Powdered milk is a manufactured milk product which is manufactured by drying out dairy milk by means of evaporation. One of the major purposes for drying out milk is for preservation, as powdered milk has a longer shelf-life than regular liquid milk, and it doesn't have to be chilled.
One of the more general uses for powdered milk is for the production of infant/baby formula. It is also used for confectionery such as caramel candy and chocolate, and baked goods where adding liquid milk can make the product too thin.
There's a large export market for Skimmed Milk with the manufacture of powdered milk in Europe approximated to be at 800 thousand tonnes.