There's a problem with this scenario.

The Earth is traveling around the Sun at approximately 67,000 mph. When the earth and its atmosphere collide with comet dust at that speed we can observe shooting stars. If sand is pushed out of the space station the collision force is much smaller and the maximum speed that it will achieve will be limited by the terminal velocity. Every grain of sand will meet the ground virtually intact. I don't want to go through the calculation at this time but to illustrate the point: If we pushed out a bowling ball from the ISS it would travel at a terminal velocity of 350 mph when it met the ground...only then would it be a real sight to see.
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Good atmosphere and good conversation...that's the best.