Question: Is it possible to "pump" a powder the same way liquids can be pumped?

If so, what are the challenges? If not, what are some alternatives?

Answer: 
In food process you can "pump" powder with vacuum, sugar works very well, and some other products need sometimes some technical adjustment (pression or open/close cycles valves) .
But water in the pipes is ban and last point it's only for small quantities and short distance 20meters max i think.
We have dry cement bulkers truck running on local roads, feeding dry cement to mixer factory where it is turned into wet mixed cement. Pump air into the truck to 'blow' cement out.

This [video](http://youtube.com/watch?v=p74BAe-OYq0) shows cement and sand are 'blow' by air. Powder (cement/sand) are placed in closed container. Air blow in and powder come out on, says, 2 to 3 inch diameter, tubing. Powder can be transferred in construction site, at horizontal and vertical distance of tens of meters. You can see the blue air-compressor in the video. Here is a similar [video](http://youtube.com/watch?v=p74BAe-OYq0).