Reply #9: Found the answer. To keep Iodide from breaking down to iodine (link here...)

[uppityperson]

http://sci-toys.com/ingredients/table_salt.html

Glucose is a sugar (the main sugar in corn syrup), and is added in small amounts (0.04%) to salt to prevent the potassium iodide from breaking down into iodine, which evaporates away (sublimes). Other potassium iodide stabilizers include sodium bicarbonate (baking soda), sodium carbonate, and sodium thiosulfate.

Calcium silicate

Calcium silicate is an anti-caking additive. Salt is hygroscopic, meaning it absorbs water from the air. This water dissolves the salt, and the resulting salt water combines with the remaining salt, cementing the grains together into a solid mass. Calcium silicate absorbs moisture from the air better than salt, and does not dissolve in the water it absorbs. This protects the salt from caking, and ensures that it pours freely. Less that 0.5% is generally used, so in very humid weather, the salt may still become lumpy.