The difference between "anti-icing" and "de-icing" is that the former ideally happens before snow falls. The chemicals used in this process aren't meant to melt the snow, but rather keep it from bonding to pavement. They're usually a liquid mixture of brine and chemicals like calcium chloride, magnesium chloride or potassium acetate. Sometimes these chemicals are used for both anti-icing and de-icing. They're a growing trend with snow management contractors, with sugary liquid products (like beet juice) working better on heavy wet snow, while calcium or magnesium chloride work better on lighter snow.