What is bulk dry density of barite?

It really depends on the particle size of the product and whether it is loose or compacted. A typical 1u median particle size (mps) product might be ~60 lbs/ft3 loose and ~100 lbs/ft3 compacted. A 10u mps product might be closer to ~100 lbs/ft3 loose and ~150 lbs/ft3 compacted.
Here is a link to a representative TDS: http://www.cimbar.com/pdf/CimbarProdsTDS.pdf
Hope that helps