Process for drying high-lactose aqueous fluids

A method of crystallizing lactose from a highly concentrated high-lactose aqueous fluid containing from about 70 to about 80% solids, wherein at least about 50% of the solids are lactose and the temperature of the highly concentrated high-lactose aqueous fluid is greater than about 50 degrees Celsius, the method comprising the steps of:

• introducing the highly concentrated high-lactose aqueous fluid into a cooling, concentrating, crystallizing apparatus in which the highly concentrated high-lactose aqueous fluid is exposed both to mixing and to movement of a gaseous fluid at a temperature, moisture content and air speed effective to create a cooling, concentrating, crystallizing cascade in which evaporative cooling causes loss of moisture and an increase in solids which in turn facilitate lactose crystallization which in turn releases lactose's heat of crystallization which in turn increases fluid temperature which in turn facilitates more evaporative cooling, so that a partially crystallized high-lactose aqueous fluid containing from about 78 to about 88% solids is generated;
• and
• spraying the partially crystallized high-lactose aqueous fluid into an enclosed drying chamber containing hot air to form a high-solids crystalline product rich in crystalline alpha-lactose monohydrate crystals;
• wherein the high-solids crystalline product contains some residual moisture and from about 90 to about 99% solids, wherein from about 80 to about 100% of the residual moisture in the high-solids crystalline product is incorporated within alpha-lactose monohydrate crystals.