/cm³ in anhydrous form, which gives an idea about how heavy it feels in a scoop. The HS Code attached to calcium chloride runs as 28272000 for trade and customs purposes.

Product Forms and Variants

Manufacturers offer calcium chloride in a few forms. The most known versions appear as powder, flakes, pearls, solid chunks, and granular crystals, plus as a liquid solution. The powder type spreads smoothly for mixing in food, industrial, or road applications. Flake and pearl versions, larger and textured, work well for de-icing roads. Liquids suit areas where fast-melting ice or ready mixing matters most, such as in brine for refrigeration or dust suppression on construction sites. All types share the same base chemical character. Moisture content changes the look and bulk density of each form. For solids, the density holds steady, but when dissolved in water, calcium chloride forms a clear and colorless solution.

Chemical Properties and Structure

Calcium chloride holds two chloride anions for each calcium cation. The strong ionic bond between calcium’s double positive charge and the chloride’s single negative charge creates a stable and highly soluble structure. The powder melts at about 772 °C and boils at over 1600 °C. Water thrown on the powder kicks off an exothermic reaction, so the container gets warm quickly. This heat-producing property means it melts ice and snow on contact, releasing enough warmth to turn frozen chunks to water. The solubility in water reaches 745 g/L at 20°C for the anhydrous type. Solutions feel distinctly salty. Calcium chloride’s hygroscopic nature sets it apart from similar salts. Anyone storing it long-term needs a tight container, or else it cakes up and loses flow.

Specifications and Purity

Pure calcium chloride powder usually measures over 95% purity, sometimes as high as 99%. Other common ions, like sodium and potassium, show up as trace impurities depending on the manufacturing route. Industrial users look for specs like particle size, granule strength, and heavy metal content. The powder generally passes the 60-80 mesh sieve for most uses. Flake size ranges wide, sometimes from 2 mm to 6 mm or larger. Recognizing specific requirements helps the food sector avoid products designed just for de-icing. For food and pharma, look for “food grade” marks and tighter limits on impurities like arsenic and lead.

Applications and Material Uses

Calcium chloride works as a desiccant, dust suppressant, ice melter, and food additive. Humidity control in warehouses depends on its thirst for water vapor. De-icing relies on its heat release. Asphalt paving crews pour its powder into water tankers as a base for dust and erosion control on roads. Cheese makers sprinkle tiny amounts to firm up curds. In the oil field, accelerator blends for concrete include calcium chloride to speed up curing. The pharmaceutical sector values the substance as an electrolyte or preservative. As a raw material, the powder drives reactions in labs experimenting with calcium compounds or chloride sources.

Safe Handling and Hazards

My firsthand experience storing calcium chloride in non-lab environments quickly taught me the importance of tight lids and careful weighing. The powder irritates skin and stings the eyes. Fine dust in the air catches in the throat if inhaled. Spilled powder or solution on concrete leaves white stains, sometimes slippery. Industrial safety sheets describe calcium chloride as an “irritant” and “harmful if swallowed in large amounts.” Direct contact leads to rough patches or redness. Anyone using it should wear gloves and safety glasses, wash after spills, and store away from kids and pets. Eating moderate traces through prepared food is considered safe. In emergencies, flush eyes or skin with water, and call for help if anyone swallows more than a taste. Workers need good ventilation in storage rooms. For bulk transport, UN number 1779 covers labeling and spill response on trucks and rail cars.

Environmental Impact and Disposal

Calcium chloride breaks down in the environment as natural calcium and chloride ions, so it does not stick around in soil or water. That said, releasing huge amounts through runoff can hurt plant roots and raise salt levels in streams. Most cities have guidelines for de-icing salt use near water. Good practice means collecting or reusing spilled powder and diluting used solutions. Throwing the product in the regular trash in small amounts poses no risk. Never dump concentrated solution near garden beds unless the plants can take extra calcium and salt.