The pickup velocity you need depends on the kind of conveying you’re doing.
If you want to convey in dilute phase, the minimum pickup velocity will be slightly higher than the saltation velocity (the velocity at which the solids begin to settle out of the air or gas stream). But that doesn't mean you can't use a higher velocity if your process warrants it. Using a higher velocity will result in smoother delivery of the material, which would be very important in feeding fuel to a burner in a boiler or kiln, for example. You’d use the minimum velocity above saltation, what we refer to as minimum pickup velocity, to minimize the amount of conveying gas, reduce the horsepower, reduce wear, and reduce material degradation.